Travel Distance to Subspecialty Clinic and Outcomes in Patients with Fibrotic Interstitial Lung Disease

Abstract

Rationale: Early access to subspecialty care is associated with improved outcomes for patients with fibrotic interstitial lung disease (ILD). Access to ILD care may be limited for patients living far from subspecialty clinics. Objectives: To test the hypothesis that greater travel distance to access ILD clinical care would be associated with more severe disease at time of referral and worse clinical outcomes. Methods: Patients with fibrotic ILD were recruited from a multicenter national pulmonary fibrosis registry. Residential postal codes were geocoded to estimate travel distance from the home to the clinic. Travel distance was dichotomized at ⩽70 km (near) and >70 km (far). Demographics and disease severity at the initial referral, changes in lung function, and the risk of death or lung transplant were analyzed in unadjusted and adjusted models for their association with travel distance. Results: The cohort included 1,162 patients, of whom 856 lived near to their ILD clinic and 306 lived far from their ILD clinic. Patients residing farther from their clinic were younger, more likely to have smoked, had a greater 6-minute-walk distance, and had lower composite risk scores than patients residing closer to their clinic. In models adjusted for age, sex, and baseline forced vital capacity, patients from farther away had a greater risk of death or lung transplant than patients residing closer (hazard ratio, 1.52; 95% confidence interval [CI], 1.10-2.11), a finding predominantly driven by patients with connective tissue disease-related ILD (hazard ratio, 2.14; 95% CI, 1.16-3.94). Conclusions: Patients with fibrotic ILD with a longer travel distance to their ILD clinic had better prognostic indices at baseline but had a higher risk of death or lung transplant in the total cohort and in patients with connective tissue disease-related ILD. Assuming that disease epidemiology and severity are distributed evenly across geographic regions, these findings raise important questions about equitable access to patient care in large healthcare regions with centralized subspecialty programs.

Keywords: epidemiology; geography; pulmonary fibrosis; registries.