Abstract Body (Do not enter title and authors here): Background: Participation in cardiac rehabilitation (CR) is enhanced by proximity to CR facilities and communication between inpatient and outpatient settings but may become fragmented when patients are distant from their discharging hospital and nearest CR facility.

Research Question: This study investigates how patient distance to both hospitals and CR facilities impacts the rates of CR participation.

Methods: This study included 100% Medicare fee-for-service claims for beneficiaries with 12 months of continuous Part A/B coverage who had coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or surgical or transcatheter aortic valve replacements (SAVR or TAVR) between 07/2016-12/2018, excluding patients discharged to hospice or died within 30 days. Google Maps defined travel distances from the patient to hospital and CR facility locations using geographic centroids of ZIP codes, which were then categorized into quartiles. CR enrollment was defined as attending at least one session within one year of discharge. Logistic regression models estimated marginal CR enrollment rates across both hospital and CR facility distance categories adjusting for patient, hospital, and regional factors.

Results: The study included a total sample of 501,049 beneficiaries undergoing PCI (62%), CABG (19%), SAVR (7%), and/or TAVR (15%). The median travel distance to the hospital was 18.6 miles (IQR 8.2-43.3 miles) and to the CR facility was 7.7 miles (IQR 2-15.3 miles). A total of 188,963 (37.7%) beneficiaries attended at least one CR session, which varied across categories of distance to hospital (Q1: 36.8% to Q4: 37.5%) and CR facility (Q1: 44.7% to Q4: 30.0%, p<0.01). Adjusted CR enrollment rates improved when beneficiaries lived farther from their admitting hospitals but closer to CR facilities (Figure 1), with the highest enrollment for those located farthest from their admitting hospital but closest to the CR facility (47.5%) and lowest enrollment among those closest to the hospital but farthest from the CR facility (20.6%).

Conclusions: Greater distance to the admitting hospital was associated with higher CR enrollment, while greater distance to the CR facility was associated with lower enrollment among eligible Medicare beneficiaries. Addressing geographic barriers to CR participation may require tailored solutions based on patient proximity to hospitals and CR facilities.