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Burden of Stroke in India During 1960 to 2018: A Systematic Review and Meta-Analysis of Community Based Surveys
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.317240
Keywords: Burden, cerebrovascular disease, incidence, mortality, prevalence, strokeKey Message: There is a paucity of surveys in India determining the epidemiological parameters of stroke and further there is a wide variation across the country. There is thus a need for nationwide multi-center surveys using uniform methodology for determining the burden of stroke.
The term cerebrovascular disease (CVD) refers to all disorders leading to stroke which can be either ischemic or hemorrhagic. There has been a global rise in the burden of cerebrovascular disease. CVD/stroke continues to be second only to ischemic heart disease in contributing to the global share of deaths since 1990 to 2016.[1] Low and middle-income countries account for 85.5% of total stroke deaths worldwide and the number of disability-adjusted life years in these countries was approximately seven times that in high-income countries.[2] Feigin et al. reported that in 2013 globally there were nearly 25.7 million stroke survivors, 6.5 million deaths due to stroke, 113 million disability-adjusted life years (DALYs) lost because of stroke and 10.3 million new cases of stroke.[3] The incidence of stroke is increasing chiefly due to aging population and other risk factors such as type-2 diabetes and hypertension. Further, in low and middle-income countries (LMIC), number of young people affected by stroke is increasing. Incidence, prevalence and mortality of CVD differ between geographical regions, countries, and ethnic groups.[4] It has been established that people from South Asians countries including India are at adisproportionately higher risk of CVD due to their disturbed cardio-metabolic profile and susceptibility to cardio-metabolic dysfunction.[5] In order to scale up the efforts towards the prevention and treatment of stroke, there is a need for robust data on assessment of burden of CVD in Indian population. To address this issue, we conducted a systematic review of all the community-based studies reporting data on stroke prevalence, incidence and mortality in urban, rural and both population settings. Objective: To estimate the burden of stroke, a systematic review of community-based studies was conducted. The PICO as applicable to the systematic review was: P-All age groups; I- NA; C-NA; O-Prevalence, Incidence and Mortality rates of stroke in India
Search strategy and Selection criteria A systematic search of Medline/PubMed and Google scholar was carried out independently by two of the authors (SK and SS) and all studies from January 1960 to December 2018 were included. The search string used was (“Stroke” OR “Cerebrovascular Accident”) AND (“India”) AND (“Incidence” OR “Prevalence” OR “Mortality” OR “Burden” OR “Morbidity”). An additional search was conducted on Google Scholar and reference lists of relevant studies to identify publications that could have been omitted in the database searches. Different subsets of studies were potentially eligible for different parts of this review. Only papers published in English were reviewed. Relevant articles were also retrieved from the cross-references of identified articles. The quality of studies was individually checked by two of the authors using the JBI tools. Studies were selected based on the following inclusion criteria:
The exclusion criteria for the studies were:
The diagnosis of stroke was based on the standard WHO definition, defined as ''Rapidly developing clinical signs of focal (or global) disturbance of cerebral function lasting longer than 24 hours, unless interrupted by death, with no apparent cause other than that of vascular origin''.[6] Data extraction and statistical analysis Data was retrieved by two authors (SK and SS) in an independent parallel search and all extracted data was tabulated in a Microsoft Excel file format. The articles were screened from title and abstract based on the relevance followed by full text review of selected articles. In case of disagreement among the two authors opinion of third author (MGD) was taken. Data related to study location, study period, mean age or age range, person years or sample size, incident cases of stroke their respective age- and sex-specific incidence or prevalence rates and the number of deaths due to stroke were extracted. The extracted data were sorted into incidence, prevalence and mortality data separately for urban and rural communities for analysis. The studies were considered as urban or rural studies based on the study area and the sample selection declared by the authors. For repeat studies conducted on the same site, population or cohort, the first publication was selected, and all additional data from other studies were compared for consistency and included in the selected paper. From reported overall crude incidence or prevalence of stroke in a given study, a random effect meta-analysis was conducted with pooled effect of stroke expressed per 100,000 population. A systematic review of all included studies was performed on crude stroke incidence, prevalence, and mortality rates in total, urban and rural population. Meta-analysis was attempted only if a minimum of three studies were present in the group. A random effect proportion meta-analysis was conducted. Heterogeneity was calculated based on I[2] value and publication bias was represented with funnel plot. PRISMA guidelines were followed. All statistical analyses were conducted on Medcalc statistical software version 19.2.6.
Systematic review The literature search returned 680 publications from Medline/PubMed and 17,300 from Google scholar. In total, 510 studies remained after removing reviews, non-English articles and non-human/animal model studies. On screening titles for relevance (stroke studies conducted primarily on Indian populations), 471 studies were excluded, giving a total of 39 full texts that were assessed. After applying the inclusion and exclusion criteria, 12 studies were further excluded. A total of 27 studies were finally retained for the review [Figure 1].
Study characteristics The studies which were finally included in the systematic review have been conducted across the various regions of India. After following a vigorous and systematic methodology finally there were 27 studies. The prevalence rates of stroke were reported in 21 publications,[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27] the incidence rates in 5[17],[22],[28],[29],[30] and mortality rates in 6 studies.[22],[29],[30],[31],[32],[33] Some of the studies had reported more than one of these parameters. Duration of study was mentioned in all the publications, except three.[11],[24],[27] There were six longitudinal studies.[17],[22],[28],[29],[30],[31] The study period varied from 1 to 7 years. The period was 1 year for the study done by Banerjee et al.,[17] 2 years by Das et al.,[22] 4 years by Aho et al.,[28] 5 years by Bhattacharya et al.[30] and 7 years for the study by Ray et al.[29] and Banerjee et al.[31] Seven studies used census data to define study areas and denominators.[8],[9],[10],[14],[19],[20],[30] Gourie-Devi et al. conducted a study in the Gowribidanur town Bangalore.[8] According to census 1981, the entire area surveyed under the Thondebhavi primary health center had a population of 1, 19, 290. A house to house survey of the town and systematic random survey of every third house in the rural area was carried out.[8] Bharucha et al. used the data of census 1971, where it was mentioned that 71% of the 91,000 total population of Parsis in India lived in Bombay and they lived in Parsi colonies of Bombay. The Parsis who were residents of Parsi colony in Bombay city on March 1, 1985 were included in the study.[9],[10] Das et al. conducted neuro-epidemiological survey in the Malda district of Rural Bengal. They surveyed the three Gram Panchayat area under Malda, taking the population profile as per census 1981.[14] Saha et al. surveyed the cluster of 12 villages from Baruipur block a rural area in West Bengal.[19] These villages had a stable population of 20842 individuals as per the census 1991.Entire population was screened for the neurological disorders.[19] Gourie-Devi et al. used the census data 1991 for selecting the study participants in Bangalore.[20] They identified the sample within the municipal limits, which were divided into census divisions and census enumeration blocks. In the first stage 10% of the total census divisions randomly were included. Then they took 20% of the census enumeration blocks (CEBs) from each of the census division. Only individuals residing in these blocks for a minimum of 6 months or more were included in the study.[20] Bhattacharya et al. conducted a 5 year longitudinal prospective study on the total population of South 24 Parganas, West Bengal.[30] The total population under the survey area was 20842, according to census 1991.[30] Das et al. used National Sample Survey Organization (NSSO) demarcated blocks to define study area, Banerjee et al. used municipal blocks and Ray et al. also utilized NSSO data.[21],[17],[29] Bansal et al. and Ferri et al. did not provide details regarding determining the denominator.[15],[24] In another study by Das et al., it was reported that inhabitant selected was a resident of the city for at least 1 year prior to date of survey and Kolkata municipal corporation data along with NSSO data was used.[21] Kapoor et al. had used the data from the census conducted by the multipurpose workers in the study area, prior to data collection.[11] Razdan et al. used the Integrated child development scheme (ICDS) estimated population.[12],[13] The response rate was mentioned only in 7 studies and varied from 94.2% to 99.4%.[9],[10],[20],[21],[25],[27],[30] Prevalence rate of stroke Of the 21 articles which reported the prevalence rates of stroke [Table 1], [Table 2] and [Table 3], 6 studies were done in both urban and rural areas.[7],[8],[15],[16],[20],[24] 7 in urban population[9],[10],[17],[21],[22],[23],[25] and 8 in rural population.[11],[12],[13],[14],[18],[19],[26],[27]
Incidence rate of stroke Of the five studies included in the systematic review for the incidence rates of stroke [Table 4], four studies reported incidence rates for urban population.[17],[22],[28],[29] There was only 1 study which described incidence rates in rural population.[30]
Mortality rates of stroke The 6 studies included in the systematic review for mortality rates of stroke comprised of [Table 5], 3 studies in the urban population[22],[29],[31] and 3 in rural population.[30],[32],[33]
Outcomes of the study Prevalence of Stroke Prevalence of Stroke in combined urban and rural population There were 6 studies done in both urban and rural areas [Table 1].The crude prevalence for the total population was mentioned in 5 studies.[7],[8],[15],[16],[20] Abraham et al. conducted a study on a total population of 258576 in Vellore, in the state of Tamil Nadu, South India and reported the total crude prevalence of stroke as 57 per 100,000 population.[7] In Gowribidanur town, situated North of Bangalore, Gourie-Devi et al. reported that the prevalence rate was 52 per 100,000 in total population of 57660.[8] In the survey of Rohtak, Haryana, on a total population of 130211 of age of 20 years and above the prevalence rate was 44.54 per 100,000 with higher rates in males (46.78 per 100,000) as compared to females (41.52 per 100,000).[15],[16] The Bangalore Urban and Rural Neuro-epidemiological (BURN) survey by Gourie-Devi et al. between January 1, 1993 and September 30, 1995 in the total population of 102557 with all age groups included, the prevalence rate was 150 per 100,000 population.[20] Ferri et al. conducted a multi centric cross- sectional survey in 11 sites in 7 low and middle-income countries including Latin America, China and India for assessing the burden of stroke in the elderly more than 65 years of age. In the publication they have mentioned the urban and rural rates separately and not the total prevalence but we calculated the rate based on the available data as 1497 per 100, 000.[24] Summary of prevalence of stroke in combined urban and rural population To summarize, in the total population, the prevalence rate varied from 44.54 to 150 per 100,000. The prevalence rate was derived from 6 studies done in both urban and rural population, publication by Dhamija et al. reported the same data as of Bansal et al.[15],[16] and another study dealt with population >65 years of age.[24] Hence these two studies were not included. It is worth noting that two studies reported that the prevalence rates were higher in rural population as compared to urban population,[8],[20] in one study it was equal in both genders[15] and in the fourth study the rates were higher in urban as compared to rural population.[7] Prevalence of Stroke in Urban population A total of 13 studies reported the prevalence of stroke in urban areas of the country.[7],[8],[9],[10],[15],[16],[17],[20],[21],[22],[23],[24],[25] [Table 2] The prevalence rate in the urban area reported in the survey of total population of 258576 comprising of both urban and rural areas, in Vellore, in the state of Tamil Nadu, South India, by Abraham et al. in the year 1968 and 1969 was 63 per 100,000 population per year with higher prevalence rate in males of 74 per 100,000 compared to 53 per 100,000 population in females.[7] In Gowribidanur town, situated North of Bangalore, Gourie-Devi et al. reported that the prevalence rate was 45 per 100,000 in an urban population of 17,734 inclusive of all age groups from March 1982 to June 1984.[8] A survey done in the city of Bombay taking March 1, 1984 as the prevalence day on a select ethnic group of 851 Parsis, Bharucha et al. reported a very high prevalence of stroke 1410 per 100,000 per year.[9] Another survey done by the same author in Bombay on 14010 Parsis taking March 1, 1985 as the prevalence day, the prevalence rate was 842.3 per 100,000 per year with higher age adjusted prevalence rates of 457 per 100,000 in males compared to 397 per 100,000 in females. The age adjusted rate for total population was 424.3 per 100,000 population.[10] Both these studies were excluded for the calculation of summarizing measures since a specific ethnic group of Parsis was surveyed and the observations cannot be projected to the general population, since the demographic profile is in variance with the population of the country. In the survey of urban area of Rohtak, Haryana, on a population of 79046 of age of 20 years and above, Bansal and Dhamija reported that the prevalence rate was 44.28 per 100,000 and the rates were higher for males (46.01 per 100,000) as compared to females (41.89 per 100,000).[15] The article by Dhamija et al. is the same data as in the above-mentioned study by Bansal and Dhamija; hence, it was not included for meta-analysis.[16] Population based cluster survey on stroke by Banerjee et al. in the four municipal blocks of southern part of Kolkata city between July 1998 and July 1999 on the population of 50291, including all age groups, the prevalence rate was 147 per 100,000 with the prevalence rate in females more than males (170.29 versus 125.9 per 100,000). The age adjusted prevalence (by adjusting as per the US population of 1996) was 334 per 100, 000.[17] The Bangalore Urban and Rural Neuro-epidemiological [BURN] survey by Gourie-Devi et al. between January 1, 1993 to September 30, 1995 in the urban population of 51502 with all age groups included, the prevalence rate was 136 per 100,000 populations.[20] The survey in 166 municipal blocks of Kolkata by Das et al. from March 2003 to February 2004 in a population of 52,377, the prevalence rate of stroke was 486.85 per 100,000, with higher prevalence rate of 510.4 per 100,000 in males as compared to 460.4 per 100,000 in females.[21] Age adjusted prevalence rate was 765.68 per 100,000 (adjusted to US population 2000).[21] A prospective survey in Kolkata by Das et al. reported the crude prevalence rate was 472 per 100,000 population with prevalence being higher in males 496 per 100,000 as compared to females 444 per 100,000 population.[22] Another publication by the same author in the same population of 166 municipal blocks of Kolkata from March 2003 to February 2004 , in 5430 elderly above 60 years of age of total 52,377, the prevalence rate of stroke was 3351 per 100,000 with higher prevalence rate in males 3645.5 per 100,000 as compared to 3047.4 per 100,000 in females.[23] Age specific prevalence rate showed increase by threefold from 7th to 8th decade and 1.08 times increase from 8th to 9th decade in males whereas in females there was two and a half times increase from 7th to 8th decade but a small decrease (4.62%) from 8th to 9th decade.[23] Multi centric cross sectional surveys were done in 11 sites in 7 low and middle income countries including Latin America, China and India by Ferri et al. for assessing the burden of stroke in terms of prevalence rates in the elderly adults more than 65 years of age.[24] A total of 1004 subjects comprised the sample of urban India and the prevalence rate was 1900 per 100, 000.[24] Mukhopadhyay et al. conducted the survey in the urban slum dwellers aged 60 years and above in the Dharavi, Mumbai (Dharavi is the largest slum in Asia) in 1726 participants and the prevalence rate was 3823 per 100, 000.[25] Studies by Das et al., Ferri et al. and Mukhopadhyaya et al. were excluded from the meta-analysis as these were done only on elderly age group.[23],[24],[25] Summary of Prevalence of Stroke in Urban population Summarizing the prevalence rates of stroke for the urban areas of India in this systematic review, we observed that the studies which included all the age groups, the prevalence rate varied from 45 to 487 per 100,000 populations.[8],[21] One study had included the population 20 years and above and the prevalence rate of stroke was 44.28 per 100,000.[15] Two studies included the elderly age group of 60 years and above and the prevalence was 3351 and 3823 per 100,000 population, respectively.[23],[25] Another study which had included subjects of elderly population above 65 years of age, the prevalence rate was 1900 per 100,000 populations. The prevalence rates in the elderly age group were much higher and were different from all other studies.[24] All the studies mentioned above[7],[8],[9],[10],[15],[16],[21],[22],[23],[24],[25] showed higher prevalence rate in males as compared to females except one study in which the prevalence rate was higher in females.[17] Prevalence of Stroke in Rural population A total of 14 studies reported the prevalence of stroke in rural areas in different regions of the country.[7],[8],[11],[12],[13],[14],[15],[16],[18],[19],[20],[24],[26],[27] [Table 3] It is noteworthy that all were community-based house-to-house surveys. One of the first epidemiological studies on stroke was done by Abraham et al. on a population of 258576 including the rural and urban population of Vellore in the state of Tamil Nadu, South India in the year 1968 and 1969.[7] Prevalence rate of stroke in rural areas was 31 per 100,000 and was higher in males (64 per 100,000) as compared to females (38 per 100,000). This pioneering study activated interest in epidemiology of Neurological disorders.[7] Unfortunately, this pivotal study could not to be included in the meta-analysis since the population denominator for urban and rural area was not separately mentioned. Gourie-Devi et al. conducted a survey in the Gowribidinaur town, 80 km North of Bangalore in the state of Karnataka, between March 1982 and June 1984 on the rural population of 39926 and all age groups were surveyed.[8] The prevalence of stroke was 55 per 100, 000.[8] In the rural community of the Intensive Field Practice Area of All India Institute of Medical Sciences, New Delhi, Kapoor and Banerjee provided the prevalence rate of stroke as 88 per 100,000 in the population of 48798 in 28 villages.[11] In the population survey of Kuthar valley of Anantnag district of South Kashmir from July 1986 to November 1986 by Razdan et al., November 1, 1986 was taken as the point prevalence day and the population covered was 63645. The prevalence rate of stroke was 143 per 100,000 with the rate being higher in males 187 per 100,000 as compared to 94 per 100,000 in females.[12] Another publication by the same author in 1994 was not included to avoid duplication since the same data as earlier publication was reported.[13] A survey was done in the Malda district, 350 km away from Kolkata (earlier known as Calcutta) on a rural population of 37,286 by Das and Sanyal from June 1, 1989 to March 31, 1990, with point prevalence day as March 31, 1989.[14] The prevalence rate of stroke was 126 per 100,000 and the gender specific prevalence showed higher prevalence in males 199.36 per 100,000 as compared to 57.2 per 100,000 in females.[14] A community based collaborative study of stroke coordinated by WHO was done by Bansal and Dhamija in Rohtak town and 14 villages around the health institution between 1971 and 1974.[15] The population surveyed in the rural area was 51165 and adults above 20 years of age were screened. The prevalence rate of stroke was 44.28 per 100,000 with higher prevalence in males [47.96 per 100,000] compared to females [40.99 per 100, 000].[15] Dhamija published an article which is a report of the same survey published as above and hence was excluded to avoid duplication.[16] A survey of a population of 10,368 people 15 years and above done in Srinagar, Jammu and Kashmir by Salaam between October 1999 to March 2000, showed prevalence rate of 559 per 100, 000.[18] In the rural area of Eastern India, 12 villages of Baruipur block in West Bengal with a population of 20842 a study was done by Saha et al. for a period of one year from May 1, 1992 to April 30, 1993.[19] The prevalence rate of stroke was 147 per 100,000 and the male and female prevalence rates were almost equal and the risk of suffering from stroke increased four folds after the age of 61 years.[19] In the urban and rural area of Bangalore, South India a study was done by Gourie-Devi et al. called as the Bangalore Urban and Rural Neuro-epidemiology study (BURN) from January 1, 1993 to September 30, 1995.[20] In the rural population of 51055 with all the age groups included the prevalence rate of stroke was 165 per 100,000 population.[20] Multi-centric cross-sectional survey was done in 11 sites in 7 low and middle-income countries including Latin America, China and India by Ferri et al. for assessing the burden of stroke in terms of prevalence rates in the elderly adults more than 65 years of age.[24] A total of 999 subjects comprised the sample of rural India and the prevalence rate was 1100 per 100, 000.[24] This study was not included in the meta-analysis since all age groups were not included but restricted to a specific age group of 65 years and above. Three phase community based, cross-sectional survey was done by Kalkonde et al. in the rural clusters of 39 villages in the Gadchiroli district of India, from January 2014 to May 2014 on a population of 45,053.[26] Of the 845 subjects who were positive on screening, only 175 were diagnosed as stroke. The crude prevalence rate of stroke was 388.4 and the age standardized stroke prevalence was 535.58 per 100,000 individuals. The crude prevalence rate was twice in men as compared to women.[26] A two stage, door to door survey of neurological diseases was done by Mansukhani et al. in the villages of Motivahiyal, Arnai and Chavshala in the Karpadataluka in the Valsad district of Gujarat.[27] The population in these villages is mainly tribal. Data was obtained from 8217 individuals from 1464 households; 9 cases of stroke were diagnosed and the crude prevalence rate was found to be 109.53 per 100,000 population. Highest prevalence of stroke was seen in the age group above 70 years. The prevalence was two times more in males as compared to females.[27] Summary of Prevalence of Stroke in Rural population Summarizing the prevalence rates of stroke for the rural areas of India in this systematic review, we observed that the studies which included all the age groups, the prevalence rate varied from 55 to 388.4 per 100,000 populations.[8],[26] Two studies had included population ≥15 years and reported the prevalence rate of stroke as 143 per 100,000 and 559 per 100,000 population, respectively.[12],[18] In one study the subjects ≥20 years were included and the prevalence rate was 44.28 per 100,000 population.[15] In another study which had included subjects of elderly population above 65 years of age, the prevalence rate was 1100 per 100,000 population. Obviously, this prevalence rate was much higher as expected in view of the age group selected and hence was different from all other studies.[24] All the studies mentioned above[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[18],[20] showed higher prevalence rates in males as compared to females except one study in which the prevalence rates were equal in males and females[19] Age standardized Prevalence rates Age standardized prevalence rates have been reported by some of the studies[9],[12],[17],[20],[21],[22],[26] Age standardized Prevalence rates in Urban and Rural population Gourie-Devi et al. had conducted a study in the urban (population 51,502) and rural (population 51,055) of Bangalore and reported the age standardized prevalence as 262 per 100,000 population.[20] As was a practice in the earlier years, the age standardized rates were calculated based on the US population however recently it was suggested by Ahmad et al. to standardize the rates of the population from the third world countries on the basis of World standard population [WSP] which is the authentic depiction of population age composition of the third world countries.[34] Age standardized Prevalence rates in Urban population Bharucha et al. reported the age standardized rates, using the US population as the standard population.[9] Their results were 424 per 100,000. This was a select ethnic group of Parsis therefore the results were quite high.[9] Banerjee et al. used the US population for age standardization and reported that the age standardized prevalence rate in the urban areas of Calcutta (now known as Kolkata) was 334 per 100,000 per year.[17] Das et al.(2006) had conducted a study in the city of Kolkata and standardized the rates using Kolkata urban population based on 2001 census data, Indian population census 2001 and also US population of year 2000 and reported the age standardized prevalence rates (95%CI) as 486.85 (377-551), 331.55 (291.76-375.31) and 765.68 (673.80-866.75) per 100000 per year, respectively.[21] Das et al. had conducted a study in urban Kolkata in a population of 52377 and the age standardized prevalence rates was 545 per 100000 per year (95%CI, 479.68 to 617.08) using the World standard population as the standard population.[22] Age standardized Prevalence rates Rural population Razdan et al. had used US population as the standard population and the age standardized prevalence rate was 244 per 100,000 per year.[12] In a study conducted in 39 villages of rural Gadchiroli in the population of 45053 by Kalkonde et al. the age standardized stroke prevalence rate per 100000 was 535.58 (95% CI 492.41-583.01).[26] They had calculated the age standardized rates using the WHO world standard population.[26] Summary of age standardized prevalence rates To summarize, the age standardized prevalence rate in total population was 262 per 100,000 population.[20] Among urban regions the age standardized prevalence rate varied from 334 to 765 per 100,000 population[17],[21] and in rural region the rates varied from 244[12] to 535.6 per 100, 000.[26] Incidence rate Incidence of Stroke in Urban population Four studies reported incidence of stroke in urban population[17],[22],[28],[29] [Table 4]. In the city of Rohtak, a center from India in the WHO collaborating study from 1971 to 1974 in a population of 124,700 with all age groups included, the incidence rate was 33/100,000.[28] The annual incidence rate of stroke was 36/100,000 population in one year survey from July 1998 to June 1999 by Banerjee et al. in a population of 50,291 with all the age groups included in the four municipal blocks in the Southern part of the city of Calcutta (now Kolkata).The age adjusted incidence rate was 105 per 100,000 when adjusted to the US population of 1996. Age adjusted annual incidence rate was higher in women (204 per 100,000) as compared to men (43 per 100,000).[17] The authors have attributed the higher incidence rate in women to uncontrolled hypertension. A survey was conducted twice in an year for 2 successive years from March 2003 to 2005 on a population of 52,377 subjects in the Kolkata city by Das et al.[22] The annual incidence rate per 100,000 per year for a 2 year period was reported to be 123.15 and was higher among females (149.9) than males (99.54).Age standardized incidence rates when standardized to world population was 145.30 per 100,000 (120.39 to 174.74).When standardized to European population and US population, age standardized incidence rate of stroke was 190.49 (157.54 to 228.06) and 215.53 (177.06 to 257), respectively.[22] Ray et al. conducted a prospective study over a period of seven years from March 2003 to February 2010.[29] The sample was identified based on National sample survey organization block. In a total of 282 blocks with a population of 100,802, the annual incidence rate was reported to be 108.13 per 100,000 in the subjects more than 40 years of age. The age adjusted annual incidence rate was 140.61 per 100,000 (standardized based on world population)[29] [Table 4]. Incidence of Stroke in Rural population There is only one study done in rural India by Bhattacharya et al. in the state of West Bengal from 1992 to 1997 on a population of 20717, [Table 4] and the average annual incidence rate was 123.57 per 100,000.[30] Age adjusted annual incidence rate was estimated to be 262 per 100,000 and was higher in females as compared to males[30] [Table 4]. Summary of Incidence rates of stroke Summarizing the results for incidence rate in the urban area, there were three studies which had included all the age groups, and the incidence rate varied from 33/100,000 to 123/100, 000.[17],[22],[28] One study by Ray et al. reported annual incidence of 108.13/100,000 in the population >40 years of age.[29] In the rural area only one study has been done and annual incidence rate was estimated to be 123.57 per 100, 000.[30] Mortality rates of Stroke Mortality rates of Stroke in Urban population Mortality rates of stroke in urban population were reported in three studies[22],[29],[31] [Table 5]. Das et al. screened population of 52,377 in the city of Kolkata, twice a year for two successive years from March 2003 to February 2005.[22] Of the 129 incident cases of stroke, 53 (21 men and 32 women) died within 30 days with a case fatality rate of 41.08% (95%CI, 30.66 to 53.80). Females had higher case fatality rate (43.24%) as compared to males (38.18%).[22] Ray et al. conducted a survey over 7 years period from March 2003 to February 2010 in Kolkata.[29] A cohort of 763 stroke cases was followed up and at 30 days post stroke there were 321 deaths; 253 of them occurred within 7 days with a case fatality rate of 33.16% and the 30 days case fatality rate was 42.07%[29] [Table 5]. Mortality rates of Stroke in Rural population Three studies reported mortality rates of stroke in rural population[30],[32],[33] [Table 5]. Bhattacharya et al. conducted a study in the rural population of the state of West Bengal for five years and recorded first 30 days mortality of stroke cases as 18% with men suffering more as compared to the women.[30] Joshi et al. recorded the deaths occurring in 45 villages (in a population of 180162) in the East and West Godavari districts in Andhra Pradesh for a 12 month period from 2003 to 2004.[32] Multipurpose primary care health workers were trained for using the verbal autopsy tool. A total of 1354 deaths were recorded of which 170 were due to stroke. 13% of the total deaths were due to stroke, 14% in females and 12% in males.[32] Kalkonde et al. recorded information on cause of deaths using a well validated verbal autopsy tool in a rural population of 94154 people residing in 86 villages in rural Gadchirolli from April 2011 to March 2013.[33] There were 1599 deaths during this period and 229 (14.3%) deaths were due to stroke. They reported that stroke was the most frequent cause of death. In those who died due to stroke the mean age was 67.47 ± 11.8 years and 48.47% were women. Crude stroke mortality was 121.6 per 100,000 and age standardized mortality rate was 191.9 per 100,000 population. One third of the deaths due to stroke patients occurred within first one week and 46.3% (106) within 30 days after onset of stroke[33] [Table 5]. Summary of mortality rate of stroke Summarizing the data of above available studies, the proportional mortality rates of stroke is 13% to 14.3%[32],[33] As far as 30 days case fatality rate of stroke is concerned it varied from 18% to 46.3%.[30],[33] Meta-analysis of Stroke prevalence and incidence rates The pooled prevalence rates by random effect Meta-analysis was 184/100,000 per year (95% CI = 63.4 to 368, I[2] = 98.97%, P < 0.0001) in urban studies [Figure 2] and [Figure 3] as compared to 158/100,000 per year (95% CI = 95-237, I[2] = 96.65%, P = 0.0001) in rural studies [Figure 4] and [Figure 5]. The random effect meta-analysis of population-based incidence rates was 99.4/100,000 per year (95% CI = 22.8-230/100,000, I[2] = 98.99%, P < 0.0001) in three urban studies [Figure 6] and [Figure 7]. Meta-analysis of Incidence studies in rural areas could not be attempted as there was only one study.[30]
Stroke has been an important area of research and several epidemiological studies on stroke have been done in the developed countries but in the developing countries there is paucity of such epidemiological studies.[35] Over the past few decades, the burden of stroke in developing countries has grown to epidemic proportions. Worldwide in 1990, cerebro-vascular accidents were responsible for 4.4 million deaths.[36] In 2005, stroke accounted for nearly 5.7 million cases worldwide.[37] Ischemic heart disease was the leading cause of DALY'S in India in 2016 and stroke the fifth leading cause. Stroke contributed 7.1% (6.6-7.5) of total deaths and 3.5% (3.2-3.9) of total DALY's. The proportion of deaths and DALY's for stroke was similar in both the genders.[1],[38] Although stroke is a major cause of death and disability globally, the burden is far greater in developing countries accounting for about two-thirds of total cases worldwide.[39] In this study an attempt has been made to compile and depict the burden of stroke including the prevalence, incidence and mortality rates through a systematic review and meta-analysis of the community based studies conducted over a period of six decades (from 1960 to 2018). Prevalence rate of stroke for total population inclusive of urban and rural population, varied from 44.54 to 150/100000. For the urban population prevalence rate was 45 to 487/100000 and 55 to 388.4/100000 for rural population. This wide variation in the prevalence rate may be attributed to (i) the studies having been done over six decades consequently there might have been a changing profile of risk factors of stroke and ii) age groups in the studies were different, some included all age groups, others more than 15 years or more than 20 years. The random effect meta-analysis of population-based studies yielded the pooled prevalence rate in urban area as 184 per 100,000 (95% CI 63.4 to 368) and 158 per 100,000 (95% CI 95 to 237) in the rural area. Meta-analysis of studies conducted from 1980 to 2001 gave a weighted average of prevalence rate of 154 per 100, 000.[40] Anand et al. reported the prevalence as 203 per 100,000 population above 20 years accounting for approximately one million cases in the country.[41] In the present study, the crude incidence rate was observed to vary from 33 to 124 per 100,000 population.[28],[30] The age standardized incidence rate varied from 105 to 262 per 100,000 population.[17],[30] According to The Asian Stroke Advisory Panel, the overall incidence ranged from 116 to 483/100,000 per year in Asia.[42] The average annual IR of stroke in India is 145 per 100,000 population.[43] In a recent systematic review of ten community-based cross-sectional Indian studies on stroke published between 1960 and 2015, Kamalakannan et al. reported the overall incidence between 105 to 152 per 100,000 population.[44] These results are similar to a developing country like China (76 to 150 per 100,000) as well as developed countries like Australia (160 per 100,000) and United kingdom (130 per 100,000).[45] In the present study, meta-analysis was attempted for studies only for urban population since in rural area there was only a single study. The pooled incidence rate by random effect meta-analysis in the urban area was 99.4 per 100,000 population (95% CI 22.8 to 230). The 30 days case fatality rate for stroke ranged from 18% to 46.3% in our study. Anand et al. provided the mortality due to stroke in India, and made an estimate of 102,000 deaths which represented 1.2% of total deaths in all ages in the country, for that year. The proportion of stroke deaths increased with age and in the oldest age group (≥70) contributed to 2.4% of all deaths.[41] The disability and mortality rates due to stroke are far greater in developing countries than developed nations.[46] According to the GBD (Global Burden of Diseases, Injuries, and Risk Factors) 2010 study, 63% of 11,569,000 incident ischemic stroke events were reported in low- and middle-income countries (LMIC); 57% deaths in LMIC from ischemic stroke of 2,835,000 deaths and 64% DALY lost due to ischemic stroke in LMIC of 39,389,000. Among broad GBD regions, India, China and Russia were ranked highest in both 1990 and 2010 studies for deaths due to ischemia attributable to tobacco consumption.[47] The age and gender-standardized mortality was found to be lowest in Japan and highest in Mongolia.[48] Europe and North America had lower mortality rate due to stroke. Some countries such as Taiwan, urbanized areas of China, Korea and Japan have been successful in limiting the mortality due to stroke and case fatality by controlling the risk factors and through improvement in stroke care.[49] South Asians including Indians are disproportionately more susceptible to stroke due to the presence of cardio-metabolic risk factors.[4] Systematic review and meta-analysis of the community-based studies have reaffirmed that the stroke burden in India is quite high. In India, the significant rise in the incidence of stroke in the last decade can be attributed to various socio-economic changes that resulted in altered lifestyle with restricted physical activity, excessive intake of processed food and increased stress at work place leading to enhanced development of risk factors including type-2 diabetes, hypertension, obesity and hyper-lipedema. Ischemic stroke is the most common accounting for around 80% of total stroke cases in India. Around 10% to 15% of all strokes occur in the young affecting people below 40 years.[50] Dalal et al. reported a crude prevalence rate of 200 per 100,000 population., based on community survey data for 'hemiplegia' caused by stroke from different regions of India.[51] Attempt to reduce the stroke burden in India with a large population of 1.3 billion across a number of states, inequalities of health indices and infrastructure and also varying diverse cultural ethos, is an extremely challenging and arduous task. To minimize the detrimental effect of stroke on the health status of the population, awareness should be created among community regarding preventable risk factors of stroke.[49],[50] Further, the cost of treatment and rehabilitation of patients with stroke will put tremendous burden on existing basic health-care resources and care givers. Therefore, the priority should be on preventive strategies of strokes along with inclusion of rehabilitation in stroke management at different levels of health care namely at primary, secondary and tertiary centers. The coordination and data gathering should be precisely done as it would help create specific prevention programs.[51] In January 2008, the Government of India initiated the pilot phase of National Program for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS) with a focus on early diagnosis, management, public awareness and infrastructure for major non-communicable diseases including stroke.[52] There is an urgent need for convergence of government and private sector health providers, public health institutions and Non-governmental organizations to contain the stroke epidemic. Strength of the study In the present systematic review attempt was made to look for the burden of stroke in terms of community-based prevalence, incidence and mortality rates. A meticulous search of the published studies and an effort was made to ensure that the data accuracy was maintained. The study period included 58 years which is a substantially long period to assess the pattern of disease burden. Besides the systematic review, meta-analysis for prevalence and incidence studies was also done which yielded the pooled estimates. Limitations of the study Most of the studies were conducted in the Southern and Eastern regions of India but very few from the Northern and Western India. Significant parts of the country, have not been adequately represented. Only few of the studies have mentioned the age specific and age adjusted rates. Therefore, there is a limitation in projecting the data to the entire nation. Addressing these issues and overcoming barriers and challenges there is an urgent need to conduct nationwide epidemiological surveys of stroke using uniform methodology for determining the prevalence, incidence and mortality rates due to stroke. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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