Abstract
BACKGROUND: Exertional desaturation is an important predictor of mortality in patients with interstitial lung disease. We evaluated the prevalence of exertional desaturation in subjects with interstitial lung disease and determined its relationship with the prescription of ambulatory oxygen therapy.
METHODS: Our retrospective analysis examined prospectively collected data from interstitial lung disease registries of 2 Melbourne hospitals: Alfred Health and Austin Health. All patients with baseline the 6-min walk tests on room air were included. We evaluated the prescription of ambulatory oxygen therapy, up to 3 months after 6-min walk tests, among those with exertional desaturation.
RESULTS: Of the 400 subjects, 214 (54%) had exertional desaturation. The prevalence of desaturation increased with the severity of lung function impairment (FVC measurement: 33% for > 75% predicted, 69% for 50–75% predicted, 86% for < 50% predicted; diffusing capacity of the lung for carbon monoxide measurement: 20% for > 55% predicted, 64% for 36–55% predicted, 93% for ≤ 35% predicted, P < .001 for both severity classifications). There was no difference in the prevalence of exertional desaturation among common disease subtypes (P = .17). Among the desaturators, 14 (7%) had resting hypoxemia and all were prescribed long-term oxygen therapy. Of the remaining 200 with exertional desaturation only, 58 (29%) were prescribed ambulatory oxygen therapy. Multiple logistic regression showed independent associations between the ambulatory oxygen therapy prescription and shorter 6-min walk distance (P < .001) as well as worse FVC (% predicted, P = .037).
CONCLUSIONS: Exertional desaturation is common in subjects with interstitial lung disease. More severely impaired exercise capacity and worse lung function are associated with the prescription of ambulatory oxygen therapy in interstitial lung disease.
Footnotes
- Correspondence: Yet Hong Khor MD, Department of Respiratory and Sleep Medicine, Austin Health, 145 Studley Road, Heidelberg, Victoria, Australia 3084. E-mail: yethong.khor{at}austin.org.au.
Dr Khor is supported by the National Health and Medical Research Council Postgraduate Scholarship.
Dr Khor presented a version of this paper at the Congress of the Asia Pacific Society of Respirology 2017, held November 25, 2017, in Sydney, Australia, and at the American Thoracic Society International Conference 2018, May 20, 2018, in San Diego, California.
Dr Khor discloses relationships with Air Liquide, Boehringer Ingelheim, the National Health, and Medical Research Council. Dr Goh discloses relationships with Air Liquide and Boehringer Ingelheim. Dr Glaspole discloses relationships with Boehringer-Ingelheim; Roche; and Air Liquide. Dr Holland discloses relationships with Air Liquide and Boehringer Ingelheim. Dr McDonald discloses relationships with Boehringer Ingelheim, Novartis, GSK, Pfizer, Menarini, and Air Liquide.
Supplementary material related to this paper is available at http://www.rcjournal.com.
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