Direct assessment of extracellular water volume by the bromide-dilution method in growth hormone-deficient adults

Body composition and water content were assessed in 36 growth hormone deficient (GHD) patients (M:23, F:13) and 14 controls (M:7, F:7) using anthropometry, hydrodensitometry, bioelectrical impedance measurement and the bromide-dilution method, with which extracellular water volume can be measured directly. GHD patients, compared to controls, did not differ in extracellular water volume, in hydration state and water distribution. A higher BMI (P = 0.002) and a higher body fat mass (P < 0.0001) were found in the patients. Based on circumference measurements, the GHD patients had a higher waist/hip ratio (P = 0.0001). This study shows that GHD patients, in comparison with healthy controls, have a normal extracellular water volume. The finding that extracellular water volume is within the normal range in GHD patients may be clinically relevant as it is well known that in the first months after initiating GH-replacement therapy, most patients have signs and symptoms of excessive water retention.