Effects of quality improvement strategies for type 2 diabetes on glycemic control: a meta-regression analysis.
BACKGROUND
There have been numerous reports of interventions designed to improve the care of patients with diabetes, but the effectiveness of such interventions is unclear.


OBJECTIVE
To assess the impact on glycemic control of 11 distinct strategies for quality improvement (QI) in adults with type 2 diabetes.


METHODS
MEDLINE (1966-April 2006) and the Cochrane Collaboration's Effective Practice and Organisation of Care Group database, which covers multiple bibliographic databases. Eligible studies included randomized or quasi-randomized controlled trials and controlled before-after studies that evaluated a QI intervention targeting some aspect of clinician behavior or organizational change and reported changes in glycosylated hemoglobin (HbA1c) values.


METHODS
Postintervention difference in HbA1c values were estimated using a meta-regression model that included baseline glycemic control and other key intervention and study features as predictors.


RESULTS
Fifty randomized controlled trials, 3 quasi-randomized trials, and 13 controlled before-after trials met all inclusion criteria. Across these 66 trials, interventions reduced HbA(1c) values by a mean of 0.42% (95% confidence interval [CI], 0.29%-0.54%) over a median of 13 months of follow-up. Trials with fewer patients than the median for all included trials reported significantly greater effects than did larger trials (0.61% vs 0.27%, P = .004), strongly suggesting publication bias. Trials with mean baseline HbA1c values of 8.0% or greater also reported significantly larger effects (0.54% vs 0.20%, P = .005). Adjusting for these effects, 2 of the 11 categories of QI strategies were associated with reductions in HbA(1c) values of at least 0.50%: team changes (0.67%; 95% CI, 0.43%-0.91%; n = 26 trials) and case management (0.52%; 95% CI, 0.31%-0.73%; n = 26 trials); these also represented the only 2 strategies conferring significant incremental reductions in HbA1c values. Interventions involving team changes reduced values by 0.33% more (95% CI, 0.12%-0.54%; P = .004) than those without this strategy, and those involving case management reduced values by 0.22% more (95% CI, 0.00%-0.44%; P = .04) than those without case management. Interventions in which nurse or pharmacist case managers could make medication adjustments without awaiting physician authorization reduced values by 0.80% (95% CI, 0.51%-1.10%), vs only 0.32% (95% CI, 0.14%-0.49%) for all other interventions (P = .002).


CONCLUSIONS
Most QI strategies produced small to modest improvements in glycemic control. Team changes and case management showed more robust improvements, especially for interventions in which case managers could adjust medications without awaiting physician approval. Estimates of the effectiveness of other specific QI strategies may have been limited by difficulty in classifying complex interventions, insufficient numbers of studies, and publication bias.
Shojania
Kaveh G
KG
Ottawa Health Research Institute and Department of Medicine, University of Ottawa, Ottawa, Ontario. kshojania@ohri.ca
Ranji
Sumant R
SR
McDonald
Kathryn M
KM
Grimshaw
Jeremy M
JM
Sundaram
Vandana
V
Rushakoff
Robert J
RJ
Owens
Douglas K
DK
D001786:Blood Glucose; D019090:Case Management; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000628:therapy*; D004493:Education; D006442:Glycated Hemoglobin; D006801:Humans; D008485:Medical Audit; D016347:Medical Records Systems, Computerized; D011785:Quality Assurance, Health Care; D012044:Regression Analysis; D017010:Reminder Systems
D001786:Blood Glucose; D006442:Glycated Hemoglobin