Abstract TMP43: Ischemic Stroke Hospitalization Rates by State and Age

Abstract

Background: Medicare data show regional differences in stroke hospitalizations for older patients, but data on regional patterns for younger patients are limited. We assessed geographic patterns of ischemic stroke hospitalizations rates by state for younger and older U.S. adults. Methods: Ischemic stroke hospitalizations (ICD-9 433, 434, 436) were identified using the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project (HCUP) for 2007-2008. Rates were expressed per 100,000 person-years (P-Y) with state-level age- and sex-specific Census data as a denominator. A hierarchical random effects Poisson model estimated state-specific risk-adjusted rates, adjusting for age-sex and applying HCUP sampling weights. Bootstrapping simulation was used to obtain interval estimates of rates for each state and age group (18-64 and 65+). Rates were categorized as being significantly higher, no different, or significantly lower than the national average based on their interval estimates. Results: More than half of strokes in older patients occurred in women (54.4%) compared to 43.5% in younger patients. The prevalence of many comorbidities (COPD, HF, HTN, and renal failure) was expectedly higher for older patients, but the prevalence of diabetes was higher in the younger group (36.2% vs. 30.5%, p<0.001). The overall stroke hospitalization rate was 93 per 100,000 P-Y in the younger group and 1134 per 100,000 P-Y for those 65+ yrs. Ten states’ classifications differed between age groups indicating moderate state-level variance, with rates above the national average tending to cluster in the southeast (figure). Conclusion: Geographic patterns of hospitalization were moderately different for younger and older patients with ischemic stroke. Understanding factors contributing to regional heterogeneity may help target areas in need of improved stroke prevention interventions.