Predictors of Virologic Suppression and Rebound Among HIV-Positive Men who have Sex With Men in a Large Multi-Site Canadian Cohort

Objectives: Men who have sex with men (MSM) represent the largest HIV transmission category in Canada, but there are limited pan-provincial data regarding combination antiretroviral therapy (cART) treatment outcomes. We sought to identify socio-demographic and clinical correlates of virologic suppression and rebound in this population. Methods: Our analysis included MSM participants in the Canadian Observational Cohort (CANOC) collaboration ≥ 18 years old who initiated ART naïvely between 2000 and 2011. We used accelerated failure time models to identify factors predicting time to suppression and time to subsequent rebound. Results: 3,180 participants were eligible for inclusion, of whom 2,616 (82.3%) achieved virologic suppression in a median time of 4 months. Our analysis identified more recent era of ART initiation, no history of injection drug use, older age, lower baseline viral load, higher viral load testing rate, and being on an initial regimen consisting of nonnucleoside reverse transcriptase inhibitors as significant predictors of virologic suppression. Subsequent virologic rebound was experienced by 298 participants (11.4%) in a median time of 22 months. Significant factors predicting rebound were more recent era of ART initiation, IDU history, younger age, higher baseline CD4 cell count, > 6 annual viral load tests, and living in British Columbia. Conclusion: The majority of HIV-positive MSM on ART are successfully achieving virologic suppression, which marks significant improvements in the health of HIV-positive MSM in Canada since the emergence of ART. A minority of MSM experience an increased risk of virologic rebound. Priority target groups include younger MSM and those with a history of IDU.