National income inequality and ineffective health insurance in 35 low- and middle-income countries.

Global health policy efforts to improve health and reduce financial burden of disease in low- and middle-income countries (LMIC) has fuelled interest in expanding access to health insurance coverage to all, a movement known as Universal Health Coverage (UHC). Ineffective insurance is a measure of failure to achieve the intended outcomes of health insurance among those who nominally have insurance. This study aimed to evaluate the relation between national-level income inequality and the prevalence of ineffective insurance. We used Standardized World Income Inequality Database (SWIID) Gini coefficients for 35 LMICs and World Health Survey (WHS) data about insurance from 2002 to 2004 to fit multivariable regression models of the prevalence of ineffective insurance on national Gini coefficients, adjusting for GDP per capita. Greater inequality predicted higher prevalence of ineffective insurance. When stratifying by individual-level covariates, higher inequality was associated with greater ineffective insurance among sub-groups traditionally considered more privileged: youth, men, higher education, urban residence and the wealthiest quintile. Stratifying by World Bank country income classification, higher inequality was associated with ineffective insurance among upper-middle income countries but not low- or lower-middle income countries. We hypothesize that these associations may be due to the imprint of underlying social inequalities as countries approach decreasing marginal returns on improved health insurance by income. Our findings suggest that beyond national income, income inequality may predict differences in the quality of insurance, with implications for efforts to achieve UHC.