Effect of gender, age, transmission category, and antiretroviral therapy on the progression of human immunodeficiency virus infection using multistate Markov models

This article illustrates the use of time homogeneous Markov models with covariates to estimate the AIDS incubation period distribution from prevalent cohorts and to evaluate the effect of factors such as gender, age, human immunodeficiency virus (HN) transmission category, and antiretroviral therapy on disease progression We applied this methodology to the analysis of data from a cohort of 3,027 patients enrolled from a hospital-based surveillance system of HIV infection in the Bordeaux University Hospital and four secondary public hospitals in southwestern France. A total of 998 individuals (33%) progressed to AIDS during a median follow up period of 34 months. Based on a progressive three state Markov model, the estimated mean and median incubation periods were 9.1 years [95% confidence interval(CI) = 8.7-9.6] and 7.5 years (95% CI = 7.2-7.9), respectively. Our analyses showed a similar disease progression in men and women; we observed a more rapid progression for older subjects compared with younger ones and for homosexual men compared with heterosexuals, intravenous drug users, and transfusion recipients, who had similar disease progression rates after adjusting for age. The use of antiretroviral therapy appeared to slow disease progression. Moreover, the results indicated that a combination therapy of zidovudine with another antiretroviral drug may be more efficient than zidovudine monotherapy.