Effectiveness of the chronic care model for adults with type 2 diabetes in primary care: a systematic review and meta-analysis

BACKGROUND: Mixed evidence exists regarding the effectiveness of the Chronic Care Model (CCM) with patient outcomes. The aim of this review is to examine the effectiveness of CCM interventions on hemoglobin A1c (HbA(1c)), systolic BP (SBP), diastolic BP (DBP), LDL cholesterol and body mass index (BMI) among primary care adults with type 2 diabetes. METHODS: PubMed, Embase, CINAHL, Cochrane Central Registry of Controlled Trials, Scopus and Web of Science were searched from January 1990 to June 2021 for randomized controlled trials (RCTs) comparing CCM interventions against usual care among adults with type 2 diabetes mellitus in primary care with HbA(1c), SBP, DBP, LDL cholesterol and BMI as outcomes. An abbreviated search was performed from 2021 to April 2022. This study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines for data extraction and Cochrane risk of bias assessment. Two reviewers independently extracted the data. Meta-analysis was performed using Review Manager software. Heterogeneity was evaluated using χ(2) and I(2) test statistics. Overall effects were evaluated using Z statistic. RESULTS: A total of 17 studies involving 16485 patients were identified. Most studies had low risks of bias. Meta-analysis of all 17 studies revealed that CCM interventions significantly decreased HbA(1c) levels compared to usual care, with a mean difference (MD) of −0.21%, 95% CI −0.30, −0.13; Z = 5.07, p<0.00001. Larger effects were experienced among adults with baseline HbA(1c) ≥8% (MD −0.36%, 95% CI −0.51, −0.21; Z = 5.05, p<0.00001) and when four or more CCM elements were present in the interventions (MD −0.25%, 95% CI −0.35, −0.15; Z = 4.85, p<0.00001). Interventions with CCM decreased SBP (MD −2.93 mmHg, 95% CI −4.46, −1.40, Z = 3.75, p=0.0002) and DBP (MD −1.35 mmHg, 95% CI −2.05, −0.65, Z = 3.79, p=0.0002) compared to usual care but there was no impact on LDL cholesterol levels or BMI. CONCLUSIONS: CCM interventions, compared to usual care, improve glycaemic control among adults with type 2 diabetes in primary care, with greater reductions when the mean baseline HbA(1c) is ≥8% and with interventions containing four or more CCM elements. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021273959 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13643-022-02117-w.