Weight changes after initiation of CPAP in sleep apnea patients

Background: obesity is considered a major risk factor of obstructive sleep apnea (OSA). Studies shows that weight loss reduces apnea-hypopnea index (AHI). However there is still a debate if continuous positive airway pressure (CPAP) therapy helps to lose weight or leads to weight gain in sleep apnea patients. Aims: to evaluate weight (body mass index - BMI) changes after 3 and 9 months after CPAP initiation in OSA patients. Methods: prospective study was performed. Patients diagnosed with OSA to whom CPAP therapy was prescribed were included. BMI changes after 3 and 9 months were analyzed. BMI change by 5% was considered as clinically significant. Epworth sleepiness scale (ESS) changes were also analyzed, > 10 points were considered as increased daytime sleepiness. BMI and ESS changes were calculated using paired samples t-test. Results: a total of 119 patients were included (male 75%), mean age 57±10 yrs. Majority of them were diagnosed with severe (83%) OSA with and average AHI 55. BMI at time of diagnosis was 41 ± 8 kg/m2. Almost 60% of patients had ESS ≥10 points. 55 patients returned after 3 months. The average BMI was 40 ± 7 kg/m2. Clinically significant weight loss was seen in 34% of the patients. Majority of the them (62%) had almost the same weight. For 4% of the patients body weight increased. ESS was After 9 months BMI was 40 ± 7 kg/m2 (n = 32). Significant weight loss was registered in 47% of the patients, for 6% of the patients body weight increased, 47% had the same weight. Most of the patients didn`t have daytime sleepiness (84%). Conclusions: in a short time period almost half of OSA patients lost weight after the initiation of CPAP therapy.