Objectives
This systematic review aimed to evaluate the effectiveness of co-created lifestyle interventions in modifying health behaviour, and mental/physical health outcomes in individuals with non-communicable diseases (NCDs).

Study design
A systematic review of Randomized Control Trials (RCTs).

Methods
A systematic search of nine databases from inception until March 2023 was performed, plus weekly email alerts of new literature until March 2025. Studies comparing co-created lifestyle interventions with any control were included. Meta-analysis using the random effects model was conducted. Risk of bias was assessed using the Cochrane-RoB-2, and quality of evidence was assessed using GRADE system.

Results
Sixteen RCTs (2201 participants; 74.2 % female; mean 53.8 years) were included. Meta-analysis showed that at <6 months, there is moderate quality evidence that co-created lifestyle interventions significantly improve health behaviour (moderate effect; SMD = 0.49, 95 %CI: 0.33–0.65) and physical health (small effect; SMD = 0.21, 95 %CI: 0.09–0.34), and mental health (small effect; SMD = 0.29, 95 %CI: 0.14–0.43), in individuals with NCDs. At ≥6 months, there is moderate quality evidence that co-created interventions improve health behaviour (small effect; SMD = 0.21, 95 %CI: 0.07–0.35), and mental health (small effect; SMD = 0.19, 95 %CI: 0.12–0.26). A small effect with low quality evidence (SMD = 0.11, 95 %CI: 0.09-0.32) was also observed for physical health, however, it was not statistically significant.

Conclusions
There is moderate quality evidence that co-created lifestyle interventions for secondary prevention of NCDs have a significant positive impact on the target health behaviour, and on mental health, and physical health outcomes.