Chest
Volume 136, Issue 3, September 2009, Pages 772-778
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Original Research
Sleep Medicine
Obstructive Sleep Apnea Is Common in Idiopathic Pulmonary Fibrosis

https://doi.org/10.1378/chest.08-2776Get rights and content

Background

From 1984 to 2006, studies of sleep in patients with interstitial lung disease revealed disturbed sleep, frequent nocturnal desaturations, nocturnal cough, and obstructive sleep apnea (OSA). Our goal was to analyze OSA in an outpatient population of stable patients with idiopathic pulmonary fibrosis (IPF).

Methods

Patients with IPF who had been followed up in the Vanderbilt Pulmonary Clinic were asked to participate. All patients were given a diagnosis of IPF by the 2000 American Thoracic Society consensus statement criteria. Subjects completed an Epworth sleepiness scale (ESS) questionnaire and a sleep apnea scale of sleep disorders questionnaire (SA-SDQ) before undergoing nocturnal polysomnography (NPSG). OSA was defined as an apnea-hypopnea index (AHI) of > 5 events per hour.

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.

Section snippets

Subjects

This study was approved by the Vanderbilt Institutional Review Board. Sixty-eight subjects visiting the Vanderbilt Pulmonary Clinic for the follow-up of IPF between August 2006 and February 2008 who met study criteria were asked to participate. The study criteria included the following: age > 18 years; ability to provide informed consent; stable dyspnea; and a confirmed diagnosis of IPF by the American Thoracic Society 2000 consensus statement criteria.8 To include an unbiased representative

Results

Forty-four of 50 subjects (88%) had OSA as defined by an AHI of > 5 events per hour. 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). The subject demographic data in relation to the AHI are shown in Table 1. Age was well matched across AHI categories. The BMI and neck circumference increased with an increase in AHI. The BMI only weakly correlated (BMI: r = 0.30; p = 0.05; Neck circumference: r = 0.23; p

Discussion

We believe that our study represents the first prospective study of OSA in patients who were given a diagnosis of IPF according to the American Thoracic Society 2000 consensus statement criteria.8 The vast majority of patients (88%) had OSA as defined by an AHI of > 5 events per hour. Sleep-disordered breathing in this population predominantly manifested as hypopneas rather than apneas. Neither oxygen saturation nor oxygen use predicted AHI or the severity of desaturation. FVC, lung volumes,

Acknowledgments

Author contributions: Drs. Lancaster, Rice, Loyd, Milstone, Collard, and Malow, Ms. Mason, and Mr. Parnell meet the criteria of authorship as a group, as outlined by CHEST Authorship and Contributorship requirements. As the principal investigator, Dr. Lancaster had complete access to all the data, and takes full responsibility for the reliability of the data and the accuracy of the data analysis. Ms. Mason, the corresponding author, bears full responsibility for the absolute integrity of the

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This study was completed at Vanderbilt University Medical Center.

Funding/Support: This work was supported by the National Center for Research Resources [grant No. HL081431] and Vanderbilt Clinical and Translational Science Award (CTSA) grant one UL1 RR024975.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/site/misc/reprints.xhtml).

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