Cell-associated infectious HIV-1 viral load as a predictor of clinical progression and survival among HIV-1 infected injection drug users and homosexual men

Cell-associated infectious HIV-1 viral load was measured using semi-quantit ative microculture techniques to determine its predictive capability for pr ogression to AIDS or survival among HIV-1 infected injecting drug users (ID U) and homosexual men (HM). The authors followed 296 IDU and 240 HM from Fe bruary 1992 through September 1995 for: (i) death, (ii) AIDS, and (iii) AID S or bacterial infection. At baseline, viral load was quantified using micr oculture techniques to determine infectious units per million peripheral bl ood mononuclear cells (IUPM). Data were analyzed using standard statistical methods for survival analysis. Of the 536 total participants, 106 died (20 %), and 98 of the 481 AIDS-free participants developed AIDS (20%). The rela tive hazard of AIDS for a viral load of greater than or equal to 100 IUPM, relative to a negative culture (0 IUPM), was 6.73 (95% CI: 2.23-20.3) after adjusting for risk group, initial CD4(+) count, and other covariates. The adjusted relative hazard of death for a viral load of greater than or equal to 100 IUPM vs. 0 IUPM was 2.57 (95% CI: 0.97-6.80). Viral load predicted time to death within the < 200 cells/mu l CD4(+) stratum. The predictive va lue of viral load on HIV-1 progression did not vary by risk group. These da ta show that cell associated infectious HIV-1 viral load was significantly predictive of progression across risk groups for AIDS and death among those severely immune compromised.