LAUSR

BACKGROUND Obstructive sleep apnea (OSA), a common co-morbidity in ILD, could contribute to a worsened course if untreated. It is unclear if adherence to CPAP therapy improves outcomes. METHODS We conducted a ten-year retrospective observational multicenter cohort study, assessing adult patients with ILD who had undergone polysomnography. Subjects were categorized based on OSA severity into 'no/mild OSA' (AHI <15) or 'moderate/severe OSA' (AHI ≥15). All subjects prescribed and adherent to CPAP were deemed to have 'treated OSA'. Cox regression models were used to examine the association of OSA severity and CPAP adherence with all-cause mortality risk and progression-free survival (PFS). RESULTS Of 160 subjects that met inclusion criteria, 131 had OSA and were prescribed CPAP. 66 patients (41%) had no/mild untreated OSA, 51 (32%) had moderate/severe untreated OSA, and 43 (27%) had treated OSA. Subjects with no/mild untreated OSA did not differ from those with moderate/severe untreated OSA in mean survival time (127±56 months vs 138±93 months; P=0.61) and crude mortality rate (2.9/100 person-years vs 2.9/100 person-years; P=0.60). Adherence to CPAP was not associated with improvement in all-cause mortality risk (HR, 1.1; 95% CI=0.4-2.9; P=0.79), or PFS (HR, 0.9; 95% CI=0.5-1.5; P=0.66) compared to those that were non-adherent or untreated. Among subjects requiring supplemental oxygen, those adherent to CPAP had improved PFS (HR, 0.3; 95% CI, 0.1-0.9; P=0.03) compared to non-adherent or untreated subjects. CONCLUSIONS Neither OSA severity nor adherence to CPAP was associated with improved outcomes in ILD patients except those requiring supplemental oxygen.