Application of the Lancet Commission Criteria for the Diagnosis of Obesity to a Clinical Trials Population: The LEAP Trial.

OBJECTIVE: This study aimed to apply The Lancet Diabetes & Endocrinology criteria for diagnosing obesity among clinical trial participants and understand participants' characteristics by obesity status. METHODS: The criteria were operationalized and applied to baseline data from the Long-term Effectiveness of the Anti-obesity medication Phentermine (LEAP) trial (NCT05176626). Excess adiposity, organ and tissue dysfunction, and limitations to daily activities were assessed. We examined differences between participants with "no obesity," "pre-clinical obesity," and "clinical obesity." RESULTS: Among the 860 participants, 0.8% had no obesity (mean BMI 29.0 kg/m2 [SD 0.6]), 18.7% had pre-clinical obesity (mean BMI 35.2 kg/m2 [SD 3.5]), and 80.5% had clinical obesity (mean BMI 35.9 kg/m2 [SD 4.3]). Participants with no/pre-clinical obesity had lower mean SF-12 mental component scores and greater baseline engagement with weight control strategies compared to those with clinical obesity. Participants with clinical obesity were older and, by definition, had a greater burden of cardiometabolic risk factors. CONCLUSIONS: Among clinical trial participants eligible for obesity pharmacotherapy, 19.5% were classified as having no/pre-clinical obesity using the Lancet criteria. Applying the criteria was complicated in a well-resourced trial setting, which suggests potential challenges in implementing these guidelines in real-world practice.