Stroke patient outcomes in US hospitals before the start of the Joint Commission Primary Stroke Center certification program.

BACKGROUND AND PURPOSE The Joint Commission (JC) began certifying Primary Stroke Centers in November 2003. Cross-sectional studies assessing the impact of certification could be biased if these centers had better outcomes before the start of the program. We determined whether hospitals certified within the first years of the JC program had better outcomes than noncertified hospitals before the start of the certification program. METHODS The study sample included Medicare fee-for-service beneficiaries >or=65 years of age discharged with ischemic stroke in 2002 from 5070 hospitals, 317 of which were JC-certified by June 2007. Hierarchical logistic regression and Cox proportional hazards models were used to compare in-hospital mortality, 30-day mortality, and 30-day readmission for patients treated at future JC-certified versus noncertified hospitals. RESULTS Among 366 551 patients, 18% (66 300) were treated at hospitals with centers that were JC-certified within the first few years of the program. These patients were younger, more likely to be white and male, and had fewer comorbidities and hospitalizations within the prior year. Unadjusted in-hospital mortality (4.7% versus 5.5%), 30-day mortality (9.8% versus 11.3%), and readmissions (13.8% versus 14.6%) were lower in the future JC-certified hospitals (all P<0.001). These differences remained after risk adjustment (in-hospital mortality: OR, 0.93; 95% CI, 0.90 to 0.96; 30-day mortality: OR, 0.92; 95% CI, 0.87 to 0.96; 30-day readmission: hazard ratio, 0.97; 95% CI, 0.95 to 0.99). CONCLUSIONS JC Primary Stroke Center-certified hospitals had better outcomes than noncertified hospitals even before the program began. Cross-sectional studies assessing the effects of stroke center certification need to account for these pre-existing differences.