Results: Fifty subjects enrolled and completed a NPSG. The mean age was 64.9 years, and the mean BMI was 32.3. OSA was diagnosed in 88% of subjects. Ten subjects (20%) had mild OSA (AHI, 5 to 15 events per hour), and 34 subjects (68%) had moderate-to-severe OSA (AHI, > 15 events per hour). Only 6 subjects (12%) had a normal AHI. One patient was asymptomatic as determined by ESS and SA-SDQ, but had an AHI of 24 events per hour. The sensitivity of the ESS was 75% with a specificity of 15%, whereas the SA-SDQ had a sensitivity of 88% with a specificity of 50%. BMI did not correlate strongly with AHI (r ‫؍‬ 0.30; p ‫؍‬ 0.05). Conclusions: OSA is prevalent in patients with IPF and may be underrecognized by primary care providers and specialists. Neither ESS nor SA-SDQ alone or in combination was a strong screening tool. Given the high prevalence found in our sample, formal sleep evaluation and polysomnography should be considered in patients with IPF.(CHEST 2009; 136:772-778)

Rationale: Idiopathic pulmonary fibrosis (IPF) is a rare but devastating disease with no effective therapy. Previous studies have shown that up to 88% of patients with IPF also suffer from obstructive sleep apnea (OSA). We hypothesize that treatment of obstructive sleep apnea will slow disease progression of IPF and improve survival. Methods: A cohort of 32 patients diagnosed with both IPF (by high resolution CT scan according to ATS consensus statement criteria or lung biopsy) and OSA (OSA was defined as an apnea hypopnea index of 5 or greater on polysomnography) were followed for 2-10 years after diagnosis of OSA. Compliance with CPAP therapy was determined by patient report (31%) or smart card data (69%). Patients were followed for length of survival after diagnosis of OSA. Results: Baseline characteristics were similar between both groups. There was no statistically significant difference in age, sex, comorbidities (hypertension, pulmonary hypertension, obesity, type 2 diabetes mellitus, congestive heart failure, coronary artery disease), forced vital capacity at enrollment, or percentage of patients requiring oxygen, between CPAP compliant and non-compliant groups. Kaplan-Meier survival analysis showed a statistically significant difference in survival between the two groups, favoring those who were compliant with CPAP (p<0.03). At five years after diagnosis of OSA 40% of the non-compliant group were still living compared with 90% of those who were compliant with CPAP therapy. Conclusions: In patients with both IPF and OSA, CPAP use may improve survival. Potential mechanisms for this benefit include decreasing gastroesophageal reflux and a decrease in inflammatory cytokine production. Further studies should be directed toward both understanding treatment of OSA in IPF patients and the mechanisms by which OSA may contribute to disease progression. Our study is limited by a small sample size, however the results are striking and should be confirmed in a larger studies. Screening of all IPF patients for OSA is encouraged. Fig. 1 Kaplan-Meier survival analysis of patients with IPF and OSA comparing CPAP compliant to non-compliant patients (p<0.03). Non-lethal events were censored in the analysis. Number at risk table shows number of each patients in analysis after censoring.