Overnight desaturation in interstitial lung diseases: links to pulmonary vasculopathy and mortality

George A Margaritopoulos; Athanasia Proklou; Athina Trachalaki; Diana Badenes Bonet; Maria Kokosi; Vasilis Kouranos; Felix Chua; Peter George; Elisabetta A Renzoni; Anand Devaraj; Sujal Desai; Andrew G Nicholson; Katerina M Antoniou; Athol U Wells

doi:10.1183/23120541.00740-2023

Overnight desaturation in interstitial lung diseases: links to pulmonary vasculopathy and mortality

ERJ Open Res. 2024 Feb 12;10(1):00740-2023. doi: 10.1183/23120541.00740-2023. eCollection 2024 Jan.

Authors

George A Margaritopoulos^{1

2

3}, Athanasia Proklou^{3

4

5}, Athina Trachalaki^{3

5}, Diana Badenes Bonet^{3

6}, Maria Kokosi³, Vasilis Kouranos³, Felix Chua³, Peter George³, Elisabetta A Renzoni³, Anand Devaraj⁷, Sujal Desai⁷, Andrew G Nicholson^{8

2}, Katerina M Antoniou^{9

5}, Athol U Wells^{3

5}

Affiliations

¹ Interstitial Lung Disease Unit, London North West University Hospital Healthcare Trust, London, UK.
² National Heart and Lung Institute, Imperial College, London, UK.
³ Interstitial Lung Disease Unit, Royal Brompton Hospital, London, UK.
⁴ Intensive Care Unit, University Hospital of Herakleio, Heraklion, Greece.
⁵ These authors contributed equally.
⁶ Hospital del Mar, Parc de Salut Mar, Barcelona, Spain.
⁷ Radiology Department, Royal Brompton Hospital, London, UK.
⁸ Department of Histopathology, Royal Brompton and Harefield Hospitals, Guy's and St Thomas' NHS Foundation Trust, London, UK.
⁹ Interstitial Lung Disease Unit, University Hospital of Herakleio, Heraklion, Greece.

Abstract

Background: Overnight desaturation predicts poor prognosis across interstitial lung diseases (ILDs). The aim of the present study was to investigate whether nocturnal desaturation is associated with pulmonary vasculopathy and mortality.

Methods: A retrospective single centre study of 397 new ILD patients was carried out including patients with idiopathic pulmonary fibrosis (IPF) (n=107) and patients with non-IPF fibrotic ILD (n=290). This is the largest study to date of the effect of significant nocturnal desaturation (SND) (≥10% of total sleep time with oxygen saturation ≤90% measured by pulse oximetry).

Results: The prevalence of SND was 28/107 (26.2%) in IPF and 80/290 (27.6%) in non-IPF ILD. The prevalence of SND was higher in non-IPF ILDs than in IPF (p=0.025) in multivariate analysis. SND was associated with noninvasive markers of pulmonary hypertension (PH): tricuspid regurgitation velocity (TRV) (p<0.0001), brain natriuretic peptide (p<0.007), carbon monoxide transfer coefficient (p<0.0001), A-a gradient (p<0.0001), desaturation >4% in 6-min walking test (p<0.03) and pulmonary artery diameter (p<0.005). SND was independently associated with high echocardiographic PH probability in the entire cohort (OR 2.865, 95% CI 1.486-5.522, p<0.002) and in non-IPF fibrotic ILD (OR 3.492, 95% CI 1.597-7.636, p<0.002) in multivariate analysis. In multivariate analysis, SND was associated with mortality in the entire cohort (OR 1.734, 95% CI 1.202-2.499, p=0.003) and in IPF (OR 1.908, 95% CI 1.120-3.251, p=0.017) and non-IPF fibrotic ILD (OR 1.663, 95% CI 1.000-2.819, p=0.041). Separate models with exclusion of each one of the diagnostic subgroups showed that no subgroup was responsible for this finding in non-IPF ILDs. SND was a stronger marker of 5-year mortality than markers of PH.

Conclusion: SND was associated with high echocardiographic probability and mortality and was a stronger predictor of mortality in IPF and non-IPF ILDs grouped together to power the study.