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Cover of Closing the Quality Gap: A Critical Analysis of Quality Improvement Strategies (Vol. 2: Diabetes Care)

Closing the Quality Gap: A Critical Analysis of Quality Improvement Strategies (Vol. 2: Diabetes Care)

Technical Reviews, No. 9.2

Investigators: , MD, , MD, , BA, , BA, , BSc, , MD, , MM, and , MD, MS.

Stanford-UCSF Evidence-based Practice Center
Rockville (MD): Agency for Healthcare Research and Quality (US); .
Report No.: 04-0051-2

Structured Abstract


Care remains suboptimal for a substantial proportion of the more than 17 million patients in the United States with diabetes. This review examines strategies for improving the quality of care for adult type 2 diabetic patients, through changes in provider behavior and modifications to the organization of care.

Search Strategy and Inclusion Criteria:

The researchers searched the MEDLINE® database, the Cochrane Collaboration's Effective Practice and Organisation of Care (EPOC) registry, article bibliographies, and relevant journals for experimental evaluations of quality improvement (QI) interventions involving outpatient care for adults with type 2 diabetes mellitus. The investigators included randomized or quasi-randomized controlled trials, controlled before-after studies, and interrupted time series in which at least one reported outcome involved changes in serum hemoglobin A1c or a measure of provider adherence to a recommended process of care.

Data Collection and Analysis:

Two reviewers independently abstracted relevant data, including classifying the components of each QI intervention as provider education, provider reminders, facilitated relay of clinical information, patient education, promotion of self-management, patient reminders, audit and feedback, organizational change, or financial incentives. Certain categories were further subdivided into major subtypes (e.g., professional meetings for provider education and disease management for organizational change). The investigators also assessed the impact of clinical information systems as a mediator for interventions of all types. They compared different QI strategies in terms of the median effects achieved for glycemic control and for a generalized measure of clinician adherence. In addition, linear regression analyses were performed using methodologic features and QI types as predictors, taking into account baseline groups differences and study size.

Main Results:

Fifty-eight articles reporting a total of 66 trials met the established inclusion criteria. The most common interventions employed were organizational change in 40 trials, patient education in 28 trials, and provider education in 24 trials. Fifty-two trials involved interventions employing more than one QI strategy, with a median of 2 strategies per trial and a maximum of 5. The included trials reported a median absolute reduction in HbA1c of 0.48% (interquartile range: 0.20%, 1.38%), and a median improvement in clinician adherence of 4.9% (interquartile range: 3.8%, 15.0%). Trials in the lower 2 quartiles of sample size reported substantially larger effect sizes, as did non-randomized trials, strongly suggesting the presence of publication bias, with publication of smaller non-randomized trials occurring more often when reported improvements are large. Multifaceted trials reported a median reduction in HbA1c of 0.60% (interquartile range: 0.30%, 1.40%), compared to a median reduction of 0.0% (interquartile range: -0.08%, 0.16%) for trials of a single intervention (p=0.01). The benefit of employing more than one QI strategy appeared to persist among larger, randomized trials, but the small numbers of studies limits the reliability of this impression. The investigators did not find any specific type of QI strategy to confer unambiguous benefit. Provider education and disease management were the only strategies to approach statistical significance, compared with interventions absent these strategies.


The authors' analysis of quality improvement strategies for diabetes care showed no particular type of QI to have an advantage over others, but suggested that employing at least two strategies provides a greater chance of success than single-faceted interventions, in terms of improving glycemic control or provider adherence. These conclusions are limited by probable publication bias favoring smaller trials and non-randomized trials, and the confounding presence of multiple QI strategies in a given intervention, as well as important patient and provider factors, and organizational characteristics.


Managing Editor: Amy J Markowitz, JD. Series Editors: Kaveh G Shojania, MD, Kathryn M McDonald, MM, Robert M Wachter, MD, Douglas K Owens, MD, MS.

Prepared for: Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services.1 Contract No. 290-02-0017. Prepared by: Stanford University-UCSF Evidence-based Practice Center.

Suggested citation:

Shojania KG, Ranji SR, Shaw LK, Charo LN, Lai JC, Rushakoff RJ, McDonald KM, Owens DK. Diabetes Mellitus Care. Vol. 2 of: Shojania KG, McDonald KM, Wachter RM, Owens DK. Closing The Quality Gap: A Critical Analysis of Quality Improvement Strategies. Technical Review 9 (Contract No. 290-02-0017 to the Stanford University-UCSF Evidence-based Practice Center). AHRQ Publication No. 04-0051-2. Rockville, MD: Agency for Healthcare Research and Quality. September 2004.

The authors of this report are responsible for its content. Statements in the report should not be construed as endorsement by the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services of a particular drug, device, test, treatment, or other clinical service.


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Bookshelf ID: NBK43938PMID: 20734526


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