Real world evidence of acute interstitial lung disease-related hospital admissions infers complex, multifactorial association between social deprivation and 90-day all-cause mortality outcomes: data from the North West of England

Abstract Background Social deprivation impacts chronic disease and acute admission outcomes. In interstitial lung disease (ILD), prior British Thoracic Society registry data for idiopathic pulmonary fibrosis has shown high deprivation was associated with poorer long-term outcomes. However, its impact on acute admissions in ILD is not known. Methods We undertook a multicentre, retrospective study of ILD-related admissions between 1 st January 2017 and 31 st December 2019 across 11 hospitals in the North West of England, utilising available real-world data. We determined social deprivation geographically by the 2019 English Indices of Deprivation deciles. The primary outcome was 90-day all-cause mortality. Results 999 admissions met the inclusion criteria. 327/999 (32.7%) of admissions came from individuals geographically in the most deprived 20%. Across 999 admissions, in unadjusted survival analysis we observed a non-linear relationship between deprivation and 90-day all-cause mortality. In complete case multivariate modelling, deprivation demonstrated borderline significant association with all-cause mortality (HR 1.038, 95% CI 1.00 – 1.077, p = 0.050). However, this effect was lost in pooled analysis using multiple imputation (HR 1.001, 95% CI 0.971 – 1.033, p = 0.928). Male sex and pre-admission long-term oxygen were consistently associated with increased 90-day all-cause mortality across both models. Lower TLCO values were significantly associated with increased 90-day mortality in pooled analysis. Conclusion We observe a high burden of acute ILD-related hospital admission amongst the most deprived 20%, suggesting geographical deprivation may impact acute healthcare seeking behaviours. Once admitted, the impact of deprivation appears more complex and multifactorial. Further studies which assess geographical and individual-level deprivation are needed to validate our findings. Key Messages What is already known on the topic? The British Thoracic Society idiopathic pulmonary fibrosis registry has previously demonstrated that higher social deprivation is associated with worse long-term outcomes. In other respiratory diseases, social deprivation impacts acute admission patterns and outcomes. What this study adds To the best of our knowledge, this is the first study examining the relationship between social deprivation and acute ILD-related admission outcomes. This study demonstrates high acute admission burden from the geographically most deprived 20%. Once admitted, the association between geographical social deprivation and mortality outcomes appears complex and multifactorial in our modelling. How this may affect research, practice or policy This study highlights the acute admission burden from highly deprived communities and the need for additional research to further understand the individual-level and geographical-level deprivation patients with ILD experience. We suggest the need for community outreach to build trust with deprived communities, alongside increasing awareness amongst patients, caregivers and primary care physicians in such communities. Deprivation must remain an important consideration in any new service or intervention to prevent worsening of health inequalities.