Background: Our objectives were to determine whether there is an association between ischemic stroke patient insurance and likelihood of transfer overall and to a stroke center and whether hospital cluster modified the association between insurance and likelihood of stroke center transfer.
Methods: This retrospective network analysis of California data included every nonfederal hospital ischemic stroke admission from 2010 to 2017. Transfers from an emergency department to another hospital were categorized based on whether the patient was discharged from a stroke center (primary or comprehensive). We used logistic regression models to examine the relationship between insurance (private, Medicare, Medicaid, uninsured) and odds of (1) any transfer among patients initially presenting to nonstroke center hospital emergency departments and (2) transfer to a stroke center among transferred patients. We used a network clustering method to identify clusters of hospitals closely connected through transfers. Within each cluster, we quantified the difference between insurance groups with the highest and lowest proportion of transfers discharged from a stroke center.
Results: Of 332 995 total ischemic stroke encounters, 51% were female, 70% were ≥65 years, and 3.5% were transferred from the initial emergency department. Of 52 316 presenting to a nonstroke center, 3466 (7.1%) were transferred. Relative to privately insured patients, there were lower odds of transfer and of transfer to a stroke center among all groups (Medicare odds ratio, 0.24 [95% CI, 0.22-0.26] and 0.59 [95% CI, 0.50-0.71], Medicaid odds ratio, 0.26 [95% CI, 0.23-0.29] and odds ratio, 0.49 [95% CI, 0.38-0.62], uninsured odds ratio, 0.75 [95% CI, 0.63-0.89], and 0.72 [95% CI, 0.6-0.8], respectively). Among the 14 identified hospital clusters, insurance-based disparities in transfer varied and the lowest performing cluster (also the largest; n=2364 transfers) fully explained the insurance-based disparity in odds of stroke center transfer.
Conclusions: Uninsured patients had less stroke center access through transfer than patients with insurance. This difference was largely explained by patterns in 1 particular hospital cluster.
Competing Interests: Disclosures Dr Zachrison reports research funding from National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS), CRICO, the American College of Emergency Physicians, and the Massachusetts General Hospital Executive Committee on Research as well as honoraria from the American Heart Association and UpToDate unrelated to this work. Dr Schwamm reports relationships relevant to research grants or companies that manufacture thrombolysis or thrombectomy products even if the interaction involves nonthrombolysis products: scientific consultant regarding trial design and conduct to Genentech (late-window thrombolysis) and steering committee membership (TIMELESS https://www.clinicaltrials.gov; Unique identifier: NCT03785678); consultant to LifeImage and Massachusetts Department of Public Health; member of Data Safety Monitoring Boards (DSMB) for Penumbra (MIND; https://www.clinicaltrials.gov; Unique identifier: NCT03342664) and Diffusion Pharma PHAST-TSC; https://www.clinicaltrials.gov; Unique identifier: NCT03763929); National PI for Medtronic (Stroke AF; https://www.clinicaltrials.gov; Unique identifier: NCT02700945); National Co-PI, late window thrombolysis trial, NINDS (P50NS051343, MR WITNESS; https://www.clinicaltrials.gov; Unique identifier: NCT01282242; alteplase provided free of charge to Massachusetts General Hospital and supplemental per-patient payments to participating sites by Genentech); and Site PI, StrokeNet Network NINDS (New England Regional Coordinating Center U24NS107243). The other authors report no conflicts.