Effectiveness of Different Online Intervention Modalities for Middle-Aged Adults with Overweight and Obesity: A 20-Year Systematic Review and Meta-analysis.

The main objectives of this systematic review and meta-analysis study include evaluating the methodological quality of existing randomized controlled trials (RCTs) for weight loss and features of online intervention [OI]s in each trial, examining the associations between the methodological quality, intervention features and the effectiveness of OIs, and comparing the effectiveness of OIs and other intervention modalities through systematic review and meta-analysis. Systematic searches were conducted using PubMed, Cochrane Library, CINAHL, and PsycINFO in the past two decades (2000 through 2019). Inclusion criteria includes Online intervention (intervention modality), middle-aged adults with overweight or obesity, at least six months or longer study period, an RCT, and 70% plus retention rate. Risk of Bias was assessed using Miller et al. in (Hester, Miller (eds) Handbook of alcoholism treatment approaches: Effective alternatives (3rd ed.). Allyn & Bacon, Boston, 2003)'s Methodological Quality Rating Scale (MQRS) and GRADE. MOOSE guidelines was referred for data synthesis. In total, 29 OIs were evaluated using 10 criteria for methodological quality and eight criteria for intervention features. Results revealed that the mean methodological quality score of the RCTs was 12.1 (out of 16), and the mean intervention features score was 6.6 (out of 8). RCTs with higher scores were more effective in weight loss than those with lower scores. Results of meta-regression showed that methodological quality was more important than intervention features to increase the effectiveness. Results of meta-analysis showed that OIs were significantly more effective than controls. Compared to OIs only, OIs with interactions with others and professionals were more effective. The study limitation includes assessing 'effectiveness' based on weight only due to lack of other indicators to compare between studies; some results are self-reported; and feedback from intervention participants were hard to review. Nevertheless, this study may contribute to improving the effectiveness of existing OIs for weight loss considering methodological quality and better intervention features.