580. Key Factors for Treatment Changes Within 1 Year After Starting ART in the German ClinSurv Cohort: Between 2005 and 2014

BACKGROUND: Initiation of combined antiretroviral therapy (cART) has markedly increased survival and quality of life in HIV-infected patients. With the advent of new treatment options, including an increasing number of single-tablets, the durability of first-line ART regimes is developing. METHODS: We used data from the prospective multicenter German Clinical Surveillance of HIV Disease (ClinSurv) cohort of the Robert-Koch-Institute. Time to event was calculated as time between initiation of first-line cART and therapy change. We used a Cox model to assess predictors of treatment change 1 year after starting cART. RESULTS: We included 6,894 patients who initiated ART between 2005 and 2014. The sample population was predominantly men (79%) with German origin (69.8%), of which 49.6% were reporting sex with men (MSM) as main risk factor. Median age (IQR) was 38 (31–46) years. The most frequently treatment combinations were 2NRTI/PIr (48.1%) and 2NRTI/1NNRTI (42.2%), 2NRTI/1II (5.2%). 22.6% patients changed their first-line treatment within 1 year. Median (IQR) length between first intake and stop of the regime was 105 (35–214) days, which did not change significantly between 2005 (108; 38–217) and 2014 (128; 74–200) (P = 0.28). Most common documented causes were side effects of drugs 418 (44.0%) and non-adherence 173 (18.2%). In the Cox model (Figure 1), we identified numerous covariates associated with discontinuation of the first-line regime. A 2NRTI/1NNRTI regime was associated with higher rates (hazard ratio [HR] 1.28, 95% CI 1.06–1.55) and a 2NRTI/1II regime with lower rates (HR 0.34, 95% CI 0.23–0.51) of treatment modification (ref.: 2NRTI/1PIr). The HR increased markedly with the amount of daily-administered tablets from HR 2.15, 95% CI 1.48–3.11 (2–3 tablets) to HR 3.98, 95% CI 2.16–7.31 (10 tablets) (ref.: one tablet). We observed an association with a baseline viral load (VL) of >100 copies/mL (HR 0.65, 95% CI 0.53–0.81) and >100.000 copies/mL (HR 0.68, 95% CI 0.54–0.85) (ref.: VL > 1 Mio. copies/mL). CONCLUSION: Our analysis revealed, that side effects of drugs, the number of tablets per day and the VL at baseline are significantly associated with treatment change within the first year. A first-line regime with 2NRTI/1II seems to improve the adherence to the initial regime significantly. [Image: see text] DISCLOSURES: All authors: No reported disclosures.