We found good evidence for the ability of current health care interventions to enhance diabetes care, improve diabetes health outcomes (control of diabetes, hypertension, and dyslipidemia; microvascular and macrovascular complications), and potentially reduce health disparities among racial/ethnic minorities, including African Americans, Latinos, and Native Americans. While these findings are quite promising, the design and evaluation of current health care interventions leave us with many unanswered questions regarding the benefits of cultural tailoring, the impact of interventions on health disparities, and the ideal target of interventions (patient, provider, organization).
One particular question facing health care leaders is whether cultural tailoring of diabetes QI programs produces benefits above and beyond that of generic diabetes QI programs. Unfortunately, our review did not allow us to answer this question definitely because there were few head-to-head comparisons. The majority of interventions involved the application of generic diabetes QI programs to racial/ethnic minority populations. Sixteen interventions were culturally tailored for the racial/ethnic group under study; interventions primarily targeted patients through the use of culturally appropriate patient education and/or case management (often with the use of CHWs), or the use of community outreach (i.e., health fairs) and partnerships. Although there was no comparison between patient intervention types, the meta-analysis of culturally tailored patient interventions resulted in a larger reduction in HbA1c values than the analysis of general QI patient interventions. We found only one provider-targeted intervention that incorporated a culturally tailored component. Physician cultural competency training was included as part of a multitarget intervention, and as such the independent effects of this training component could not be ascertained (Hosler, Godley, and Rowland 2002
). We found no culturally tailored interventions that targeted health organizations (i.e., the use of interpreter services or bilingual communications technology).
A more fundamental question is whether health disparities are affected by current diabetes QI interventions. To address this question, studies must separately track the health outcomes of both non-Hispanic whites as well as racial/ethnic minorities. We found only two studies that collected data on non-Hispanic whites as a comparison group and measured a change in diabetes health disparities (all other studies examined change within a given racial/ethnic minority population). One of these studies included whites in the intervention group (an initiative that targeted both patients and providers), thereby allowing researchers to compare the program’s efficacy by race (Sequist et al. 2006
). While significant reductions in disparate care were reported, the investigators found that the intervention produced smaller reductions (lipid control) or no effect (diabetes control) for individual health outcomes. In the other study, whites were used as the usual-care comparison group, which gave insight into the ability of a racially targeted intervention to reduce health disparities (Jenkins et al. 2004
). This intervention incorporated a community-based component and reported a reduction of all disparities in care (except aspirin usage) and outcomes. Although caution must be used in generalizing findings from two studies, this research suggests that—like patient-targeted interventions—culturally tailored programs with enhanced community involvement may be an important factor in the success of multitarget interventions at improving diabetes health outcomes. Nonetheless, much more research needs to be done evaluating program effectiveness at reducing health disparities before any conclusions can be made.
We found interventions that took place in a variety of clinical settings and geographic locations, suggesting that improvements in diabetes care and outcomes can be achieved under heterogeneous circumstances, including underresourced environments such as public hospitals and community health centers. Only a few of the studies in our review had long-term follow-up, which is necessary to assess the sustainability of interventions and to capture the effect on health outcomes that may take longer to manifest. For example, one study of community health centers reported no change in diabetes outcomes at 1 and 2 years of follow-up (Landon et al. 2007
), yet another study of community health centers in the same Health Disparities Collaborative reported improvements in glucose and lipid control after 2 and 4 years of follow-up (Chin et al. 2007
In terms of the ideal target for diabetes disparities interventions, our review indicates that there is no single optimal target for interventions. In fact, we found that interventions targeting patients, providers, and health care organizations were all able to bring about improvements in the care and health outcomes of racial/ethnic minorities. There are specific lessons learned from each of these intervention categories.
Successful patient-targeted interventions tended to utilize interpersonal (rather than computer-based) skills and social networks such as family members, peer support groups, interactive or one-on-one education, and CHWs. In addition to the benefits of interpersonal interventions, we found that culturally tailored interventions were much more effective among racial/ethnic minorities, while the effects of generalized diabetes self-management training interventions were modest. This is not surprising given that multiple observational studies have found that culture, socio-economic status, and psychosocial factors such as social support, self-efficacy, and coping skills play a large role in explaining diabetes self-care and health outcomes (Chipkin and de Groot 1998
; Fitzgerald et al. 1997
). For example, one study found that 16%-40% of low-income African American and Latino patients limited diabetes care because of financial concerns (Horowitz et al. 2004
). Limited access to recreational facilities and supermarkets with recommended diabetes food items disproportionately limit the participation of racial/ethnic minorities in recommended physical activity and healthy nutritional habits (Bach et al. 2004
; Benjamin, Schneider, and Hinchey 1999
; California Medi-Cal Type 2 Diabetes Study Group 2004
; Clancy et al. 2003
; Glasgow et al. 2003
Among the various types of provider interventions, several studies found that in-person feedback to providers was superior to computerized decision-support in effecting sustained provider behavioral change and health outcomes (diabetes and blood pressure control) (Phillips et al. 2002
; Phillips et al. 2005
; Ziemer et al. 2006
). Some of the findings from provider interventions were particularly relevant for racial/ethnic minorities, who are less likely to have access to subspecialty care and who are more likely to have worse control of their diabetes compared to whites. In one intervention, primary care providers who received feedback and reminders had patients with equivalent diabetes control to those seen in the diabetes specialty clinic, indicating real promise for primary care provider interventions to affect health outcomes (Phillips et al. 2005
). In a separate provider intervention, patients with higher HbA1c values at baseline had the greatest improvements in glycemic control (Benjamin, Schneider, and Hinchey 1999
). These results suggest that targeting providers and facilities that serve racial/ethnic minority populations may be a highly effective public health strategy to improve diabetes outcomes.
Health Care Organization Interventions
The majority of health system interventions focused on innovative use of human capital, including nurse case management, CHWs, nonphysician clinicians, and staff-led prescription assistance programs.
Case management and CHWs
Our review found strong evidence for the effectiveness of nurse case managers to affect quality of care as well as patient outcomes, including diabetes control and the onset of retinopathy. More than half of the health care organization interventions incorporated case management as a key component. More modest outcomes were reported in studies using telemedicine case management than in those using on-site nursing staff. CHWs were effective in the following: making and keeping appointments with PCPs and subspecialists; acting as a patient adjunct to the primary care team; and perhaps being as effective as a nurse in case management, which, for health centers with limited resources, may make case management a financially viable option (Gary et al. 2004
). Case management is particularly important within medically underserved racial/ethnic minority populations because it addresses barriers to adherence by educating patients in the areas of nutrition, exercise, and self-management; identifying adjunct health services (i.e., home health); providing ancillary services such as laboratory testing and vaccination; and addressing logistical issues such as transportation (California Medi-Cal Type 2 Diabetes Study Group 2004
). CHWs may also be particularly important to health care teams serving racial/ethnic minority populations. CHWs can overcome the social, cultural, and linguistic barriers of underserved women and have been shown to be powerful change agents within African American, Latino, Native American, and Asian communities (Erwin et al. 1996
; Gotay et al. 2000
; Gray 1980
; Navarro et al. 1998
; Strum et al. 2005
We found good evidence that nurses acting as clinicians (via treatment algorithms and physician support) can produce significant improvement in both process and outcome measures, and were more effective than when they were employed as case managers. Nurse clinicians were equally effective in community health centers and academic settings, indicating that medically underserved clinics with nurse-directed care can provide comparable care to health care organizations with better infrastructure and ready access to endocrinologists (Fanning et al. 2004
). Unlike nurse-led care, pharmacist-directed care was significantly more labor intensive, with patient visits occurring every 1-4 weeks (Jaber et al. 1996
). Although it led to significant improvement in glycemic control, physician resistance and limited insurance reimbursement may inhibit the widespread application of this method (Jaber et al. 1996
Medical Assistance Programs (MAPs)
We found one study that improved diabetes and dyslipidemia control after helping patients obtain free medications for these chronic diseases (Strum et al. 2005
). MAPs have been shown to increase prescription adherence, improve clinical outcomes, decrease hospitalizations, and reduce hospital costs (Nykamp and Ruggles 2000
; Schoen et al. 2001
). For federally funded community health centers and hospitals that provide prescriptions to uninsured patients, MAPs can result in cost savings that can be reallocated for direct patient care.
Disease management systems
Disease management has been defined as “an organized, proactive, multicomponent approach to health care delivery that involves all members of a population with a specific disease entity such as diabetes” (Norris et al. 2002
, 19). Disease management consists of the following four elements: (1) identification of a population with the disease (i.e., diabetes registry), (2) guidelines for performance standards for care, (3) management of identified people (i.e., nurse case management), and (4) health information systems for tracking and monitoring (Norris et al. 2002
). However, they may also contain additional components such as patient or provider education, visit reminders, and practice redesign.
None of the health care organization interventions in our review met the definition of disease management, although many had one or more components. One study included a diabetes registry, case management, and visit reminders (Bray, Roupe, et al. 2005
; Bray, Thompson, et al. 2005
). This intervention improved both process and outcome measures. A systematic review of the effectiveness of disease management among patients with diabetes reported better diabetes control and increased screening for neuropathy, dyslipidemia, and microalbuminuria (Norris et al. 2002
). However, this review was based primarily on small efficacy trials. A recent study of 63 physician groups and 11 health plans found that disease management programs were associated with better processes of care, but not with improvements in health outcomes or intensity of medication management (Mangione et al. 2006
Multi-target interventions provide several sources of unique information in our review: data about the effectiveness of interventions among Native Americans (significant health outcomes were noted; Rith-Najarian et al. 1998
), information about macrovascular outcomes (48% reduction in lower extremity amputations; Rith-Najarian et al. 1998
), and evidence about the reduction of health disparities in addition to improvements in health outcomes (Jenkins et al. 2004
; Sequist et al. 2006
Current Research Limitations and Future Directions
Our review has identified health care interventions that have the potential to improve diabetes health outcomes and reduce disparities among racial/ethnic minorities. However, there are limitations to the current body of evidence and many remaining unanswered questions. In this section, we discuss such limitations, identify ongoing public health initiatives not included in this review, and offer recommendations in the areas of research methodology and program design to help advance the field of diabetes health disparities research.
It is first important to recognize that this review is limited by potential publication bias, where studies with positive findings are more likely to be published than those with negative findings. Many health care organizations undertake diabetes care improvement interventions that are undocumented in the medical literature. Another challenge in interpreting our findings is that interventions often depend on organizational culture and infrastructure, which vary between organizations and are typically not assessed, thus making it difficult to make comparisons across studies.
In addition, we found only two reports that investigated the effectiveness of a health care intervention at reducing health disparities; all other reports documented changes in health outcomes among racial/ethnic minority populations. While understanding what works within minority communities is important, we also need information about what works to reduce the existing gap in health care delivery and health outcomes.
Relatively few interventions in our review reported both process and outcome measures. It is important to know whether an intervention changed how health care was delivered (process measures) and whether it affected health status (outcome measures) in order to fully understand its effectiveness. As such, future research should assess both process and outcome measures in order to draw better inference about a correlation between the two.
There is also a need to develop better process measures that are tightly linked, or well correlated, to outcome measures because growing evidence suggests that measuring testing rates (i.e., HbA1c or LDL testing) does not correlate well with diabetes health outcomes (Grant et al. 2004
; Sequist et al. 2006
; Trivedi et al. 2005
). This may be due to the multiple intermediate processes that must occur in order for a test to affect health outcomes. Physicians must receive the test result, communicate findings to patients, and recommend changes in the treatment regimen; patients must share the goal of improved disease control and be willing and able to adhere to changes in their treatment. Future research should identify more downstream process measures that are tightly linked to health outcomes. For example, the intensification of treatment for patients with diabetes may be an important process measure that correlates better with health outcomes (A. Brown et al. 2005
; Rodondi et al. 2006
Moreover, future research should explore which downstream activities have the most potential to affect diabetes disparities. For example, one health plan reported a larger reduction in the disparity for LDL testing than in LDL control that researchers attribute to the higher rates of statin use among whites in the health plan (Sequist et al. 2006
). Determining whether physician prescribing patterns or patient adherence accounted for the differential use of statins would help to identify important targets for future interventions.
Finally, studies with longer periods of follow-up are needed in order to understand the sustainability of health care interventions and to capture long-term effects on health outcomes.
Broader expansions into racial/ethnic minority populations.
We found only one health system intervention that targeted racial/ethnic minorities other than African American or Hispanic American populations. More research is needed in NA/AN and AA/PI populations who have documented disparities in diabetes prevalence, control, and comorbid conditions as well as lower rates of patient satisfaction and appropriate care delivery (Saha, Arbelaez, and Cooper 2003
). In addition, older racial/ ethnic minorities are largely understudied, despite the fact that they represent the fastest growing population of persons with diabetes and have unique challenges to diabetes management and control (Peek and Chin 2007
Patients on the fringe of the health system
All of the interventions in our review were designed to improve care for patients that are well established within the health system—those with a regular primary care provider and an established medical home. However, the patients most at risk for poor health outcomes are those on the fringe of health care systems—those who disproportionately rely on urgent and emergent care facilities for routine care. Finding innovative ways of transitioning these persons into the primary care system will be important to future efforts at reducing racial/ethnic disparities in chronic disease outcomes such as diabetes.
Results from two pilot studies show promise in the ability to provide chronic disease management to patients without primary care providers (Ezike and Vachon 2006
; Khan et al. 2005
). In one intervention, an urban public hospital created a diabetes walk-in clinic consisting of aggressive optimization of medication management and an interactive patient education computer module that focuses on self-management (Khan et al. 2005
). At 3 months, improvements in systolic blood pressure, fasting blood glucose, dietary habits, and diabetes knowledge were reported, and more than 70% of patients were prescribed aspirin, an angiotensin-converting enzyme inhibitor, and a statin (Khan et al. 2005
). Patients are seen regularly in the walk-in clinic until their appointment with a new primary care provider. The second pilot targets persons with diabetes who are on a waiting list to become patients at an urban community health center (Ezike and Vachon 2006
). Study participants utilize monthly health fair-style group visits and also receive RN case management and 5-min physician encounters to adjust medications. Patients with four or more visits had better control of their diabetes, blood pressure, and cholesterol (Ezike and Vachon 2006
Although the majority of provider interventions focused on physician education, none in our review involved intensive training of PCPs in diabetes care. There are, however, several innovative programs designed to do so, and because racial/ethnic minorities are less likely to have access to subspecialist care, such programs have the potential to reduce disparities by providing high-quality diabetes care within the primary care setting. For example, the National Committee for Quality Assurance (NCQA) provides special diabetes certification for providers that, in partnership with the not-for-profit organization Bridges to Excellence, offers physician incentives for the delivery of safe, effective diabetes care (Bridges to Excellence 2007
; NCQA 2007a
). In addition, the American Board of Internal Medicine and American Board of Family Practice offer practice improvement modules in diabetes.
None of the provider-targeted interventions in our review addressed provider communication, cultural competence, or shared decision making, despite a growing literature correlating positive health outcomes, including diabetes control, with enhanced communication and shared decision making (Greenfield et al. 1988
; Greenfield, Kaplan, and Ware 1985
; Stewart 1995
). This is particularly relevant for racial/ethnic minorities, who have less shared decision making, less patient-centered care, and more physician verbal dominance in their clinical encounters (Cooperet al. 2003
, Johnson et al. 2004
). Moreover, there is a growing awareness that provider bias may be an important contributor to health disparities (Beach et al. 2005
; Bogart et al. 2000
; Finucane and Carrese 1990
; van Ryn and Burke 2000
). Future diabetes disparities research targeting providers should include consideration of components that address patient/provider communication, cultural competence, and potential provider bias as means to reduce diabetes health disparities.
Health Systems Interventions
Health systems change (i.e., disease registries) is currently a major focus of QI initiatives seeking to improve health care quality and health outcomes. For example, New York recently began a citywide diabetes registry (via mandatory reporting of elevated HbA1c values) that allows a better coordination of diabetes services between health care institutions and represents true innovation in health system change (Steinbrook 2006
). Other health system initiatives are discussed below.
Community-based partnerships and initiatives
The REACH 2010 initiatives provide an excellent example of such promise. REACH 2010 was implemented as the federally funded mechanism to address the Healthy People 2010 goal of eliminating long-standing health disparities in diabetes and five other priority areas (Jenkins et al. 2004
). Unfortunately, rigorous evaluation of REACH programs’ outcomes has been lacking. Of the 17 REACH initiatives that address diabetes disparities, we were able to identify only two reports in peerreviewed journals that reported on changes in process and/or outcome measures (Jenkins et al. 2004
; Two Feathers et al. 2005
). To obtain information about lessons learned and essential programmatic components for successful interventions, more scientifically rigorous evaluation of these programs will be critical.
Strengthening the safety net
There is evidence that a majority of racial/ethnic minority patients may receive care from a relatively small number of providers (Bach et al. 2004
; Forrest and Whelan 2000
; Massing et al. 2003
). A recent study of Medicare beneficiaries found that 80% of visits by African Americans were seen by 22% of the physicians in the study (Bach et al. 2004
). These doctors were more likely to provide care to the uninsured and persons with Medicaid, practice in low-income neighborhoods, and report difficulty accessing high-quality specialists, diagnostic imaging, and nonemergency hospital admissions (Bach et al. 2004
). Thus, the differential access of safety-net providers, who provide a disproportionate amount of care to racial/ethnic minorities, to quality health systems resources may be a crucial contributor to disparities in diabetes health outcomes.
A recent federal initiative to increase the number of community health centers will help to strengthen the safety net (U.S. Department of Health and Human Services 2006
). Yet equally important is the provision of federal funds to safety-net hospitals and subspecialty clinics, which provide the secondary and tertiary care that are necessary adjuncts to community health centers. Future research should evaluate the impact of enhanced resources within the safety net on diabetes health outcomes and health disparities among racial/ethnic minorities.
National diabetes QI initiatives
Although the interventions that met our inclusion criteria were generally local in scope, it is important to acknowledge that there are ongoing national diabetes QI efforts that have the potential to improve health outcomes and reduce health disparities among racial/ethnic minorities. For example, the Diabetes Quality Improvement Project (DQIP) has been an important step in addressing deficiencies in quality of care. DQIP is a collaborative effort of diabetes health care providers, health care organizations, insurance organizations, researchers, diabetes organizations, and health services organizations (Fleming et al. 2001
DQIP has provided a uniform set of diabetes performance measures that are used to assess, compare, and improve the quality of care (Hayward et al. 2004
). Six of the original eight DQIP measures were adopted by the NCQA to use in HEDIS (Health Plan Employer Data and Information Set), a key component of the NCQA Quality Compass that allows businesses and consumers to compare the quality of health insurance plans quickly and easily (NCQA 2007b
). Thus, the public availability of quality measures can motivate health care organizations to pursue QI initiatives because such information can be utilized by companies and individuals when purchasing health plans.
In addition to collaborating on the development of DQIP, the Centers for Medicare and Medicaid Services (CMS) has invested heavily in demonstration projects to evaluate whether disease management services can, as an adjunct to existing physician care, improve the management of chronic diseases such as diabetes (Casalino 2005
). For example, in the Medicare Quality Improvement Organization Program, Medicare spends approximately $200 million annually to contract with networks of nonprofit quality improvement organizations (QIOs) that collaborate with hospitals, nursing homes, and outpatient practices to improve quality of care (CMS 2006
; Massing et al. 2003
). From 1999 to 2002, QIOs began 13 projects that focused on diabetes screening and prevention. The effectiveness of these QIOs has not been thoroughly evaluated, and early research reported that hospitals participating in QIOs have the same outcomes in 14 of 15 quality indicators as hospitals that did not collaborate with QIOs (Snyder and Anderson 2005
Evaluation of federal initiatives such as the QIOs should include an assessment of their ability to improve health outcomes among racial/ethnic minorities and reduce health disparities. Since 1995, Medicare has funded nearly 50 different demonstration initiatives, only 1 of which specifically addresses health care delivery to racial/ethnic minorities (U.S. Department of Health and Human Services 2005
). Such federal programs should integrate mechanisms that measure and reduce racial disparities; they currently represent a significant missed opportunity to learn more about the impact of national policy on the heath status of this country’s racial/ethnic minority populations. Collaboration between initiatives such as REACH 2010, which seek to reduce health disparities, and general QI initiatives such as the Medicare-funded QIOs could provide an excellent opportunity to do just this.