Cerebrovascular disease in the community: results of a WHO Collaborative Study*

Bulletin of the World Health Organization, 58 (1): 113-130 (1980) Cerebrovascular disease in the community: results of a WHO Collaborative Study* K. AHO,1 P. HARMSEN,2 S. HATANO,3 J. MARQUARDSEN,4 V. E. SMIRNOV,5 & T. STRASSER 6, on behalf of the participants in the WHO Collaborative Study on the Control of Stroke in the Community 7 In a cooperative study coordinated by WHO, stroke was registered between 1971 and 1974 in 17 centres both in developing and developed countries. A common operating protocol was used to obtain comparable data. Age-adjusted incidence of stroke shows moderate geographical variations, cerebrovascular accidents being common in all the contrastingpopulations studied in variousparts ofthe world. Data were also obtained on the types of management of stroke patients, their survival rates, and functional prognosis. Control ofhypertension, although known to be effective in theprevention ofstroke, seemed to be insufficient in most countries. It is concluded that stroke registers may be used as a source ofinformationfor theplanning and implementation ofstroke controlprogrammes in the community. Leading specialists in stroke participated in a WHO meeting on cerebrovascular diseases in Monaco in 1970 (1). They recommended that WHO should develop methods for collecting reliable information on the magnitude and nature of stroke in com- munities, as a basis for planning and implementing activities for the prevention of stroke, and care and rehabilitation of stroke patients. Following up this recommendation, a group of interested investigators worked out the methodology for a community-based stroke register, by which com- parable data could be gathered from all over the world. The purpose of the stroke register was outlined and it was decided that more accurate information should be collected on: (a) the magnitude of the problem of stroke in the community; (b) the social and clinical profile of stroke patients; * Requests for reprints of this article should be addressed to: Dr T. Strasser, Cardiovascular Diseases, World Health Organiz- ation, 1211 Geneva 27, Switzerland. I Department of Neurology, University of Helsinki, Finland. 2 Department of Neurology, Sahlgren's Hospital, Goteborg, Sweden. 3 Department of Epidemiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan. I Department of Neurology, Frederiksberg Hospital, Copen- hagen, Denmark. 5 Institute of Neurology, Academy of Medical Sciences of the USSR, Moscow, USSR. 6 Medical Officer, Cardiovascular Diseases, World Health Organ- ization, Geneva, Switzerland. 7 Listed on page 128. (c) the preventive measures, diagnostic procedures, and rehabilitation applied to the patient; and (d) the natural history of stroke. After a pilot trial lasting several months, a study on stroke registration in the community was started in 1971. Seventeen centres joined the WHO-coordinated study and 15 continued to register new patients until December 1974, following up their progress for 1 year after the onset of stroke (2). This is a concise report of the WHO stroke regis- tration project. Its intention is to highlight the most important findings of the study, without going into too much detail. METHODS The basic operating protocol that was followed ensured that great care was given to uniform data col- lection according to pre-determined standards (3, 4).a Seventeen centres from 12 countries participated in the study. The World Health Organization acted as coordinating centre and collated and processed the data. Table 1 summarizes the characteristics of the studied populations at the outset. Data obtained from the latest population census, and also previous censuses in some areas, were used for calculation of the incidence rates. In some centres, these data were not available and incidence rates were not calculated. The total background population a See also: Community control ofstroke and hypertension. Report of a WHO meeting, Goteborg, 29 November-3 December 1971 (Unpublished WHO document CVD/72. 1). 3931 -113- WHO COLLABORATIVE STUDY Table 1. Study areas and populations Population structure Total Characteristics of study area population Men/ Percentage Code Centre Country and population (thousands) women > 65 years 01 Gothenburg Sweden Urban. Age up to 65 years at entry 450.9 0.98 13.1 05 Copenhagen8 Denmark Mainly residential and commercial; 100.0 0.82 21.5 + light industry 06 Dublin Ireland Mainly residential 133.7 0.91 8.4 21 Espoob Finland Developing neighbouring town to Helsinki. 103.5 0.93 5.0 Commerce, services, and industry 22 North Karelia Finland Mainly agricultural. Emigration continues 178.3 1.00 8.9 28 MoscowC USSR Urban data not available 29 Zagreb Yugoslavia Urban 87.gd 0.84d 12.8d 33 Zerifin Israel Urban and rural: 50% Afro-Asian and 218.4 1.02 6.9 50% Euro-American origin 39 Ibadan Nigeria Urban 803.1 1.33 1.4 45 Akita Japan Rural. Agriculture and commerce 36.1 0.95 5.9 46 Saku Japan Rural. Mainly agriculture + commerce, 105.2 0.92 10.5 light industry 47 Fukuoka Japan Urban. Part of Fukuoka City + 3 towns. 36.8 0.94 7.2 Age below 65 years in part 48 Osaka Japan Semi-urban. Commuter area to Osaka. 40.4 0.93 4.7 Services, agriculture, and commerce 49 Japan Japan Male employees of a company in the Tokyo 76.8 - 0 National region. Age up to 59 years Railways 55 Ulan Bator Mongolia Urban 261.3 1.04 4.4 81 Rohtak India Urban 124.7 1.16 5.3 83 Colombo Sri Lanka Urban 562.4 1.29 3.6 B Area of study: Frederiksberg, Copenhagen. b Area of study: Espoo and Kauniainen. c Area of study: Tusino, Moscow. d Population size is known up to age 74 years. e Area of study: Ramle and Rehovot. covered by all registers amounted to more than 2.6 million people, without counting two centres- Rohtak and Colombo-which joined later. Criteriafor inclusion For the purpose of this study, stroke was defined as "rapidly developed clinical signs of focal (or global) disturbance of cerebral function, lasting more than 24 hours or leading to death, with no apparent cause other than of vascular origin". This definition obviously includes most cases of subarachnoid haem- orrhage, intracranial haemorrhage, and cerebral infarction, but not cases of transient ischaemic at- tacks. The term "global" disturbances of cerebral function refers only to patients with subarachnoid haemorrhage without focal neurological deficits. Patients who were permanent residents of one of the study areas and who during the study period suf- fered a stroke as defined above were eligible for regis- 114 CEREBROVASCULAR DISEASE 115 tration. In all but three centres stroke patients were registered irrespective of age and sex. Patients who were initially registered as stroke cases but who were later proved to have nonvascular brain lesions were excluded from the final data. Casefinding In each of the study areas, a stroke register was set up in a local hospital or a health centre, usually staffed by one or more doctors, a secretary, and an inter- viewer. Before the project was started, all hospital doctors, general practitioners, nursing institutions, and health authorities in the area were contacted, informed of the study, and asked to report every sus- pected case of stroke coming to their attention in the study report (5, 6). In order to make registration as complete as possible, regularly repeated checks were made of local medical records, social insurance records and, in particular, all death certificates issued in the area. However, certified deaths from cerebro- vascular accidents, even if confirmed by autopsy, were registered only if preceded by a clinical "stroke", according to the above definition. For each case of stroke, the relevant data were entered on a record form.b Whenever possible, patients who were reported to the register were seen by a doctor or an interviewer sent by the registry, whether in hospital or at home. Follow-up All surviving patients were contacted 3 weeks, 3 months, and 1 year after the stroke and a follow-up record form was completed.b Information about new strokes in the follow-up period was entered on a special recurrence record form. However, new epi- sodes occurring within the first 3 weeks were regarded as a progression of the original attack and were not recorded as a recurrence. In all cases of death within 1 year of stroke, the causes of death were recorded according to death certificates or autopsy findings. In order to obtain comparable data, the record forms were designed to include only information that could readily be obtained in all the participating centres, irrespective of the availability of advanced medical facilities. Diagnostic methods The use of diagnostic procedures varied widely, depending on local possibilities and routine in the centres. Nearly all patients were seen by a physician. In the total series, more than one-half were examined b Specimens are available on request from Cardiovascular Diseases, WHO, 1211 Geneva 27, Switzerland. by a neurologist, the proportion ranging from 12-85%. In all but a few centres, lumbar puncture was performed in about one-third of the cases; cere- bral angiography was made in less than 10%. At the time of the registration, computerized tomographic (CT) scanning was not available in any of the partici- pating centres. At the 3-week follow-up the diagnosis of the type of stroke (ICD, 1965 revision)c was recorded, based on clinical or laboratory examinations. If the diagnosis of the type of stroke had to be revised later, for example on the basis of autopsy findings, the final diagnosis was used in the analysis. In order to assess the comparability of diagnoses made in different centres, a diagnostic reliability test was made, based on 60 cases selected from the various centres (7, 8). The clinical diagnosis of stroke itself (versus non-stroke) was found to be valid, showing only small inter- and intraobserver variability, where- as diagnosis of the type of stroke varied considerably between centres and also was less consistent among the individual observers. Autopsy diagnosis was used for analysis whenever available. Autopsy rates varied widely between centres (Fig. 1). 100 Number of deaths (x 10) 33 52 29 17 40 46 24 58 12 16 38 9 8 5 29 2 9 0 Centre No.1 5 6 21 22 28 29 33 39 45 46 47 48 49 55 81 83 Europe Japan Fig. 1. Autopsy rates. Subjects studied After a pilot study undertaken during 1971, regis- tration of stroke patients with a uniform record was carried out from May 1971 until December 1974. Most centres started in 1972. Two Asian centres that joined in June 1974 continued the registration for 1 year. The duration of registration thus varied from 1 to 4 years. Nine centres registered more than 500 cases and 12 centres more than 300 cases. Altogether, 9064 cases, including suspected ones, were registered by 17 c Manual of the international statistical classification ofdiseases, injuries, and causes ofdeath, Eighth Revision, Geneva, World Health Organization, 1969. WHO COLLABORATIVE STUDY centres, but 310 cases were eventually excluded from the analysis because stroke was not confirmed in the final diagnosis. The numbers of registered stroke patients are shown in Table 2. There were more men in the younger and more women in the older age groups. The age- distribution of the patients varied widely among the centres, depending on the background populations. Table 2. Numbers of registered patients with stroke by age group Age groups (years) Centre All No. < 45 45-54 55-64 65-74 > 75 ages 01 92 157 474 61 - 784 05 13 27 143 264 444 891 06 29 38 118 183 174 539 21 34 35 62 99 73 303 22 69 105 237 318 209 938 28 41 142 240 357 251 1031 29 23 71 126 235 176 631 33 12 47 206 343 308 916 39 93 71 71 51 14 300 45 29 57 96 142 58 382 46 27 63 144 244 230. 708 47 10 14 43 50 17 134 48 5 9 36 57 51 158 49 35 100 7 - - 141 55 59 126 217 186 65 653 81 9 9 30 18 16 82 83 17 30 37 53 26 163 Total 597 1098 2286 2661 2112 8754 INCIDENCE RATES All strokes For epidemiological purposes it is customary to base incidence rates only on first attacks. From the community point of view, however, subsequent at- tacks are also important, since they require medical services. In this report, incidence rates are therefore given both for first attacks and for all strokes, includ- ing recurrences. The incidence of stroke, unlike that of myocardial infarction, showed only moderate variations between different parts of the world (Table 3). For first attacks, rates were about 5 per 1000 in males aged 65-74 years; the rates in females were about 30% lower than in males. Compared with the European incidence rates, those found in Mongolia and Nigeria were rather similar in the middle-aged population, but were lower in older age groups; this may reflect dif- ficulties in the registration of cases in very old patients in some areas. Higher rates were found in Finland and Japan (9), particularly in Akita, where the incidence of stroke was apparently twice that of other Japanese areas (10-13). These differences are in accordance with the trends found in national mortality statistics. The incidence rates for all attacks were about 20-30% higher than those for first attacks only and showed similar variations between centres to those described above (Table 3). Age-adjusted incidence rates are shown in Table 4. The "standard population" was the pooled popu- lation of all centres truncated at age 45 years, since it was felt that while the number of cases of stroke below age 45 was relatively low, the majority of the pooled population were below this age, giving a relatively high weight to an age category with relatively low incidence. By truncating at age 45 years, the following weights for age standardizing were derived: 45-54 years 38% 55-64 years 32% 65-74 years 20% ) 75 years 10% Types ofstroke Differences in rates for various types of stroke are certainly influenced by variations in local diagnostic habits and the availability of diagnostic facilities, but may nevertheless reflect true differences. Subarachnoid haemorrhage, which can usually be diagnosed with a high degree of reliability, occurred at higher rates in Finland and two rural areas in Japan, than in Copenhagen and Zerifin. Subarachnoid haem- orrhage seems to be the only type of stroke of which the incidence rises only slightly with age. In some areas, rates were higher for females, in others for males. The incidence of presumed intracerebral haemor- rhage was found to rise markedly with age, being generally higher for males than for females. Finnish and Japanese centres, particularly Akita, reported especially high rates, mostly in males. For cerebral infarction, incidence rates were found to rise steeply with age. In the younger age groups the rates were higher for males, in older age groups for fe- males. Geographical differences were unremarkable. The number of cases labelled "type unknown" varied considerably, but was highest in some Euro- pean centres; the proportion of such cases may reflect the strictness of the diagnostic criteria for type diagnosis used in individual centres. CEREBROVASCULAR DISEASE Table 3. Annual incidence rates for stroke per 1000 population (roman figures -all attacks; italic figures -first attacks only) Age group (years) Centre No. Sex -. 44 45-54 55-64 65-74 475 All ages 01 M 05 06 21 22 29 33 45 46 47 48 49 55 83 39 81 F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F M F M+F 0.10 O.Qo 0.94 0.91 0.07 0.06 0.56 0.53 0.08 0.oe 0.75 0.72 0.07 0.08 0.82 0.72 0.07 0.06 0.48 0.44 0.07 0.08 0.63 0.56 0.13 0.13 1.38 1.32 0.06 0.06 0.83 a78 0.09 0.ao 1.07 1.02 0.18 0.16 2.28 1.97 0.20 0. 19 1.53 1.44 0.19 0.17 1.88 1.69 0.22 0.20 2.82 2.51 0.17 0.15 1.29 1.22 0.20 0. 18 2.02 1.83 0.14 0.11 1.64 1.30 0.09 0.06 1.28 0.99 0.11 0.08 1.45 1.14 o. lo a0 10 0.09 0.12 0.11 0.11 a. 10 0.38 0.38 7.15 6.80 0.11 a0.t 3.31 3.02 0.24 0.23 5.04 4.72 0.47 a54 0.22 a20 0.39 0.36 0.07 ao7 1.51 1.51 0.04 0.02 0.98 0.98 0.05 a0o. 1.21 1.21 0.04 0.04 0.82 0.82 0.04 0.04 0.97 0.65 0.04 0.04 0.90 0.72 0.22 0.22 1.39 1.39 0.22 0.22 1.39 1.39 0.04 0.03 1.66 1.24 0.08 0.08 4.31 2.71 0.06 0.04 2.43 1.66 0.03 0.03 0.79 0.59 0.03 0.03 0.48 a43 0.03 a03 0.67 0.52 0.03 0.038 0.70 0.a8 0.04 0.05 0.58 a053 0.04 0.04 0.63 a57 0.05 0.04a 0.33 0.258 0.03 a0a3 0.45 0.41 0.04 0.03 0.38 0.32 3.08 2.71 1.65 1.52 2.32 2.08 3.88 3.40 1.76 1.50 2.65 2.30 4.73 4.39 2.60 2.49 3.55 3.04 5.22 4.37 2.87 1.27 3.93 3.23 5.61 4.66 3.89 3.38 4.67 3.98 4.66 3.93 2.05 1.46 2.97 2.34 4.08 3.23 3.10 2.72 3.58 2.97 12.75 11.72 6.71 6.12 9.67 8.86 6.51 5.91 3.72 2.89 5.00 4.27 6.06 5.87 1.59 1.12 3.67 3.33 4.93 4.41 3.61 3.61 4.21 3.97 31.96 31.96 31.96 31.96 4.71 3.39 3.26 2.31 3.96 2.83 1.52 1.06 1.20 1.03 1.38 1.05 1.95 1.758 1.35 1.23 1.71 1.55 1.52 1. 17a 1.17 1.06 1.34 1.12 7.65 6.37 15.04 13.12 4.65 4.04 15.35 13.08 5.74 4.89 15.26 13.09 9.50 8.92 18.40 17.71 8.01 7.22 20.56 18.69 8.62 791 19.85 18.37 14.25 11.98 30.27 25.42 11.58 8.84 27.06 24.24 12.63 10.08 28.08 24.62 11.51 9.30 18.16 16.97 9.35 8.34 18.18 15.44 10.26 8.75 18.17 16.X0 7.71 4.76 not available 4.72 3.18 not available 5.98 3.85 not available 13.42 10.81 15.28 12.47 14.37 11.66 28.98 24.90 28.57 28.57 25.15 21.98 35.19 30.56 26.93 23.32 32.58 29.78 14.18 11.25 27.97 22.67 8.99 7.52 24.83 20.23 11.38 9.24 26.04 21.17 9.11 8.20 6.60 4.95 4.94 4.69 4.39 3.91 6.81 6.26 5.21 4.29 15.84 14.88 40.59 35.29 9.11 7.Z6 26.67 26.67 12.08 10.81 31.55 29.69 6.37 5.09 5.22 4.79 4.56 3.26 13.43 10.36 5.47 4.18 7.79 6.47 4.26 3.86 5.79 5.79 2.97 2.68 4.01 2.68 3.63 3.29 4.81 4.07 4.61 3.75a 3.02 2.498 1.24 1.13 0.85 a077 3.38 3.07 2.09 1.9) 5.04 3.88a 1.95 1.77 3.56 2.97 8 The age groups for centres 39 and 81 were slightly different: from right to left they were-< 40 years, 40-49 years, 50-59 years, 60-69 years (> 60 years for centre 81), and > 70 years. 2.37 2.70 2.55 1.44 1.58 1.51 1.42 1.50 1.46 1.96 1.98 1.97 2.23 1.90 2.05 1.32 1.47 1.40 3.61 2.76 3.17 2.78 2.14 2.45 1.19 0.65 0.91 1.25 1.11 1.17 0.61 0.61 0.71 0.65 0.68 0.32 0.26 0.29 0.19 0.14 0.17 0.57 0.21 0.33 2.04 2.32 2.19 1.36 1.45 1.41 1.14 1.19 1.17 1.69 1.74 1.71 1.59 1.36 1.47 1.07 1.23 1.15 3.31 2.44 2.87 2.36 1.76 2.05 1. 11 a57 a83 1.14 1.02 1.08 0.61 a61 0.54 0.45 0.5 0.26 a22 0.24 0.17 a03 0.15 a34 a019 0.27 117 WHO COLLABORATIVE STUDY Table 4. Age-adjusted annual incidence rates for stroke per 1000 population (all cases) Sex Centre No. Male Female Total M/F 01 0.538 0.32a 0.438 1.7 05 5.55 3.73 4.44 1.5 06 5.71 4.77 5.20 1.2 21 8.34 6.45 7.23 1.3 22 7.18 5.55 6.30 1.3 29 3.92 2.21 2.88 1.8 33 2.70 2.66 2.58 1.0 45 15.12 11.84 13.44 1.3 46 7.60 5.32 6.26 1.4 47 8.73 4.35 6.35 2.0 48 9.04 6.01 7.21 1.5 49 0.618 - - _ 55 4.13 3.28 3.69 1.3 83 2.19 1.56 1.89 1.4 8 Crude incidence rates. Age-adjusted rates could not be com- puted, since in centres 01 and 49 subjects were registered only up to 65 years of age (in centre 49 only males). Geographical differences in the incidence of cerebral haemorrhage The higher incidence of cerebral haemorrhage in Japan than elsewhere, having been reported also by several earlier workers, has given rise to many com- ments, one of these being that there is only a difference in diagnostic habits, but not in the true incidence rate. On the basis of a closer analysis of the present series (and assuming that light cases of stroke were indeed registered to the same extent in the Japanese centres as elsewhere) the following three pieces of evidence can be presented: (a) Cerebral haemorrhage is known to be the com- monest cause of coma in stroke patients. Both the relative frequency and the incidence of comatose patients were higher in Japan than in other countries (Table 5), particularly in males. Particularly high rates were found in Akita, for both sexes and most ages. (b) In cerebral haemorrhage, blood pressure is often elevated as a sign of serious and extended cere- bral damage. The mean blood pressures of Japanese stroke patients significantly exceeded those of Euro- peans (Table 6) (P< 0.001 for systolic and P< 0.01 for diastolic pressures, ages and sexes combined). (c) In the relatively small group of autopsy-verified cases, cerebral haemorrhage was more frequent in Japan than in European countries. On the basis of these three arguments it seems likely that the reported high incidence of cerebral haemor- rhage in Japan is real (14). PAST MEDICAL HISTORY Previous stroke Earlier stroke had been experienced by 14%/ of the patients under 65 years and by 18% of those over that age (Table 7). Sex differences were negligible except in a few centres where the calculations were based on small numbers of patients. Rates found in different centres varied considerably, the highest values being reported from Moscow, Ulan Bator and Zagreb; among the Western European centres, only small vari- ations were found. Myocardial infarction About 7% of all registered patients had a history of myocardial infarction, men much more frequently than women, particularly at younger ages (Table 7). The figures were high in Israel and Europe, especially in the Finnish centres and Moscow, negligible in the Japanese centres, and zero in Nigeria. Other heart disease About 20% of the younger and about 35% of the older patients had a history of some heart disease other than myocardial infarction (Table 7); in general, prevalence was somewhat higher in women. The variation between individual centres was very wide. Highest values were observed in Moscow and in the Finnish centres, and lowest ones in Rohtak, Ulan Bator, Colombo, and Ibadan. Hypertension A history of hypertension was obtained in about half of the patients (Table 7), with a higher prevalence in women. In the Japanese centres the prevalence was about 75%, in Moscow and in Ulan Bator even higher. In the Western European centres it was less than 50% with the exception of only one centre. About one-third of the patients were under treatment for hypertension at the time of stroke. More than one-third of the patients with a history of hypertension were not re- ceiving treatment when they suffered the stroke. Diabetes mellitus About 8% of the younger and 11I% of the older patients were known diabetics (Table 7). The preva- lence was a little higher in women than in men. The values were highest in the Finnish centres, and in Zagreb, and Zerifin, clearly lower in the Japanese centres, and lowest in Ulan Bator. 118 CEREBROVASCULAR DISEASE Table 5. Annual incidence rate for stroke patients with coma within 24 hours of onset of first stroke Age group (years) Centre No. Sex < 45 46-54 55-64 65-74 > 75 All ages 01 M F M+F 05 M F M+F 06 M F M+F 21 M F M+F 22 M F M+F 29 M F M+F 33 M F M+F 45 M F M+F 46 M F M+F 47 M F M+F 48 M F M+F 49 M F M+F 55 M F M+F 83 M F M+F 39 M F M+F 81 M F M+F 0.04 0.17 0.03 0.17 0.03 0.17 0.02 0.00 0.01 0.04 0.01 0.02 0.04 0.30 0.02 0.20 0.03 0.25 0.08 0.52 0.09 0.27 0.08 0.39 0.02 0.24 0.02 0.14 0.02 0.19 - 0.07 - 0.03 0.01 0.00 0.16 1.22 0.05 0.56 ,0.10 0.85 0.12 0.06 0.08 0.14 0.00 0.04 0.05 0.02 0.03 0.07 0.00 0.00 0.00 0.01 0.01 0.01 0.018 0.02 0.01 0.00a 0.00 0.00 0.33 0.27 0.30 0.26 0.16 0.20 0.40 0.41 0.41 0.71 0.69 0.70 0.47 0.28 0.37 0.27 0.06 0.14 0.10 0.24 0.17 2.55 1.68 2.11 1.35 0.89 1.10 2.69 0.53 1.53 0.81 0.66 0.72 1.79 0.08 0.09 0.09 0.13 0.34 0.22 0.328 0.21 0.27 0.00a 0.00 0.00 0.65 0.42 0.25 0.14 0.37 0.00 0.06 0.03 0.10 0.11 0.10 0.198 0.08 0.14 0.00a 0.10 0.05 0.30 0.84 0.46 1.64 0.40 1.42 0.88 1.17 0.87 3.30 0.88 2.60 3.87 4.84 2.32 7.89 2.93 6.92 0.77 2.41 0.87 2.65 0.80 2.56 0.30 not available 0.22 not available 0.25 not available, 0.40 1.39 0.91 4.74 3.32 4.39 9.33 4.56 6.97 2.04 4.28 1.71 4.08 1.86 4.15 2.23 0.00 1.08 1.75 1.59 1.14 3.35 12.31 1.47 8.11 2.30 9.59 0.34 0.37 0.04 0.00 0.19 0.16 0.93 2.07 0.99 1.67 0.96 1.85 1.448 0.978 0.57 0.31 1.04 0.66 0.148 0.00 0.07 8 The age groups for centres 39 and 81 were slightly different -see footnote to Table 3. 0.12 0.28 0.21 0.16 0.24 0.20 0.32 0.38 0.35 0.17 0.21 0.19 0.10 0.08 0.11 0.04 0.13 0.08 0.69 0.60 0.64 0.50 0.46 0.48 0.35 0.16 0.25 0.29 0.26 0.28 0.17 0.02 0.01 0.01 0.06 0.09 0.07 0.06 0.03 0.05 0.01 0.01 0.01 119 WHO COLLABORATIVE STUDY Table 6. Mean blood pressure in kPa (mmHg) after onset of stroke Europe and Israel Japan Mongolia Nigeria India Sri Lanka <65 >65 <65 >65 <65 >65 <65 >65 <65 >65 <65 >65 years years years years years years years years years years years years (n= (n= (n= (n= (n= (n= (n= (n= (n= (n= (n= (n= 2383) 3273) 650) 829) 234) 65) 402) 251) 45) 31) 83) 78) systolic 23.4 22.9 24.2 24.1 23.3 23.4 23.7 26.1 21.1 22.2 22.9 22.6 (176.1) (172.2) (182.0) (181.4) (174.9) (176.3) (178.0) (196.3) (158.6) (166.7) (172.0) (169.9)males diastolic 13.7 13.0 14.0 13.3 14.4 14.1 14.6 16.6 13.4 13.2 13.5 13.0 (102.9) ( 97.7) (105.1) (100.3) (108.5) (105.7) (109.9) (124.5) (100.9) ( 99.5) (101.6) ( 98.0) systolic 23.9 23.8 24.8 24.2 21.7 22.2 25.2 25.8 19.2 20.6 22.5 22.6 (179.8) (179.1) (186.6) (182.0) (163.4) (167.0) (189.8) (194.2) (144.3) (154.7) (168.8) (170.2)females diastolic 13.8 13.2 13.9 13.2 13.4 13.1 15.5 15.6 11.6 12.5 12.7 12.3 (103.5) ( 98.9) (104.8) ( 99.3) (100.7) ( 98.5) (116.4) (117.5) ( 87.3) ( 94.3) 95.5) ( 92.2) Negative medical history diseases was probably influenced by local factors, Only about 36% of the younger and 26%o of the such as availability of health services and screening older patients were reported to be free from all the procedures for cardiovascular diseases, some of the above-mentioned diseases (Table 7). Negative differences undoubtedly reflect genuine geographical histories were particularly rare in elderly women. The variations in the prevalence of certain diseases. An highest number of previously "healthy" subjects was example is the remarkable difference between the pre- found in Rohtak, the lowest in Moscow and Ulan valence of myocardial infarction the Finnish Bator. the Japanese centres. In the present community-based study, the preva- Comment lence of the above-mentioned diseases was of the same magnitude as, or somewhat lower than, those given in Although the patients' awareness of their previous earlier reports based on hospitalized stroke patients Table 7. Frequency (%) of past medical history of stroke patients, by age, sex and geographical area Europe and Japan Nigeria Mongolia India Sri Lanka All centres Israel History Age group Age group Age group Age group Age group Age group Age group (years) (years) (years) (years) (years) (years) (years) <65 >65 <65 >65 <65 >65 <65 >65 <65 >65 <65 >65 <65 >65 Stroke M 14.3 19.5 4.3 16.0 6.2 13.3 27.4 18.0 21.9 23.1 24.1 6.5 13.2 18.3 F 13.6 18.3 14.7 14.5 7.9 15.0 33.5 26.8 6.3 12.5 13.3 18.2 15.8 18.0 Myocardial M 14.3 12.7 0.4 1.4 0.0 0.0 1.0 1.4 6.3 7.7 11.1 2.2 9.3 9.2 infarction F 5.6 7.2 1.0 1.6 0.0 0.0 0.0 0.9 0.0 12.5 10.0 6.1 4.1 6.0 Other heart M 25.3 37.1 9.1 14.8 7.5 6.7 3.4 5.0 6.3 0.0 3.7 0.0 18.3 28.6 disease F 28.5 46.6 19.9 19.3 10.1 5.0 3.6 2.7 6.3 0.0 20.0 3.0 23.0 39.3 M 43.2 40.4 53.2 78.3 26.7 22.2 76.4 94.2 15.6 26.9 44.4 37.0 46.8 50.9Hypertension F 49.1 50.3 75.4 79.0 14.6 35.0 88.1 93.8 0.0 37.5 23.3 45.5 54.1 56.5 Treated M 25.7 23.9 18.8 36.9 19.2 13.3 74.5 92.1 3.1 15.4 22.2 15.2 27.8 30.4 hypertension F 31.0 29.7 39.3 41.0 12.4 30.0 85.6 90.2 0.0 12.5 10.0 6.1 36.9 33.7 M 10.3 12.7 2.5 4.8 6.2 6.7 0.5 1.4 6.3 7.7 7.4 15.2 7.5 10.3Diabetes F 12.3 14.5 3.1 3.7 2.2 15.0 0.5 2.7 6.3 12.5 23.3 15.2 9.4 12.3 Noneof diseases M 38.9 33.2 44.3 16.9 64.4 68.9 12.5 3.6 45.6 53.8 31.5 52.2 39.5 29.4 listed above F 37.3 24.9 16.8 17.2 76.4 65.0 5.2 1.8 81.3 50.0 40.0 39.4 33.6 23.3 Total numbersof M 1466 1438 483 420 146 45 208 139 32 26 54 46 2389 2114 patients(= 100%) F 1072 2057 191 429 89 20 194 112 16 8 30 33 1592 2659 120 CEREBROVASCULAR DISEASE (15-17). Comparisons between the stroke patients and the corresponding general populations were made in some centres (5, 18-20). Most of the diseases under study were significantly more frequent in stroke patients than in the population at large. The fact that nearly three-quarters of all stroke patients had associated diseases, mostly in the cardio- vascular system, supports the view that in most cases stroke is merely an incident in the slowly progressive course of a generalized vascular disease. From the pre- ventive point of view it is particularly important that over one-third of the patients with known hyperten- sion were not receiving antihypertensive treatment at the time of the stroke. CLINICAL MANIFESTATIONS IN THE ACUTE PHASE Clinical signs observed in the acute phase of stroke were analysed in order to assess the severity of stroke in different parts of the world and to obtain a baseline for the evaluation of the effects of rehabilitation. A detailed analysis of the neurological signs was neither intended nor feasible, since many of the registered patients were not hospitalized. About one-half of the registered patients were fully conscious at the time of registration, one-fifth were comatose-i.e., unresponsive to painful stimuli-the remaining patients being either somnolent or semi- comatose. The state of consciousness was not appreci- ably influenced by the age and sex of the patients (Table 8). The predominant neurological deficit was hemi- plegia, observed in over two-thirds of the patients; it was probably present also in many cases in which motor function could not be assessed because of coma. A small group of patients were recorded as having "no neurological deficit", which means no impairment of consciousness, speech, or muscle power in the limbs (Table 8). Such cases were particularly frequent below the age of 55, one of the reasons undoubtedly being the relatively higher incidence of subarachnoid haemorrhage in young people; otherwise no significant correlation was found between age of the patient and neurological deficit. A comparison between different centres revealed that severe impairment of consciousness was twice as frequent in the Japanese as in the European patients; conversely, cases with only mild neurological deficits were seen more often in Europe (Table 8). The neurological findings in various types of stroke were not compared, since the diagnosis of type of stroke often remained unverified and the types of stroke were often classified on the basis of neuro- logical findings. In the total series, the average systolic blood pressure, as recorded in the acute phase of the stroke, was 23.5 kPa (176 mmHg) in men and 23.9 kPa (179 mmHg) in women, the diastolic values being 13.5 kPa (101 mmHg) for both sexes. As shown in Table 6, age had only a slight influence on blood pressure. Blood pressure levels were much higher in comatose patients than in those who were alert, probably Table 8. Proportion (%) of patients with consciousness or neurological deficits (within 24 hours of onset) Europe and Japan Nigeria Mongolia India Sri Lanka Israel Deficit Age group Age group Age group Age group Age group Age group (years) (years) (years) (years) (years) (years) <65 >65 <65 )65 <65 >65 <65 >65 <65 )65 <65 >65 Consciousness Fully conscious 57.9 49.2 40.4 39.3 11.2 11.6 47.7 47.7 47.9 44.1 31.0 26.4 Somnolent 16.2 20.6 15.4 16.7 60.7 54.6 11.1 6.2 22.9 23.5 21.4 20.3 Semicomatose or comatose 23.1 29.0 43.4 43.3 28.1 33.9 40.0 44.6 29.2 32.3 46.4 53.2 Consciousness not assessed 2.8 1.1 0.7 0.6 0.0 0.0 1.3 1.5 0.0 0.0 1.2 0.0 Neurological deficit None 10.0 2.8 8.3 3.2 1.3 1.5 0.0 0.0 2.1 0.0 0.0 0.0 Speech only 4.4 5.7 3.1 1.4 2.1 1.5 7.7 2.4 2.1 5.9 0.0 2.5 Monoplegia 5.7 5.6 3.3 1.5 5.1 3.1 0.0 0.4 2.1 14.7 0.0 0.0 Hemiplegia 64.0 70.4 68.8 79.4 73.2 70.8 84.6 88.8 83.3 73.5 84.5 79.8 Paraplegia or multiple paralysis 3.6 2.7 3.7 5.2 5.5 7.7 4.0 4.8 2.1 0.0 7.2 3.8 Not assessed 12.4 12.7 13.2 9.3 12.8 15.4 3.5 3.6 8.3 5.9 8.3 13.9 Total numbers of patients 2538 3495 674 849 235 65 402 251 48 34 84 79 (=100%) 121 WHO COLLABORATIVE STUDY because most of the comatose patients had cerebral haemorrhage. The comparison between centres showed that systolic blood pressures in every age group were con- siderably higher in Japanese than in European patients, whereas the diastolic values differed only slightly. In summary, in the acute phase of stroke, impairment of consciousness was observed in about one-half and hemiplegia in over two-thirds of the patients. Coma and hemiplegia were more frequent in the Japanese than in Europeans. Also blood pressure levels were higher in the Japanese. TYPE OF MANAGEMENT The management of stroke patients is an important aspect of the public health problem posed by cerebro- vascular disease (21-22). One of the objectives of the study was to analyse how stroke was being managed in various parts of the world. Information was collected on hospital admission rates, bed usage, rehabilitation procedures, utilization of nursing institutions, etc., in order to assess the quality of care and the burden that stroke imposed on the health services. These data are also of great importance for the plan] services (23). Hospital admissions In the European centres and Israe" quarters of the patients were admitte Europe Japan Hospitlized Not hospitalized 0 Fig. 2. Admission to hospital. whereas in Japan more than half the patients were treated at home (Fig. 2). In some of the centres the admission rates reported may be low, owing to lack of medical facilities. The admission rates in Japan were influenced by factors such as age and sex of the patient; they were much lower for elderly stroke patients than for younger ones and much lower for females than for males. In Europe and Israel such trends were negligible. Hospital admission was apparently independent of whether the patients were living alone or with relatives, but less than half the patients who were living in nursing institutions were transferred to hospital-even in centres with high overall admission rates. As regards the influence of the clinical state, most non-hospitalized patients either had mild strokes that were treated at home or had particularly severe strokes that became fatal before admission could be arranged. However, in the Japanese centres hospital admission seemed to be independent of the severity of the stroke. An important aspect of acute stroke care is the length of the interval between onset and hospitaliz- ation. For all centres combined, 80% of the patients who were referred to hospital were admitted on the day of onset, and only 11% were admitted later than the third day after onset. In this respect, differences between the centres were small. ning of health In centres with high admission rates and aged populations, a substantial proportion of the strokes (10-161o) occurred in patients who were already in hospital for other reasons. These patients were characterized by a high cardiovascular morbidity; 1 about three- about 807o of them gave a history of at least one d to hospital, previous cardiovascular disease or of diabetes. In some of these patients, the pre-existing disease (e.g., myocardial infarction) or the treatment given in hospital (e.g., dehydration, blood transfusion, surgi- cal procedures) might have been the direct cause of the -'11,4 recent stroke, but the number of such instances cannot be assessed on the basis of the available data. About one-fifth of all the patients who left the hospital alive were discharged within 2 weeks of the stroke, but about 54% stayed for more than 4 weeks. Of those who died in hospital, 59% died within 2 weeks and 29% after more than 4 weeks (Table 9). After 3 months, 17% of the patients still remained in hospital. There were wide variations not only between different parts of the world, but also between 49 55 81 83 "'neighbouring" centres. For example, the proportion of survivors who stayed in hospital longer than 4 weeks in the whole series, ranged from 16% to 94%, and was 65%o in one Scandinavian centre but only 4607o Stroke occurrd in another. Long stays were frequent in Japan, but n hospal rare in Ibadan. The date of discharge from hospital was not always recorded; hence the mean duration of stay could not be calculated. 122 CEREBROVASCULAR DISEASE Table 9. Duration of stay in hospital Number of Percentages of patients whose length of stay in hospital were: hospitalized Centres Discharge status patients 1-7 days 8-14 days 15-21 days 22-28 days 29 days Europe Patients discharged alive 2638 10.5 12.7 16.3 10.5 50.0 and Israel Patients discharged dead 2417 43.0 14.7 8.1 5.5 28.6 Japan Patients discharged alive 525 1.3 3.0 4.6 4.4 86.7 Patients discharged dead 329 45.9 10.3 6.1 4.6 33.1 Nigeria Patients discharged alive 150 28.0 7.3 18.0 12.7 34.0 Patients discharged dead 119 52.9 13.4 4.2 5.9 23.5 Mongolia Patients discharged alive 249 10.4 6.4 38.6 3.2 41.4 Patients discharged dead 101 53.5 5.0 2.0 1.0 38.6 India Patients discharged alive 32 31.3 25.0 18.8 9.4 15.6 Patients discharged dead 14 50.0 14.3 7.1 0.0 28.6 Sri Lanka Patients discharged alive 73 4.1 4.1 16.4 17.8 57.5 Patients discharged dead 87 67.8 6.9 4.6 9.2 11.5 All centres Patients discharged alive 3667 9.9 10.6 16.2 9.4 53.9 Patients discharged dead 3067 44.8 13.7 7.4 5.4 28.8 Rehabilitation Rehabilitation policies were the same in age groups under and over 65 years. Rehabilitation was started before 3 weeks in two-thirds or more of the patients in most of the European centres. Early start and termination of rehabilitation was common in Israel, but very infrequent in the Japanese centres (except centre 46). More than 400o of the whole series of patients were given rehabilitative treatment up to 3 months or even longer. About one-third did not receive any such treatment at all. As expected, the proportion of those without rehabilitation was higher when the disability was either slight or extremely severe; rehabilitation was obviously considered unnecessary in the former category and hopeless in the latter. SURVIVAL OF STROKE PATIENTS The magnitude of the stroke problem is strongly reflected in the case-fatality or survival rates (18, 23-25). For all centres combined, survival rates at various points in time after stroke onset are shown in Fig. 3. It appears that most deaths occurred within the first 1 or 2 weeks, and stabilization of the survival rates was characteristic after 3 weeks. Arbitrarily, there- fore, deaths within the first 3 weeks after stroke can be termed "initial mortality". Influence of age Also in Fig. 3, survival of patients of 55-64 years of age at stroke onset is compared with that of patients of 65 years and over. During the first few days, survival was almost identical for the two age groups (it may even have been poorer for the younger group), but, thereafter, survival rates decreased more rapidly with Fig. 3. Mean survival rates for all centres and centres with highest and lowest rates. 123 WHO COLLABORATIVE STUDY time in the older group. These differenc the fact that in the younger age group th suffering stroke of the subarachnoid or haemorrhage type was larger than in the with a correspondingly large early fatali group had an increased risk over the 3 kinds of fatal disease and may have si more advanced underlying disease. Survival rates in males and females c substantially. Disturbance of consciousness at onset The lowest level of consciousness noti first 24 hours after stroke onset was r categories. The survival rates for each shown in Fig. 4. With decreasing levels ness, survival markedly decreased, and occurred almost exclusively within the fii onset. 100 90 80 ..5 70 "' .. S4 60 L 50 40 N " .N. 30 20 '_._ _ 10 1 2 3 5 7 10 14 21 28 Interval since onset (days) Fig. 4. Survival rates by level of consciousi hours of onset. Hypertension No substantial differences were foun late mortality between stroke patients wil untreated hypertension. Analysis of the results of the first me; blood pressure after stroke onset showec blood pressure of 26.9 kPa (200 mmHg) related to poor survival. The differenc were less pronounced at lower initial bl levels. Systolic blood pressures of less ti (160 mmHg) shortly after stroke onset related to poorer survival than pressures (160-179 mmHg). The decrease in es may reflect ie proportion intracerebral older group, ty. The older oung for all Lffered from lid not differ ed during the ecorded in 4 of these are cf conscious- this decrease rst week after almost exclusively during the first few days after onset. It thus seems that, though high blood pressure at the onset of stroke may reflect the pre-existence of hypertension, it may also indicate the severity of the cerebral lesion caused by the stroke. In both cases poorer survival could be expected. Recurrent stroke Initial survival of stroke patients was little influenced by the presence of a history of previous stroke. However, one year after the attack those with a history of previous stroke had 20-25%7o lower survival rates than those who had a first attack. The pattern was similar for both the younger and older age groups. Registered patients with recurring stroke during the study period had slightly poorer survival rates than the average survival for the whole series. Survival was poorer for female than for male patients. Dependence and self-care before stroke In 134 patients (13%0o of the whole series) assistance by others in daily self-care was needed prior to stroke =4014 onset. This group had poorer survival rates compared with the group of non-dependent patients. At one year, survival was 27%1o in dependent and 57% in the mmnol;nt non-dependent patients. - 1789) Variation with place ofstudy For comparison of survival rates between centres, miom.tO#se only the age group 55-64 years from each centre was = 9M)o considered. In Fig. 3 is shown the range of survival rates at various points in time after stroke onset bmatote together with the mean for all centres. Even though the remaining centres produced curves with some variations, most were close to the mean curve. l There were differences between centres regarding 90 365 both survival rates during the initial few days after stroke onset and later survival (between 21 days and 12 months), and the two were not always related. A good ness within 24 initial survival was not followed by a good late survival in some centres and vice versa. In order to evaluate the statistical significance of the differences between centres, survival rates at 21 days were considered. When the maximum survival rate tdin etardy or (centre 05) was compared with the minimum valuehtreated and (centre 47), it was found that the difference did not reach statistical significance at the 5%o level. This does asurement olf not, however, preclude the existence of true differ- at systovlc ences that were not detectable with the number of an.d over was registered patients available in each centre. es in survival ood pressure Functional prognosis han 21.3 kPa seemed to be For patients who have survived the acute phase of a )f 21-24 kPa stroke, the most important questions are to what survival was extent they will recover physically and mentally, and 124 2t CEREBROVASCULAR DISEASE whether they will eventually be able to return home and take up former activities. The attending clinician can often give fairly reliable answers to such questions, based on assessment of the clinical picture. Numerous follow-up studies have established the unfavourable influence on the prognosis of such factors as: age over 70, severe motor deficit, impair- ment of consciousness, and conceptual disorders. It was not an aim of the study to find further prognostic factors that might be useful in individual cases, but rather to study the recovery and social readaptation in large groups of stroke patients in different parts of the world. Clinical state As stated earlier, a total of 6217 patients, or 71% of the whole series, had hemiplegia or paraplegia at the initial examination, whereas the remaining patients had monoplegia, multiple paralysis, or merely speech disturbances; only 441 patients (5%) did not exhibit any of these types of deficit (but might have had cranial nerve pareses, sensory impairment, etc.). Three weeks after onset the number of patients with hemiplegia had been reduced to 3731, or 67% of those surviving at that time; after one year, hemiplegia or hemiparesis was still present in 1744 patients (46%). In contrast, the number of patients with "no deficit" rose steeply to 857 at 3 weeks, and subsequently to 1370 at 1 year, the latter figure representing over one- third of the 1-year survivors. Similar trends are observed when the diagnostic subgroups are con- sidered separately, but some differences exist: at 1 year, neurological impairment (in the above sense) was absent in 74% of the patients with subarachnoid haemorrhage, in 24-34% of those with cerebral infarction or unspecified stroke, and in only 22% of those with cerebral haemorrhage. A comparison of selected European and Japanese centres shows that, at each follow-up term, neurological deficits were less severe in Europe than in Japan. The proportion of 1-year survivors without neurological impairment was 39% in Europe and 28% in Japan (Table 10). Disability grade At the time of the first follow-up, only 29% of patients were fully independent in self-care; 39% were partially dependent, and the remaining 32% were completely incapacitated. Over the following months, this pattern gradually changed, so that after 1 year 62% were independent in self-care, and only 9% were still totally dependent on other people. A comparison between European and Japanese centres shows the following trend: before the stroke, nearly all Japanese patients were fully independent in self-care, whereas 10-20% of the European (and Israeli) patients were more or less disabled; 3 weeks after the stroke only a quarter of the Japanese stroke survivors had regained independence, as against over 30%7 of the European patients; the difference disap- peared at 3 months (Table 11). At each follow-up term, the proportion of patients with disturbance of bladder function was similar to that of patients who were totally dependent in self- care. In Europe, almost two-thirds of the 3-week sur- vivors were staying in an institution (nursing-home or hospital), and after 1 year about 16% were still insti- tutionalized. In Japan, the respective figures were Table 10. Proportion (%) of patients with certain clinical conditions at different intervals after stroke Europe and Israel Japan Nigeria Mongolia India Sri Lanka Time 3 3 1 3 3 1 3 3 1 3 3 1 3 3 1 3 3 1 wks mths year wks mths year wks mths year wks mths year wks mths year wks mths year No deficit 18.0 30.0 39.0 11.1 18.0 28.0 14.0 9.7 25.6 2.0 6.0 44.3 7.0 22.2 41.4 0.0 0.0 0.0 Speech only 7.0 6.0 5.0 2.0 3.0 3.0 2.0 0.0 0.0 3.0 3.0 0.0 2.0 2.2 0.0 0.0 0.0 0.0 Monoplegia 9.0 10.0 11.0 5.0 7.0 6.0 4.0 5.6 0.0 0.3 0.0 0.0 11.0 15.6 17.0 2.0 19.0 30.7 Hemiplegia or 61.0 50.0 42.0 78.0 68.0 59.0 70.8 77.8 74.4 92.0 54.3 47.0 79.0 60.0 38.0 80.0 58.6 69.2paraplegia Multiple paralysis 2.0 1.0 1.0 3.0 2.0 2.0 2.0 4.2 0.0 1.5 2.9 0.0 1.6 0.0 0.0 2.0 1.7 0.0 Not assessed 2.0 2.0 1.0 2.0 1.0 1.0 7.0 2.8 0.0 2.2 28.6 8.9 0.0 0.0 3.5 15.0 20.7 0.0 Total number 3945 3308 2830 989 884 770 161 72 39 324 35 79 61 45 29 87 58 13(=100%) 125 WHO COLLABORATIVE STUDY slightly lower, and in Ibadan, Ulan Bator, Rohtak, and Colombo, few patients were living in institutions after 1 year. It is striking that in Asia and Africa nearly all the patients who were staying in private homes were living with relatives, whereas a considerable pro- portion of the European patients were living alone. Return to work In all centres together, only 10% of the survivors at 3 months were back in gainful work (5.4% working full-time, 4.5%0 only part-time); at 1 year the number of patients who had resumed work had almost doubled. Similarly, domestic activities had been resumed by 23% at 3 months, and by 26% at 1 year. Comparison between centres disclosed only moderate variations, but it is noted that the highest percentage of patients going back to work was seen in one Japanese centre, where all patients were members of a large occupational group, and nearly all ofwhom were under the age of 55. Table 11. Patients' conditions before and after stroke, Self-care Control of Living conditions Working conditionsbladder Centre Time 1 2 3 U 1 2 U 1 2 3 U 1 2 3 4 5 6 UCen e % % %% % %% % % %% %% %% %% % Europe Before attack 81 14 3 2 89 8 3 15 79 5 2 24 44 20 9 1 0 3 and Israel 3weeksafter 32 38 30 0 74 25 1 3 32 65 0 1 1 35 4 7 41 12 3 months after 51 35 14 0 86 14 1 8 67 25 0 5 3 29 10 18 30 6{n =6033) 1 yearafter 60 30 9 1 90 10 1 9 74 16 1 10 4 27 14 18 26 2 Japan Before attack 94 5 1 0 97 2 0 3 96 1 0 49 19 8 11 14 0 0 3weeks after 24 35 41 0 76 24 0 1 45 54 0 1 2 60 0 2 35 1(n= 1523) 3monthsafter 52 31 17 1 86 14 1 1 65 33 1 6 9 51 2 6 25 1 1 yearafter 68 22 11 0 90 10 0 1 85 14 1 14 17 40 4 7 17 1 Nigeria Before attack 83 4 1 13 73 5 22 2 95 0 3 65 4 8 14 1 0 7 3 weeks after 20 37 37 6 61 30 9 0 36 63 1 2 4 89 0 0 2 3ln = 300) 3monthsafter 28 40 18 14 76 10 14 0 75 25 3 1 11 82 1 0 0 4 1 yearafter 69 26 0 5 95 0 5 0 95 5 0 26 28 33 5 0 0 8 Mongolia Beforeattack 99 1 0 0 90 8 2 5 95 0 1 23 52 23 1 0 0 1 3 weeks after 15 61 23 2 39 61 0 1 44 55 0 1 0 99 0 0 0 0(n = 653) 3monthsafter 20 26 26 29 57 14 29 0 89 9 3 0 0 97 0 0 0 3 1 year after 67 22 3 9 86 5 9 5 91 4 0 6 0 94 0 0 0 0 India Before attack 88 7 4 1 96 2 1 1 99 0 0 31 67 0 0 0 0 2 3 weeks after 69 15 16 0 92 7 2 0 93 5 2 12 12 20 18 21 16 2(n = 82) 3 monthsafter 84 11 4 0 98 2 0 0 98 0 2 18 16 9 18 20 20 0 1 yearafter 83 14 3 0 100 0 0 0 100 0 0 38 0 10 28 7 14 3 Sri Lanka Before attack 70 22 1 2 88 4 8 13 82 3 3 29 62 0 0 0 0 10 3 weeks after 1 59 31 9 55 35 10 1 15 76 8 0 0 33 0 0 59 8(n= 163) 3monthsafter 40 41 0 19 71 10 19 0 76 0 24 0 28 17 0 26 10 19 1 yearafter 46 54 0 0 92 8 0 0 92 0 8 8 0 46 8 0 39 0 8 Keys to classification: Self-care: 1 = independent 2 = partially dependent 3 = totally dependent U = unknown Control of bladder: 1 = not disturbed 2 = disturbed U = unknown Living conditions: 1 = in private household, alone 2 = in private household, not alone 3 = permanently living in institution U = unknown Working conditions (before attack): 1 = in gainful work 2 = retired because of ill health 3 = retired because of age 4 = housewife 5 = other U = unknown Working conditions (after attack): 1 = working as much as before 2 = working less than before 3 = not working 4 = domestic activities as before 5 = domestic activities less than before 6 = no domestic activities U = unknown 126 CEREBROVASCULAR DISEASE Comments The results confirm the clinical experience (24-26) that many stroke patients make partial recoveries, but very few are definitely "cured": 1 year after the stroke two-thirds of the survivors still had hemiplegia, mono- plegia, or speech disturbances, more in the Japanese than in the European centres. One reason for this difference might be that the number of severe strokes -most of which were probably cerebral haemor- rhages-appeared to be higher in Japan than else- where. As expected, disability roughly paralleled the motor deficit; the proportion of patients who had regained full independence in self-care rose from 29% at 3 weeks to 62% at 1 year. During the first few months of the follow-up period the Japanese patients, in accordance with their more severe neurological deficits, were more often disabled than their European counterparts, but at 1 year the difference was no longer present. It is tempting to associate the delayed improvement of the Japanese stroke victims with the fact that-as stated above-early start of rehabilitation was less frequent in Japan than in Europe. However, since several other factors may account for the above difference, the final assessment of the effects of stroke rehabilitation will still have to await the results of controlled studies. The social readaptation of survivors from stroke depends not only on the grade of physical disability, but to a considerable extent also on the structure of the community in which the patients live, and on pre- vailing patterns of family life. Thus, in the Western European centres about 25% of the 1-year survivors were staying in institutions, whereas in the Asian and African communities nearly all survivors, no matter how disabled, were cared for by their relatives at home. The community problems created by cerebro- vascular disease are therefore different in various parts of the world. Finally, the results have shown the extent (and limits) of occupational resettlement as a goal of stroke rehabilitation. One year after the stroke, only some 20% of the survivors were in gainful work. GENERAL DISCUSSION The present study has clearly demonstrated the magnitude of the stroke problem in many parts of the world. In the populations studied, stroke incidence rates ranged from 0.2 to 2.5 per 1000 population per year, the variations being mainly due to differences in the age structure of the populations involved. Assum- ing that these incidence rates can be applied to larger population groups, it can be estimated that in the European countries the annual number of strokes may amount to nearly one million and in Japan to 200 000. As in most previous studies, the incidence rates were found to rise steeply with advancing age. From the point of view of community medicine, however, it is important that most of the stroke victims under 65 years of age had been active members of their com- munities up to the time of the stroke. In spite of all modern therapeutic possibilities, stroke is still a severe threat to life. Of the total series of patients, 23% died within 1 week, 31%o within 3 weeks and 48%o within 1 year. As in other studies, unfavourable prognostic factors were old age, impair- ment of consciousness, and high blood pressure. Differences between fatality rates in various centres were only moderate. For those who survive a stroke, the consequences are often, though not invariably, grave. One year after the stroke, two-thirds of the survivors still had some neurological deficit, nearly 400Vo had not regained independence in self-care, while some 20% were back in gainful work. Further, the importance of the structure of the local community in which the patient lives is clearly shown by the fact that in the Asian and the African centres, nearly all the survivors, irres- pective of their disability grade, were cared for by their relatives at home, whereas in the European centres (except Moscow and Zagreb) 25%o of the 1-year sur- vivors had remained inpatients. Vast numbers of hospital beds are occupied by stroke patients: in the total series, nearly three- quarters of the patients were hospitalized because of the stroke and about half of the survivors spent more than 4 weeks in hospital. However, the proportion of stroke patients admitted to hospital varied widely, ranging from less than half (Japan and India) to about three-quarters (Europe, Israel and Nigeria). It is a crucial question whether, from the point of view of benefits to the patients, the former admission rates are too low or the latter unnecessarily high. Since specific diagnostic procedures, except lumbar puncture, were used only sparingly, the majority of patients must have been admitted mainly for reasons of better care, such as nursing or rehabilitation. Unfortunately, since the criteria on which patients were hospitalized in individual centres cannot be defined, it is impossible to assess the influence of hospital treatment and rehabilitation measures on the outcome of the disease. From the point of view of prevention of stroke, it is important to stress that three-quarters of all the registered stroke patients gave a history of previous cerebrovascular or cardiovascular diseases, or of diabetes. In particular, over half of the patients had arterial hypertension in their history, and only one- third of these were under treatment. 127 128 WHO COLLABORATIVE STUDY CONCLUSIONS 1. Cerebrovascular accidents are common in the contrasting populations of the various countries studied all over the world. Age-adjusted incidence of stroke, unlike that of myocardial infarction, shows only moderate geographical variation. Intracerebral haemorrhage seems to be more frequent in countries where hypertension has been reported to be common, particularly in Japan. 2. The impact of stroke on the community depends on such factors as the age structure of the population, the sociocultural pattern, and the availability of medical facilities. Particularly in the developed countries, large numbers of hospital beds are occupied by stroke patients; half of the hospitalized patients stay longer than 1 month. 3. Both in developed and developing countries nearly one-third of stroke patients die within 3 weeks, and only a few recover completely. It is still uncertain to what extent the patients' chances of survival and recovery are influenced by the type of management, in particular hospitalization. 4. Control of hypertension, although known to be effective in the prevention of stroke, is insufficient in most countries. 5. Stroke registers may be used as a source of infor- mation needed for the implementation of stroke con- trol programmes in the community. ACKNOWLEDGEMENTS Dr A. Bekessy and Mr E. Dowd were of very great help in providing statistical assistance and participating in data analysis. Dr I. Shigematsu and Dr M. Ashizava coordinated the Japanese centres and their assistance is gratefully acknowledged. K. Aho, Department of Neurology, University of Helsinki, Finland 0. 0. Akinkugbe, Faculty of Medicine, University of Ibadan, Nigeria B. C. Bansal, Medical College Hospital, Rohtak, India N. Dondog, Department of Cardiovascular Diseases, Medical Research Institute, Ulan Bator, Mongolia M. L. Gander, International Classification of Diseases, World Health Organization, Geneva, Switzerland L. Geltner, Asaf Harofe Government Hospital, Tel Aviv University Medical School, Zerifin, Israel P. Harmsen, Department of Neurology, Sahlgren's Hospital, Goteborg, Sweden S. Hatano, Department of Epidemiology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan K. Isomura, Saku Central Hospital, Nagano, Japan S. Kojima, Central Institute of Health, Akita, Japan Y. Komachi, Centre for Adult Diseases, Osaka, Japan K. Kondo, Central Health Institute, Japan National Railways, Tokyo, Japan T. A. Makinskij, Institute of Neurology, Academy of Medical Sciences of the USSR, Moscow, USSR J. Marquardsen, Department of Neurology, Fred- eriksberg Hospital, Copenhagen, Denmark T. Omae, Faculty of Medicine, Kyushu University, Fukuoka, Japan B. 0. Osuntokun, Faculty of Medicine, University of Ibadan, Nigeria J. B. Peiris, General Hospital, Colombo, Sri Lanka Z. Poljakovic, Centre for Cerebrovascular Diseases, Zagreb, Yugoslavia P. Puska, North Karelia Project, University of Kuopio, Finland A. Radic, Medico-Social Research Board, Dublin, Ireland K. Salmi, North Karelia Central Hospital, Joensuu, Finland E. E. Shmidt, Institute of Neurology, Academy of Medical Sciences of the USSR, Moscow, USSR V. E. Smirnov, Institute of Neurology, Academy of Medical Sciences of the USSR, Moscow, USSR K. Uemura, Division of Health Statistics, World Health Organization, Geneva, Switzerland CEREBROVASCULAR DISEASE 129 RSUMt MALADIES CEREBROVASCULAIRES DANS LA COLLECTIVITP: RESULTATS D'UNE ENQUETE COLLECTIVE DE L'OMS Des specialistes 6minents de 1"'attaque" cerebrale se sont rencontres en 1970 A la faveur d'une reunion sur les maladies cerebrovasculaires organis&e par l'OMS A Monaco. Ils ont recommande que l'Organisation mette au point une methodologie pour l'etablissement de registres de I'apo- plexie dans des collectivites determinees, afin de pouvoir disposer de donnees fiables sur la prevalence et les caracte- ristiques des attaques et d'etre ainsi en mesure d'engager des actions planifi6es pour prevenir celles-ci ou en soigner et readapter les victimes. L'enquete definitive sur l'enregistrement des episodes apoplectiques dans une collectivite, qui a ete precedee d'une etude pilote de plusieurs mois, a debute en 1971 avec la parti- cipation de 17 centres dans 12 pays. L'Organisation mondiale de la Sante, agissant comme centre de coordina- tion, s'est chargee du collationnement et du traitement des donnees. La population de reference totale pour l'ensemble des registres etait de plus de 2,6 millions de personnes, aux- quelles sont venus s'ajouter les groupes couverts par les deux centres-Rohtak et Colombo-dont la participation a commence plus tard. Dans chacune des regions concernees, un registre de l'apoplexie a e ouvert dans un h8pital ou centre de soins local, et tous les medecins hospitaliers ou generalistes, insti- tutions dispensant des soins et autorites sanitaires ont et informes de l'execution de l'enquete et pries d'y collaborer en signalant tous les episodes pouvant etre consideres comme apoplectiques survenus dans leur secteur et en fournissant aux fins du rapport d'enquete les details disponibles pour chaque cas. Tous les sujets ayant survecu A une attaque ont e suivis pendant 12 mois et les cas de nouvelle attaque survenue pendant cette periode ont e enregistres sur un formulaire conqu specialement A cet effet. Cependant, tout nouvel episode se produisant au cours des trois premieres semaines a e consid6re comme une aggravation du premier et ne constituant pas une nouvelle attaque. En cas de deces survenu dans l'annee suivant l'attaque, les causes de la mort indiquees dans le rapport d'enquete etaient celles figurant sur le certificat de deces ou sur le rapport d'autopsie. L'enquete a mis clairement en lumiere l'etendue du probleme que posent les cas d'apoplexie dans de nombreuses parties du monde. Au sein des populations etudiees, les taux d'incidence allaient de 0,2 a 2,5 pour 1000 par annee, la variation de ce pourcentage etant liee principalement A la structure par Age de la population concernee. Si l'on considere un taux d'incidence de cet ordre comme etant valable pour de plus vastes groupes de population, le nombre annuel de cas d'apoplexie dans les pays europeens pourrait etre estime A pres d'un million et au Japon A 200 000. En ce qui concerne la variation de l'incidence selon la structure par age, on a constate que les taux augmentaient tres fortement avec l'Age. Le pourcentage de deces pour l'ensemble des sujets suivis a et de 23% au cours de la premiere semaine apres l'attaque, 31% dans les 3 semaines et 48% dans le dMlai d'une annee. Parmi les facteurs justifiant un pronostic defavorable, on notait l'Age avance, I'affaiblissement des sens et une pression arterielle elevee. Peu de differences ont e constatees entre les divers centres en ce qui concerne les taux de mortalite enregistres. Un an apres avoir et frappees, pres des deux tiers des victimes d'attaque souffraient encore d'une deficience neurologique ou l'autre, et pres de 40% n'etaient pas capables de prendre soin d'elles-memes, alors que 20% avaient pu reprendre un travail remunere. Dans les centres participants d'Asie et d'Afrique, presque tous les survi- vants, quel que soit leur taux d'invalidite, etaient soignes a domicile par les membres de leur famille, alors que dans les centres europeens (sauf ceux de Moscou et de Zagreb) 25% des survivants se trouvaient encore A l'hopital un an apres l'episode apoplectique. En moyenne, pres des trois quarts des victimes d'une attaque ont e hospitalisees et pres de la moitie des survivants ont passe plus de 4 semaines A l'hopital. Mais, A l'interieur de cette moyenne, la proportion d'admissions A l'h6pital etait tres variable selon la region, allant de moins de la moitie des sujets frappes au Japon et en Inde aux trois quarts environ en Europe, en Israel et au Nigeria. Plus de la moitie des victimes d'attaque avaient souffert d'hypertension arterielle A un moment ou l'autre de leur vie, mais le tiers seulement d'entre elles avaient e ou etaient soignees pour cette cause. 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