When clinicians group together: a scoping review of clustering in patient-sharing networks

Background: Improvements in patient safety and quality of care can be achieved by improvements in clinicians’ teamwork, coordination, and communication. Growing research examines the structure and dynamics of clinician networks using social network analysis. Such networks can have clusters of healthcare professionals within them, but systematized knowledge on these clusters is lacking. Our goal was to review the literature on determinants and characteristics of healthcare professional clustering in patient-sharing networks and their associations with patient outcomes. Methods: We performed a scoping review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis for scoping reviews (PRISMA-ScR). We searched Medline and EMBASE in January 2021 and again in May 2025. We included English-language peer-reviewed studies that examined the clustering of healthcare professionals in patient-sharing networks (either based on regional or institutional boundaries or cohesive relations), used network analysis techniques, and reported at least one patient outcome. After rounds of title and abstract and full-text screening, through pairwise independent review, we extracted study information such as study design and setting, population, patient-sharing definition, network measures, clustering definition, health outcomes, and reported associations. We descriptively summarized the characteristics of studies, methods of clustering, and outcome measures, and synthesized the association between clustering and health outcomes. Results: The thirteen eligible studies varied considerably in definitions and measures of patient-sharing relations, definitions and structural measures of network clusters, settings, study population, and health outcomes. Three studies found that busier physician networks (i.e., networks with more connections among physicians) are associated with worse health outcomes. Five studies reported that better-connected physician networks (more cohesive or more persistent) are associated with better health outcomes. Conclusion: Most existing studies were exploratory and lacked explicit a priori hypotheses regarding the impact of clustering on outcomes. Our findings suggest potential associations between cluster size, cohesiveness, and the outcomes, warranting further hypothesis-driven research.