Factors influencing adherence to continuous positive airway pressure treatment in obstructive sleep apnea and mortality associated with treatment failure - a national registry-based cohort study

Objectives: Adherence to continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea (OSA) is crucial. Our aim was to identify protective and risk factors against the discontinuation of CPAP treatment in patients with OSA and to estimate the mortality risk in those who were non-adherent to CPAP therapy. Methods: This was a registry-based cohort study from 37 centers across Sweden with OSA patients on CPAP in the Swedevox Swedish national registry between July 2010 and March 2017. Results: In 16,425 patients (70.8% men) with complete follow-up data after 1.2 +/- 0.8 years the adjusted relative risk ratio (aRRR) for the discontinuation of CPAP was 0.57 (95% confidence interval (CI) 0.50-0.65) for use of humidifier, 0.87 (95% CI 0.82-0.92) for increasing age per 10 years, 0.80 (95% CI 0.77-0.83) for increasing apnea hypopnea index (AHI) per 5 units/hour, and 0.96 (95% CI 0.95-0.97) per increased unit on the Epworth Sleepiness Scale (ESS). Increasing BMI was associated with increased adherence up to BMI 35. Women and patients with hypertension ran an increased risk of discontinuing CPAP treatment, aRRR 1.28 (95% CI 1.12-1.46) and 1.24 (95% CI 1.12-1.42) respectively. The adjusted hazard ratio (HR) for mortality was 1.74 (95% CI 1.32-2.28) among those who did not adhere to CPAP (median follow-up period 2.4 years after the one year adherence evaluation). Conclusion: Use of humidifier is associated with greater adherence to CPAP treatment. Other factors predicting adherence are increasing age, more severe OSA and overweight up to BMI 35, whereas female gender and coexisting hypertension are risk factors for discontinuation of CPAP. Failure to adhere to CPAP is associated with increased mortality. (C) 2018 Elsevier B.V. All rights reserved.