Overnight desaturation in ILDs: links to pulmonary vasculopathy and mortality

Abstract

BackgroundOvernight desaturation predicts poor prognosis across ILDsAimTo investigate whether nocturnal desaturation is associated with pulmonary vasculopathy and mortality.MethodsRetrospective single center study. 397 new ILD patients: IPF (n=107), non-IPF fibrotic ILD (n=290). This is the largest cohort where the effect of significant nocturnal desaturation (SND) (≥10% of total sleep time with SpO2≤90%) evaluated with pulse oxymeter, was investigated.ResultsThe 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 non-invasive markers of pulmonary hypertension (PH): TRV (p<0.0001), BNP (p<0.007), Kco (p<0.0001), A-a gradient (p<0.0001), desaturation >4% in 6MWT (p<0.03), pulmonary artery diameter (<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.ConclusionSND 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.