Differences in disease characteristics and outcomes as determined by biological sex in a large UK IPF population: Analysis from the British Thoracic Society, Interstitial Lung Disease (BTS-ILD) registry data

IntroductionGrowing evidence suggests that biological sex influences the incidence, presentation, diagnosis and outcomes of many lung diseases. Understanding these differences is the first step towards precision medicine to improve patient care. MethodsIn this cross-sectional study IPF patients enrolled in a national, multicentre registry (UK BTS-ILD) were categorised by sex and analysed for differences in demographics, pulmonary function tests, HRCT radiological pattern, eligibility/uptake of antifibrotics and survival. ResultsOf 7177 cases, 77.8% (n=5587) were male, median age 75 years (IQR 69.5-80.5) for both sexes (p=0.83). Males were more likely to have a history of smoking (p<0.001) and lower baseline median FVC % predicted (males 76.4%, IQR 66.2-86.7 vs females 78.8%, IQR 68.6-89.1, p<0.001). Diabetes, cardiovascular disease and gastro-oesophageal reflux disease were statistically more common in males (p<0.001), whilst major depressive illness was more common in females (p<0.001). Significantly more females experienced symptoms for >24 months prior to first clinic appointment (females 40.1% vs males 36.6%, p=0.028). Whilst more males in the cohort met eligibility criteria for antifibrotics at baseline (p<0.001), a larger proportion chose not to commence antifibrotic treatment (males 47.0% vs females 29.6%, p<0.001). Female sex was associated with longer mean survival (female 9.99 years (95% CI 9.18-10.79) vs males 8.57 years (95% CI 8.15-8.99), p<0.001). Male sex, higher age, lower baseline FVC % predicted and co-existent lung cancer were all independently associated with worse survival (p<0.001). ConclusionThis is the first UK study to use national registry data to systematically evaluate IPF disease characteristics stratifying by biological sex and highlights distinct characteristics between groups. Future clinical trials should explicitly explore sex-specific targeted interventions and analyses, to optimise future IPF patient care. What is already known about this topic?Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung condition with a poor prognosis. There are established sex differences in the incidence and prevalence of IPF, and reports of differing lived experience. What this study adds?This study is the first to report on UK real-world registry dataset to systematically evaluate sex differences in clinical disease characteristics, treatments and outcomes. The results of this study suggest that IPF has distinct characteristics depending on biological sex. How this study might affect research, practice or policy?These findings highlight key areas that could be addressed to improve patient outcomes and care within the UK. It creates the opportunity to explore tailored approaches to care.