Methods:

GWTG-Stroke is a national quality improvement initiative and registry. The authors compared hospitals that implemented GWTG-Stroke between 2003 and 2008 with matched control hospitals. Matching was determined based on a variety of factors, including teaching status, stroke volume, and stroke mortality. A single control hospital was identified for each GWTG-Stroke hospital. The study examined four time points: Pre period, 18-6 months prior to joining GWTG-Stroke; Run-Up, 6 months to 1 day prior to joining GWTG-Stroke; Early, day 0-6 months after joining GWTG-Stroke; and Sustained, 6-18 months after joining GWTG-Stroke. The primary comparison was between the Pre and Sustained periods. Ischemic stroke patients were identified using International Classification of Diseases Ninth Revision codes. Patient outcome information was identified using Centers for Medicare and Medicaid Service (CMS) data sets, and stroke admissions were linked to CMS data.

The primary outcomes analyzed included discharge disposition (home versus other) and mortality at 30 days and 1 year. Differences in outcome between GWTG-Stroke hospitals and controls were compared across the four time epochs using Cox proportional hazard models, adjusted for hospital as well as patient factors. A difference-in-differences analysis was used to compare temporal changes in GWTG-Stroke hospitals with the control hospitals. Cox proportional hazard models were used for time to event outcomes, and logistic regression models were used for dichotomous outcomes.