Cain, LaurenCaniglia, EllenPhillips, AndrewOlson, AshleyMuga, RobertoPérez-Hoyos, SantiagoAbgrall, SophieCostagliola, DominiqueRubio, RafaelJarrín, InmaBucher, HeinerFehr, Janvan Sighem, ArdReiss, PeterDabis, FrançoisVandenhende, Marie-AnneLogan, RogerRobins, JamesSterne, Jonathan A. C.Justice, AmyTate, JanetTouloumi, GiotaPaparizos, VasilisEsteve, AnnaCasabona, JordiSeng, RémonieMeyer, LaurenceJose, SophieSabin, CarolineHernan, Miguel2016-11-182016Cain, L. E., E. C. Caniglia, A. Phillips, A. Olson, R. Muga, S. Pérez-Hoyos, S. Abgrall, et al. 2016. “Efavirenz versus boosted atazanavir-containing regimens and immunologic, virologic, and clinical outcomes: A prospective study of HIV-positive individuals.” Medicine 95 (41): e5133. doi:10.1097/MD.0000000000005133. http://dx.doi.org/10.1097/MD.0000000000005133.0025-7974http://nrs.harvard.edu/urn-3:HUL.InstRepos:29408418Abstract Objective: To compare regimens consisting of either ritonavir-boosted atazanavir or efavirenz and a nucleoside reverse transcriptase inhibitor (NRTI) backbone with respect to clinical, immunologic, and virologic outcomes. Design: Prospective studies of human immunodeficiency virus (HIV)-infected individuals in Europe and the United States included in the HIV-CAUSAL Collaboration. Methods: HIV-positive, antiretroviral therapy-naive, and acquired immune deficiency syndrome (AIDS)-free individuals were followed from the time they started an atazanavir or efavirenz regimen. We estimated an analog of the “intention-to-treat” effect for efavirenz versus atazanavir regimens on clinical, immunologic, and virologic outcomes with adjustment via inverse probability weighting for time-varying covariates. Results: A total of 4301 individuals started an atazanavir regimen (83 deaths, 157 AIDS-defining illnesses or deaths) and 18,786 individuals started an efavirenz regimen (389 deaths, 825 AIDS-defining illnesses or deaths). During a median follow-up of 31 months, the hazard ratios (95% confidence intervals) were 0.98 (0.77, 1.24) for death and 1.09 (0.91, 1.30) for AIDS-defining illness or death comparing efavirenz with atazanavir regimens. The 5-year survival difference was 0.1% (95% confidence interval: −0.7%, 0.8%) and the AIDS-free survival difference was −0.3% (−1.2%, 0.6%). After 12 months, the mean change in CD4 cell count was 20.8 (95% confidence interval: 13.9, 27.8) cells/mm3 lower and the risk of virologic failure was 20% (14%, 26%) lower in the efavirenz regimens. Conclusion: Our estimates are consistent with a smaller 12-month increase in CD4 cell count, and a smaller risk of virologic failure at 12 months for efavirenz compared with atazanavir regimens. No overall differences could be detected with respect to 5-year survival or AIDS-free survival.en-USObservational StudyatazanavirefavirenzHIVmortalityobservational studiesJournal Article2016-11-1810.1097/MD.0000000000005133