Factors associated with clinical trial participation in patients with IPF: data from the IPF-PRO Registry

The extent to which patients who participate in clinical trials represent the broader community of patients with idiopathic pulmonary fibrosis (IPF) remains unclear. We evaluated how frequently patients in the IPF-PRO Registry met criteria commonly used as eligibility criteria for clinical trials and identified factors associated with trial participation. The IPF-PRO Registry enrolled patients with IPF at 46 US centers between June 2014 and October 2018. Patients who were participating in an interventional clinical trial were not eligible for enrollment, but patients could join such trials after enrollment. The proportions of patients who met seven criteria, similar to those used as inclusion criteria in contemporary clinical trials, were assessed at enrollment. Cox proportional hazards models were used to evaluate associations between demographic, clinical, and socioeconomic characteristics and the probability of trial participation. Among 1001 patients who had follow-up data in the registry, 143 (14.3%) participated in a clinical trial during follow-up. Median (Q1, Q3) time from enrollment in the registry to entering a clinical trial was 13.0 (4.6, 23.8) months. At enrollment into the registry, 609 patients (60.8%) met all seven eligibility criteria studied. Patients who were older (hazard ratio [HR] 0.84 [95% CI: 0.75, 0.93] per 5 years), had Medicare/Medicaid rather than private insurance (HR 0.66 [95% CI: 0.46, 0.95]), or who lived in a rural area (HR 0.60 [95% CI: 0.37, 0.98]) were significantly less likely to participate in a clinical trial, while patients using antifibrotic therapy (HR 1.78 [95% CI: 1.26, 2.52]) were significantly more likely to participate. There were no significant differences in trial participation based on number of comorbidities, patient-reported outcomes, lung function, or ZIP code income. Among patients in the IPF-PRO Registry, 14% participated in a clinical trial despite a substantially larger proportion meeting eligibility criteria similar to those used in contemporary trials. The probability of clinical trial participation differed by age, insurance, rural location and access to specialized care, suggesting that improving participation and representativeness in IPF clinical trials will likely require patient-centered protocol and operational strategies beyond eligibility criteria alone. ClinicalTrials.gov: NCT01915511; registered August 5, 2013.