Nocturnal Hypoxemia Associates With Symptom Progression and Mortality in Patients With Progressive Fibrotic Interstitial Lung Disease.

BACKGROUND: OSA and nocturnal hypoxemia (NH) are common in patients with fibrotic interstitial lung disease (F-ILD), but their relationship with disease outcomes remains unclear.

RESEARCH QUESTION: What is the relationship between NH and OSA and clinical outcomes in patients with F-ILD?

STUDY DESIGN AND METHODS: This was a prospective observational cohort study of patients with F-ILD and without daytime hypoxemia. Patients underwent home sleep study at baseline and were followed up for at least 1 year or until death. NH was defined as ≥ 10% of sleep with oxygen saturation of < 90%. OSA was defined as an apnea-hypopnea index of ≥ 15 events/h.

RESULTS: Among 102 participants (male, 74.5%; age, 73.0 ± 8.7 years; FVC, 2.74 ± 0.78 L; 91.1% idiopathic pulmonary fibrosis), 20 patients (19.6%) demonstrated prolonged NH and 32 patients (31.4%) showed OSA. No significant differences were found between those with and without NH or OSA at baseline. Despite this, NH was associated with a more rapid decline in both quality of life as measured by the King's Brief Interstitial Lung Disease questionnaire (change, -11.3 ± 5.3 points in the NH group vs -6.7 ± 6.5 in those without NH; P = .005) and higher all-cause mortality at 1 year (hazard ratio, 8.21; 95% CI, 2.40-28.1; P < .001). No statistically significant difference was seen between the groups in annualized change in measures of pulmonary function testing.

INTERPRETATION: Prolonged NH, but not OSA, is associated with worsening disease-related quality of life and increased mortality in patients with F-ILD.