AIDS mortality before and after the introduction of highly active antiretroviral therapy:: does it vary with socioeconomic group in a country with a National Health System?

Background: The aim of this study is to determine whether socioeconomic AIDS mortality inequalities before and after the introduction of highly active antiretroviral therapy (HAART) have increased or decreased in a Spanish city where HAART is free. Methods: The study used a trend design, including all Barcelona residents older than 19 years of age. All AIDS deaths, which occurred among these residents between 1991 and 2001 were included. The variables studied were age, sex, socioeconomic (SES) group and HIV transmission group. AIDS age-standardized mortality rates for each year were estimated. Poisson regression models were fitted to obtain the relative risk (RR) of AIDS death for each socioeconomic group with respect to the reference group. Results: AIDS mortality increased up until 1995 and subsequently decreased due to the introduction of HAART. The increase in AIDS mortality was greater in the lowest SES group, which had higher rates and a RR of dying larger than that of the highest SES group, fact that remained fairly stable over the whole period. A similar pattern was observed in intravenous drug users. In the homosexual transmission group, rates for the lowest SES group were higher for the whole period and increased until 1996, while rates for the other SES groups were lower and decreased over the entire period. Conclusions: The fact that inequalities in AIDS mortality by SES group remained fairly stable for the whole period suggests that perhaps access to HAART, or adherence, is lower than desirable, in people of lower SES groups. These results ought to be taken into account when implementing treatment and prevention strategies.