Effectiveness of extended contact interventions for weight management delivered via text messaging: a systematic review and meta-analysis.

BACKGROUND: Extended contact interventions provide support for continued weight management (weight loss/prevention of weight regain) following a weight loss intervention. Text messages offer a medium for delivery in a potentially cost-effective, broad-reach manner. OBJECTIVES: This study aims to examine (i) the effectiveness of extended contact, text message interventions for adults in supporting weight management, and (ii) which intervention characteristics are common to those that are effective. METHODS: A systematic database search (to 19 September 2016) was conducted. Meta-analyses were performed to quantify the average weight changes (kg) during the extended contact intervention, net of control (if a control group was present) and within-group. RESULTS: Seven studies were eligible for inclusion. The pooled effect of the extended contact intervention compared with control (n = 3 studies) was -0.82 kg (95% confidence interval -1.43, -0.21), while the pooled within-group weight loss (n = 6 studies) during the extended contact interventions was -2.16 kg (95% confidence interval -3.40, -0.91). Interventions considered 'effective' (n = 4) were more likely to be >12 weeks duration, compared with interventions considered 'ineffective' (n = 3). CONCLUSION: Evidence from the small number of studies reviewed suggests that extended contact, text message-delivered interventions are effective. Further research is required to elucidate effective intervention components and the longer-term impact on weight, diet and physical activity behaviour.