Prevalence of Hypertension in Indian Tribes: A Systematic Review and Meta-Analysis of Observational Studies

Introduction: In India there is an increasing trend in hypertension prevalence among the general population. Studies have shown that tribal populations in India are also experiencing this burden. Objective: The aim was to estimate the pooled prevalence of primary hypertension among adult tribal populations of India. Methods: A systematic search was conducted in MEDLINE, IndMed, Web of Science, Google Scholar and major journals for studies published between 1981 and 2011. Two authors independently reviewed the studies, did quality assessment and extracted data in pre-coded spread-sheets. Pooled estimates of prevalence of hypertension were calculated using DerSimonian-Laird random effects model. Subgroup and sensitivity analyses and meta-regression were performed. Results: Twenty studies or 53 subpopulations with 64 674 subjects were included in final review. The pooled estimate of hypertension prevalence was 16.1% (95% CI: 13.5, 19.2). There was significant heterogeneity among the studies (I-2 = 99% and Q = 4624.0, df = 53, p, < 0.001). Subgroup analyses showed that year of study, acculturation status, special features, and BP measurement techniques significantly influenced prevalence, but after meta-regression analyses, 'decade of study' remained the only covariate that significantly and independently influenced prevalence (R 2 = 0.57, Q = 119.2, df = 49, p value,0.001). Conclusion: An increasing trend was found in the prevalence of hypertension in adult tribal populations across three decades. Although acculturation was probably the underlying agent that caused this increase, other unmeasured factors that need further research were also important. Concerned policy makers should focus on the changing health needs of tribal communities.