Prognostic value of plasma HIV RNA in the natural history of Pneumocystis carinii pneumonia, cytomegalovirus and Mycobacterium avium complex

Objectives: To use follow-up on untreated HIV-positive men to assess the pr ognostic information provided by baseline data on plasma HIV RNA, CD4 cell count, age, and HIV-related symptom status, separately for three specific A IDS-defining illnesses: Pneumocystis carinii pneumonia (PCP), cytomegalovir us (CMV), and Mycobacterium avium complex (MAC). Methods: The study population were 734 HIV-positive homosexual men enrolled in the Multicenter AIDS Cohort Study, with follow-up (1984-1985 through mi d-1988) restricted to the antiretroviral treatment-free and prophylaxis-fre e era. Baseline marker values were categorized and assessed as predictor va riables in separate time-to-event analyses for each of the three specific o utcomes. Results: A total of 138 cases of PCP, 25 cases of CMV, and 25 cases of MAC were observed. For PCP and CMV, higher categories of HIV RNA and lower cate gories of CD4 cell count were associated with increased risk relative to th e respective reference groups. For MAC, oral candidiasis or fever and eleva ted HIV RNA at baseline were the primary risk factors. Further analysis hig hlighted the importance of monitoring HIV RNA levels in addition to CD4 cel l counts when evaluating patients' risk of developing PCP. Conclusions: In the absence of treatment, plasma HIV RNA levels provide pro gnostic information about the risk of these three specific AIDS-defining il lnesses, independently of the CD4 cell count. These data provide a useful r eference as researchers investigate changing patterns in the incidence and predictors of opportunistic infections in the era of increasingly active an tiretroviral therapies. (C) 1999 Lippincott Williams & Wilkins.