Socioeconomic inequality in disability among adults: a multicountry study using the World Health Survey.

Objectives: We compared national prevalence and wealth-related inequality in disability across a large number of countries from all income groups. Methods: Data on 218 737 respondents participating in the World Health Survey 2002–2004 were analyzed. A composite disability score (0–100) identified respondents who experienced significant disability in physical, mental, and social functioning irrespective of their underlying health condition. Disabled persons had disability composite scores above 40. Wealth was evaluated using an index of economic status in households based on ownership of selected assets. Socioeconomic inequalities were measured using the slope index of inequality and the relative index of inequality. Results: Median age-standardized disability prevalence was higher in the low- and lower middle-income countries. In all the study countries, disability was more prevalent in the poorest than in the richest wealth quintiles. Pro-rich inequality was statistically significant in 43 of 49 countries, with disability prevalence higher among populations with lower wealth. Median relative inequality was higher in the high- and upper middle-income countries. Conclusions: Integrating equity components into the monitoring of disability trends would help ensure that interventions reach and benefit populations with greatest need