Impact of expanding Medicaid contracts at Dana-Farber Cancer Institute.

e13513 Background: In December 2020, Dana-Farber Cancer Institute (DFCI) contracted with Boston Medical Center HealthNet Plan (BMCHP), the second largest Medicaid plan in Massachusetts. This contract expanded DFCI network access from two sites to all DFCI locations for BMCHP members. The impact of this expansion on DFCI's patient demographics and utilization by BMCHP members remained unknown. Methods: Using electronic health record data from 2018 to 2023, we calculated the annual number of unique patients utilizing outpatient physician services at DFCI. Annual averages were calculated for pre-contract (2018-2020) and post-contract (2021-2023) periods. The same analysis was repeated at the monthly level. Patients were assigned to the insurance with which they had most physician encounters each year. We conducted descriptive demographic analyses, chi-square tests comparing BMCHP versus non-BMCHP patient characteristics, and linear spline analyses with a January 2021 breakpoint. Results: The average annual number of unique BMCHP patients doubled from the pre- to post-contract period (274 to 552), while total DFCI patient volume increased 1.2-fold (72,150 to 84,395) (Table). Monthly analyses showed a significant increase in BMCHP patient rates post-contract (slope change: 0.00007187, p < 0.001). BMCHP patients were significantly more likely to be non-White, Hispanic, and non-English speaking compared to non-BMCHP patients (all p < 0.001) (Table). However, as BMCHP patients represented less than 1% of total DFCI volume, overall center demographics remained largely unchanged post-contract. Conclusions: The DFCI-BMCHP contract successfully increased access for Medicaid patients, demonstrating the importance of insurance network expansion in improving cancer care accessibility. Despite BMCHP's large membership of 325,000, the modest absolute increase in BMCHP patient volume suggests minimal impact on institutional resources while achieving meaningful expansion of access. Demographics of unique patients per year at DFCI pre- and post-BMCHP contract (2018-2023)*. Pre-Contract, 2018-2020(annual average) Post-Contract, 2021-2023(annual average) BMCHP Patients All Patients BMCHP Patients All Patients Unique patients per year (N, standard deviation) 274 (23) 72,150 (3,349) 552 (150) 84,395 (7,473) Insurance (N, %) Medicaid (BMCHP) 274 (100.0%) 274 (0.4%) 552 (100.0%) 552 (0.6%) Medicaid (Other) 6,859 (9.5%) 9,010 (10.6%) Commercial/Medicare 27 (83.5%) 71,821 (85.1%) Race (N, %) White 175 (63.9%) 63,090 (87.4%) 378 (68.6%) 72,899 (86.4%) Black 53 (19.2%) 2,824 (3.9%) 83 (15.1%) 3,588 (4.2%) Asian 9 (3.4%) 2,134 (3.0%) 28 (5.2%) 2,570 (3.0%) Other 30 (10.8%) 2,323 (3.2%) 42 (7.6%) 3,415 (4.0%) Ethnic Group (N, %) Hispanic 13 (4.7%) 1,109 (1.5%) 17 (2.9%) 1,796 (2.1%) Language (N, %) Non-English 28 (10.3%) 3,120 (4.3%) 56 (10.0%) 3,807