BACKGROUND: Weight loss observed in clinical trials has failed to translate into real world clinical settings. The aim of the current investigation was to quantify patient weight loss using various approaches tested in primary care and to unveil relevant contextual factors that could improve patient weight loss on a long-term basis. METHODS: This systematic review and meta-analysis was limited to randomized clinical trials conducted in people with overweight or obesity in a primary care setting where the intervention was administered by a primary care provider for at least 6 months. The major outcome was patient weight loss. All investigators identified studies and independently abstracted data using COVIDENCE systematic review software. RESULTS: The seven studies included 2,187 people with obesity who had weight-related comorbidities or risk factors. Strategies tested for patient weight loss included 1) anti-obesity medication, 2) the combination of anti-obesity medication, intensive lifestyle counseling and meal replacements, and 3) physician training to better counsel patients toward intensive lifestyle modification. Substantial heterogeneity in the outcomes was observed, as well as bias toward lack of published studies showing no effect. The random effect model estimated a treatment effect for the aggregate efficacy of primary care interventions -3.54 kg (95% CI: -5.61 kg to -1.47 kg). Interventions that included a medication component (alone or as part of a multipronged intervention) achieved a greater weight reduction by -2.94 kg (p<0.0001). In all interventions, efficacy declined with time (reduction in weight loss by 0.53 kg per six months, 95%CI: 0.04-1.0 kg, p-value=0.04). CONCLUSIONS: Weight loss interventions administered by a primary care provider can lead to modest weight loss. Weight loss is approximately doubled if anti-obesity medication is part of the treatment strategy. Nevertheless, weight loss is attenuated over time and underscores the need for long-term treatment.  

The authors have declared no competing interest.

The study did not receive any funding

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