Intensive management of obesity in people with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is characterised by childhood-onset hyperphagia and obesity however limited data are available to guide treatment of obesity in this population. We aimed to evaluate the safety, tolerability, and efficacy of intensive medical weight loss interventions (very-low-energy diets [VLED] and/or pharmacotherapy) in individuals with PWS attending a specialist obesity management service.

A retrospective audit was undertaken of individuals with PWS attending the Austin Health Weight Control Clinic between January 2010-April 2021. Main outcome measures were weight outcomes, duration of use, and adverse effects.

Data were available for 18 patients, of whom 15 were treated with intensive weight loss interventions. Median (interquartile range, IQR) age at baseline was 20 years (19-32) with median body weight 90 kg (75-118) and BMI 37 kg/m² (30-51). Median weight loss during VLED (n = 7) was 14 kg (1-20 kg) over 60 weeks. Median weight loss with phentermine-topiramate (n = 7) was 17 kg (IQR 9-19 kg) over 56 weeks. Median weight loss with liraglutide 0.6-3 mg (n = 7), prescribed with topiramate in 3 individuals, was 9 kg (2-14 kg) over 96 weeks. Naltrexone-bupropion resulted in weight loss in 2 of 4 individuals. Thirteen individuals achieved ≥10% weight loss but only 5 individuals maintained ≥10% weight loss at last follow-up. Five individuals discontinued pharmacotherapy due to adverse effects.

VLED and pharmacotherapy can achieve substantial weight loss in some individuals with PWS though non-adherence results in substantial weight regain. Adverse effects were ascribed to phentermine and topiramate, whereas liraglutide was well-tolerated in this population.