Neighborhood Health and Outcomes in Idiopathic Pulmonary Fibrosis

Rationale: Living in a disadvantaged neighborhood has been associated with worse survival in people with idiopathic pulmonary fibrosis (IPF), however, prior studies have only examined the impact of neighborhood health on outcomes in IPF as a composite measure. Objectives: To investigate the association between neighborhood health and disease severity, measured by pulmonary function at presentation, and death in follow-up, with an additional focus on the contributions of the neighborhood's underlying physical and social factors to these outcomes. Methods: In a retrospective study of participants from the University of California, San Francisco, IPF Cohort (2001-2020), geocoded home addresses were matched to the California Healthy Places Index (HPI), a census-tract measure of neighborhood health. The HPI comprises 25 indicators of neighborhood health that are organized into eight physical and social domains, each of which is weighted and summed to provide a composite HPI score. Regression models were used to examine associations between the HPI as a continuous variable, in quartiles, and across each physical and social domain of the HPI (higher values indicate greater advantage) and forced vital capacity (FVC) percent predicted (% predicted), diffusing capacity of the lung for carbon monoxide (Dl_CO) % predicted, and death, adjusting for demographic and clinical covariates. We also studied the interaction between disease severity at presentation and neighborhood health in our time-to-event models. Results: In 783 participants with IPF, each 10% increase in HPI was associated with a 1% increase in FVC % predicted and Dl_CO % predicted (95% confidence intervals [CIs] = 0.55, 1.72; and 0.49, 1.49, respectively). This association appeared primarily driven by the economic, education, access, and social HPI domains. We also observed differences in the associations of HPI with mortality depending on disease severity at presentation. In participants with normal to mildly impaired FVC % predicted (⩾70%) and Dl_CO % predicted (⩾60%), decreased HPI was associated with higher mortality (hazard ratio = 2.91 Quartile 1 vs. Quartile 4; 95% CI = 1.20, 7.05). No association was observed between the HPI and death for participants with moderate to severely impaired FVC % predicted and Dl_CO % predicted. Conclusions: Living in disadvantaged neighborhoods was associated with worse pulmonary function in participants with IPF and was independently associated with increased mortality in participants with normal to mild physiological impairment at presentation.