Association between early body weight reduction and treatment outcomes in participants with obstructive sleep apnoea and obesity: a post hoc analysis of SURMOUNT-OSA trials

Background Obesity is a major modifiable risk factor for obstructive sleep apnoea (OSA). Although previous studies have demonstrated that greater weight reduction is associated with larger decreases in apnoea-hypopnoea index (AHI) and improvements in cardiometabolic outcomes, the significance of early weight reduction is not fully understood. Methods We conducted a post hoc analysis of the SURMOUNT-OSA randomised trials (ClinicalTrials.gov, NCT05412004), which included 469 participants. Participants were divided by the percent of weight reduction at week 20: <5%, ≥5% to <10%, ≥10% to <15%, and ≥15%. The key endpoint was the change in AHI from baseline to week 52. Findings Participants who achieved ≥15% body weight reduction at week 20 demonstrated significantly greater AHI improvement at week 52 compared to those who achieved <5% weight reduction (p < 0·001), and the magnitude of AHI changes at week 52 was associated with greater early weight reduction in both trials. Participants in the ≥15% weight reduction group also had higher rates of clinically meaningful AHI reduction (≥50%), OSA remission, and greater improvements in sleep apnoea specific hypoxic burden, body weight, and cardiometabolic factors at week 52. Greater weight reduction at week 20 was associated with improvements in sleep apnoea-specific hypoxic burden, body weight, and cardiometabolic risk factors at week 52 in both trials. Interpretation These findings indicate that early substantial weight reduction (≥15%) is associated with sustained improvements in OSA and related cardiometabolic outcomes, supporting early weight management as a key therapeutic strategy for OSA, regardless of positive airway pressure therapy use. Funding The study was funded by Eli Lilly and Company.