Survival of AIDS patients in Sao Paulo-Brazil in the pre- and post-HAART eras: a cohort study

Abstract

Background: Brazil was the first middle-income country to provide free and universal access to AIDS treatment. Understanding the impact of this policy is key to promote ongoing improvement of current intervention strategies. The aim of this study was to compare mortality rates and survival in a cohort of AIDS patients before and after the introduction of antiretrovirals (ARV) and to investigate predictors of survival.

Methods: A retrospective cohort study of AIDS patients aged 13 years or more living in the city of Sao Paulo was conducted. All patients were recruited from an STD/HIV outpatient clinic between 1988 and 2003 and followed up until 2005. We estimated AIDS mortality rates in person-years (py) and carried out a survival analysis using the Kaplan-Meier method. The Cox proportional hazards model was used to assess predictors of survival in AIDS patients.

Results: The study cohort comprised 6,594 patients. The yearly mean mortality rates were 17.6, 23.2, and 7.8 per 1,000 py for the study periods 1988-1993, 1994-1996, and 1997-2003, respectively. Median survival time was 13.4 and 22.3 months for patients entering the study in the first and second study periods and survival time was 108 months or more in 72% of those entering the study during 1997-2003. Factors independently associated with shorter survival included: AIDS diagnosis during the 1994-1996 (HR 2.0) and 1988-1993 (HR 3.2) periods; 50 years of age or more (HR 2.0); exposure category of injection drug users (IDU) (HR 1.5); 8 years of schooling or less (HR 1.4); no schooling (HR 2.1); and CD4+ counts between 350 and 500 cells/mm(3) (HR 1.2) and less than 350 cells/mm(3) at AIDS diagnosis (HR 1.3).

Conclusions: The study showed a strong impact following the introduction of HAART in 1996 with decreased AIDS mortality, increased survival rates, and benefits with early introduction of HAART. However, some groups of patients were less likely to benefit from the new drug regimens. Public policies promoting health equity create an enabling environment helping AIDS control programs in developing countries to achieve their goals as effectively as in developed countries.

Figure 1

Study design flow chart for AIDS cohort study. AIDS Cohort, CRT-DST/AIDS, 1988-2003.

Figure 2

AIDS mortality rates and proportion of drug regimens prescribed by year of AIDS diagnosis. AIDS Cohort, CRT-DST/AIDS, 1988-2003.

Figure 3

Cumulative probability of survival in patients diagnosed with AIDS, by study periods. AIDS-Cohort, CRT-DST/AIDS, 1988-2003.

Figure 4

Cumulative probability of survival in patients with AIDS for the three study periods* according to age, exposure category, schooling and CD4+ count at AIDS diagnosis**. AIDS Cohort, CRT-DST/AIDS, 1988-2003. *AIDS diagnosis periods (A) = the period from 1988 to 1993, (B) =1994-1996; (C) =1997-2003. **Log rank tests performed for each variable second periods of diagnosis.