Impact of new antiretroviral combination therapies in HIV infected patients in Switzerland: prospective multicentre study

Abstract

Objectives: To examine trends in disease progression and survival among patients enrolled in the Swiss HIV cohort study during 1988–96 and to assess the influence of new antiretroviral combination therapies. Design: Prospective multicentre study, with follow up visits planned at six monthly intervals. Setting: Seven HIV units at university centres and cantonal hospitals in Switzerland. Patients: 3785 men (mean age 35.0 years) and 1391 women (30.3 years) infected with HIV. 2023 participants had a history of intravenous drug misuse; 1764 were men who had sex with men; 1261 were infected heterosexually; and 164 had other or unknown modes of transmission. 601 participants had had an AIDS defining illness. Results: During more than 15 000 years of follow up, there were 1456 first AIDS defining diagnoses and 1903 deaths. Compared with those enrolled during 1988-90, the risk of progression to a first AIDS diagnosis was reduced by 18% (relative risk 0.82 (95% confidence interval 0.73 to 0.93)) among participants enrolled in 1991-2, by 23% (0.77 (0.65 to 0.91)) among those enrolled in 1993-4, and by 73% (0.27 (0.18 to 0.39)) among those enrolled in 1995-6. Mortality was reduced by 19% (0.81 (0.73 to 0.90)), 26% (0.74 (0.63 to 0.87)), and 62% (0.38 (0.25 to 0.97)) respectively. Compared with no antiretroviral treatment, the risk of an initial AIDS diagnosis after CD4 lymphocyte counts fell to 6/l was reduced by 16% (0.84 (0.73 to 0.97)) with monotherapy, 24% (0.76 (0.63 to 0.91)) with dual therapy, and 42% (0.58 (0.37 to 0.92)) with triple therapy. Mortality was reduced by 23% (0.77 (0.68 to 0.88)), 31% (0.69 (0.60 to 0.80)), and 65% (0.35 (0.20 to 0.60)) respectively. Conclusions: The introduction of antiretroviral combination therapies outside the selected patient groups included in clinical trials has led to comparable reductions in disease progression and mortality. The Swiss HIV cohort study is an ongoing prospective study that includes a large proportion of the patients infected with HIV in Switzerland Antiretroviral combination therapy with two nucleoside analogues was introduced in 1995, and triple therapy with protease inhibitors was introduced in 1996 The risk of AIDS and death was substantially lower among patients enrolling in 1995 and 1996 than among those enrolled in earlier years Reductions in disease progression were similar among men and women and among patients from different transmission groups In Switzerland the introduction of antiretroviral combination therapies outside selected patient groups included in clinical trials has led to similar reductions in disease progression