Air Leak is Associated with Poor Adherence to Autopap Therapy

STUDY OBJECTIVES: To our knowledge, a systematic study of the effect of air leak on adherence to auto-titrating positive airway pressure (autoPAP) therapy has not been reported. We hypothesized that in patients with obstructive sleep apnea (OSA), greater levels of air leak were associated with poor adherence to autoPAP therapy. DESIGN: Retrospective cohort study SETTING: Academic Center PARTICIPANTS: Ninety-six consecutive patients with high probability for OSA. INTERVENTIONS: N/A. MEASUREMENTS: Patients with OSA received 1 week of autoPAP therapy following which both adherence data and air leak information was downloaded from the device. Continuous positive airway pressure (CPAP) therapy was issued for a 5-week period with pressure determined by 90th percentile of that delivered during autoPAP therapy. Adequate adherence was defined as average usage > 4 h per night on all nights. RESULTS: Forty-three patients were adherent to autoPAP therapy (350 ± 67SD min/day), whereas 53 patients were not (122 ± 65 min/day; P < 0.0001). Air leak that was adjusted for pressure delivered was greater in non-adherent patients (7.0 ± 3.5 L/min/cm H(2)O) than that in adherent patients (4.9 ± 1.7 L/min/cm H(2)O; P < 0.0001). Greater residual respiratory events (measured as autoPAP-derived hypopnea index) and proportion of time spent at large leak levels were associated with non-adherence. Patients who were adherent to autoPAP therapy received higher average therapeutic pressures from the autoPAP device than non-adherent patients. Multivariate logistic regression revealed that higher levels of air leak were associated with non-adherence to autoPAP therapy (odds ratio 1.43; 95% CI, 1.03, 1.98; P = 0.03). Moreover, adherence to autoPAP therapy was strongly correlated with subsequent adherence to CPAP therapy (R(2) = 0.74; P < 0.0001). CONCLUSION: Air leak was associated with poor adherence to autoPAP therapy. We speculate that air leak could be a potential target for future studies aimed at enhancing adherence to autoPAP therapy.