Use of indices to measure socio-economic status (SES) in South-Asian urban health studies: a scoping review

BACKGROUND: Universal health coverage (UHC) is a key area in post-2015 global agenda which has been incorporated as target for achieving health-related Sustainable Development Goals (SDGs). A global framework has been developed to monitor SDG indicators disaggregated by socioeconomic and demographic markers. This review identifies the indices used to measure socio-economic status (SES) in South Asian urban health studies. METHODS: Two reviewers searched six databases including Cochran Library, Medline, LILACS, Web of Science, Science Direct, and Lancet journals independently. All South Asian health studies covering urban population, with any research-designs, written in English language, and published between January 2000 and June 2016 were included. Two reviewers independently screened and assessed for selection of eligible articles for inclusion. Any conflict between the reviewers was resolved by a third reviewer. RESULTS: We retrieved 3529 studies through initial search. Through screening and applying inclusion and exclusion criteria, this review finally included 256 articles for full-text review. A total of 25 different SES indices were identified. SES indices were further categorized into 5 major groups, e.g., (1) asset-based wealth index, (2) wealth index combining education, (3) indices based on income and expenditure, (4) indices based on education and occupation, and (5) “indices without description.” The largest proportion of studies, irrespective of country of origin, thematic area, and study design, used asset-based wealth index (n = 142, 54%) as inequality markers followed by the index based on income and expenditure (n = 80, 30%). Sri Lankan studies used income- and expenditure-based indices more than asset-based wealth index. Majority of the reviewed studies were on “maternal, neonatal, and child health” (n = 98, 38%) or on “non-communicable diseases” (n = 84, 33%). Reviewed studies were mostly from India (n = 145, 57%), Bangladesh (n = 42, 16%), and Pakistan (n = 27, 11%). Among the reviewed articles, 55% (n = 140) used primary data while the rest 45% studies used secondary data. CONCLUSION: This scoping review identifies asset-based wealth index as the most frequently used indices for measuring socioeconomic status in South Asian urban health studies. This review also provides a clear idea about the use of other indices for the measurement SES in the region. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13643-018-0867-6) contains supplementary material, which is available to authorized users.