Untreated Obstructive Sleep Apnea in Interstitial Lung Disease and Impact on Interstitial Lung Disease Outcomes

In a recent review, Karuga and colleagues 81 concluded that OSA is more common in subjects with IPF than in the general healthy population. As studies evaluating the rates of OSA in subjects with IPF do not include a control healthy group, authors obtained this result deriving the rates of OSA in healthy controls matched for age, gender, body mass index, and race. Our narrative review confirms that OSA is highly prevalent both in subjects with IPF-only and in mixed ILD populations, but it is difficult to draw other conclusions from available studies for several reasons. First, monitoring devices used in sleep studies were different. Studies evaluating the prevalence of OSA in ILD populations have used different type III or IV monitoring devices and different scoring criteria to categorize OSA. Second, studies in ILD populations had small sample size and participants showed different characteristics. Third, inclusion criteria differed with variations in enrolments from referral clinics, inclusion based on symptoms or findings during clinic visits, or patient recruitment through clinics versus open invitation. However, it is clear that at present subjects with ILD are underdiagnosed for OSA and sleep -related hypoxemia. The finding of many previous studies that subjects with ILD and OSA had relatively mild symptoms compared to those with only ILD without OSA may have contributed to inadequate screening for underlying OSA and sleep -related hypoxemia in these populations. In addition, there is no guideline recommendation for OSA screening in subjects with ILD.