Sleep Oxygen Desaturation Predicts Survival in Idiopathic Pulmonary Fibrosis
1Second Pulmonary Department, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece; 2Seventh Pulmonary Department, Sotiria Hospital for Chest Diseases, Athens, Greece; 3First Department of Respiratory Diseases, Sotiria Hospital for Chest Diseases, Medical School, National and Kapodistrian University of Athens, Athens, Greece; 4Sixth Pulmonary Department, Sotiria Hospital for Chest Diseases, Athens, Greece; 5Genomics and Proteomics Research Units, Center of Basic Research II, Biomedical Research Foundation, Academy of Athens, Athens, Greece
Recent studies suggest poor sleep quality in patients with idiopathic pulmonary fibrosis (IPF). However, so far, the impact of IPF-related sleep breathing disorders (SBDs) on survival has not been extensively studied.
In a cohort of 31 (24 males) treatment-naïve, newly diagnosed consecutive IPF patients, we prospectively investigated the relationship of SBD parameters such as apnea-hypopnea index (AHI), maximal difference in oxygen saturation between wakefulness and sleep (maxdiff SpO2), and lowest sleep oxygen saturation (lowest SpO2) with clinical (survival, dyspnea, daytime sleepiness), pulmonary function, submaximal (6-min walk test [6MWT]) and maximal exercise variables (cardiopulmonary exercise test [CPET]), and right ventricular systolic pressure (RVSP).
Sleep oxygen desaturation exceeded significantly that of maximal exercise (p < 0.001). Maxdiff SpO2 was inversely related to survival, DLCO%, and SpO2 after 6MWT, and directly with dyspnea, AHI, and RVSP. The lowest SpO2 was directly related to survival and to functional (TLC%, DLCO%) as well as submaximal and maximal exercise variables (6MWT distance, SpO2 after 6MWT, peak oxygen consumption/kg, SpO2 at peak exercise), while an inverse association with dyspnea score, AHI, and RVSP was observed.
Our findings provide evidence that intermittent sleep oxygen desaturation significantly exceeds that of maximal exercise and is associated with survival in IPF patients. Furthermore, they imply the existence of a link between lung damage and apnea events resulting to the induction and severity of intermittent sleep oxygen desaturation that aggravate pulmonary arterial hypertension and influence IPF survival.
A commentary on this article appears in this issue on page
Kolilekas L; Manali E; Vlami KA; Lyberopoulos P; Triantafillidou C; Kagouridis K; Baou K; Gyftopoulos S; Vougas KN; Karakatsani A; Alchanatis M; Papiris S. Sleep oxygen desaturation predicts survival in idiopathic pulmonary fibrosis. J Clin Sleep Med 2013;9(6):593-601.
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