Relationship between weight gain and insulin resistance in people living with HIV switching to INSTI-based regimens

Objective: The primary objective was to explore weight and BMI changes in people with HIV (PWH) undergoing integrase strand transfer inhibitors (INSTI)-based regimens (vs. non-INSTI) in a large cohort and in the subsets of individuals without diabetes and insulin resistance (IR) at the time of switch to INSTI. The secondary objective was to identify risk factors for IR and cut-off of weight or BMI increase associated with IR in PWH switching to INSTI. Design: A longitudinal matched-cohort study including PWH attending Modena HIV Metabolic Clinic, Italy. Methods: PWH were divided into two groups: non-INSTI and INSTI-switch. The effect of switching to INSTI on weight and BMI change was tested through a linear mixed model. A mediation analysis explored the mediation effect of weight and BMI change in the association between the switch to INSTI and IR. Results: We analyzed 2437 PWH (1025 INSTI-switch, 1412 non-INSTI), in 54 826 weight assessments. Trends for weight increase were significantly higher in early-INSTI-switch (vs. early-non-INSTI), but no difference was observed in the late period after the switch. In the subset of 634 PWH without IR, switching to INSTI (vs. non-INSTI) was associated with a lower risk of IR (hazard ratio = 0.70, 95% confidence interval: 0.51, 0.98). A weight increase by 1% reduced the total protective effect of INSTI by 21.1% over 1 year of follow-up, which identifies a 5% weight increase as a clinically meaningful weight gain definition. Conclusion: A cut-off of 5% weight gain from the time of INSTI-switch is associated with IR, which may be a clinically meaningful endpoint to could be used in clinical and research settings.