In 18 adults with obesity and obstructive sleep apnea who completed both sleep studies, Roux-en-Y gastric bypass reduced weight from 104.4 to 68.5 kg and BMI from 38.8 to 25.8 kg/m². The apnea-hypopnea index fell from 23.7 to 8.7 events/h, a mean drop of 15 events/h (95% CI 11.2-18.7). Even so, 15 of 18 participants (83%) still had an AHI of 5 or higher about six months after surgery. Upper-airway findings, sleepiness, and quality-of-life measures also improved.
The pattern fits the broader bariatric literature: surgery produces large, reliable reductions in apnea severity, but 'improved' is not 'cured.' Earlier meta-analyses reported similar results, with mean AHI falling roughly 60 percent while most patients retained some residual disease. Here the finding is sharpened by the fact that BMI reached the normal range, so persistent apnea likely reflects anatomy, such as craniofacial structure or pharyngeal collapsibility, rather than leftover weight alone. The practical message for adults is clear: patients should not stop CPAP or other therapy on the assumption that weight loss fixed the problem, and a repeat sleep study after surgery is worth requesting.
Limitations are substantial. The cohort is tiny, with only 18 of 33 assessed patients completing objective follow-up, which invites attrition bias, since those who felt better or worse may have differed in returning. There is no control group, follow-up is short, and weight regain could erode gains later. Confirmatory rather than paradigm-shifting, but a useful caution against over-promising remission.