Effectiveness of quality improvement strategies on the management of diabetes: a systematic review and meta-analysis

Background The effectiveness of quality improvement (QI) strategies on diabetes care remains unclear. We aimed to assess the effects of QI strategies on glycated haemoglobin (HbA(1c)), vascular risk management, microvascular complication monitoring, and smoking cessation in patients with diabetes. Methods We identified studies through Medline, the Cochrane Effective Practice and Organisation of Care database (from inception to July 2010), and references of included randomised clinical trials. We included trials assessing 11 predefined QI strategies or financial incentives targeting health systems, health-care professionals, or patients to improve management of adult outpatients with diabetes. Two reviewers independently abstracted data and appraised risk of bias. Findings We reviewed 48 cluster randomised controlled trials, including 2538 clusters and 84 865 patients, and 94 patient randomised controlled trials, including 38 664 patients. In random effects meta-analysis, the QI strategies reduced HbA(1c) by a mean difference of 0.37% (95% CI 0.28-0.45; 120 trials), LDL cholesterol by 0.10 mmol/L (0.05-0.14; 47 trials), systolic blood pressure by 3.13 mm Hg (2.19-4.06, 65 trials), and diastolic blood pressure by 1.55 mm Hg (0.95-2.15, 61 trials) versus usual care. We noted larger effects when baseline concentrations were greater than 8.0% for HbA(1c), 2.59 mmol/L for LDL cholesterol, and 80 mm Hg for diastolic and 140 mm Hg for systolic blood pressure. The effectiveness of QI strategies varied depending on baseline HbA(1c) control. QI strategies increased the likelihood that patients received aspirin (11 trials; relative risk [RR] 1.33, 95% CI 1.21-1.45), antihypertensive drugs (ten trials; RR 1.17, 1.01-1.37), and screening for retinopathy (23 trials; RR 1.22, 1.13-1.32), renal function (14 trials; RR 128, 1.13-1.44), and foot abnormalities (22 trials; RR 1.27, 1.16-1.39). However, statin use (ten trials; RR 1.12, 0.99-1.28), hypertension control (18 trials; RR 1.01, 0.96-1.07), and smoking cessation (13 trials; RR 1.13, 0.99-1.29) were not significantly increased. Interpretation Many trials of QI strategies showed improvements in diabetes care. Interventions targeting the system of chronic disease management along with patient-mediated QI strategies should be an important component of interventions aimed at improving diabetes management. Interventions solely targeting health-care professionals seem to be beneficial only if baseline HbA(1c) control is poor.