HIV disease progression in 854 women and men infected through injecting drug use and heterosexual sex and followed for up to nine years from seroconversion. Italian Seroconversion Study.

OBJECTIVE--To compare the progression of HIV-1 infection in men and women followed up for up to nine years after an accurately estimated date of seroconversion. DESIGN--Prospective observational study. SETTING--16 HIV outpatient clinics across Italy. SUBJECTS--321 women and 533 men infected with HIV through injecting drug use or heterosexual sex and with accurately estimated dates of seroconversion. MAIN OUTCOME MEASURES--Progression to severe CD4 lymphocytopenia (CD4 lymphocyte count < 200 x 10(6)/l), development of AIDS defining diseases, and death from AIDS. RESULTS--Thirty two women and 67 men developed AIDS at Kaplan-Meier progression rates of 25% (95% confidence interval 13.8% to 35.5%) and 23% (15.6% to 30.4%), respectively, 7 years after seroconversion. In a Cox proportional hazards model the relative hazard was 0.93 (that is, a slightly lower hazard in women) before and 1.10 (0.70 to 1.72) after adjusting for age, HIV exposure group, and year of seroconversion. When CD4 lymphocytopenia and death from AIDS were used as end points the results were similar, with adjusted relative hazards of 0.95 (0.63 to 1.42) and 0.72 (0.48 to 1.79) respectively. In both women and men the risk of developing AIDS before the CD4 lymphocyte count had declined below 200 x 10(6)/l was small (3% in women, 6% in men). The estimated median count at which AIDS developed in women (34 x 10(6)/l; 10 x 10(6) to 44 x 10(6)) was similar to that for men (44 x 10(6)/l; 22 x 10(6) to 60 x 10(6)). CONCLUSION--There seems to be little evidence for appreciable differences in the natural course of HIV infection between men and women followed up from the time of seroconversion.