Characteristics of urologists participating in Medicare Advantage networks and implications for prostate cancer care.

Background: Enrollment in Medicare Advantage (MA) has expanded rapidly and MA plans may rely on selective provider networks to manage utilization. While selective contracting has been described for primary care physicians, less is known about how MA networks are constructed for surgical specialists such as urologists, who manage common and costly conditions including prostate cancer. Methods: We conducted a national observational study using a 20% sample of Medicare fee-for-service claims (2016 to 2021) linked to 2021 MA network data. We identified 9124 urologists practicing in hospital referral regions (HRRs) with at least 1 MA network. Urologists were classified as in-network or out-of-network within each network HRR and further categorized by network breadth, defined as narrow (<30% of local urologists) or broad. Outcomes were weighted by network enrollment and included urologist characteristics, prostate cancer-related and benign procedure volume, and 2 claims-based quality measures: use of magnetic resonance imaging (MRI) prior to prostate biopsy and consultation with radiation oncology after new prostate cancer diagnosis. Results: Among 9124 urologists, 98% participated in at least 1 MA network. Across 7516 network-HRR combinations, networks included a mean (SD) of 42 (47) urologists, with inclusion ranging from 9% to 100% of local urologists. Compared with the average urologist excluded from a network in the HRR, the average in-network urologist had a higher annual patient volume (107 vs 95; Conclusion: MA urology networks vary widely in breadth and composition. Narrow networks are associated with distinct prostate cancer management patterns that may have implications for access and quality, underscoring the need to assess specialty network adequacy standards.