Randomized controlled trial of the effects of nurse case manager and community health worker interventions on risk factors for diabetes-related complications in urban African Americans

Abstract

Background

African Americans suffer disproportionately from diabetes complications, but little research has focused on how to improve diabetic control in this population. There are also few or no data on a combined primary care and community-based intervention approach.

Methods

We randomly assigned 186 urban African Americans with type 2 diabetes (76% female, mean Å SD age 59 Å 9 years) to 1 of 4 parallel arms: (1) usual care only; (2) usual care + nurse case manager (NCM); (3) usual care + community health worker (CHW); (4) usual care + nurse case manager/community health worker team. Using the framework of the Precede–Proceed behavioral model, interventions included patient counseling regarding self-care practices and physician reminders.

Results

The 2-year follow-up visit was completed by 149 individuals (84%). Compared to the Usual care group, the NCM group and the CHW group had modest declines in HbA_1c over 2 years (0.3 and 0.3%, respectively), and the combined NCM/CHW group had a greater decline in HbA_1c (0.8%. P = 0.137). After adjustment for baseline differences and/or follow-up time, the combined NCM/CHW group showed improvements in triglycerides (−35.5 mg/dl; P = 0.041) and diastolic blood pressure, compared to the usual care group (−5.6 mmHg; P = 0.042).

Conclusions

Combined NCM/CHW interventions may improve diabetic control in urban African Americans with type 2 diabetes. Although results were clinically important, they did not reach statistical significance. This approach deserves further attention as a means to reduce the excess risk of diabetic complications in African Americans.

Introduction

Type 2 diabetes is responsible for a tremendous public health burden and is associated with long-term complications that lead to serious illness and disability [1]. The burden of type 2 diabetes affects African Americans disproportionately. The prevalence and incidence of diabetes is higher in Blacks than in Whites [2], [3], [4]. Furthermore, the rates of diabetic retinopathy, diabetic nephropathy including ESRD, and lower extremity amputations are also substantially greater in Blacks compared to Whites [2]. Growing evidence suggests that the excess risk of complications in African Americans is modifiable, and that the disparity stems in large part from poorer control of major risk factors like glycemic control and blood pressure [5], [6], [7]. Control of these factors depends on the behaviors of patients (e.g., diet, physical activity) and physicians (e.g., treatment threshold and target), and on the structure of the health care system (e.g., access to care, continuity of care) [3], [8], [9], [10], [11].

Recent evidence from the Diabetes Control and Complications Trial (DCCT) [12] and the United Kingdom Prospective Diabetes Study (UKPDS) [13] suggests that achieving tight glycemic control can substantially reduce the risk of complications. Strong evidence also favors blood pressure control, regular foot care, and smoking cessation [13], [14], [15]. However, the manner by which such knowledge will be translated into clinical practice is still unclear. One approach has been the use of nurses in the clinical setting to supplement diabetes care by providing case management and education [16], [17], [18], [19], [20], [21], [22], [23], [24]. Another approach is the use of community health workers to serve as liaisons between the health care system and the family, in addition to providing diabetes education and social services [25], [26], [27]. While these two would appear complementary and potentially synergistic, they have not been tested together. Moreover, they have not been adapted for use in urban African American populations. Therefore, we conducted a randomized controlled trial to determine whether multifaceted, culturally sensitive, primary care-based behavioral interventions implemented by a nurse case manager (NCM) and/or a community health worker (CHW) could improve HbA_1c, a measure of long-term blood glucose control, and other indicators of diabetic control (i.e., lipids and blood pressure) in a sample of urban African Americans with type 2 diabetes.