Background: Prognostic markers for HIV monitoring are needed for resource-limited regions. Prior research has demonstrated rapid declines in total lymphocyte count (TLC) and hemoglobin levels before AIDS, but the prognostic accuracy of these declines has not been examined prospectively.
Methods: Longitudinal TLC and hemoglobin data from men in the Multicenter AIDS Cohort Study (MACS) before the introduction of potent HIV therapy were used to identify the first time when the TLC was <or=1200 cells/mm, TLC declined by >33% per year, and hemoglobin declined by >11.6% per year. The prognostic value of these declines for AIDS was evaluated by Cox regression models and Kaplan-Meier survival curves.
Results: Rapid declines in TLC or hemoglobin were associated with progression to AIDS (relative hazard [RH]=4.70, 95% confidence interval [CI]: 3.23-6.86 for TLC; RH=5.55, 95% CI: 3.69-8.36 for hemoglobin). The World Health Organization criterion for initiating therapy, a TLC<or=1200 cells/mm, was also predictive of progression to AIDS (RH=6.14, 95% CI: 4.33-8.71). Even among those with a TLC>1200 cells/mm, a rapid decline in TLC or hemoglobin was strongly associated with progression to AIDS (RH=2.53, 95% CI: 1.56-4.10 for TLC; RH=5.28, 95% CI: 3.11-8.97 for hemoglobin).
Conclusions: In the MACS, rapid declines in TLC or hemoglobin concentration indicated an increased likelihood of progression of HIV infection to AIDS. These results support the potential utility of these markers for monitoring HIV-infected people in resource-limited regions, but critical levels and rates of decline of markers for such regions remain to be defined.