Personalisation of the Dutch combined lifestyle intervention SLIMMER improves participant retention and weight loss in people at risk for cardiometabolic disease

The Dutch combined lifestyle intervention (CLI) program SLIMMER is effective in changing lifestyle behaviour. However, achieving and maintaining a healthier lifestyle is difficult. Here, a personalised version of the SLIMMER CLI was evaluated for effects on lifestyle advice adherence as primary outcome and effects on weight loss, metabolism and inflammation as secondary outcomes. In this cluster-allocated controlled open-label parallel intervention study with 4 different health care sites per cluster, 61 participants in the personalised and 60 participants in the regular SLIMMER CLI (control) were included. Adults at risk for cardiometabolic disease were followed for 6 months. Adherence to lifestyle advice, Dutch Healthy Diet Index (DHDI), self-efficacy, lifestyle maintenance and quality of life (QoL) was assessed by questionnaires. Body composition and blood samples were measured at baseline and end of study. At 6 months the dropout rate was lower in the intervention group (11%) than in the control group (23%, p < 0.001). Self-reported adherence to lifestyle advice and DHDI improved in both groups at 3 and 6 months, whereas self-efficacy and lifestyle maintenance did not change as a result of the intervention. At 6 months self-reported adherence to physical activity guidelines and QoL was higher in favour of control. At 6 months, body weight (-4.5 kg, p = 0.006), BMI (-1.5 kg/m², p = 0.009) and body fat percentage (-3.5%, p = 0.002) improved more in the intervention than control group (-2.0 kg; -0.7 kg/m², and - 1.0% respectively). No consistent difference in cardiometabolic or inflammatory outcomes was found between groups. Personalisation of an already effective CLI increased participants retention, unexplained by differences in adherence to lifestyle advice. Increased retention and a higher degree of weight loss could potentially lead to favourable long-term health outcomes.