Between-Practice Traditional Medicare Spillover Effects of the Oncology Care Model on Non-Traditional Medicare Patients: Evidence from Colorado

The Oncology Care Model (OCM), introduced in 2016 by the Center for Medicare & Medicaid Innovation, aimed to enhance care quality, reduce costs, and improve outcomes for traditional Medicare (TM) beneficiaries undergoing chemotherapy. While designed for TM patients, the OCM may generate spillover effects for non-TM patients treated within the same practices. This study evaluates these effects in Colorado, focusing on healthcare utilization and patient-centered outcomes.

A quasi-experimental difference-in-differences (DiD) design was used to assess OCM spillover effects on non-TM patients. Data were drawn from the Colorado All-Payer Claims Database and the Colorado Central Cancer Registry (2013–2019). The analysis targeted four screen-amenable cancers: breast, colorectal, lung, and prostate. Outcomes of interest included emergency department (ED) visits, inpatient visits, 30-day readmission rates, and depression screening and management. Propensity score matching was applied to control for potential selection bias between the intervention (OCM) and control (non-OCM) groups.

The DiD analyses revealed significant variations in healthcare utilization and patient-centered outcomes across payer groups. Interventions at practices participating in the OCM were associated with a reduction in ED visits among TM patients, but an increase among those with private insurance from the unadjusted model. Adjusted model only showed a rise in ED visits for Medicaid patients. The likelihood of 30-day readmissions showed mixed results: reductions were observed for dual-eligible patients (any Medicare plans with Medicaid) in unadjusted model, while increases were noted for the Medicare Advantage (MA) population in adjusted model. Importantly, depression screening rates improved significantly across most payer groups, particularly among TM, MA, dual-eligible, and private insurance patients.

While OCM primarily targets TM patients, spillover effects influence care for other payer groups, highlighting broader implications for oncology care equity. Integrating mental health services and tailoring interventions to diverse populations could enhance outcomes across payer groups.