Background: Prader-Willi syndrome (PWS) is characterised by hyperphagia with childhood-onset obesity. Strict dietary supervision and restriction is integral to prevent weight gain, but limited data are available to guide intensive weight loss interventions (VLED, pharmacotherapy, bariatric surgery) in this population. The aim of this study was to evaluate the safety, tolerability and efficacy of intensive weight loss interventions in individuals with PWS.
Methods: A retrospective audit was undertaken of individuals with PWS attending the Austin Health Weight Control Clinic between July 2005-April 2021. Main outcome measures of intensive weight loss interventions (VLED, pharmacotherapy) were duration of use, weight outcomes, and adverse effects.
Results: Data were available for 18 individuals, of whom 14 were treated with intensive weight loss interventions. Mean body weight at baseline was 96.8 kg (BMI 40.8 kg/m2). Mean weight loss during VLED (n=7) was 11.7 kg over 132 weeks, though did not result in weight loss in two individuals. Combination pharmacotherapy was most commonly prescribed. Mean weight loss with phentermine-topiramate (n=7) was 16.2 kg over 56 weeks. Mean weight loss with liraglutide 0.6-3mg (n=7), prescribed with topiramate in 3 individuals, was 14.9kg over 138 weeks. Weight loss was documented in 5 of 7 individuals treated with liraglutide. Naltrexone-bupropion resulted in weight loss in 2 of 4 individuals. Five individuals discontinued pharmacotherapy due to adverse effects (phentermine: psychosis, insomnia; topiramate: rash, depression, memory impairment). Five individuals maintained >10% weight loss at last follow-up. Non-adherence with prescribed regimen resulted in weight regain; mean weight at last follow-up was 98.4 kg (BMI 41.3 kg/m2). No individual underwent bariatric surgery.
Conclusions: VLED and pharmacotherapy can be successfully utilised in some individuals with PWS though non-adherence results in substantial weight regain. Adverse effects were ascribed to phentermine and topiramate and resulted in discontinuation, whereas liraglutide was well-tolerated in this population.