The recent impact of antiretroviral combination therapy on CD4 counts, AIDS and death in HIV-infected persons: routine HIV surveillance in Scotland

Abstract

Our aim was to investigate if the clinical benefits of combination antiretroviral therapy recently reported from clinical trials are reproduced in a population-based HIV surveillance scheme. This surveillance scheme is estimated to cover 90% of the HIV-positive population currently under immunological monitoring in Scotland. Our results showed a considerable reduction in new AIDS cases among this group from 107 in 1995 to 59 in 1996 and an estimated 58 in 1997 (allowing for reporting delay). There was a similar fall in deaths from 75 in 1995 to 59 in 1996 and an estimated 24 in 1997. These observations are temporally associated with increasing prescription of antiretroviral therapy in Scotland throughout 1996 and 1997. Examination of those individuals monitored in both 1996 and 1997 showed that from their first CD4 count in 1996 to their first count in 1997 there has been a median gain of 6 CD4 cells/mm 3 (95%CI 0-12) compared with a median fall of 27 CD4 cells/ mm3 (95%CI 35, 17) for those monitored in both 1995 and 1996. Highest median gains in CD4 cell counts from 1996 to 1997 were seen in those receiving triple or quadruple therapy (median gain 32 CD4 cells/mm 3). These results are further strengthened by the results of a separate longitudinal analysis showing a highly significant ( P 0.001) effect of treatment on CD4 cell loss with the highest mean CD4 gains being seen in those in triple or quadruple therapy. Our results indicate that the benefits of combination antiretroviral therapy previously seen in clinical trials are being reproduced at a population level. It remains to be seen if these benefits can be sustained in the long term.