Abstract
Background and aim
Studies addressing the burden of sleep-related breathing disorders (SRBD) and evaluating polysomnography data in patients with idiopathic pulmonary fibrosis (IPF) are scarce. This work aims to illuminate the prevalence of SRBD in IPF patients, explore the effect of IPF on polysomnographic variables, and to identify the possible associations with air trapping and obesity.
Patients and methods
Institutional Review Board approval and formal patients' consent were obtained from 39 patients enrolled in the study. Twenty patients were confirmed as IPF cases and 19 normal age-matched and sex-matched controls. Overnight polysomnography was performed to all patients. Pulmonary function test and high-resolution computed tomography were done for IPF cases.
Results
Half of IPF patients suffered from obstructive sleep apnea. Sleep efficiency, minimum SpO(2), and baseline O-2 saturation were significantly lower among IPF cases compared with controls (P< 0.05), whereas apnea-hypopnea index, respiratory disturbance index, number desaturations less than 90, SpO(2) time less than 90, average circulatory delay, arousal total rapid eye movement, and pulse transit time were significantly higher among IPF cases compared with controls (P< 0.05). IPF patients with air trapping showed significantly higher baseline O-2 saturation and average circulatory delay compared with patients without air trapping (P< 0.05). Significant positive correlations were observed in IPF patients between PaCO2 and both number desaturations less than 90% (r=0.655) and arousal total rapid eye movement (r=0.464). In contrast, significant negative correlations were observed between forced vital capacity% and average circulatory delay (r=-0.568) as well as forced vital capacity and apnea-hypopnea index (r=-0.430). Nonsignificant differences were observed between nonobese and obese IPF patients in polysomnography variables.
Conclusion
SRBD is of high prevalence in IPF patients and obesity is an insignificant comorbidity. Air trapping is surprisingly beneficial in IPF patients by maintaining oxygen saturation during sleep. Detection and proper treatment of comorbid SRBD may improve the natural course of this fatal illness.