Although the absolute differences were small, a higher proportion of hospitals with a JC-certified PSC had 30-day RSMRs that were lower than the national average as compared with hospitals without a JC-certified PSC, but 30-day RSRRs were similar regardless of JC-certified PSC status. There was heterogeneity in the distribution of risk-standardized outcomes for hospitals, with considerable overlap between these groups. The data suggest that JC PSC certification identifies a large number of high-performing hospitals for mortality outcomes, but does not necessarily guarantee better performance than may be found in hospitals without a JC-certified PSC. Moreover, the lack of certification does not necessarily indicate poorer hospital performance.
The majority of prior studies that have evaluated the impact of organized stroke care have focused on mortality and did not assess readmission rates or compare hospital-level outcomes. Similar to our findings, studies conducted outside of the United States have demonstrated that organized stroke care is associated with lower mortality, although there have been inconsistent results as to whether patients uniformly benefit from organized care based on stroke type.25–28
One study found that stroke units improve the outcome in patients with large-vessel infarcts, but not in those with lacunar syndromes.28
Analyses of organized stroke care in Canada show that all age groups and stroke subtypes benefit from organized care, even after adjusting for stroke severity.26,27
Additional work found that an increasing level of organized care was associated with improved survival after stroke.25
There was heterogeneity in hospital performance within certification categories as well as overlap between JC-certified PSC and noncertified hospitals. This may be partially explained by the variation in the comprehensiveness of care provided within these facilities. In addition, there may be unmeasured factors that contribute to heterogeneity in outcomes. The JC-certified PSC status may be a proxy measure for the resources available at a given facility which serves as an overall indicator of quality of hospital care, but may not adequately measure the variability in the comprehensiveness of care provided.
The present study has several potential limitations. The index ischemic stroke cases were identified using ICD-9-CM codes, and miscoding can occur. Positive predictive values for the selected codes for ischemic stroke, however, are relatively high,23,24
and there is no reason to suspect differences in data coding across institutions by JC PSC certification status. Medicare inpatient data do not contain information on stroke severity, an important predictor of outcome. Although discharge location and length of stay at least partially reflect stroke severity, these outcomes are also affected by quality of care. Their inclusion in risk-adjusted models, as well as receipt of therapies such as tissue plasminogen activator use, would therefore confound the analyses. Not adjusting for factors that reflect hospital-level care is consistent with other NQF-endorsed measures used to compare hospital performance. Although studies show that the benefits of organized stroke care do not differ by age group or stroke severity,26
there may be variations in referral patterns to facilities. For example, depending on local referral patterns and service availability, moribund patients might be more likely to be kept at local facilities whereas patients with acute symptoms, who may be amenable to thrombolytic therapy, might be preferentially routed to a JC-certified PSC, contributing to better outcomes. There may be additional unmeasured factors that could explain the observed differences in outcomes. Finally, because our analyses are limited to FFS Medicare beneficiaries 65 years or older, the results may not be applicable to those without FFS Medicare coverage or to stroke patients younger than age 65 years, although Medicare FFS patients in this age group represent the majority of ischemic stroke events.
There are more than 4.4 million stroke survivors in the United States, with approximately 795,000 new strokes identified annually.29,30
Stroke is also one of the 10 highest contributors to Medicare costs.31
Among the elderly, stroke and TIAs are a leading cause of hospitalization.32,33
Recurrent events, which occur in 185,000 stroke survivors in the United States each year, are associated with higher mortality rates, greater levels of disability, and increased costs as compared with initial stroke events.34
For stroke survivors, significant disability, preventable complications, and discharge to settings with substantial requirements for ongoing care are common. Due to its high prevalence, adverse outcomes, and large economic burden, stroke represents an important condition to target strategies to reduce mortality and avoidable rehospitalizations. Our study provides initial data on how hospital-level outcome measures, potentially reflecting quality of care, differ by JC PSC certification status. The analysis of hospital-level outcomes after ischemic stroke shows that JC certification of PSCs identifies many high-performing hospitals, but there remains considerable overlap in outcomes between hospitals with and without a JC-certified PSC. Additional research is needed to identify the key determinants of hospital performance, to reduce variability and improve patient outcomes. Risk-standardized stroke mortality and readmission may be used to inform and motivate health care quality improvement efforts.