Transtheoretical Model-based Dietary and Exercise Interventions for Glycemic Control in Type 2 Diabetes: Systematic Review and Meta-analysis.

Context: The pillars of diabetes treatment include pharmacotherapy, healthy eating, physical activity, self-monitoring, education, mental health support, and smoking cessation. Interventions based on the Transtheoretical Model of Change, which consider a patient's readiness to behavioral change, may be effective for promoting sustainable self-care. However, the impact of such interventions on diabetes management requires systematic evaluation.

Objective: To systematically review the effect of diet and/or exercise interventions based on the Transtheoretical Model of Change on glycemic control, body weight, and glucose-lowering medication medications in adults with type 2 diabetes.

Data sources: PubMed, Web of Science, Embase, Scopus, and PsycInfo were searched through June 2024. Randomized controlled trials (RCTs) with adults having type 2 diabetes were included; those involving pregnant or lactating women were excluded.

Data extraction: Studies were selected based on (P) individuals with type 2 diabetes, (I) diet and/or exercise interventions based on Transtheoretical Model of Change, (C) usual care, and (O) glycated hemoglobin, fasting glucose, body weight, body mass index, and medication dosage. Two reviewers independently screened RCTs, extracted data, and assessed quality using the Cochrane Risk of Bias tool.

Data analysis: Twelve RCTs (n = 2484) were included. Two studies involved dietary strategies only, 4 involved exercise interventions only, and 6 involved multicomponent interventions. Interventions based on the Transtheoretical Model of Change reduced glycated hemoglobin by 0.73% (n = 11 RCTs, 1.292 participants; 95% CI, -1.10 to -0.36; I2 = 75%) compared to usual care. Egger's test (P = .43) suggested no publication bias, but evidence certainty was very low. Meta-analysis of body weight and medication use was not feasible because of limited data.

Conclusion: Interventions based on the Transtheoretical Model of Change had a positive effect on glycemic control in adults with type 2 diabetes, but evidence was limited by methodological concerns, highlighting the need for well-designed future trials.

Systematic review registration: PROSPERO registration no. CRD42022301516.