Evolution of HIV incubation times in AIDS patients

Since introduction of highly active antiretroviral therapy (HAART), the incidence of AIDS has gradually declined, although the incidence of HIV infection is largely unknown. We have studied a sample with 10,571 patients whose data were recorded by Spain's public health system, in the Andalusian Register of Cases of AIDS. The diagnoses correspond to the period January 1981 to June 2008. For this period, AIDS incubation times were analyzed by means of the survival and risk functions, using R survival and DTDA libraries. We have studied the evolution of incubation mean times according to specific variables from database. The obtained results show that the mean times of viral incubation presented a growing trend that was greater among women when the study was limited to heterosexual transmission. Stratifying by category of transmission, the longest incubation period was seen for intravenous drug users (IDU). Both gender and IDU transmission were associated with significantly greater survival without AIDS. In contrast, heterosexual transmission or pneumonia diagnosis were associated with lower survival without AIDS.