Blacks are disproportionately afflicted with diabetes and suffer higher rates of complications2,25
and mortality than whites.1
While the cause of these disparities is unclear, higher diabetes-associated morbidity and mortality are likely due largely to the combination of poor blood pressure, lipid, and glycemic control in blacks. Although racial disparities in health care are well recognized, and process measures have improved,11,26
differences in outcomes have shown little or no improvement.8-11,27
Indeed, a recent analysis of trends in glycemic control in a Medicare population showed that the gap between blacks and whites increased during the 5-year period, even after adjusting for socioeconomic factors.11
Moreover, in both a Medicare managed-care and a health maintenance organization (HMO) population, where blacks and whites have equal access to care, blacks continued to have higher A1c levels than whites.8,27
Our study sought to determine (a) whether racial differences in glycemic control can be attributed to differences in demographic/clinical characteristics, patient adherence measures, and/or measures of care by providers, and (b) whether use of a uniform algorithm for diabetes management can alleviate racial differences in glycemic control.
In our study, blacks had higher A1c levels than whites at presentation, but differences narrowed after 1 year of care, and after 2 years of follow-up care, differences in A1c levels disappeared. The racial differences observed at presentation could not be explained by other important clinical characteristics (ie, age, BMI, diabetes duration, etc), and the reduction of such differences after 1 and 2 years of care occurred in a setting where important patient and provider behaviors were similar between groups.
Previous studies have found that blacks have higher A1c levels than whites at presentation,5-8
but most were unable to determine whether differences could be attributed to potential confounders, such as gender, BMI, diabetes duration, diabetes therapy, patient adherence, and/or provider management. For example, the subanalysis of type 2 diabetes patients in the Insulin Resistance Atherosclerosis Study (IRAS) database excluded insulin-treated patients,6
the Health ABC study investigated only patients 70 to 79 years of age,7
and the National Health and Nutrition Examination Survey (NHANES) III survey (1988-1994) did not adjust for diabetes therapy, patient adherence, or provider behavior.5
More recent studies that adjusted for socioeconomic factors did not adjust for diabetes therapy, patient adherence, or provider behavior.11,26,28
Moreover, many of these studies were performed in different sites without adjustment for potential differences in providers and access to healthcare resources. In contrast, we were able to examine a large number of patients both at initial presentation, after 1 year of follow-up, and after 2 years of follow-up in a single healthcare unit where access to resources was uniform, where quality improvement efforts were routine,18,29
and where it was possible to assess the potential contributions of demographic and clinical characteristics, patient adherence, and the pattern of provider management. Similar to the other studies, we did find racial disparities in glycemic control at presentation, but these differences dissipated during follow-up.
Racial disparities in medical care and health outcomes have been attributed to patient-related factors such as genetic differences,30
low socioeconomic conditions,32
limited access to health care,33
negative attitudes toward health and providers,34
and personal preferences35
; and/or provider factors such as clinical training,12
and racial (interpersonal) bias13,15,16
; and limitations in systems support.12
the provider's perception that patients are poorly compliant with therapy,36
and/or poor communication14
are potential problems underlying inadequate provider action. Our study shows that glycemic disparities at presentation may have been caused by racial differences in patient adherence and/or provider behavior prior
to care at our clinic. In contrast, during follow-up in our clinic, patient adherence and provider behavior were similar for blacks versus whites. The differences in A1c levels at presentation disappeared after 2 years of care, which may reflect the time required for the effects of improved provider intensification (and possibly improved patient adherence) to take place. These results support our previous findings that both patient adherence and provider behavior are important for glycemic control23
and that use of interventions that help to overcome clinical inertia and improve provider behavior can enhance glycemic control.29
There was no way to fully test the hypothesis that the observed racial difference in glycemic control was caused by differences in patient adherence and/or provider behavior prior to care at our clinic. However, it was possible to explore antecedent provider behavior according to the dosage of insulin in patients who were using this agent at presentation. In such patients (1405 blacks, 69 whites), average A1c at presentation was 9.5% in blacks versus 9.0% in whites, but average insulin dosage was 0.42 units/kg/d in blacks versus 0.53 units/kg/d in whites (P = .016)—evidence that care prior to presentation was less intensive in blacks despite higher A1c levels.
The findings of this study suggest that with appropriate implementation of a uniform algorithm for diabetes management, racial disparities may be minimized or even eliminated. Recently, the ADA and the European Association for the Study of Diabetes (EASD) published a joint consensus statement providing an algorithm for the management of hyperglycemia in type 2 diabetes.37-39
They recommend beginning treatment with both lifestyle intervention (weight loss and increased physical activity) and metformin therapy titrated to its maximally effective dose for 1 to 2 months. If after 2 to 3 months glycosylated hemoglobin is still not at the goal of <7%, additional treatment with a basal insulin, a SU, or a thiazolidinedione should be prescribed. Titration of insulin doses should be performed frequently, based on fasting glucose (fingerstick) measurements, to reach a goal of 70 to 130 mg/dL (3.9-7.2 mmol/L). Continued titration of doses and/or addition of medications, including those not listed as second-line agents, should ensue until optimal glycemic control has been obtained.37-39
However, different algorithms and guidelines have often not succeeded in bringing patients to optimal glycemic control because they have not provided recommendations that are individualized, timely, and specific. The impact of the ADA/EASD guidelines might also be limited, as they are based on A1c levels that may not be available at the time of the visit, and because they offer a variety of choices that may not be specific enough to aid clinical decision making.
In contrast, our algorithm19
is driven by point-of-care glucose measurements, facilitating immediate implementation, and provide specific instructions as to which medications to add and/or how to adjust dosages. It is possible that the use of this algorithm contributed significantly to the improvements in diabetes control we observed.
Our study has some limitations. Potential differences in socioeconomic status and healthcare access could not be accounted for, but there was no association between socioeconomic factors and glycemic control in the NHANES III database,5
and in a multicenter managed care population26
potential confounding by socioeconomic differences is unlikely in our municipal population (in which most patients are poor and uninsured); a recent study in our clinic failed to show racial differences in socioeconomic factors and healthcare access.40
Patient dropout between the 1- and 2-year follow-up visits may have led to selection bias, but the demographic/clinical characteristics of those who returned were similar in blacks and whites. It is also possible that the characteristics of our population (predominantly urban, uninsured, and low income) may limit generalizability of the findings.
The escalation in the prevalence, complications, and healthcare costs of diabetes poses a particular burden on blacks who suffer disparities in health. Recent studies demonstrating the persistence of racial disparities in health care and outcomes underscore the critical need for healthcare workers not only to acknowledge such differences but also to develop strategies which ameliorate these differences. These findings suggest that differences in glycemic control between blacks and whites disappear under conditions where a uniform management protocol is used, helping to overcome any tendencies toward interpersonal bias and/or clinical inertia of the providers.