{"doi":"10.1001/jamanetworkopen.2025.38770","title":"Health System Affiliation and Care for Dual-Eligible and Non–Dual-Eligible Medicare Beneficiaries","abstract":"Importance: Physician organization (PO) affiliation with health systems and its association with health care disparities for dual-eligible Medicare and Medicaid beneficiaries, who face significant barriers to care, remains underexplored. Objectives: To estimate the association of health system affiliation with disparities in quality of care and health care utilization for dual-eligible beneficiaries relative to non-dual-eligible Medicare beneficiaries and to decompose these associations into within-PO and between-PO components. Design, Setting, and Participants: This cohort study used data from 2013 to 2019 on primary care POs and beneficiaries enrolled in traditional Medicare. Statistical analysis was performed from April 2024 to March 2025. Exposures: Affiliation with health systems, defined as ownership or management relationships, using Medicare Provider Enrollment, Chain, and Ownership System data and Internal Revenue Service Form 990 data. Main Outcomes and Measures: Eight quality measures assessing receipt of preventive services, chronic condition management, medication adherence, and care coordination and continuity and 5 measures of health care utilization in different settings and with different physician specialists. Linear mixed-effects models were used to estimate changes in disparities before and after affiliation for primary care POs between 2013 and 2019. Results: A total of 5005 primary care POs and more than 5.6 million Medicare beneficiaries (mean [SD] age, 75.5 [7.5] years; 58.4% women) were analyzed, including approximately 700 000 dual-eligible beneficiaries. Affiliation with health systems was associated with widened disparities in diabetic eye examinations (3.5 percentage point larger relative reduction for dual-eligible beneficiaries compared with non-dual-eligible beneficiaries) and follow-up visits after acute events (3.5 percentage point larger relative reduction). On the other hand, dual-eligible beneficiaries experienced relative improvements in continuity of care with primary care clinicians (1.9 percentage points) and POs (1.4 percentage points) compared with non-dual-eligible beneficiaries, as well as larger relative improvements in statin prescribing (1.8 percentage points), widening preaffiliation differences that favored dual-eligible beneficiaries. Four of these 5 measures were associated with widening within-PO and between-PO disparities. Despite moderate and large preaffiliation disparities in primary care clinician visits and specialist visits, respectively, for dual-eligible beneficiaries relative to non-dual-eligible beneficiaries, disparities in primary care clinician visits widened (21 fewer visits per 100 beneficiaries) while disparities in specialist visits did not change meaningfully. Conclusions and Relevance: In this cohort study, health system affiliation by primary care POs was associated with both positive and negative associations with disparities for dual-eligible beneficiaries and did not reduce the largest preaffiliation disparities. Health systems must strengthen their care delivery models to expand access to specialists and avoid exacerbating disparities in follow-up care. Health systems could identify factors associated with improved care at high-percentage dual POs for replication.","journal":"JAMA Network Open","year":2025,"id":578891,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9598,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":911055,"name":"Maria DeYoreo","orcid":"0000-0002-3847-1030","position":1,"is_corresponding":false},{"id":249690,"name":"Denis Agniel","orcid":"0000-0003-1483-2724","position":2,"is_corresponding":false},{"id":1113777,"name":"Shiyuan Zhang","orcid":"0000-0003-0615-1347","position":3,"is_corresponding":false},{"id":593777,"name":"José J. Escarce","orcid":null,"position":4,"is_corresponding":false},{"id":1488745,"name":"Justin W. Timbie","orcid":"0000-0002-9955-5270","position":0,"is_corresponding":true}],"reference_count":33,"raw_metadata":null,"created_at":"2026-07-19T02:58:24.957414Z","pmid":"41129151","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}