Baseline predictors of adherence to positive airway pressure therapy for sleep apnea: a 10-year single-center observational cohort study.

BACKGROUND

Positive airway pressure (PAP) therapy is the standard treatment for obstructive sleep apnea syndrome (OSAS).

OBJECTIVES

The aim of the current study was to determine operational long-term adherence to PAP and its predictors.

METHODS

In a retrospective single-center observational cohort study, we analyzed all patients referred to our center with suspected OSAS between November 2001 and November 2011. Baseline results and last follow-up data of each patient were analyzed. Kaplan-Meier estimates of adherence and Cox proportional hazard regression for age, gender, Epworth sleepiness scale (ESS) scores, body mass index, apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were performed. Evolution of adherence was analyzed in yearly cohorts comparing the proportion of patients discontinuing PAP within 6 and 12 months.

RESULTS

Of 4,638 referrals, 2,187 confirmed OSAS patients started PAP, 297 (14%) were referred out to other centers to follow-up, 42 (2%) died, and 92 (5%) no longer needed PAP. Of 1,756 patients, the median follow-up was 36 months [95% confidence interval (CI) 33.6-37.8], and adherence at 1, 5 and 10 years was 74 (CI 71-75; n = 1,028), 55 (CI 53-58; n = 281) and 51% (CI 48-55; n = 10), respectively. Adherence is associated with ESS score [hazard ratio (HR) 0.60; CI 0.47-0.78], ODI (HR 0.50; CI 0.32-0.77) and AHI (HR 0.56; CI 0.37-0.85). In yearly cohorts according to inclusion date, the absconder rate at 6 and 12 months was 20 (CI 18-22) and 27% (CI 25-30) for the first 8 years and improved to 10 (CI 7-15) and 14% (CI 10-19) for the last 2 years, respectively.

CONCLUSIONS

Long-term adherence to PAP in OSAS is associated with baseline measures of disease severity. After 2009, an improvement in the adherence rate was observed.