HIV drug therapy duration; a Swedish real world nationwide cohort study on InfCareHIV 2009-2014

BACKGROUND As HIV infection needs a lifelong treatment, studying drug therapy duration and factors influencing treatment durability is crucial. The Swedish database InfCareHIV includes high quality data from more than 99% of all patients diagnosed with HIV infection in Sweden and provides a unique opportunity to examine outcomes in a nationwide real world cohort. METHODS Adult patients who started a new therapy defined as a new 3rd agent (all antiretrovirals that are not N[t]RTIs) 2009-2014 with more than 100 observations in treatment-naive or treatment-experienced patients were included. Dolutegravir was excluded due to short follow up period. Multivariate Cox proportional hazards models were used to estimate hazard ratios for treatment discontinuation. RESULTS In treatment-naïve 2541 patients started 2583 episodes of treatments with a 3rd agent. Efavirenz was most commonly used (n = 1096) followed by darunavir (n = 504), atazanavir (n = 386), lopinavir (n = 292), rilpivirine (n = 156) and raltegravir (n = 149). In comparison with efavirenz, patients on rilpivirine were least likely to discontinue treatment (adjusted HR 0.33; 95% CI 0.20-0.54, p<0.001), while patients on lopinavir were most likely to discontinue treatment (adjusted HR 2.80; 95% CI 2.30-3.40, p<0.001). Also raltegravir was associated with early treatment discontinuation (adjusted HR 1.47; 95% CI 1.12-1.92, p = 0.005). The adjusted HR for atazanavir and darunavir were not significantly different from efavirenz. In treatment-experienced 2991 patients started 4552 episodes of treatments with a 3rd agent. Darunavir was most commonly used (n = 1285), followed by atazanavir (n = 806), efavirenz (n = 694), raltegravir (n = 622), rilpivirine (n = 592), lopinavir (n = 291) and etravirine (n = 262). Compared to darunavir all other drugs except for rilpivirine (HR 0.66; 95% CI 0.52-0.83, p<0.001) had higher risk for discontinuation in the multivariate adjusted analyses; atazanavir (HR 1.71; 95% CI 1.48-1.97, p<0.001), efavirenz (HR 1.86; 95% CI 1.59-2.17, p<0.001), raltegravir (HR 1.35; 95% CI 1.15-1.58, p<0.001), lopinavir (HR 3.58; 95% CI 3.02-4.25, p<0.001) and etravirine (HR 1.61; 95% CI 1.31-1.98, p<0.001).Besides the 3rd agent chosen also certain baseline characteristics of patients were independently associated with differences in treatment duration. In naive patients, presence of an AIDS-defining diagnosis and the use of other backbone than TDF/FTC or ABC/3TC increased the risk for early treatment discontinuation. In treatment-experienced patients, detectable plasma viral load at the time of switch or being highly treatment experienced increased the risk for early treatment discontinuation. CONCLUSIONS Treatment durability is dependent on several factors among others patient characteristics and ART guidelines. The choice of 3rd agent has a strong impact and significant differences between different drugs on treatment duration exist.