Outcomes after ischemic stroke for hospitals with and without Joint Commission-certified primary stroke centers

Abstract

Background: The Joint Commission (JC) began certifying primary stroke centers (PSCs) in the United States in 2003. We assessed whether 30-day risk-standardized mortality (RSMR) and readmission (RSRR) rates differed between hospitals with and without JC-certified PSCs in 2006.

Methods: The study cohort included all fee-for-service Medicare beneficiaries ≥65 years old discharged with a primary diagnosis of ischemic stroke (International Classification of Diseases, ninth revision, Clinical Modification 433, 434, 436) in 2006. Hierarchical linear regression models calculated hospital-level RSMRs and RSRRs, adjusting for patient demographics, comorbid conditions, and hospital referral region. Hospitals were categorized as being higher than, no different from, or lower than the national average.

Results: There were 310,381 ischemic stroke discharges from 315 JC-certified PSC and 4,231 noncertified hospitals. Mean overall 30-day RSMR and RSRR were 10.9% ± 1.7% and 12.5% ± 1.4%, respectively. The RSMRs of hospitals with JC-certified PSCs were lower than in noncertified hospitals (10.7% ± 1.7% vs 11.0% ± 1.7%), but the RSRRs were comparable (12.5% ± 1.3% vs 12.4% ± 1.7%). Almost half of JC-certified PSC hospitals had RSMRs lower than the national average compared with 19% of noncertified hospitals, but 13% of JC-certified PSC hospitals had lower RSRRs vs 15% of noncertified hospitals.

Conclusions: Hospitals with JC-certified PSCs had lower RSMRs compared with noncertified hospitals in 2006; however, differences were small. Readmission rates were similar between the 2 groups. PSC certification generally identified better-performing hospitals for mortality outcomes, but some hospitals with certified PSCs may have high RSMRs and RSRRs whereas some hospitals without PSCs have low rates. Unmeasured factors may contribute to this heterogeneity.

Figure 1. Frequency distribution of 30-day risk-standardized mortality rate (RSMR) and risk-standardized readmission rate (RSRR) by Joint Commission (JC)–certified primary stroke center (PSC) status

(A) Box and whisker plots of RSMR and RSRR by JC-certified PSC status. The upper boundaries of the boxes represent the 25th percentile, the lines bisecting the boxes represent the median or 50th percentile, and the lower boundaries of the boxes represent the 75th percentile. The lower and upper boundaries of the whiskers are set at the 5th and 95th percentiles, with dots representing hospitals beyond these percentiles. (B) Frequency distributions of RSMR and RSRR by JC-certified PSC status.

Figure 2. Categorization of hospital-level risk-standardized mortality rate (RSMR) and risk-standardized readmission rate (RSRR) relative to the national average by Joint Commission (JC)–certified primary stroke center (PSC) status

Stacked bars represent the proportions of hospitals significantly higher than (dark blue/green), no different from (medium blue/green), or significantly lower than (light blue/green) the national RSMR and RSRR, stratified by JC-certified PSC status.