BACKGROUND: Stroke is a leading cause of death and hospitalization in the United States with added disability burden. Measures have been put forward to reduce stroke burden at various geographical levels. Maricopa is the largest county in Arizona with over 4 million residents. Maricopa County Department of Public Health (MCDPH) is working to strengthen the capacity of public health surveillance and cardiovascular disease is one of 5 priorities set forth in the Community Health Improvement Plan. This study assesses the current and historical burden of ischemic stroke and hemorrhagic stroke in small areas by major demographic characteristics in Maricopa County, Arizona.
METHODS: Based on literature review, we systematically examined two major types of stroke, ischemic and hemorrhagic (ICD-9 codes 431-2, 435-8), from hospital discharge data between 2009 and 2013 for both inpatient (IP) and emergency department (ED) admissions. Descriptive statistics are used to assess occurrence by demographic and SES dimensions, and GIS is used to identify geographic hot spots at the zipcode level. Analysis was completed using SAS EG v5.1 and ArcGIS 10.3.1.
RESULTS: The overall rate of admission for stroke between 2009 and 2013 was 289.4 per 100,000 residents. The rate of inpatient admission for ischemic stroke was much higher than hemorrhagic stroke (217.20 vs. 23.84 occurrences per 100,000, respectively); a smaller difference in rates was seen when comparing ischemic and hemorrhagic strokes managed in the ED (35.60 vs. 12.72 occurrences per 100,000, respectively). The majority of patients were 45 years and older and of White or Hispanic race /ethnicity (Chi-square test, p-value <0.0001). We were also able to account for multiple stroke incidents per patient as well as readmissions. During this period, 9.68% of IP admissions were repeated occurrence and 2.73% of ED admissions, this did not differ by stroke type. For ED admission, hotspot analysis shows more ischemic stroke admission in the Southeast zipcodes while more hemorrhagic stroke admission in the Southwest zipcodes. For IP admission, significant admissions for both types of stroke are shown in the area south of the urban core. Additional analysis included length of stay and discharge disposition by stroke type.
CONCLUSIONS: There is a higher rate of ischemic stroke admission than that of hemorrhagic stroke in Maricopa County. The distributions also vary by geography and demographics within each stroke type. The systematic analysis will allow MCDPH to better tailor improvement activities and targeted interventions for cardiovascular disease and specifically stroke.