PURPOSE: Obesity is causally linked to OSA. Weight change after treatment with CPAP is not clear. Although hormonal changes would predict weight loss, decreasing energy expenditure (EE) by reducing work of breathing would predict weight gain. We hypothesize that weight may increase in OSA patients after starting CPAP. The purpose of the study was to determine weight change associated with CPAP therapy.
METHODS: We conducted a retrospective chart-review of a clinical cohort of veterans diagnosed with OSA and treated with CPAP from January - May 2005. OSA was defined as apnea hypopnea index ≥5 (Medicare definition). We reviewed the electronic medical records for baseline data, sleep apnea severity, weight, blood pressure (BP) and blood glucose (BG) before and after initiation of CPAP. We excluded patients who had prior CPAP treatment; central sleep apnea; head and neck deformity; immunosuppression; malignancy; bariatric surgery; and death. We determined changes in weight, BP and BG over a 3 year period after initiating CPAP treatment.
RESULTS: A total of 61 patients met inclusion criteria (58 males, 3 females). Mean (SD) age was 63.8 (9.9) years. Mean (SD) weight at the time of study was 114 (25.7) kg. Mean (SD) weights at 6 months, 1 year, 2 years and 3 years after CPAP initiation were 115.6 (28.4), 115.7 (27.0), 116.6 (25.5), and 117.3 (25.5) kg respectively. There was a trend towards weight gain at 1 year (p=0.06) after CPAP initiation and a statistically significant weight gain at 2 years compared to baseline (p = 0.02). 64% of patients gained a mean of 4.9 kg. In multivariate analysis,age (p=0.03) was the only predictor for weight gain . No statistically significant change in BP and BG was seen.
CONCLUSIONS: CPAP therapy was associated with weight gain at 2 years in a cohort of predominantly older male patients with OSA.
CLINICAL IMPLICATIONS: We found weight gain after OSA treatment with CPAP. Weight gain is likely due to reduction in EE. Further prospective studies assessing weight change with CPAP and its underlying mechanisms are needed.
DISCLOSURE: The following authors have nothing to disclose: Amarbir Mattewal, Supriya Singh, Max Hirshkowitz, Amir Sharafkhaneh
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