A Randomized Study on the Effect of Weight Loss on Obstructive Sleep Apnea Among Obese Patients With Type 2 DiabetesThe Sleep AHEAD StudyEffect of Weight Loss on Obstructive Sleep Apnea

Abstract

Weight loss is frequently recommended to improve obstructive sleep apnea (OSA) among obese patients, yet the empirical support for this recommendation is weak.^1,2 Descriptive studies have assessed the apnea-hypopnea index (AHI) before and after weight loss, although most have examined the effects of surgically induced weight loss.³ The existing studies are limited by small samples (N = 8-26 participants), short durations (≤6 months), predominantly male samples (90%), and the lack of comparison groups that do not lose weight.³ One nonrandomized study of 23 participants with a mean (SD) AHI of 55 (8) events per hour and a mean (SD) weight of 112 (7) kg found that the AHI was reduced by 46% in those individuals who had lost 10% of initial weight, while those who were weight stable demonstrated no change in AHI.⁴ The only randomized study to date was among 72 predominantly male patients with mild apnea (AHI, 5-15) who weighed approximately 97 kg. An 11-kg weight loss reduced the risk of OSA by 76% relative to the control group, which lost 2 kg.⁵ Epidemiological studies have shown that weight loss reduced the AHI and weight gain increased the AHI, but very few participants in those cohorts had OSA or lost clinically significant amounts of weight.^6,7 Therefore, there are few studies indicating whether the amount of weight loss (10%) recommended by expert and government panels is sufficient to improve OSA.⁸ Such data are necessary to help physicians and their patients understand the expected benefits of weight loss in the management of OSA.