Do gender differences in CD4 cell counts matter?

Objective: To examine the effect of gender on disease progression and wheth er gender differences in CD4 lymphocyte counts persisted for the entire cou rse from HIV seroconversion until (death from) AIDS. Methods: CD4 lymphocyte counts were modelled in 221 female and 443 male ser oconverters following seroconversion, backwards From AIDS and backwards fro m death using regression analysis for repeated measurements. Results: In the period before use of highly active antiretroviral therapy ( HAART), progression to AIDS and to death were marginally slower in women th an in men as assessed by proportional hazards analysis. Women seroconverted for HIV, developed AIDS and died at higher CD4 cell counts than men (women : 815, 146 and 44 x 10(6) cells/l, respectively; men: 727, 49 and 22 x 10(6 ) cells/l, respectively), although differences were only statistically sign ificant at AIDS onset. Declines in CD4 lymphocyte counts were not significa ntly affected by gender and absolute differences between men and women were stable, with exception for the trajectory close to AIDS when the decline b ecame steeper for men than women. Conclusion: These gender differences in CD4 lymphocyte counts suggest a del ay of initiation of therapy in women compared with men (our model predicted that women reach the threshold of starting HAART at about 12 months later than men). If this delay unfavourably influences progression, treatment gui delines should be revised so that women can benefit equally from HAART. (C) 1999 Lippincott Williams & Wilkins.