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Diabetes: Case Management Interventions to Improve Glycemic Control


What the Task Force Found

About The Systematic Review

The Task Force finding is based on evidence from a systematic review of 15 studies (search period through December 2000). The review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice, and policy related to diabetes prevention and control.


  • Diabetes case management involves appointing a professional case manager, who does not provide healthcare services directly, but who oversees and coordinates all of the services received by someone with the disease.
  • Case management has five essential features: 1) identifying all those affected by the disease that are eligible for a case manager, 2) assessing current levels of healthcare and needs of eligible participants, 3) developing an individual care plan for each participant, 4) putting the care plan into action, and 5) monitoring of results.
  • Case management can be delivered as a single intervention or as part of a multicomponent intervention (e.g., disease management).

Summary of Results

Fifteen studies qualified for the review.

  • Glycated hemoglobin (GHb) levels: Median decrease of 0.53 percentage points (interquartile range: –0.65% to –0.46%; 11 studies) when case management was implemented with disease management and of 0.40 percentage points (range: –0.6% to –0.16%; 3 studies) without it.
  • Healthcare providers monitoring of GHb levels: median increase of 33% when implemented with disease management (interquartile interval, 13% to 42%; 5 studies).
  • Additional physiologic outcomes examined in this review include:
    • Lipid concentrations (3 studies)
    • Body mass index (1 study)
    • Weight (4 studies)
    • Blood pressure (2 studies)
  • The reviewed studies showed that case management helped adults with type 2 diabetes who were in managed care systems; whether or not the results apply beyond adults with type 2 diabetes in managed care systems has not been determined.

Summary of Economic Evidence

An economic review of this intervention did not find any relevant studies.


Based on results for interventions in different settings and populations, findings are applicable to the following:

  • Adults with type 2 diabetes in managed care settings in community clinics in the United States
  • Interventions delivered in conjunction with disease management or with one or more educational, reminder, or support interventions

Evidence Gaps

Each Community Preventive Services Task Force (Task Force) review identifies critical evidence gaps—areas where information is lacking. Evidence gaps can exist whether or not a recommendation is made. In cases when the Task Force finds insufficient evidence to determine whether an intervention strategy works, evidence gaps encourage researchers and program evaluators to conduct more effectiveness studies. When the Task Force recommends an intervention, evidence gaps highlight missing information that would help users determine if the intervention could meet their particular needs. For example, evidence may be needed to determine where the intervention will work, with which populations, how much it will cost to implement, whether it will provide adequate return on investment, or how users should structure or deliver the intervention to ensure effectiveness. Finally, evidence may be missing for outcomes different from those on which the Task Force recommendation is based.

Identified Evidence Gaps

The following outlines evidence gaps for disease and case management interventions to control diabetes.

Even though disease and case management were found effective in the managed care setting for improving glycemic control and provider monitoring of certain important outcomes, several important evidence gaps were identified in this review. One of the most pressing needs is to better define effective interventions. Disease management has multiple component interventions. To make optimal use of resources, however, only the interventions that contribute most to positive outcomes should be implemented, and these need to be defined. Case management interventions are also usually delivered with other interventions, and the effectiveness of these also needs to be defined. Are case management interventions delivered with disease management more effective than case management delivered as a single intervention? Are there specific additional interventions that augment the effectiveness of disease and case management, such as DSME? Additional research questions relating to case management include identifying the optimal intensity (frequency and duration) of patient contact and determining whether professionals other than nurses (e.g., social workers or pharmacists) could function as case managers.

How best to integrate disease and case management interventions into existing healthcare systems also needs to be addressed. What are the strengths and limitations of delivering these interventions as part of primary care or specialty care, or might they best be delivered by contracted organizations and provider networks that are separate from the patient's healthcare delivery system (i.e., the carve-out model)?

Although the existing effectiveness literature examines many important outcomes, research is needed to determine the effect of disease and case management on long-term health and quality of life outcomes, including cardiovascular disease events, renal failure, visual impairment, amputations, and mortality. Further work is also needed to determine the effect of case management on blood pressure, weight, lipid concentrations, and provider screening rates for retinopathy, peripheral neuropathy, and microalbuminuria. In addition, provider and patient satisfaction with these interventions need much more attention from researchers.

As discussed above, the applicability of these data are somewhat limited, leaving numerous important questions unanswered. For example, are disease and case management effective in settings other than HMOs and community clinics, such as academic clinics and independent private practices? Do these interventions work better in some types of delivery systems than others? Are they effective for adolescents with diabetes? How do the cultural, educational, and socioeconomic characteristics of a population affect outcomes? What are the key barriers that providers perceive for disease and case management? How would it be best to obviate them? Do patients perceive any barriers to these interventions?

Numerous deficiencies in the methodologies of these studies were identified. Often there was inadequate descriptive information; studies need to include adequate demographic information (at a minimum, age, gender, race or ethnicity, and type of diabetes), a description of the delivery system infrastructure (automated information systems, prior use of guidelines, resource support, management [medical and non-medical] commitment and support), and details of the intervention (components, frequency and duration of patient contact, who delivered the intervention, whether and which clinical practice guidelines were used, and degree and type of interface with primary care). In addition, more studies are needed with a concurrent comparison group to control for secular trends in healthcare delivery and patient practices. Finally, studies are needed in which a broad range of providers is recruited.


Study Characteristics

  • Except for one study in the United Kingdom, all studies were performed in the United States.
  • Settings were primarily managed care organizations, although an academic center, community clinics, a U.S. military clinic, and a U.S. veterans hospital were included as well.
  • In most studies the entire eligible population of providers at a clinic or in a healthcare organization was recruited to participate; in three studies the researcher selected a subset of providers.
  • Study populations were predominantly mixed by gender and race, and they were mainly adults with type 2 diabetes. One study was of children with type 1 diabetes (mean age, 9.8 years).
  • Case management was implemented along with disease management in 11 of the studies. In other studies additional interventions were used, including diabetes self-management education, telemedicine support, insulin-adjustment algorithms, group support, visit reminders, and hospital discharge assessment and follow-up. It was not possible to determine the isolated effect of case management in these studies.