Trends in Use of Combination Antiretroviral Therapy and Treatment Response from 2000 to 2016 in the Canadian Observational Cohort (CANOC): A Longitudinal Cohort Study

Background: Advances in treatment have turned HIV from a terminal illness to a more manageable condition. Over the past 20 years, there have been considerable changes to HIV treatment guidelines, including changes in preferred antiretrovirals and timing of initiation of combination antiretroviral therapy (cART).Objective: To examine real-world trends in cART utilization, viral control, and immune reconstitution among people living with HIV in Canada.Methods: Data were obtained from the Canadian Observational Cohort (CANOC). CANOC participants were eligible if they were antiretroviral therapy-naive at entry and initiated 3 or more antiretrovirals on or after January 1, 2000; if they were at least 18 years of age at treatment initiation; if they were residing in Canada; and if they had at least 1 viral load determination and CD4 count within 1 year of CANOC entry. Baseline and annual mean CD4 counts were categorized as less than 200, 200-350, 351-500, and more than 500 cells/mm3. Annual mean viral loads were reported as suppressed (< 50 copies/mL), low (50-199 copies/mL), or high detectable (>= 200 copies/mL). The cART regimens were reported yearly.Results: All CANOC participants were included (n = 13 040). Over the study period, the proportion of individuals with an annual mean CD4 count above 500 cells/mm3 increased from 16.3% to 65.8%, while the proportion of individuals with an undetectable mean viral load increased from 10.6% to 83.2%. As of 2007, the most commonly prescribed 2-agent nucleoside reverse transcriptase inhibitor backbone was tenofovir disoproxil fumarate and emtricitabine. In terms of third agents, non-nucleoside reverse transcriptase inhibitors were the most common class in the periods 2000-2003 and 2014-2015, protease inhibitors were most common in the period 2004-2013, and integrase inhibitors were most common in 2016.Conclusions: Concordance with treatment guidelines was demonstrated over time with respect to cART prescribing and immunologic and virologic response.