Weight Loss Outcomes of Routine Dietetic Treatment in Primary Care.

Clinically relevant weight loss (≥ 5%) is a key treatment goal in dietetic care for patients with overweight or obesity. While clinical trials often demonstrate successful weight loss, less is known about success rates in routine dietetic practice, timing of weight loss and maintenance. This study examined when patients achieve and maintain ≥ 5% weight loss during 12 months of dietetic treatment in Dutch primary care, and how this relates to treatment intensity and patient characteristics. In this retrospective cohort study, routinely collected data from dietetic electronic health records (EHRs) was used. Follow-up duration was 12 months. Weight change was analysed at 3, 6, 9 and 12 months. The study included 4503 adults (≥ 18 years) with overweight or obesity (BMI ≥ 25 kg/m2) receiving dietetic treatment between 2016 and 2020 in over 70 primary care dietetic practices in the Netherlands. The primary outcome was achieving and maintaining ≥ 5% weight loss from baseline at 3, 6, 9 and 12 months. Multivariable logistic regression assessed associations of ≥ 5% weight loss with visit frequency, visit time, sex, age, BMI and comorbidity. Overall, 33% of patients achieved ≥ 5% weight loss. Of these, 60% did so within 3 months. Each additional visit in the first 3 months was associated with threefold higher odds of success (OR = 3.0). In months 3-6, each additional visit was associated with 61% higher odds of success. Early dietetic treatment intensity is strongly associated with weight loss success. Structuring care around the early treatment phase warrants prospective evaluation in routine dietetic practice.