Durability of first-line antiretroviral regimens in the era of integrase inhibitors: a cohort of HIV-positive individuals in Spain, 2014-2015.

BACKGROUND: We compared time to treatment change (TC), viral suppression (VS) and change in CD4+ T-cell counts of first-line antiretroviral regimens (ART).

METHODS: We analysed HIV treatment-naive adults from the Cohort of the Spanish HIV/AIDS Research Network (CoRIS) initiating the most commonly used ART regimens from September 2014 to November 2015. We used proportional hazards models on the sub-distribution hazard to estimate sub-distribution hazard ratios (sHR) for time to TC, logistic regression to estimate odds ratios (ORs) for VS (viral load <50 copies/ml), and linear regression to assess mean differences in CD4+ T-cell changes from ART initiation.

RESULTS: Among 960 individuals, tenofovir (TDF)/emtricitabine (FTC)/rilpivirine (RPV) was the most frequently prescribed regimen (24.2%), followed by elvitegravir (EVG)/cobicistat (COBI)/TDF/FTC (22.8%), abacavir (ABC)/lamivudine (3TC)/dolutegavir (DTG; 17.4%), TDF/FTC+darunavir/ritonavir (DRV/r) or darunavir/cobicistat (DRV/c; 12.1%), TDF/FTC/efavirenz (EFV; 8.8%), TDF/FTC+raltegravir (RAL; 7.7%) and TDF/FTC+DTG (7.0%). Initiating ART with TDF/FTC+DRV/r or DRV/c (adjusted sHR: 2.96; 95% CI: 1.44, 6.08), TDF/FTC/EFV (2.18; 0.98, 4.82), TDF/FTC+RAL (2.37; 1.08, 5.22) and TDF/FTC+DTG (6.34; 3.18, 12.64) was associated with a higher risk of TC compared to ABC/3TC/DTG. At 24 weeks, VS was lower in TDF/FTC+DRV/r or DRV/c (adjusted OR: 0.37, 95% CI: 0.18, 0.74) compared with ABC/3TC/DTG, and CD4+ T-cell increase was lower in patients initiating with TDF/FTC/RPV (adjusted mean difference: -75.9, 95% CI: -130.6, -21.2) compared with those who did with ABC/3TC/DTG.

CONCLUSIONS: Time to TC, VS and change in CD4+ T-cell counts varies by initial regimen. These differences may be useful for making decision when initiating ART.