Predictors of compliance with continuous positive airway pressure treatment in patients with obstructive sleep apnea and metabolic syndrome

Objective: Continuous positive airway pressure (CPAP) applied via a tight-fitting mask is the most effective treatment for obstructive sleep apnea (OSA) and has potential to improve the cardiovascular prognosis in such patients. Adequate compliance with the use of CPAP is essential for achieving the cardiovascular and metabolic benefits of this treatment. This prospective study aimed to assess factors related to objective compliance with CPAP treatment in Slovakian patients with metabolic syndrome and newly diagnosed OSA. Patients and methods: Fifty-one patients (42 men) with metabolic syndrome and OSA (mean age, 54.5 +/- 1.5 years; mean apnea-hypopnea index 59.0 +/- 3.9 events/h of sleep; mean lowest sleep transcutaneous oxygen saturation [SpO(2)] 66.0 +/- 2.7%) underwent pressure titration during overnight polysomnography using the Autoset self-adjusting CPAP device. Metabolic syndrome was diagnosed according to the recent definition of the International Diabetes Federation. Objective compliance was assessed electronically at the 8-week follow-up visit. Results: Obesity was present in all (100%) the patients and arterial hypertension in 48 (94%); fasting plasma glucose levels were increased in 27 (55%) patients and serum triglycerides in 36 (71%); serum HDL cholesterol was reduced in 30 (59%) patients. Two patients did not use CPAP at all and were excluded from further analyses. The remaining 49 patients were divided into two groups: CPAP compliant (>= 4 h/night, mean use 5.52 +/- 0.19 h/night, n = 30) and CPAP non-compliant (<4 h/night; mean use 1.94 +/- 0.27 h/night, n = 19). Mask leak was significantly higher in the non-compliant patients (43.0 +/- 4.4 vs. 31.9 +/- 2.7 l/min, P = 0.027). No relationships were observed between CPAP compliance and age, apnea-hypopnea index, arousal index or variables of sleep architecture. In contrast, CPAP compliance was significantly related to mean sleep SpO(2) (r = 0.314, P = 0.028), the lowest sleep SpO(2) (r = 0.297, P = 0.038) and mask leak (r = -0.376, P = 0.008). A close relationship between BMI and mask leak was also observed (r = 0.579, P < 0.001). In multiple linear regression analyses with CPAP compliance as an independent variable, and age, sex, mask leak, BMI and mean sleep SpO(2) as dependent variables, mask leak was the only independent predictor of CPAP compliance (R-2 = 0.382, P = 0.009). Conclusion: The study demonstrates the relationship between reductions in mask leak and good compliance with CPAP treatment in central European patients with OSA and concurrent metabolic syndrome. Strategies to maintain low leakage of the CPAP mask are warranted, particularly in grossly overweight patients.