Impact of injecting drug use on response to highly active antiretroviral treatment in HIV-1-infected patients: A nationwide population-based cohort study

Abstract

The objective of this study was to determine the effect of highly active antiretroviral therapy (HAART) in human immunodeficiency virus (HIV)-infected patients infected through injecting drug use (injecting drug users, IDUs) compared to patients infected via other routes (non-IDUs). We conducted a nationwide population-based cohort study of all HIV-infected patients who initiated HAART during the study period of 1 January 1995 to 31 December 2007. We compared changes in CD4⁺ cell counts, percentage of full viral suppression (<500 copies/ml) and mortality from start of HAART, as well as differences in initial HAART regimen. Three thousand six hundred and fifteen patients were included in the study, representing 22,804 person-y of observation. A total of 346 (9.6%) were categorized as IDUs. Of IDUs, 55% gained full viral control within the first y after HAART compared to 76% of non-IDUs (p = 0.0002). Absolute CD4⁺ cell count and survival were lower for IDUs compared to non-IDUs (adjusted mortality rate ratio 3.6 (95% CI 2.9–4.3)). IDUs were more likely to receive a first regimen based on protease inhibitors (PIs) compared to non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens for non-IDUs, and IDUs initiated HAART later than non-IDUs. In conclusion, more than half of the HIV-infected patients in Denmark infected through injecting drug use gained full viral suppression after initiating HAART. Absolute CD4⁺ cell count was lower and mortality higher among IDUs than non-IDUs.

Acknowledgements

The authors thank the staff at the participating clinical departments for their continuous support and enthusiasm. Centres in The Danish HIV Cohort Study: Departments of Infectious Diseases at Copenhagen University Hospitals, Rigshospitalet (J. Gerstoft, N. Obel) and Hvidovre (G. Kronborg), Odense University Hospital (B. Røge), Aarhus University Hospitals, Skejby (C. S. Larsen) and Aalborg (G. Pedersen), Herning Hospital (A. L. Laursen), Helsingør Hospital (L. Nielsen) and Kolding Hospital (J. Jensen). The study has been financed by Region Hovedstaden, Hvidovre Hospital's Research Fund, Thora og Viggo Grove's Mindelegat and Christian Larsen og dommer Ellen Larsens Legat. The Danish HIV Cohort Study has received financial support from the University of Copenhagen and Rigshospitalet.

Declaration of interest: N. Obel has received research funding from Roche, Bristol-Myers Squibb, Merck Sharp & Dohme, GlaxoSmithKline, Abbott, Boehringer Ingelheim, Janssen-Cilag and Swedish Orphan. All other authors have no conflicts of interest.