Decomposing economic disparities in risky sexual behaviors among people who inject drugs in Tehran: Blinder-Oaxaca decomposition analysis

OBJECTIVES: To our knowledge, no previous study has systematically assessed the role of economic status in risky sexual behavior among people who inject drugs (PWID) in Iran. In this study, we used Blinder-Oaxaca (BO) decomposition to explore the contribution of economic status to inequality in unprotected sex among PWID in Tehran and to decompose it into its determinants. METHODS: Behavioral surveys among PWID were conducted in Tehran, the capital city of Iran, from November 2016 to April 2017. We employed a cross-sectional design and snowball sampling methodology. We constructed the asset index (weighted by the first principal component analysis factor) using socioeconomic data and then divided the variable into 3 tertiles. We used the BO method to decompose the economic inequality in unprotected sex. RESULTS: Of the 520 recruited individuals, 20 were missing data for variables used to define their economic status, and were therefore excluded from the analysis. Not having access to harm reduction programs was the largest factor contributing to the economic disparity in unprotected sex, accounting for 5.5 percentage points of the 21.4% discrepancy. Of the unadjusted total economic disparity in unprotected sex, 52% was unexplained by observable characteristics included in the regression model. The difference in the prevalence of unprotected sex between the high-income and low-income groups was 25%. CONCLUSIONS: Increasing needle syringe program coverage and improving human immunodeficiency virus (HIV) knowledge are essential for efforts to eliminate inequalities in HIV risk behaviors among PWID.