Comparative effectiveness of non-pharmacological interventions on metabolic syndrome and its components: a systematic review and network meta-analysis

Abstract Introduction Management of metabolic syndrome is crucial in primary prevention of cardiovascular diseases. While non-pharmacological interventions are recognised as the first-line approach for managing metabolic syndrome, optimal design for this care approach remains unclear. Purpose This review aimed to evaluate the comparative effectiveness of non-pharmacological interventions on reversal of metabolic syndrome and components of metabolic syndrome (i.e., systolic and diastolic blood pressure, triglycerides, high-density lipoprotein, fasting blood glucose and waist circumference) in community-dwelling adults with metabolic syndrome. Methods A systematic search of seven databases was conducted from inception to 28th April 2023 to identify randomised controlled trials investigating the effects of non-pharmacological interventions on metabolic syndrome. A framework was used to categorise the interventions according to therapeutic content for lifestyle modification and behavioural activation strategies employed. Control included active inert control (with interventions not specifically targeting metabolic syndrome) and usual care including no intervention and standard care. Pairwise meta-analysis was performed to evaluate the effects of each intervention category. Then, a Bayesian network meta-analysis was conducted to evaluate their comparative effectiveness. Results This review included 96 eligible studies involving 11,745 participants. The interventions were categorised as dietary interventions, exercise and multi-modal interventions with enabling, motivational, and both strategies. Pairwise meta-analysis revealed the positive effects of enabling exercise, enabling multi-modal interventions and enabling plus motivational multi-modal interventions on reversal of metabolic syndrome (Table 1). Network meta-analysis indicated that enabling plus motivational dietary intervention, enabling exercise, enabling plus motivational exercise, enabling multi-modal intervention and enabling and motivational multi-modal intervention were more effective than usual care in reversing metabolic syndrome, while none demonstrated superiority to active inert control. Intervention rankings suggested that enabling and motivational exercise demonstrated the highest efficacy in reversal of metabolic syndrome and reduction in waist circumference. Enabling exercise exhibited the highest probability of being the optimal intervention for improving systolic blood pressure and high-density lipoprotein, while enabling and motivational multi-modal intervention showed to be more superior in improving diastolic blood pressure, triglycerides, and fasting blood glucose (Figure 1). Conclusion This review highlights the more superior effects of enabling exercise, enabling plus motivational exercise and enabling plus motivational multi-modal intervention on metabolic syndrome. The non-pharmacological management approach should be tailored to specific outcomes. Table 1Forest plots of meta-analysis. Figure 1Network graphs.