Asymptomatic subjects at HIV diagnosis have prolonged survival as AIDS patients

The median AIDS survival for all AIDS patients was estimated as 11 months (95% confidence interval (Cl): 8-13 months). For the group of AIDS patients who were asymptomatic when HIV seropositivity was established, the median AIDS survival was 20 months (95% Cl: 13-23 months). For the group with symptomatic HIV infection or those who already had AIDS when HIV seropositivity was established, survival was estimated to 5 months (95% Cl: 1-15 months) and 4.5 months (95% Cl: 2-8 months), respectively. By using a Cox proportional hazard model it was found that being asymptomatic when HIV seropositivity was established or having Pneumocystis carinii pneumonia as the initial AIDS-related disease were associated with long AIDS survival. Being HIV infected by transfusion was associated with short survival. Long AIDS survival in the asymptomatic group may be explained by a positive selection of slow disease progressors. Differences in diagnostic routines may also cause systematic differences in the estimated AIDS survival.