Introduction: Little is known about how hospitals are connected in the care of patients with acute ischemic stroke (IS). We aimed to describe changes over time in the IS interfacility transfer network in the Northeastern U.S.
Methods: We used data from inpatient and outpatient Medicare claims in the Northeast region to identify IS patients transferred between hospitals from 2007 to 2011. Receiving hospitals (RHs) were defined as hospitals with annual IS volume of at least 120 admissions and ≥15% of these admissions received as transfers. Transferring hospitals (THs) were defined as non-RHs that transferred ≥15% of total (ED plus inpatient) IS discharges. A connection between hospitals was defined as ≥5 patients/year transferred between any given TH and RH in the region. We generated a map of hospital connections for each year during the study period using ArcGIS 10.3.1.
Results: Among 130,338 IS admissions, we identified 6,898 (5%) patient transfers in the Northeast region from 2007-2011. The number of patients transferred increased from 960 (4%) in 2007 to 1772 (7%) in 2011 (p for trend <0.0001). Of the 402 hospitals in the region, the number of THs increased from 17 (8%) to 49 (12%); the number of RHs increased from 6 (2%) to 16 (4%) from 2007 to 2011 (p<0.0001) (Figure). 88% of RHs performed mechanical thrombectomy. Most THs were exclusively connected to a single RH (88%, n=15 in 2007, 94%, n=46 in 2011).
Conclusion: From 2007 to 2011, hospitals in the U.S. Northeast became more connected in the care of IS patients, with a growing number of connections between hospitals. Yet, by our definition, the majority of hospitals remained unconnected, potentially representing a missed opportunity. Further characterization of this transfer network will be important for understanding and improving regional stroke systems of care.