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Volume
8: No. 6, November 2011
ORIGINAL RESEARCH
Racial and Ethnic Disparities in the Quality of Diabetes Care in a Nationally
Representative Sample
Patrick Richard, PhD, MA; Pierre Kébreau Alexandre, PhD, MS, MPH; Anthony
Lara, MHSA; Adaeze B. Akamigbo, PhD, MPP
Suggested citation for this article: Richard P, Alexandre PK, Lara A,
Akamigbo AB. Racial and ethnic disparities in the quality of diabetes care in a
nationally representative sample. Prev Chronic Dis 2011;8(6):A142.
http://www.cdc.gov/pcd/issues/2011/nov/10_0174.htm. Accessed [date].
PEER REVIEWED
Abstract
Introduction
Previous studies have consistently documented that racial/ethnic minority
patients with diabetes receive lower quality of care, based on various measures
of quality of care and care settings. However, 2 recent studies that used data
from Medicare or Veterans Administration beneficiaries have shown
improvements in racial/ethnic disparities in the quality of diabetes care. These
inconsistencies suggest that additional investigation is needed to provide new
information about the relationship between racial/ethnic minority patients and
the quality of diabetes care.
Methods
We analyzed 3 years of data (2005-2007) from the Medical Expenditure Panel
Survey and used multivariate models that adjusted for sociodemographic
characteristics, regional location, insurance status, health behaviors, health
status, and comorbidity to examine racial/ethnic disparities in the quality of
diabetes care.
Results
We found that Asian patients with diabetes were less likely to have received 2 or
more glycated hemoglobin (HbA1c) tests or a foot examination during the past
year compared with their white counterparts. Hispanic patients with diabetes
were also less likely to have received a foot examination during the past year
compared with white patients with diabetes. Conversely, black patients with
diabetes were more likely to have received a foot examination during the past year
compared with white patients with diabetes. The differences in the quality of
diabetes care remained significant even after controlling for socioeconomic
status (SES), health insurance status, self-rated health status, comorbid
conditions, and lifestyle behavior variables.
Conclusions
Although the link between racial/ethnic minority status and the quality of
care for patients with diabetes is not completely understood, our results
suggest that factors such as SES, health insurance status, self-rated health
status, and other health conditions are potential antecedents of quality of
diabetes care.
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Introduction
Although diabetes is a prevalent, debilitating, and costly chronic condition
that affects the general population, evidence suggests that racial/ethnic
minority groups bear a disproportionate burden of the condition (1-5).
Racial/ethnic minority groups have a higher prevalence, worse diabetes outcomes,
and higher rates of diabetes-related complications than their white counterparts
(1-3,6,7). Previous studies have consistently documented that racial/ethnic
minority patients with diabetes receive lower quality of care, based on various
measures of quality of care and care settings (8-12). For instance, a report
published in 2006 by the Agency for Healthcare Research and Quality showed that
racial/ethnic minority groups, including patients who have diabetes, received
poorer quality of care in 22 critical measures of quality care compared with
whites (13).
However, a recent study that used data from 1997 to 2003 from Medicare
beneficiaries in managed care plans has shown that improvements have been made in racial/ethnic
disparities in the quality of diabetes care (14). Clinical
performance for patients with diabetes improved, and the gap in the quality of
diabetes care between whites and blacks narrowed for 7 of the Health Plan
Employer Data and Information Set (HEDIS) measures, including glycated
hemoglobin (HbA1c) and eye examination. Similarly, a more recent study that used
nationally representative data from the Medical Expenditures Panel Survey (MEPS)
found no significant differences in the quality of diabetes care between
racial/ethnic minority groups and white patients (15).
Additional studies that examined the Medicare and Veterans Administration
(VA) populations have suggested that recent investment in public resources to
address racial/ethnic inequalities in health and health care may have resulted
in the reduction or elimination of racial/ethnic disparities in the quality of
diabetes care (14,16,17). The results of these 2 studies are encouraging but
cannot be generalized to the US population because of systematic differences
between the general population and Medicare or VA beneficiaries. These
inconsistencies also suggest that additional investigation is needed to provide
new information about the relationship between racial/ethnic minority groups and
the quality of diabetes care.
Racial/ethnic differences in the quality of diabetes care may arise from
multiple factors and complex interactions between patients, their providers, and
the health care systems in which they operate (18). Therefore, we investigated
factors that are amenable to policy changes in our models, including
socioeconomic status (SES) and health insurance coverage, to determine
racial/ethnic differences in the quality of diabetes care. Our objective was to
examine racial/ethnic disparities in the quality of care provided to patients
with diabetes by using nationally representative data sets.
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Methods
Sample
We analyzed 3 years of data (2005-2007) from MEPS, a nationally
representative survey of health services use, health insurance coverage, medical
expenditures, and sources of payment for the US civilian noninstitutionalized
population that is cosponsored by the Agency for Healthcare Research and Quality
and the National Center for Health Statistics. For this analysis, we used the
household component (HC) file of MEPS, which is the core component of the
survey that collects data on demographic characteristics, health conditions,
self-rated health status, medical services use, access to care, satisfaction
with care, health insurance coverage status, and income for each person
surveyed.
We pooled 3 years of data to increase the sample size of the study and used a
study design that attempted to address previous shortcomings and inconsistencies
in the literature. The overlapping design of MEPS allows repeated observations
of the same people several times during the year. We combined data from
the HC files with the pooled estimation linkage file of MEPS to restrict the
analytic sample to unique individuals. By restricting the sample in this way, we
were able to compute appropriate standard errors. To construct the analytic
sample we used data from the MEPS Diabetes Care Survey, a self-administered
questionnaire to adult respondents aged 18 years or older who reported that
they had been diagnosed with diabetes by a health care professional. This survey
contains a series of questions about diabetes management for 2005, 2006, and
2007, including the number of times respondents reported having had an HbA1c test,
the number of times they reported having had their feet checked for sores or
irritation, and the last time they reported having had an eye examination during the
same period.
The resulting sample was 2,671 people who reported that they had been
diagnosed with diabetes by a health care professional during the 3 years
combined. We subsequently excluded 182 people, either because they did not
respond to the self-administered questionnaire themselves or did not
have any office visit during the time of the study. We limited the analytic
sample to people who responded to the self-administered questionnaire
by themselves, not by their spouse or another proxy, to limit reporting bias and
included only patients with diabetes who had at least 1 visit to a health
care professional during the past 12 months to capture patient-provider
interactions in measuring the quality of care for patients with diabetes.
Finally, we excluded an additional 37 people who had missing observations on the
different variables used in the analysis. The final analytic sample was
2,452 patients who reported that they had been diagnosed with diabetes by a
health care professional and were aged 18 years or older.
Variables
Consistent with American Diabetes Association guidelines for patients with
diabetes, we used 3 binary indicators to measure
quality of care for patients with diabetes, which were reporting receipt of the
following during the past year: 1) 2 or more HbA1c tests, 2) 1 foot examination,
and 3) 1 eye examination. For the HbA1c tests, MEPS asked, “During [survey
year], how many times did a doctor, nurse, or other health professional check
your blood for glycosylated hemoglobin or ‘hemoglobin A-one-C’?” For the foot
examination, MEPS asked, “How many times did a health professional check your
feet for any sores or irritations?” For the eye examination, MEPS asked, “In
which year did you have an eye examination in which your pupils were dilated?”
On the basis of previous research, we controlled for a set of patient
characteristics known to be associated with differences in quality of care
including age, race/ethnicity, sex, SES, health insurance status, smoking
status, obesity status, general health status, comorbid cardiovascular
conditions, and regional location (19-21). To assess patients’ race/ethnicity,
respondents were asked, “Which of these would you say is your main racial or
ethnic group?” Response options were non-Hispanic white, non-Hispanic African
American, Hispanic, American Indian or Alaska Native, Asian or Pacific
Islander, mixed race, or some other single race. From these responses, we
constructed 4 categories: non-Hispanic white, black, Hispanic, and Asian. We
used the MEPS body mass index (BMI) measure, calculated from respondents’
self-reported height and weight, to create an indicator variable for obesity
(BMI ≥30 kg/m2). Different categories of education and income were
used to account for the nonlinearity of the relationship between these 2
variables and the quality of care for patients with diabetes. Education levels
were defined as receiving less than a high school degree, high school degree,
college degree, or postgraduate degree. Income levels were defined as incomes
below 100% of the federal poverty level (FPL), between 100% and 199% of the FPL,
between 200% and 400% of the FPL, and above 400% of the FPL. Comorbid
cardiovascular conditions included patients who reported being diagnosed with at
least 1 of the following conditions: hypertension, angina, mild or coronary
heart attack, stroke, or other form of heart disease.
Statistical analysis
We used logistic regression models to determine the odds of receiving at
least 2 HbA1c tests, a foot examination, or an eye examination in the past year.
We conducted χ2 tests to determine differences in outcomes among the
different racial/ethnic minority groups. Significance was set at P < .10.
Because of the complex survey design of the MEPS HC file, we used special
diabetes weights from MEPS to compute robust standard errors of the estimates.
Because we pooled data over several years for a subsample of patients with
diabetes, we used the balanced repeated replication method of variance
estimation to account for the full set of survey stratum and primary sampling
units, as recommended by MEPS. Weighted proportions, adjusted odds ratios
(AORs), and 95% confidence intervals (CIs) were used to present the results. We
used Stata version 11 (StataCorp LP, College Station, Texas) to conduct the analysis.
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Results
More than 68% of respondents were aged 55 years or older, 34% of respondents
resided in families with incomes higher than 400% of the FPL, and 31% had some
form of public insurance such as Medicaid or Medicare. Approximately 78% of the
sample had other comorbid cardiovascular conditions (Table 1).
On average, about 83% of patients reported receiving at least 2 HbA1c tests;
70%, a foot examination; and 61%, an eye examination during the past 12 months.
Chi-square tests indicated significant differences between whites and Asians
receiving at least 2 HbA1c tests (P = .007) and a foot examination (P
= .002) (Table 2). Hispanic patients were less likely to receive an eye
examination during the past year than were white patients (P = .005).
Conversely, black patients were more likely to receive a foot examination than
were white patients (P = .009) and less likely to receive an eye
examination than were white patients (P = .03) during the past year.
Multivariate logistic regression analyses indicated that Asian patients with
diabetes were less likely to receive at least 2 HbA1c tests or a foot
examination in the past year than were their white counterparts
(Table 3).
Likewise, Hispanic patients with diabetes were less likely to receive a foot
examination in the past 12 months than were white patients with diabetes.
Conversely, black patients with diabetes were more likely to receive a foot
examination than were white patients with diabetes.
High school graduates were less likely to receive at least 2 HbA1c tests or a
foot examination compared with participants who did not graduate from high
school. Similarly, patients with diabetes who resided in the Midwest, South, or
West were less likely to receive a foot examination than were those who lived in
the northeastern part of the country. We also found negative associations
between receipt of eye examination and patients who were uninsured or who smoked
compared with those who were privately insured or did not smoke, respectively.
Patients who resided in families with incomes more than 400% of the FPL, were in
fair or poor health, and suffered from comorbid cardiovascular conditions were more
likely to report receiving HbA1c tests compared with those who lived in families
with incomes below 100% of the FPL, were in excellent or good health, and did not
have a comorbid cardiovascular condition. For example, patients with a comorbid
cardiovascular condition were 34% more likely to have received 2 or more HbA1c
tests than were those who did not.
Patients who resided in families with an income above 400% of the FPL, were
publicly insured with either Medicaid or Medicare, reported fair/poor health, or
had a comorbid cardiovascular condition were more likely to have a foot
examination compared with those who lived in families with incomes below 100% of
the FPL, were privately insured, were in excellent/good health, or did not have
a cardiovascular comorbid condition. Patients who had incomes greater than 400%
of the FPL were more likely to receive a foot examination than patients who
lived in families with incomes below 100% of the FPL.
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Discussion
Our study advances the literature on racial/ethnic disparities in
quality of care for patients with diabetes. We assessed racial/ethnic
disparities in the quality of diabetes care on the basis of receipt of
recommended HbA1c tests and foot and eye examinations in the previous year. We
hypothesized that racial/ethnic minority patients with diabetes would receive
lower quality of care than their white counterparts. Compared with white
patients with diabetes, Asian patients with diabetes were less likely to have received
at least 2 HbA1c tests and both Asian and Hispanic patients were less likely to
have received a foot examination in the past 12 months. Conversely, black patients
with diabetes were more likely to have received a foot examination in the past 12
months compared with white patients with diabetes. This finding may be explained
by the fact that black patients with diabetes tend to have higher rates of
diabetes complications and amputations, and recent guidelines have highlighted
the need to carefully monitor these patients as their conditions progress (22).
These differences remained significant even after controlling for SES, insurance
status, health status, comorbid conditions, and lifestyle behavior variables.
However, our results differ from those found by Lee and colleagues (19), who
found no differences in receipt of these measures among racial/ethnic
minorities. Their analysis of 2000 MEPS data found no differences among
racial/ethnic groups for most of the outcomes in diabetes care management,
including respondents who had received an HbA1c test, had their feet checked for
sores or irritation, or received an eye examination in the past year. A possible
explanation for the different findings may be differences in study
design. Contrary to the study conducted by Lee et al (19), we restricted our
sample to unique individuals to compute appropriate standard errors in pooled
estimations. Additional differences were the use of more recent data sets, the
use of special diabetes weights from MEPS, and the use of the balanced repeated
replication method variance estimation to account for the full set of survey
stratum and primary sampling units, as recommended by MEPS (23). Our results
also differ from findings of a study by Trivedi et al that found narrowing of
the gap in the quality of diabetes care between whites and blacks (14). However,
this study was limited to Medicare beneficiaries in managed care, and the
authors did not stratify by other racial/ethnic minority groups such as
Hispanics and Asians. The findings by Trivedi
et al may not be generalizable to other health systems or to other racial/ethnic
groups that may experience greater racial/ethnic disparities in the quality of
diabetes care. Conversely, our findings are consistent with those of other studies that
used both clinical and community-based data (24-29).
Our study has limitations. First, the data we used were cross-sectional, so
causal relationships cannot be established. Second, the dependent variables were
self-reported measures of process outcomes of diabetes care. Although we
controlled for patients who reported poor or fair health or comorbid cardiovascular
conditions, these patients may have visited their providers more often and thus were
more likely to receive diabetes tests compared with those who reported
excellent or good health and no comorbid cardiovascular conditions. Furthermore, no
information on glycemic control among patients with diabetes was available.
Asians may have better glycemic control and may have received HbA1c tests and
foot and eye examinations less frequently than their white counterparts.
Although the link between racial/ethnic minority status and the quality of
care for patients with diabetes is not completely understood, our study suggests
that factors such as health insurance status, SES, and self-rated health status
are potential antecedents of quality of diabetes care. Therefore, assessing the
association between racial/ethnic disparities in the quality of diabetes care and
factors such as SES, insurance status, and health behaviors is warranted because
these factors are modifiable and can serve as the focus of interventions to
reduce racial/ethnic disparities in the quality of diabetes care. Findings from
this study may have clinical, public health, public policy, and research
implications. Specifically, these results may underscore the importance of
providing diversity training to providers to improve the quality of care to
patients with diabetes. Furthermore, evidence from this study may play a key
role in informing policy makers in their continuous efforts to translate
effective research into nationwide practices to eliminate racial/ethnic
differences in quality of care, which is relevant in the context of the current
health care reform law that seeks to eliminate racial/ethnic disparities.
Additional research is needed to fully evaluate the mechanisms and sources of
racial/ethnic disparities in the quality of diabetes care.
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Author Information
Corresponding Author: Patrick Richard, PhD, MA, Assistant Research Professor,
Department of Health Policy, The George Washington University School of Public
Health and Health Services, 2021 K St, NW Ste 800, Washington, DC 20006.
Telephone: 202-994-4176. E-mail: patrick.richard@gwumc.edu.
Author Affiliations: Pierre Kébreau Alexandre, Johns Hopkins Bloomberg School
of Public Health, Baltimore, Maryland; Anthony Lara, Department of Health
Policy, The George Washington University School of Public Health and Health
Services, Washington, DC; Adaeze B. Akamigbo, Health Research & Educational
Trust, Chicago, Illinois.
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