Walkability and pulmonary hypertension outcomes: a survival analysis and cross-sectional analysis in the Pulmonary Hypertension Association Registry

Abstract

Objective We aimed to determine whether residential walkability is associated with lung transplant-free survival or baseline disease severity among adults with pulmonary hypertension, and whether these associations are modified by the Social Vulnerability Index of a participant’s census tract. Methods This study included 3,222 US adults enrolled in the Pulmonary Hypertension Association Registry between 2015 and 2025. Cox proportional hazards regression was used to evaluate the association between the National Walkability Index at participants’ residences and time to death or lung transplant, adjusted for covariates with an interaction term for walkability and rurality. Effect measure modification by Social Vulnerability Index was assessed by adding an interaction term for walkability and Social Vulnerability Index. Multiple linear regression was used to evaluate the association between walkability and metrics of disease severity upon enrollment, including pulmonary vascular resistance, six-minute walk distance, and EmPHasis-10 score. Results For each interquartile range higher walkability, the adjusted hazard of mortality or lung transplant was estimated to be 0.85 (95% CI: 0.73, 0.98) times as high among participants living in urban census tracts. There was not sufficient evidence of an association between walkability and mortality in rural census tracts, an association between walkability and our primary measures of baseline disease severity, or of effect measure modification by Social Vulnerability Index. Conclusion We found higher walkability to be associated with lower risk of mortality or lung transplant among US adults with pulmonary hypertension who live in urban census tracts, but not in rural census tracts.