Hospital Admissions for Acute Ischemic Stroke Down, Though Variation Exists Among Subgroups

Cardiovascular prevention efforts against acute ischemic stroke may be having their desired effect. Data from the Nationwide Inpatient Sample show a substantial overall decrease in hospitalizations for stroke since the turn of the century, although specific age, ethnic, and gender discrepancies still exist.

Past studies have shown a downward trend in ischemic stroke hospitalization and mortality rates in past years, but questions have lingered as to which subgroups of patients are more susceptible.

Pulling information from the Nationwide Inpatient Sample and adjusting for patient age, researchers led by Lucas Ramirez, MD (University of Southern California, Los Angeles), identified an 18.4% overall decrease in acute ischemic stroke hospitalizations throughout the United States between 2000 and 2010. Most of the decline occurred during the first 5 years, where there was an annual average rate of change of -3.89%. In the second 5 years, the decline was  only -0.03%..

Most of the decrease could be attributed to patients aged 65 years and older—hospitalization rates for those aged 65 to 84 and those 85 and older declined by 28.5% and 22.1%, respectively. In contrast, those aged 25 to 44 and 45 to 64 actually saw increases in stroke hospitalizations by 43.8% and 4.7%, respectively.

Characterizing patients by ethnicity, black patients had the highest age-adjusted annual hospitalization rate in 2010 (358 per 100,000), followed by Hispanic (170 per 100,000) and white patients (155 per 100,000). Over the study period, hospitalization rates decreased for both Hispanic (-21.7%) and white patients (-12.4%) but increased for black patients (13.7%).

Women were less likely than men to be hospitalized for stroke over the decade, and they also had a more substantial decrease in stroke hospitalization rates than men (-22.1% vs -17.8%).

Signs of Care Advances

While the findings are consistent with the literature, Ramirez and colleagues warn that their results should be interpreted with caution given that “changes in stroke hospitalization rates are affected not only by true changes in incidence, but also stroke literacy and health beliefs (influencing likelihood of seeking medical attention), prehospital recognition and triage of patients with stroke symptoms, and hospital protocols/healthcare provider literacy (affecting the likelihood of hospitalizing individuals with stroke symptoms).”

Also, they add, the ability to diagnose TIA by a new imaging-based definition and increased use of MRI could affect the number of patients ultimately diagnosed and coded as having acute ischemic stroke.

Nonetheless, the authors suggest that the downward trend in stroke hospitalizations could be directly tied to efforts to improve blood pressure and cholesterol treatment and control undertaken by medical societies, hospitals, and healthcare providers alike.

They report that patients admitted for acute ischemic stroke over the study period became progressively sicker, while in-hospital deaths decreased. This could “reflect improved acute hospital care,” Ramirez and colleagues say, adding that the plateau observed from 2006 to 2010 might possibly signal “a threshold beyond which our current prevention efforts are no longer having an effect.”

As for future research, the authors believe studies should focus on the specific causes of different hospitalization rates “to better ascertain nationwide race/ethnic-, sex-, and age-specific trends in incidence, and identify strategies to target subgroup populations who are most vulnerable.”

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