Published online before print March 5, 2009, doi: 10.1161/STROKEAHA.108.539619
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(Stroke. 2009;40:1811.)
© 2009 American Heart Association, Inc.
Original Contributions |
Use of Stroke Secondary Prevention Services
Are There Disparities in Care?
From the Department of Geriatrics and Adult Development (J.S.R.), Mount Sinai School of Medicine, and HSR&D Research Enhancement Award Program and Geriatrics Research, Education, and Clinical Center, James J. Peters Veterans Administration Medical Center, Bronx, NY; Department of Medicine (E.A.H.), University of Texas Southwestern Medical Center, Dallas; and the Department of Medicine (D.M.B.), Indiana University School of Medicine and HSR&D Center of Excellence, Richard L. Roudebush Veterans Administration Medical Center, Indianapolis.
Correspondence to Joseph S. Ross, MD, MHS, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1070, New York, NY 10029. E-mail joseph.ross{at}mssm.edu
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Abstract |
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Background and Purpose— The purpose of this study was to examine whether there are disparities in use of stroke secondary prevention services because disparities in stroke outcomes have been found among older adults, women, racial minorities, and within Stroke Belt states.
Methods— Using the nationally-representative 2005 Behavior Risk Factor Surveillance System, we examined self-reported use of 11 stroke secondary prevention services queried in the survey. We used multivariable logistic regression to examine the association between service use and age, sex, race, and Stroke Belt state residence, controlling for other socio-demographic and health care access characteristics.
Results— Among 11 862 adults with a history of stroke, 16% were 80 or older, 54% were women, 13% were non-Hispanic black, and 23% lived within a Stroke Belt state. Overall service use varied: 31% reported poststroke outpatient rehabilitation, 57% regular exercise, 66% smoking cessation counseling, and 91% current use of antihypertensive medications. Age 80 or older was not associated with lower use of any of the 11 services. Women were less likely to report poststroke outpatient rehabilitation and regular exercise when compared with men (probability values 
0.005); there were no sex-based differences in use of the 9 other services. Blacks were less likely to report pneumococcal vaccination when compared with whites, but were more likely to report poststroke outpatient rehabilitation (probability values 0.005); there were no race-based differences in use of the 9 other services. Stroke Belt state residence was not associated with lower use of any of the 11 services.
Conclusions— Use of many stroke secondary prevention services was suboptimal. We did not find consistent age, sex, racial, or Stroke Belt state residence disparities in care.
Key Words: health care • prevention • women and minorities • quality of care
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Introduction |
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Disparities in stroke incidence and outcomes have been described among older adults, women, racial minorities, and within Stroke Belt states.1–6 For instance, black Americans are twice as likely to experience a stroke when compared with non-Hispanic whites and are twice as likely to die from a first stroke.1,2 However, disparities in clinical practice and outcomes have not been as thoroughly studied for stroke care as they have been for other diseases, particularly cardiovascular care.7 National practice guidelines have been issued by the American Heart and American Stroke Associations to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack, recommending several secondary prevention services for adults who have already had a stroke to lower their subsequent risk of morbidity and mortality from their already established disease.8,9 Examples of recommended stroke secondary prevention services include vascular risk reduction through regular aspirin use, annual serum cholesterol testing and management, regular exercise, and smoking cessation, as well as hypertension and diabetes management.8,9 Differential use of these services may contribute to observed disparities in stroke incidence and stroke outcomes.1,4
Our objective was to determine whether there are disparities in use of stroke secondary prevention services, according to age, sex, race, and Stroke Belt state residence. We used the 2005 Behavioral Risk Factor Surveillance System (BRFSS), a nationally-representative telephone survey conducted by the Centers for Disease Control and Prevention (CDC). The BRFSS offers a unique opportunity to investigate this question, providing data on past medical history, health behaviors, and health care utilization in 2005, including use of 11 stroke secondary prevention services.
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Methods |
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Study Design and Sample
We performed a cross-sectional study using data from the 2005 BRFSS. The BRFSS is a federally funded cross-sectional telephone survey of the civilian noninstitutionalized adult population older than 17 years of age.10 The survey is designed and conducted annually by the CDC in collaboration with the state health departments to monitor health-related behaviors and risk factors in the U.S. population. The survey selects state-specific probability samples of households using a multistage cluster design to produce a nationally representative sample. The BRFSS uses random-digit dialing within blocks of telephone numbers to identify a probability sample of households with telephones in each state. In each household, one adult is randomly identified and interviewed and then assigned a weight within the sample. The BRFSS includes respondent weights to be used for analyses to compensate for unequal probabilities of selection, to adjust for nonresponse and telephone noncoverage, to ensure that results are consistent with population data, and to make population estimates. All 50 states, in addition to the District of Columbia, participated in the 2005 BRFSS. In 2005, the number of completed interviews per state ranged from 2707 to 22 590 with a median overall response rate of 36.5% and a median cooperation rate of 75.1%.11
The BRFSS survey instrument has two relevant parts. The core is a standard set of questions asked by all states concerning health-related perceptions, conditions, and behaviors, as well as questions on socio-demographic characteristics. The optional CDC modules are sets of questions on specific topics that states may elect to use. States that asked questions relevant to each health care service that we examined varied in number.12 Questions examining cardiovascular risk reduction services were asked within both core and optional modules, such that the number of states asking about these services varied from 17 to 51 and accounted for 32% to 100% of the weighted 2005 BRFSS sample (depending on the question). Questions examining hypertension and diabetes management services were also asked within both core and optional modules by 16 to 51 states, accounting for 31% to 100% of the weighted 2005 BRFSS sample. Questions examining infectious disease prevention services were asked within core modules by all states. Because the BRFSS is a publicly-available anonymous data source, our study was exempted from review by the Mount Sinai School of Medicine Institutional Review Board. Additional information about BRFSS survey instruments and procedures is available from the CDC.10
Our cohort included 11 862 adults aged 18 years and older from all 50 states and the District of Columbia who reported ever having had a stroke, identified by their responding "yes" to the following question: "Has a doctor, nurse, or other health professional ever told you that you had a stroke?" We excluded adults who did not report their age (0.6%) or health insurance coverage (0.5%).
Study Variables
Our dependent variables were 11 self-reported measures of recommended stroke secondary prevention for cardiovascular risk reduction, hypertension and diabetes management, and infectious disease prevention (Table 1). All dependent variables were categorized dichotomously as use or nonuse of the service within an appropriate time interval.
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Recommended services for vascular risk reduction include regular aspirin use for all adults without therapeutic contraindications, poststroke outpatient rehabilitation, annual serum cholesterol testing, regular exercise, and annual advice from a health professional regarding smoking cessation for all adults who smoke.8,9 Recommended services for hypertension management for all adults with hypertension who have had a prior stroke include regular use of antihypertensive medications and annual advice from a health professional regarding low salt and low fat diets.8,9 Recommended services for diabetes management for all adults with diabetes who have had a prior stroke include annual measurement of serum glycosylated hemoglobin (HbA1c).8,9 Recommended services for infectious disease prevention include annual influenza vaccination and pneumococcal vaccination within their lifetime.13,14 Although neither vaccination is recommended specifically for stroke secondary prevention care, because each is recommended for all adults with severe comorbid disease, such as a history of stroke, we included them in our investigation.
We examined several independent variables to determine whether there were disparities in use of stroke secondary prevention services according to age, sex, race, and Stroke Belt state residence. Age was categorized as 18 to 44 years, 45 to 64 years, 65 to 79 years, or 80 years and older. Sex was categorized as male or female. Race was categorized as white/non-Hispanic, black/non-Hispanic, or other. Stroke Belt state residence was assigned to adults living in the following states: Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia, as defined by the National Heart, Lung, and Blood Institute during its Stroke Belt Initiative of the early 1990s.15
We also categorized the sample by the following socio-demographic and health care access characteristics, all of which were included in our analyses after testing for multicollinearity: annual household income, employment, education, marital status, household size, self-reported health status, health insurance coverage, and identification of a personal health care provider. The BRFSS defined response categories for the self-report of all socio-demographic and health care access variables, including race/ethnicity, in addition to self-reported health status. Response categories were combined when necessary to ensure sufficient numbers in each group; for instance, annual household income response categories "<$10 000" and "$10 000 to $15 000" were combined into the single category "<$15 000." Socio-demographic and health care access characteristics were included in regression analyses to adjust for their effects on each outcome.
Statistical Analysis
We described respondent characteristics using standard means and frequency analyses. We used Chi-square tests to examine the bivariate relationships between use of each of the 11 recommended stroke secondary prevention services and age, sex, race, and Stroke Belt state residence. Analyses for each of the 4 main socio-demographic characteristics were conducted independently. We used multivariable logistic regression to assess the independent effect of each of our 4 main independent variables on the use of each of the 11 recommended services, creating 3 independent models for each outcome.
The first set of models examined the unadjusted relationship between each of the 11 recommended services and each main independent variable alone in independent models. Thus, as an example, we independently tested the association between regular aspirin use and age, regular aspirin use and sex, regular aspirin use and race, and regular aspirin use and Stroke Belt state residence.
The second set of models examined the adjusted relationship between each of the 11 recommended services and each main independent variable, while including all 4 variables in independent models. Thus, as another example, we tested the association between regular aspirin use and age, sex, race, and Stroke Belt state residence.
The third set of model examined the adjusted relationship between each of the 11 recommended services and each main independent variable, still including all 4 variables in independent models (age, sex, race, and Stroke Belt state residence), but also including additional socio-demographic and health care access characteristics in the models: annual household income, employment, education, marital status, household size, self-reported health status, health insurance coverage, and identification of a personal health care provider. Because the results from the second and third models were similar, we present only the results from the third model as our fully adjusted findings.
Individuals missing outcome data were excluded from the relevant adjusted analyses: data were missing for less than 4% of eligible respondents for each recommended service, except for annual glycosylated hemoglobin measurement among adults with diabetes (missing for 23%). No imputations were made for missing data. Individuals with missing socio-demographic data were also excluded from adjusted analyses (<1% of respondents for each characteristic), except annual household income, for which a category was created for those missing data because they did not know or report the information, representing 18% of the weighted sample.
To facilitate interpretation of our results given our analysis of nonrare events, odds ratios from adjusted analyses were converted to risk ratios using standard techniques.16 All analyses took into account the complex survey design and weighted sampling probabilities of the data source and were performed using SAS-callable SUDAAN statistical software (SUDAAN 9.01, Research Triangle Institute).17,18 All statistical tests were 2-tailed and used a type I error rate of 0.05, adjusted to 0.005 after a Bonferroni correction to account for multiple simultaneous comparisons among the sample for 11 outcomes.
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Results |
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There were 11 862 adults included in our sample who reported ever having had a stroke, accounting for 2.6% of the weighted 2005 BRFSS sample. The majority of this sample was between 45 and 79 years of age, female, white, poor, not in the labor force, had received a high school education or less, were married, and lived in a household with 2 or fewer people (Table 2
). Nearly one-quarter of the sample lived in a Stroke Belt state, 90% were insured, and 90% identified one or more personal healthcare providers. Only 18% self-reported having excellent or very good health status, and 62% self-reported one or more disabling health conditions. Nearly one-quarter currently smoked tobacco, 29% were obese, 68% had hypertension, 58% hyperlipidemia, 37% ischemic heart disease, and 27% diabetes mellitus.
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Use of Stroke Secondary Prevention Services
Use of stroke secondary prevention services varied widely among the different types of services (Table 3). Among cardiovascular risk reduction services, 31% received poststroke outpatient rehabilitation, whereas 77% used aspirin regularly and 81% reported annual cholesterol measurement. Among services for hypertension management, 62% received low fat diet counseling, whereas 91% used antihypertensive medications regularly; 89% reported annual glyosylated hemoglobin measurement for diabetes management. Among services for infectious disease prevention, 52% and 53% reported influenza and pneumococcal vaccination, respectively.
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Age-Based Disparities in Use of Stroke Secondary Prevention Services
In unadjusted analyses (Table 3), adults 80 years of age or older were more likely to report influenza and pneumococcal vaccination when compared with adults 65 to 79 years of age (probability values 0.005); there were no differences in use of the other 9 recommended services. In fully adjusted analyses (Table 4), adults 80 years of age or older remained 10% more likely to report influenza vaccination (relative risk [RR]=1.10, 95% confidence interval [CI], 1.06 to 1.14; P<0.001) and 7% more likely to report pneumococcal vaccination (RR=1.07, 95% CI, 1.02 to 1.11; P=0.003) when compared with adults 65 to 79 years of age.
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In unadjusted analyses (Table 3), adults 44 years of age or younger were less likely to report use of 5 of 11 recommended services when compared with adults 65 to 79 years of age (probability values 0.005), including regular use of both aspirin and antihypertensive medications, as well as cholesterol measurement. In fully adjusted analyses (Table 4), adults 44 years of age or younger remained less likely to report use of 4 of 11 recommended services when compared with adults 65 to 79 years of age (probability values 0.005).
Sex-Based Disparities in Use of Stroke Secondary Prevention Services
In unadjusted analyses (Table 3), women were less likely to report regular exercise when compared with men and were more likely to report pneumococcal vaccination (probability values 0.005); there were no differences in use of the other 9 recommended services. In fully adjusted analyses (Table 4), women were 23% less likely to receive poststroke outpatient rehabilitation (RR=0.77, 95% CI, 0.64 to 0.93; P=0.005) and 19% less likely to report regular exercise (RR=0.81, 95% CI, 0.74 to 0.89; P<0.001) when compared with men.
Race-Based Disparities in Use of Stroke Secondary Prevention Services
In unadjusted analyses (Table 3), blacks were less likely to report regular exercise and both influenza and pneumococcal vaccination when compared with whites (probability values 0.005); there were no differences in use of the other 8 recommended services. In fully adjusted analyses (Table 4), blacks remained 34% less likely to report pneumococcal vaccination when compared with whites (RR=0.66, 95% CI, 0.53 to 0.82; P<0.001), although they were also 33% more likely to receive poststroke outpatient rehabilitation (RR=1.33, 95% CI, 1.13 to 1.54; P=0.002).
Stroke Belt State Residence-Based Disparities in Use of Stroke Secondary Prevention Services
In unadjusted analyses (Table 3), adults residing in Stroke Belt states were less likely to report regular exercise and influenza vaccination when compared with adults not residing in Stroke Belt states (probability values 0.005); there were no differences in use of the other 9 recommended services. In fully adjusted analyses (Table 4), there were no differences in use of stroke secondary prevention services between adults residing in and not residing in Stroke Belt states.
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Discussion |
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Using data from a nationally-representative survey of adults, our study provides recent nationally representative estimates of the use of recommended secondary prevention services among adults who have had stroke, including services for vascular risk reduction, hypertension and diabetes management, and infectious disease prevention. Even though 90% of adults in our study had health insurance coverage and 90% identified at least one personal health care provider, use of accepted guideline-recommended care was suboptimal. Alarmingly high numbers of adults did not receive stroke secondary prevention services. Less than one-third reported poststroke outpatient rehabilitation. Just over half reported influenza and pneumococcal vaccination, as well as reported regular exercise. And only two-thirds reported smoking cessation and low-fat diet counseling.
Suboptimal care has important implications for the care of adults who have had a stroke. Regular exercise, reported by 57% in our study, is among the most straightforward stroke prevention strategies,19,20 even if limited only to modest leisure-time physical activity,21 and needs to be prioritized for counseling by primary care physicians and neurologists. Other opportunities to counsel patients, including smoking cessation as well as low-fat and low-salt dietary counseling, also need to be taken advantage of so that rates may exceed the 62% to 74% we observed. Similarly, routine monitoring of serum cholesterol and glycosylated hemoglobin are essential to determine the effectiveness of treatment, ensure appropriate control, and to identify disease complications at an early enough stage to prevent morbidity and mortality.
Our study found no consistent age, sex, racial, or Stroke Belt state residence disparities in stroke secondary prevention care. Given that disparities in stroke incidence and outcomes have been described among older adults, women, racial minorities, and within Stroke Belt states,1–6 our study provides no evidence to suggest that differential use of stroke secondary prevention services may contribute to these observed disparities. Stroke secondary prevention quality improvement efforts should focus on care which is underused by the entire population. However, our not finding disparities in stroke secondary prevention may be a consequence of adults, once experiencing a stroke, gaining improved access to care and treatment, even if such care is suboptimal. Disparities in stroke incidence, or perhaps in primary stroke prevention, may be attributable to differing access to and affordability of care among older adults, women, racial minorities, or within Stroke Belt states.
On the other hand, although our study found no consistent age, sex, racial, or Stroke Belt state residence disparities in stroke secondary prevention care, we did observe potentially important relationships that need to be further studied. For instance, we found older adults to be more likely to have reported receiving influenza and pneumococcal vaccination. Because guidelines recommend that all adults 50 years of age or older receive the influenza vaccination annually and all adults 65 years or older receive the pneumococcal vaccination in their lifetime,13,14 our findings may reflect that younger adults who have experienced a prior stroke, and their physicians, may not be aware that it is recommended that they receive such vaccinations even at younger ages because of their medical history. We also found that women were less likely, whereas blacks were more likely, to report receiving poststroke outpatient rehabilitation. Perhaps more women have inpatient rehabilitation, as opposed to outpatient rehabilitation, because they do not have a spouse at home capable of providing support in other activities of life, such as cooking and cleaning, during rehabilitation.
Our study is one of the first to examine use of a variety of recommended stroke secondary prevention services among a nationally-representative sample of adults who have had a stroke. However, there are several considerations in interpreting its results. First, the BRFSS is limited to the civilian noninstitutionalized adult population and so our findings cannot be generalized to adults who have had a stroke and now reside in institutionalized settings for care. In addition, some questions which could have improved our study were not asked, particularly with respect to clinical characteristics such as the time since an individual had a stroke, the stroke severity and residual effects, and acute treatment received for the initial stroke. However, federally funded and conducted health surveys such as this provide an ongoing and accessible data source for nationally-representative studies of health conditions and health-related behaviors and comparisons of health care quality among populations.22,23 Second, we studied poststroke outpatient rehabilitation, which may also be provided as an inpatient service, as well as two services which may not be considered stroke secondary prevention care: influenza and pneumococcal vaccination. However, we found no evidence to suggest that rehabilitation is more likely to be used as an outpatient versus as an inpatient service according to age, sex, race, and Stroke Belt state residence, although rates of use may not be as low as the 31% we observed. In addition, because each vaccination is recommended for all adults who have had a stroke, they offer the potential to illustrate possible disparities in stroke secondary preventive care. Third, the survey data are self-reported. Although the tendency of respondents to over-report health promotion and disease-prevention activities is widely recognized,24–26 there is little reason to think that over-reporting would be different according to age, sex, race, and Stroke Belt state residence. Fourth, our study focused on processes of care for stroke secondary prevention primarily delivered in the ambulatory care setting and cannot be generalized to acute or inpatient care or other important dimensions of quality, such as clinical outcomes and patient care experiences. Finally, cross-sectional data can demonstrate associations but cannot prove causality.
In conclusion, we found that despite studying a sample of adults who predominantly had health insurance coverage and access to health care professionals, adults who have had a stroke reported suboptimal rates of stroke secondary prevention services for vascular risk reduction, hypertension and diabetes management, and infectious disease prevention. In addition, we found no consistent age, sex, racial, or Stroke Belt state residence disparities in stroke secondary prevention care.
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Acknowledgments |
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Sources of Funding
This project was not directly supported by any external grants or funds. During parts of this project, Dr Ross was supported by Department of Veterans Affairs Health Services Research and Development Service project no. TRP-02-149. The views expressed in this article are those of the authors and do not necessarily represent the views of the Department of Veterans Affairs. Dr Ross is currently supported by the American Federation for Aging Research. Neither the Department of Veterans Affairs nor the American Federation for Aging Research had any role in the design or conduct of the study; collection, management, analysis or interpretation of the data; preparation, review or approval of the manuscript.
Disclosures
None.
Received October 7, 2008; revision received November 6, 2008; accepted November 7, 2008.
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