Trends in survival after stroke among Medicare beneficiaries

Estimated 10-year stroke risk by region and race in the United States: geographic and racial differences in stroke risk

OBJECTIVE

Black individuals younger than 75 years have more than twice the risk for stroke death than whites in the United States. Regardless of race, stroke death is approximately 50% greater in the "stroke belt" and "stroke buckle" states of the Southeastern United States. We assessed geographic and racial differences in estimated 10-year stroke risk.

METHODS

The Reasons for Geographic and Racial Differences in Stroke study is a population-based cohort of men and women 45 years or older, recruited February 2003 to September 2007 at this report, with oversampling of stroke belt/buckle residents and blacks. Racial and regional differences in the Framingham Stroke Risk Score were studied in 23,940 participants without previous stroke or transient ischemic attack.

RESULTS

The mean age-, race-, and sex-adjusted 10-year predicted stroke probability differed slightly across regions: 10.7% in the belt, 10.4% in the buckle, and 10.1% elsewhere (p <0.001). Geographic differences were largest for the score components of diabetes and use of antihypertensive therapy. Blacks had a greater age- and sex-adjusted mean 10-year predicted stroke probability than whites: 12.0 versus 9.2%, respectively (p <0.001). Race differences were largest for the score components of hypertension, systolic blood pressure, diabetes, smoking, and left ventricular hypertrophy.

INTERPRETATION

Although blacks had a greater predicted stroke probability than whites, regional differences were small. Results suggest that interventions to reduce racial disparities in stroke risk factors hold promise to reduce the racial disparity in stroke mortality. The same may not be true regarding geographic disparities in stroke mortality.

Is there a sex or race difference in stroke mortality?

OBJECTIVES

We sought to confirm previous studies for the presence and direction of sex and race difference in stroke mortality.

METHODS

Administrative data for 40,450 Medicare beneficiaries who were hospitalized in 1994 to 1996 with acute stroke were used in regression analyses to study sex and race differences in 1-year all-cause mortality among patients with different types of stroke and cause-specific mortality in patients with all types of stroke combined. Hazard ratios were adjusted for age, sex or race, state, year of index stroke, past stroke, subsequent stroke, and fatal coexisting conditions excluding cerebrovascular diseases.

RESULTS

Men with ischemic cerebral infarction, nonspecific stroke, or all types of stroke combined were at 21% to 35% higher risk of all-cause mortality than women, but there was no sex difference among patients with subarachnoid or intracerebral hemorrhage. Nonwhite patients with ischemic cerebral infarction had 11% higher all-cause mortality than white patients, but there were no race differences after adjustments for fatal coexisting conditions. Compared with women, mortality was higher in men with all types of stroke regardless of the cause of death. There was higher risk of death caused by cerebrovascular diseases in white patients with all types of stroke combined, but the risk of death caused by cardiovascular diseases other than ischemic heart disease was higher in nonwhite patients.

CONCLUSIONS

There was no sex or race difference in all-cause mortality in patients with hemorrhagic stroke and higher risk in men with ischemic and nonspecific stroke. Relatively higher risk of mortality caused by cerebrovascular diseases was found in men and white patients.

Cerebrovascular Diseases as Primary Hospital Discharge Diagnoses: National Trend (1970-2000) Among Older Adults

BACKGROUND

Cerebrovascular diseases are a common cause of mortality, morbidity, and hospitalization among older adults. However, the long-term national trends in cerebrovascular disease-related hospitalizations in this age group are not well known.

METHODS

We used the National Center for Health Statistics trend data from the National Hospital Discharge Surveys (1970-2000) to determine incidence of cerebrovascular disease-related hospitalizations among persons 65 years and older in the United States. Only patients discharged with a primary discharge diagnosis of cerebrovascular disease were included. We estimated rates of hospitalization per 1000 civilian residents 65 years and older, for all patients and stratified by age, sex, and race.

RESULTS

Among persons 65 years of age and older, the total number of cerebrovascular disease-related hospitalizations increased from 372,000 in 1970 to 711,000 in 2000. However, the rates of hospitalization due to cerebrovascular disease remained unchanged at 20.7/1000 in 1970 and 20.4/1000 in 2000. The rates for persons 75-84 years and >85 years were, respectively, 2 and 3 times higher than that for persons 65-74 years throughout the study period. Rates for men and women were comparable and stable during the study period. Rates for African Americans, in contrast, increased from 14/1000 in 1970 to 20.6/1000 in 2000, peaking in 1985 (27.4/1000).

CONCLUSIONS

The overall rates of hospitalization due to cerebrovascular disease remained high yet stable. However, the absolute number of hospitalizations due to cerebrovascular disease increased considerably, with potential for serious social, financial, and public health implications for the coming decades.

Short-term, intermediate-term, and long-term mortality in patients hospitalized for stroke

Cerebrovascular disease is the third leading cause of death and the primary cause of long-term disability in the United States. Although the risk factors for stroke have been well defined, less is known about stroke mortality over varying time periods within the same cohort of patients. The purpose of this study is to define rates of short-term, intermediate-term, and long-term stroke mortality among patients experiencing a first-ever hemorrhagic or ischemic stroke between 1994 and 1998. Patients were identified from the Patient Treatment Files of the Department of Veterans Affairs (VA). We included all patients who were discharged from a VA inpatient facility with a diagnosis of acute stroke. Patients were excluded from the study if they had an admission within the previous 5 years for stroke or hemiplegia. We obtained information on the patient's age, gender, and coexisting illnesses. Unadjusted and adjusted 30-day mortality rates were computed using Kaplan-Meier analyses and Cox proportional hazards regression models. The survival-dependent Cox proportional hazards regression models were run for 31-90 days and 91-365 days from the index admission date, for patients who had survived to the start of each of these time periods. Separate models were run for ischemic (n = 34,866 patients) and hemorrhagic (n = 5,442 patients) strokes. Unadjusted 30-day mortality was 8.2 and 20.5% for ischemic and hemorrhagic strokes, respectively. The adjusted 30-day mortality rate was 7.4 and 18.8% for ischemic and hemorrhagic strokes, respectively. For ischemic stroke, age 65 years and older was associated with an increased risk for short-term, intermediate-term, and long-term mortality, while chronic heart failure was associated with an increased risk for short-term and long-term mortality. For hemorrhagic stroke, age 75 years and older, malignancy, and chronic heart failure were associated with increased mortality during all three time periods. Thirty-day mortality is over two times greater following hemorrhagic stroke vs. ischemic stroke. For patients who survive 30 days after an ischemic stroke, the risk factor that remains significantly associated with long-term mortality, which may be improved with appropriate process of care, is chronic heart failure. For patients with a hemorrhagic stroke, variables that remain significantly associated with increased short-term and long-term mortality include malignant neoplasm and chronic heart failure. Information on stroke mortality is important for patients, physicians, and researchers. In addition to stroke treatment, clinicians must be able to provide families of stroke victims with appropriate prognostic information. Further work is needed to assess the impact of actual care patterns, for the above identified risk factors, on stroke prognosis over varying time periods.

Intraregional decline in case-fatality and hospital use after occlusive stroke in the southeastern United States

OBJECTIVE

To identify changes in mortality and hospital use among patients admitted for ischemic stroke in Alabama.

BACKGROUND

The decline in stroke mortality in the Southeast is greater than in other US regions. Whether this decline in a result of decreased incidence or improved case-fatality rates is unknown.

METHODS

We examined Medicare hospitalization data from approximately 625,000 beneficiaries and identified patients admitted for ischemic stroke between January 1992 and December 1994. The search was carried out using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes pertinent to all diagnoses related to ischemic stroke. Data relevant to mortality and length of stay (LOS) were collected, and comparisons were made of the average case-fatality rate and LOS in each of the 3 years.

RESULTS

No significant difference was found in the incidence of ischemic stroke during the 3 years. The number of admissions was 4438 for 1992, 4124 for 1993, and 4762 for 1994. Conversely, the average LOS showed a significant decline, with values of 10.05, 9,36, and 8.72 days, respectively (P<.0003). A significant decline in mortality, with average case-fatality rates of 11.72%, 11.56%, and 9.71%, respectively (P<.003), was also found.

CONCLUSION

These data suggest that the decline in stroke mortality in the Southeast is because of improved patient survival after stroke, rather than decreased incidence. Although several factors may be contributing to the decreased case-fatality rates, improved care of hospitalized stroke patients is likely of primary importance. Additionally, decreased mortality associated with decreased LOS suggests more efficient hospital use.

Why do we have a stroke belt in the southeastern United States? A review of unlikely and uninvestigated potential causes

Although there is widespread recognition of a region with high stroke mortality in the southeastern United States that has persisted over the past 50 years (ie, the "stroke belt"), there is little agreement as to its underlying cause(s). Herein, we review data supporting 10 potential causes for the stroke belt, and assess: (1) the likelihood that each is the contributing factor to the excess mortality, and (2) areas of investigation where data are lacking and that require additional research efforts.

The expanded racial and ethnic codes in the Medicare data files: their completeness of coverage and accuracy

OBJECTIVES

This paper evaluates the new race/ethnicity codes for Asian Americans, Hispanics, and Native Americans that have recently been added to the Medicare enrollment database.

METHODS

The race/ethnicity code revisions made by the Health Care Financing Administration are described and evaluated by (1) comparing the numbers of persons identified as Asian Americans, Hispanics, and Native Americans with corresponding population census projections and (2) determining whether Medicare enrollees born in Asian and Hispanic countries are assigned Asian and Hispanic codes.

RESULTS

Among persons 65 years of age and older, approximately 24% of Hispanics, 17% of Native Americans, and 56% of Asian Americans are identifiable by the new codes. From 18% to 29% of enrollees 65 years old or older born in Mexico, Puerto Rico, and Cuba are coded as Hispanic, and from 14% to 73% of enrollees born in nine Asian countries are classified as Asian American. Classification is not random but is related to timing of migration and to country of origin.

CONCLUSIONS

Researchers should resist the temptation to base analyses on the revised Health Care Financing Administration race/ethnicity codes, since coverage is incomplete and biased.