Time spent with residual viraemia after virological suppression below 50 HIV-RNA copies/mL according to type of first-line antiretroviral regimen

Purpose: To investigate if the regimen used when starting antiretroviral therapy (ART) affects the time spent with residual viraemia (RV) after achieving <50 HIV-RNA copies/mL. Methods: Retrospective cohort study on patients infected with human immunodeficiency virus (HIV), followed prospectively, who started ART with a boosted protease inhibitor (PI/r)-, a non-nucleoside reverse transcriptase inhibitor (NNRTI)- or an integrase inhibitor (InSTI)-based triple regimen, or a regimen with more than three drugs. RV was defined as any detectable polymerase chain reaction (PCR) signal <50 HIV-RNA copies/mL, as assessed by kinetic PCR or Abbott real-time PCR. The percentage of time spent with RV (%RV) was calculated as the cumulative follow-up time spent with RV on the observed follow-up, and was estimated using a generalized linear model. Results: Seven hundred and seventy-one patients (33%, 32%, 30% and 5% receiving PI/r-, NNRTI-, InSTI-based triple regimens, or a regimen with more than three drugs, respectively) were included in the analysis. After a median of 2.16 (interquartile range 1.27–3.16) years of follow-up, adjusted means of %RV were 37.9% [95% confidence interval (CI) 30.3–45.4%], 23.9% (95% CI 16–31.8%), 25.3% (95% CI 17.8–32.7%) and 45.5% (95% CI 34.6–56.4%) in the PI/r, NNRTI, InSTI and more than three drugs groups, respectively; %RV was significantly higher in patients who started ART with a regimen with more than three drugs (P=0.030), and was significantly lower in patients who started ART with an NNRTI-based regimen (P<0.0001) or an InSTI-based regimen (P=0.030) than in those who started ART with a PI/r-based regimen. %RV was independently associated with pre-ART HIV-RNA (P<0.0001), time to HIV-RNA <50 copies/mL (P<0.0001), NRTI backbone (P=0.037) and baseline HIV-RNA (P<0.0001). Conclusion: First-line regimens based on PIs/r or on more than three drugs are associated with a greater percentage of time spent with RV after achieving virological suppression.