Progression to AIDS slowed even more after the first two years with highly active antiretroviral therapy

Aims: The aim of this study was to describe the effectiveness of highly active antiretroviral treatment for HIV after the treatment became publicly available in Norway in August 1996 and through to the year 2000. The effectiveness was studied for the three main transmission groups for HIV in Norway. Methods: Effectiveness was measured as change in progression to AIDS after highly active antiretroviral treatment for HIV was introduced in the population of HIV-diagnosed persons. Notifications of HIV diagnosed persons and persons with AIDS from 1983 to 2000 in Norway were used in the analysis. Progression to AIDS after August 1996 compared with progression to AIDS before 1996 was analysed by Kaplan-Meier curves and Cox regression models. Results: Progression to AIDS slowed after highly active antiretroviral treatment was introduced. The intensity of getting AIDS was significantly reduced after August 1996 compared with the intensity of getting AIDS before August 1996. The reduction in intensity after August 1996 was less explicit in the two years following August 1996 than in the subsequent two and a half years from August 1998 to December 2000. The reduction was less explicit among HIV-diagnosed intravenous drug users. Conclusions: The effectiveness of highly active antiretroviral treatment lasted for at least four and a half years and increased after the first two calendar years. The problem of less effectiveness among HIV-diagnosed intravenous drug users should be addressed by the health authorities.