Weight Management Interventions Provided by a Dietitian for Adults with Overweight or Obesity: An Evidence Analysis Center Systematic Review and Meta-Analysis

Obesity is associated with a multitude of comorbidities and considerable healthcare costs.The objective was to examine the efficacy of weight management interventions provided by a registered dietitian or international equivalent (referred to as "dietitian").This systematic review and meta-analysis of randomized controlled trials (RCTs) compared weight management interventions provided by a dietitian to usual care or no intervention on several cardiometabolic outcomes and quality of life in adults with overweight or obesity. MEDLINE, Embase, PsycINFO, Cochrane CENTRAL, Cochrane Database of Systematic Reviews and CINAHL databases were searched for eligible RCTs published between January 2008 and January 2021 in the English language. Meta-analyses were conducted using a random-effects model, publication bias was assessed using funnel plots and Egger's statistics and heterogeneity was assessed by interpreting I2 values. Efficacy of intervention components, such as telehealth or group contacts, were explored in sub-group analyses. The revised risk of bias tool for RCTs (ROB 2.0) tool was used to assess risk of bias. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) method was used to determine certainty of evidence.This systematic review included 62 RCTs. Compared to control conditions, weight management interventions provided by a dietitian resulted in improved body mass index [Mean Difference (95% CI): -1.5 kg/m2 (-1.74, -1.26); moderate evidence certainty]; percent weight loss [-4.01% (-5.26, -2.75); high evidence certainty]; waist circumference [-3.45 cm (-4.39, -2.51); high evidence certainty]; blood pressure [-3.04 mmHg (-5.10, -0.98) and -1.99 mmHg (-3.02, -0.96) for systolic and diastolic, respectively; moderate and low evidence certainty] and quality of life using the SF-36 tool [5.84 (2.27, 9.41) and 2.39 (1.55, 3.23) for physical and mental quality of life, respectively; low and moderate evidence certainty].For adults with overweight or obesity, weight management interventions provided by a dietitian are efficacious for improving several examined cardiometabolic outcomes and quality of life.