LAUSR

Introduction Over the past two decades, percutaneous coronary intervention (PCI) capacity has increased while coronary artery disease has decreased, potentially lowering per-hospital PCI volumes, which is associated with less favorable patient outcomes. Trends in the likelihood of receiving PCI in a low-volume center have not been well-documented, and it is unknown whether certain socioeconomic factors are associated with a greater risk of PCI in a low-volume facility. Our study aims to determine the likelihood of being treated in a low-volume PCI center over time and if this likelihood differs by sociodemographic factors. Methods We conducted a retrospective cohort study of 374,066 hospitalized patients in California receiving PCI from January 1, 2010, to December 31, 2018. Our primary outcome was the likelihood of PCI discharges at a low-volume hospital (<150 PCI/year), and secondary outcomes included whether this likelihood varied across different sociodemographic groups and across low-volume hospitals stratified by high or low ZIP code median income. Results The proportion of PCI discharges from low-volume hospitals increased from 5.4% to 11.0% over the study period. Patients of all sociodemographic groups considered were more likely to visit low-volume hospitals over time (P<0.001). Latinx patients were more likely to receive PCI at a low-volume hospital compared with non-Latinx White in 2010 with a 166% higher gap in 2018 (unadjusted proportions). The gaps in relative risk (RR) between Black, Latinx and Asian patients versus non-Latinx white increased over time, whereas the gap between private versus public/no insurance, and high versus low income decreased (interaction P<0.001). In low-income ZIP codes, patients with Medicaid were less likely to visit low-volume hospitals than patients with private insurance in 2010; however, this gap reversed and increased by 500% in 2018. Patients with low income were more likely to receive PCI at low-volume hospitals relative to patients with high income in all study years. Conclusions The likelihood of receiving PCI at low-volume hospitals has increased across all race/ethnicity, insurance, and income groups over time; however, this increase has not occurred evenly across all sociodemographic groups.