Sleep-disordered breathing and idiopathic pulmonary fibrosis--is there an association?

Background: Very little data exists on the prevalence and impact of sleep-disordered breathing (SDB) in patients with idiopathic pulmonary fibrosis (IPF). The aim of this study was to examine the impact of SDB on newly diagnosed IPF patients and explore associations with lung function parameters.
Methods: From 2005 to 2009, a cohort of 27 newly diagnosed patients with IPF underwent unattended polygraphy. All patients were diagnosed according to ATS 2000 diagnostic criteria and were not on supplemental oxygen or other treatment. Standard statistical analysis was undertaken using SPSS v. 19 (IBM).
Results: Of the 27 patients, 19 were men. There was no correlation at baseline of apnoea + hypopnoea per time in bed (AH), oxygen desaturation index, or 4% desaturations with any lung function variables, age, or body mass index. Six patients had significant SDB (AH >20). Two patients were started on CPAP following polygraphy. No variables from the original sleep studies at baseline predicted eventual long-term oxygen therapy (LTOT) use. At 5-year follow-up, 18 of 27 patients had died (67%). Cox regression analysis showed no association of time spent at SpO2 <90% on baseline polygraphy with survival (p = 0.39). There was no association with survival for AH >20 (p = 0.4) or LTOT use (p = 0.19).
Conclusion: Our results do not support the contention that nocturnal upper airway obstruction in steroid-free patients with IPF is a common problem or correlated with lung function. In this cohort of patients, there was no evidence that significant SDB at baseline was a predictor of survival.