Identifying risk factors for racial disparities in diabetes outcomes: The translating research into action for diabetes study

Background: Versus whites, blacks with diabetes have poorer control of hemoglobin A1c (HbA1c), higher systolic blood pressure (SBP), and higher low-density lipoprotein (LDL) cholesterol as well as higher rates of morbidity and microvascular complications. Objective: To examine whether several mutable risk factors were more strongly associated with poor control of multiple intermediate outcomes among blacks with diabetes than among similar whites. Design: Case-control study. Subjects: A total of 764 blacks and whites with diabetes receiving care within 8 managed care health plans. Measures: Cases were patients with poor control of at least 2 of 3 intermediate outcomes (HbA1c ≥ 8.0%, SBP ≥ 140 mmHg, LDL cholesterol ≥ 130 mg/dL) and controls were patients with good control of all 3 (HbA1c <8.0%, SBP <140 mmHg, LDL cholesterol <130 mg/dL). In multivariate analyses, we determined whether each of several potentially mutable risk factors, including depression, poor adherence to medications, low self-efficacy for reducing cardiovascular risk, and poor patient-provider communication, predicted case or control status. Results: Among blacks but not whites, in multivariate analyses depression (odds ratio: 2.28; 95% confidence interval: 1.09-4.75) and having missed medication doses (odds ratio: 1.96; 95% confidence interval: 1.01-3.81) were associated with greater odds of being a case rather than a control. None of the other risk factors were associated for either blacks or whites. Conclusions: Depression and missing medication doses are more strongly associated with poor diabetes control among blacks than in whites. These 2 risk factors may represent important targets for patient-level interventions to address racial disparities in diabetes outcomes.