UC Berkeley

OBJECTIVE: To examine the effect of enrollee switching from a broad-network accountable care organization (ACO) health maintenance organization (HMO) to a high performance ACO-HMO with a selective narrow network and comprehensive patient navigation system on access, utilization, expenditures, and enrollee experiences. DATA SOURCES: Secondary administrative data were obtained for 2016-2020, and primary interview and survey data in 2021. STUDY DESIGN: Fixed-effects instrumental variable analyses of administrative data and regression analyses of survey data. Outcomes included access, utilization, expenditures, and enrollee experience. Background information was gathered via interviews. DATA COLLECTION/EXTRACTION METHODS: We obtained medical expenditure/enrollment and access data on continuously enrolled members in a broad-network ACO-HMO (n = 24,555), a subset of those who switched to a high-performance ACO-HMO in 2018 (n = 7664); interviews of organizational leaders (n = 13); and an enrollee survey (n = 512). PRINCIPAL FINDINGS: Health care effectiveness data and information Set (HEDIS) access measures were not different across plans. However, annual utilization dropped by 15.5 percentage points (95% CI: 18.1, 12.9) more in the high-performance ACO-HMO, with relative annual expenditures declining by $1251 (95% CI: $1461, $1042) per person per year. High-performance ACO-HMO enrollees were 10.1 percentage points (95% CI 0.001, 0.201) more likely to access primary care usually or always as soon as needed and 11.2 percentage points (95% CI 0.007, 0.217) more likely to access specialty care usually or always as soon as needed. Plan satisfaction was 7.1 percentage points (95% CI: -0.001, 0.138) higher in the high-performance ACO-HMO. Interviewees noted the comprehensive patient navigation system was designed to ensure patients remained in the narrow network to receive care. CONCLUSIONS: ACO and HMO contracts with selective narrow networks supported by comprehensive patient navigation can reduce expenditures and improve specialty access and patient satisfaction compared to broad-network plans that lack these features. Payers should consider implementing narrow networks with comprehensive support systems.