Improvement in survival among symptomatic AIDS patients by exposure category in Sao Paulo

Abstract

Objective: The study assesses AIDS survival time per AIDS-case definition and exposure category in Sao Paulo State, Brazil during the periods 1992 to 1995 and 1998 to 2001.

Methods: Case-fatality rate per AIDS case, Cox proportional hazards analysis, and Kaplan-Meier survival time.

Results: The case-fatality rate per AIDS case in 1998 to 2001 was 37.6% for symptomatic (Centers for Disease Control and Prevention/modified and/or Paho/Caracas) and 9.7% for the Brazilian asymptomatic CD4 count<350 cells/mm3 AIDS-case definitions. Heterosexual/female patients were diagnosed earlier and presented the lowest case-fatality rate, followed by homosexual/male patients, heterosexual/male patients, and injecting drug users. In the multivariate Cox proportional hazards model, the period of diagnosis (hazard ratio=2.66; 95% confidence interval [CI]: 2.58 to 2.74) and AIDS-case definition (hazard ratio=4.48; 95% CI: 4.53 to 5.16) were strong predictors of survival. For the total AIDS cases, excluding death definition and undetermined exposure category, the estimated first quarter survival time improved from 4 months in 1992 to 1995 to 50 months in 1998 to 2001. Considering only the symptomatic AIDS-case definition, however, the improvement was from 4 months in the period 1992 to 1995 to 14 months in the period 1998 to 2001.

Conclusion: The survival improvement in Sao Paulo State was attributable to the introduction of antiretroviral therapy with free universal access in 1996 and to earlier diagnosis associated with the introduction in 1998 of the Brazilian asymptomatic CD4 count<350 cells/mm3 AIDS-case definition with superior sensitivity compared with the symptomatic AIDS-case definitions.