Racial Disparities in Diabetes Care Rooted in Physician Performance

By Todd Neale
BOSTON, 10 june 2008 -- Black patients treated for diabetes had worse outcomes than whites seen by the same clinicians at a large group practice in Massachusetts, researchers here found. The black patients were significantly less likely than whites to achieve control of hemoglobin A1c, LDL cholesterol, and blood pressure (P<0.001 for all), Thomas Sequist, M.D., M.P.H., of Brigham and Women's Hospital and Harvard, and colleagues reported in the June 9 issue of Archives of Internal Medicine. Controlling for sociodemographic factors attenuated some of the differences, but the bulk of the disparity was strongly driven by individual physician activity, the researchers concluded.
"In addition, the substantial physician-level variation in [diabetes] care was not related to overall performance or volume of black patients treated," the researchers said, "suggesting that system-wide interventions will be needed to improve care for minority patients across all physicians."
These interventions might include cultural competency training and the creation of race-stratified performance reports to raise awareness of disparities, Dr. Sequist said.
Racial disparities in diabetes care -- including poor attainment of intermediate treatment goals and worse long-term outcomes for blacks compared with whites -- have been well studied, the researchers said, but few studies have examined the role that factors at the physician level might play.
To help fill the gap, Dr. Sequist and colleagues evaluated care given to adults with diabetes at an integrated multispecialty group practice. They looked at records from 90 primary care physicians practicing in 13 ambulatory health centers who cared for at least five white patients and five black patients.
Of 6,814 patients, 4,556 were white and 2,258 were black. The black patients were significantly younger, less likely to be male, and more likely to live in communities with lower median household incomes than the whites (P<0.001 for all).
Patients of both races were equally likely to receive annual testing for hemoglobin A1c and LDL cholesterol, but blacks were less likely to have received a statin prescription in the previous year (54% versus 65%, P<0.001).
Blacks were significantly less likely to achieve ideal targets -- a hemoglobin A1c level of less than 7% (39% versus 47%), an LDL cholesterol level of less than 100 mg/dL (45% versus 57%), and a blood pressure of less than 130/80 mm Hg (24% versus 30%) (P<0.001 for all).
Blacks were also significantly less likely than whites to achieve even adequate control for these three measures (P<0.001 for all), the researchers said.
Controlling for clinical factors and between-physician effects had little impact on the disparities in care.
Sociodemographic factors, including age, sex, income, and insurance status, explained 13% to 38% of the observed differences, the researchers said.
Effects at the individual physician level, however, had a substantial influence on the differences, from 66% and 68% of the differences in hemoglobin A1c and LDL cholesterol control, respectively, to 75% of the disparity in blood pressure control.
There were no significant associations between the magnitude of the racial disparities and the number of black patients treated or the overall quality of diabetes care by individual physicians.
"Our data suggest that the problem of racial disparities is not characterized by only a few physicians providing markedly unequal care," the researchers said, "but that such differences in care are spread across the entire system, requiring the implementation of system-wide solutions."
The authors acknowledged several limitations, including the fact that studying just one practice might have reduced the ability to find between-physician effects on disparities in care.
The study was also limited by the inability to analyze differences in physician practice patterns, the use of zip code estimates of median income, the lack of information on outside social factors, and the exclusion of other racial or ethnic groups.
Despite these limitations, Carolyn Clancy, M.D., director of the Agency for Healthcare Research and Quality in Rockville, Md., called the findings "important and provocative."
In an accompanying editorial, she proposed two explanations for the poorer outcomes in black patients in the study: First, aspects of care besides testing, such as teaching about medications and overall communication, might have been inferior. Second, she said, the disparities might have resulted from differences in the patients' level of engagement and support for long-term behavioral changes.
The findings illustrate the need to close the gap between ideal and actual care in diabetes, she said, noting that even in whites the level of control for intermediate outcomes fell short.
She said that public reporting of individual physicians' clinical performance might be one solution to eliminating disparities in care, although this remains controversial.
"Eliminating disparities in healthcare will require that all patients have access to care, as well as physician leadership to assure that the care provided is evidence-based, patient-centered, effective, consistent, and equitable," she concluded.
The study was funded by the Robert Wood Johnson Foundation Finding Answers: Disparities Research for Change national program.
Dr. Sequist serves as a consultant on the Aetna External Advisory Committee for Racial and Ethnic Equality. One of his co-authors serves as a consultant to RTI International and DxCG Inc. Dr. Clancy made no financial disclosures.

Primary source: Archives of Internal MedicineSource reference:Sequist T, et al "Physician performance and racial disparities in diabetes mellitus care" Arch Intern Med 2008; 168: 1145-1151. Additional source: Archives of Internal MedicineSource reference: Clancy C "Improving care quality and reducing disparities" Arch Intern Med 2008; 168: 1135-1136.