Summary of participants and data.

Demographics of participants examined in this study; Characteristics of prognostic markers of HIV-1 disease at the first three visits (1st, 2nd, 3rd) or a combination of the data available from the 2nd and 3rd visit after seroconversion (∼3, ∼9, and ∼15 months) in MACS participants from 1984 to 2005, prior to any antiretroviral therapy; Number of participants with prognostic marker data by year in quartiles, using the mean of the second (∼9 mos.) and third (∼15 mos.) seropositive visits, or one of these visits if data was not available from both.