title: Sleep oxygen desaturation predicts survival in idiopathic pulmonary fibrosis.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Second Pulmonary Department, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Likurgos
authors.initials: L
authors.lastname: Kolilekas
authors.forename: Effrosyni
authors.initials: E
authors.lastname: Manali
authors.forename: Katerina A
authors.initials: KA
authors.lastname: Vlami
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Lyberopoulos
authors.forename: Christina
authors.initials: C
authors.lastname: Triantafillidou
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kagouridis
authors.forename: Katerina
authors.initials: K
authors.lastname: Baou
authors.forename: Sotirios
authors.initials: S
authors.lastname: Gyftopoulos
authors.forename: Konstantinos N
authors.initials: KN
authors.lastname: Vougas
authors.forename: Anna
authors.initials: A
authors.lastname: Karakatsani
authors.forename: Manos
authors.initials: M
authors.lastname: Alchanatis
authors.forename: Spyros
authors.initials: S
authors.lastname: Papiris
mesh_terms: D000368:Aged; D015897:Comorbidity; D018450:Disease Progression; D004417:Dyspnea / Q000453:epidemiology; D017079:Exercise Tolerance; D005260:Female; D006115:Greece / Q000453:epidemiology; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000453:epidemiology* / Q000401:mortality; D053208:Kaplan-Meier Estimate; D016013:Likelihood Functions; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D011446:Prospective Studies; D012891:Sleep Apnea Syndromes / Q000453:epidemiology*; D015996:Survival Rate
chemical_list: D010100:Oxygen
keywords: Idiopathic pulmonary fibrosis; exercise limitation and testing; sleep disordered breathing; sleep oxygen desaturation; survival