IntroductionHospitalisations relating to acute respiratory deteriorations (ARD) in Interstitial Lung Disease (ILD) have poor outcomes. Factors predicting adverse outcomes are not fully understood and data addressing the use of illness severity scores in prognostication are limited. ObjectiveTo validate the use of CURB-65 and NEWS-2 severity scores to predict mortality following ARD-ILD hospitalisation. MethodsA dual-centre prospective observational cohort study of all adults ([≥]18y) hospitalised with ARD-ILD in Bristol, UK (n=179). Gender-Age-Physiology (GAP), CURB-65 and NEWS-2 scores were calculated for each eligible admission. Receiver operating characteristics (ROC) curve analysis was used to quantify the strength of discrimination for NEWS-2 and CURB-65 scores. Univariable and multivariable logistic regression analyses were performed to explore the relationship between baseline severity scores and mortality. ResultsGAP showed some merit at predicting 30-day mortality (AUC=0.64, P=0.015); whereas CURB-65 showed modest predictive value for in-hospital (AUC=0.72, P<0.001) and 90-day mortality (AUC=0.67, P<0.001). NEWS-2 showed higher predictive value for in-hospital (AUC=0.80, P<0.001) and 90-day mortality (AUC=0.75, P<0.001), with an optimal derived cut-off [≥]6.5 found to be sensitive and specific for predicting in-hospital (83% and 63%) and 90-day (73% and 72%) mortality. In exploratory analyses, GAP score addition improved the predictive ability of NEWS-2 against 30-day mortality and CURB-65 across all time-periods. ConclusionNEWS-2 has good discriminatory value for predicting in-hospital mortality and moderate discriminatory value for predicting 90-day mortality. The optimal NEWS-2 cut-off value determined was the same as in a previous retrospective cohort, confirming the NEWS-2 score shows promise in predicting mortality following ARD-ILD hospitalisation. KEY MESSAGESO_ST_ABSWhat is the key question?C_ST_ABS- Can NEWS-2 and CURB-65 be used to predict inpatient mortality in a cohort of patients with acute respiratory deterioration on a background of known interstitial lung disease? What is the bottom line?- The NEWS-2 score shows high sensitivity and specificity in predicting both 90-day and in-hospital mortality in patients hospitalised with ARD-ILD - Whilst the CURB-65 score showed high sensitivity for predicting mortality, there was a low specificity, and did not add value to the predictive ability of the NEWS-2 score. Why read on?- This analysis included 179 patients from two study sites and provides, for the first time, prospective evidence for utilising NEWS-2 and CURB-65 as tools to predict in-hospital and post hospitalisation morbidity.