Weight changes after antiretroviral therapy initiation in CoRIS (Spain): a prospective multicentre cohort study

Introduction Weight gain after starting antiretroviral therapy (ART) is a major problem that can increase morbidity. Our main objective was to evaluate the effects of initial ART on weight change in a large prospective cohort of HIV‐positive individuals. Methods This was a prospective cohort study of 13,198 subjects included in the Spanish HIV Research Network (CoRIS) between January 2004 and November 2018. We included subjects who started triple ART and achieved HIV RNA suppression within 48 weeks. We fitted linear mixed models adjusted for potential confounders to compare longitudinal changes in weight. We used Cox proportional‐hazard models to compare treatment groups’ times to transition to a higher body mass index (BMI) category. Results We analysed data from a total of 1631 individuals resulting in 14,965 persons/years and 14,085 observations. Individuals retained in the final multivariable model were representative of the overall cohort. NNRTI‐based first‐line ART was associated with a lower average weight gain compared to PI‐ (+0.7 kg per year, 95% CI 0.5 to 1.0, p