The prevalence of growth hormone deficiency (GHD) following traumatic brain injury (TBI) based on IGF-1 testing differs in literature between 10 and 40%. In our cohort the frequency of IGF-1 values <1 S.D. was 25%. If our patients had a minimal hepatocellular damage, the IGF-1 value could be <1 S.D. We evaluated the effects of BMI and liver function on IGF-1 and IGFBP-3 values in patients following TBI or subarachnoidal haemorrhage (SAH).
Fifty-eight consecutive patients (27 female, 29 men) of our centre (age 1978 years; mean 49 years) following TBI (n=33) or SAH (n=23) underwent baseline testing for pituitary dysfunction including IGF-1. Liver function tests included serum bilirubin (bili), γ-glutamyl transpetidase (GGT), aspertat aminotransferase (GOT), alanine aminotransferase (GPT), high sensitive C-reactive protein (hsCRP), tumor necrosis factor (TNF) and retinol binding protein (RBP). The level of the main intravascular store of IGF-1, IGFBP-3 was assessed in a reference laboratory.
Eight of 58 patients showed IGF-1 <1 S.D. and 8/58 IGFBP-3 <95% reference range. The expected positive correlation of IGF-1 and IGFBP-3 (P<0.0001) was confirmed. HsCRP was significantly negative correlated to IGF-1 (P=0.0173) and IGFBP-3 (P=0.0184). Patients with elevated hsCRP levels showed significant lower values of IGF-1 and IGFBP-3. GGT was significantly negative correlated to IGF-1 (P=0.0372) and RBP was significantly positive correlated to IGFBP-3 (P=0.0188). Interestingly no correlation of the BMI with IGF-1 (P=0.2152) or IGFBP-3 (P=0.3476) was detected.
According to our results the liver function influenced secretion of IGF1 and IGFBP-3. Evaluations of IGF-1 levels <1 S.D. as baseline screening for GHD had to consider the liver function tests (GGT, RBP and hsCRP) irrespective of the BMI.
03 - 07 May 2008
European Society of Endocrinology