The Incidence of HIV-related Disease in a Cohort of Haemophilic Men: Natural History and Changes Since the Introduction of Pre-Aids Treatment

One hundred and eleven men with haemophilia at the Royal Free Hospital Haemophilia Centre, London, became infected with HIV between October 1979 and July 1985. This paper describes the incidence of HIV-related disease in this cohort in the absence of pre-AIDS treatment and assesses the effect of antiretroviral and prophylactic therapies on this. In particular the relationship between the CD4 count and the development of HIV-related disease is investigated. Before the introduction of pre-AIDS treatment in November 1988, 60 patients (54%) had developed some type of HIV-related pre-AIDS condition or AIDS, a cumulative incidence of 77% (95% Confidence Interval 63% to 91%) by nine years after seroconversion. The probability of developing such conditions was associated with falling CD4 lymphocyte counts and an estimated 51% of patients (95% Confidence Interval 38% to 63%) would be expected to develop some manifestation of HIV-related disease before their CD4 count has fallen to 0.2 x 10(9)/1. Consequently, only conditions which develop later in HIV infection (AIDS, oral candida, herpes tester) are likely to be influenced by treatment. Since November 1988, there has been a reduction in these conditions, although the reduction in the rate of new AIDS cases was small (P=0.16). The risk of developing oral candida has been reduced at low CD4 counts from 12 cases in 76 years of experience below 0.2 x 10(9)/1, prior to November 1988, to two cases in 81 years after November 1988, (P=0.005). Similarly, since that date no herpes tester infections were observed in our cohort.