Glucose homeostasis in adults with Prader–Willi syndrome during treatment with growth hormone: Results from a 12-month prospective study

ObjectivesTo investigate glucose homeostasis in relation to body mass index (BMI) in adults with PWS before and after GH therapy.DesignWe prospectively investigated the effects of a 12-month GH treatment on body composition and glucose homeostasis in relation to BMI in 39 adults, mean (± SD) age = 28.6 (6.5) years with genetically verified PWS. We compared the results for different BMI categories (< 25 kg/m2; 25–30 kg/m2; > 30 kg/m2) and performed a regression analysis to detect predictors for homeostasis model of assessment-insulin resistance (HOMA-IR).ResultsThe baseline HOMA-IR was higher, with BMI of > 30 kg/m2. Our main findings were as follows: i) GH treatment (mean final dose, 0.6 (0.25) mg) was associated with small increases in fasting p-glucose, 2-h p-glucose by oral glucose load tolerance test, HOMA-IR and lean mass, and a reduction in fat mass. ii) Whereas the baseline HOMA-IR was associated with increased BMI (> 30 kg/m2), we found no differences in HOMA-IR among the BMI categories after 12 months of GH. iii) Stepwise linear regression identified the triglyceride level as the strongest predictor of HOMA-IR at baseline, whereas an increase in VAT was the strongest predictor of the increase in HOMA-IR after therapy.ConclusionsGH treatment for 12 months in adults with PWS resulted in an increase in HOMA-IR, irrespective of BMI, confirming that control of HbA1c is essential during GH treatment in PWS.