CD4+ count and risk of non-AIDS diseases following initial treatment for HIV infection

BACKGROUND: Reductions in AIDS-related morbidity and mortality following the advent of combination antiretroviral therapy have coincided with relative increases in chronic non-AIDS end-organ diseases among HIV+ patients. OBJECTIVE: To examine the association of latest CD4+ counts with risk of non-AIDS diseases in a cohort of 1397 patients who initiate antiretroviral therapy. METHODS: CD4+ counts and HIV RNA levels along with fatal, and non-fatal, AIDS and non-AIDS diseases (liver, cardiovascular, renal, and cancer) were assessed over a median follow-up of 5 years. Cox proportional regression models were used to study risk associations. RESULTS: A total of 227 patients experienced an AIDS event and 80 patients developed a non-AIDS disease event. Both AIDS and non-AIDS diseases rates (events/100 person-years), respectively, declined with higher latest CD4+ counts: 13.8 and 2.1 with latest CD4+ counts less than 200 cells/microl; 2.0 and 1.7 for counts of 200-350 cells/microl; and 0.7 and 0.7 for counts greater than 350 cells/microl. After adjusting for baseline covariates and the latest HIV RNA level, risk of AIDS and non-AIDS diseases were lowered by 44% (95% confidence interval for hazard ratio 0.50-0.62, P < 0.01) and 14% (95% confidence interval for hazard ratio 0.77-0.96, P = 0.01), respectively, for each 100 cell/microl higher latest CD4+ count. CONCLUSION: Higher CD4+ counts on antiretroviral therapy are associated with lower rates of non-AIDS diseases and AIDS. These findings expand our understanding of the implications of HIV-related immunodeficiency and motivate randomized studies to evaluate the effects of antiretroviral therapy on a broad set of clinical outcomes at CD4+ counts greater than 350 cells/microl.