Changes in waist-to-height ratio risk category during the first six months of medication-supported digital weight loss treatment: a real-world cohort study (Preprint)

BACKGROUND Waist-to-height ratio (WHtR) is a practical measure of central adiposity that suits remote care, but real-world evidence from medication-supported digital weight loss services (DWLSs) has focused on weight and BMI. OBJECTIVE To examine changes in WHtR risk category during the first six months of treatment at a real-world medicated DWLS. METHODS Retrospective cohort study of Australian patients who started tirzepatide or semaglutide with the Juniper DWLS between 1 January and 20 June 2026, and who submitted a self-reported baseline waist circumference and a valid measurement at 3 months (days 61–121) and/or 6 months (days 153–213). WHtR risk categories were low (<0.4), normal (0.4–0.49), increased (0.5–0.59) and high (≥0.6). Category shifts were tested with the McNemar–Bowker test. Logistic regression identified factors associated with improving by at least one category among patients starting in the increased or high-risk category. RESULTS Of 13,545 patients who started treatment, 2097 were included (1030 tirzepatide, 1067 semaglutide; mean age 44.7 years; 96% female); 44.7% were in the high-risk category at baseline. Among 1941 patients with a 3-month measurement, mean waist circumference fell by 8.0 cm (95% CI 7.7–8.2), the proportion in the high-risk category fell from 44.3% to 23.0%, and 787 (40.5%) improved by at least one category. Among 584 patients with a 6-month measurement, waist circumference fell by 11.5 cm (10.9–12.1), the high-risk proportion fell from 49.3% to 17.6%, and 337 (57.7%) improved. Only 0.9% moved to a higher-risk category at either time point, but 76.0% (3 months) and 68.1% (6 months) remained at or above 0.5. Improvement was more likely with high baseline risk category (OR 5.46 at 3 months) and a shorter distance above the threshold, with tirzepatide compared with semaglutide (semaglutide OR 0.53), and with more weekly weight tracking (OR 1.32 per 10 percentage points); it was less likely with older age, higher BMI and previous weight loss medication use. CONCLUSIONS Waist circumference and WHtR fell over the first 3 to 6 months of medication-supported digital treatment, and many patients moved to a lower risk category, although most remained at or above the 0.5 threshold. Self-reported measurements, the absence of a control group, and low follow-up data rates (14.3% of available 3-month patients, and 8.1% of 6-month patients), limit the conclusions.