Continuous Positive Airway Pressure Unrelated to Weight Gain in Sleep Apnea

man sleeping with CPAP
man sleeping with CPAP
The SAVE study was a multicenter, international clinical trial that tested the efficacy of continuous positive airway pressure and normal care in patients with sleep apnea.

Continuous positive airway pressure (CPAP) has shown no correlation with long-term weight gain among individuals with moderate to severe obstructive sleep apnea, according to a study recently published in CHEST.

This post-hoc analysis included 2483 adults from the Sleep Apnea Cardiovascular Endpoints (SAVE; Identifier: NCT00738179) study, a randomized, multicenter, international clinical trial that tested the efficacy of CPAP and normal care. Of the 2483 participants, 1248 were treated with CPAP and 1235 were controls. Participants in the treatment group had previous cerebrovascular or cardiovascular events as well as obstructive sleep apnea ranging from moderate to severe. Follow-up lasted a mean of 3.78 years.

Participants were assessed for waist and neck circumference, body mass index, and weight at the study’s initiation and throughout follow-up. Temporal differences that varied by sex were investigated using linear mixed models, while those who used CPAP for ≥4 hours per night were compared with controls using a sensitivity analysis. The apnea-hypopnea index, mean and lowest nocturnal oxygen saturation, and oxygen desaturation index were recorded for those with obstructive sleep apnea.

The difference in weight change between treatment and control groups was not significant, with men showing a 0.07-kg difference (95% CI, –0.40 to 0.54; P =.773) and women showing a –0.14-kg difference (95% CI, –0.37 to 0.09; P =.233). Body mass index and anthropometric measures also did not vary between treatment and control groups.

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More weight loss occurred in participants who were older (P <.001), heavier at baseline (P <.001), and underwent the study in either India (P =.007) or China (P <.001) vs Australia. A statistically significant difference was present among men using CPAP for ≥4 hours per night, who gained a mean of 0.38 kg (95% CI, 0.04-0.73; P =.031) more than controls. However, this difference was not present in women.

The researchers concluded that “patients with moderate-severe [obstructive sleep apnea] and co-existing cardiac or cerebrovascular disease had no significant changes in [body mass index], neck or waist circumferences from the use of CPAP over several years. We found no evidence that patients with moderate-severe [obstructive sleep apnea] and co-existing [cardiovascular] disease are susceptible to clinically concerning long-term weight change from the use of CPAP therapy.”

Disclosures: Several authors disclose fees and equipment from companies specializing in sleep respiratory products. For a full list of disclosures, visit the reference.


Ou Q, Chen B, Loffler KA, et al; on behalf of the SAVE investigators. The effects of long-term CPAP on weight change in patients with co-morbid OSA and cardiovascular disease: data from the SAVE trial [published online September 27, 2018]. CHEST. doi:10.1016/j.chest.2018.08.1082