Preoperative prediction of growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis modification and postoperative changes in candidates for bariatric surgery.

Background: Several factors alter the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in obese patients, but GH/IGF-1 correlation with anthropometric parameters and lipid metabolism is still unclear. We evaluated this relationship and the postoperative axis modifications in candidates for bariatric surgery.

Methods: Eighty-eight patients (males/females (M/F), 34/54) scheduled for bariatric surgery (biliopancreatic diversion or laparoscopic-adjustable gastric banding) between 2008 and 2010 were included in this observational, open, prospective study.

Results: Preoperative serum GH concentrations were found near the lowest limit of normal range in both sexes, with males showing the lowest values (130 vs. 1,405 pg/ml; p < 0.01). Serum concentrations of IGF-1 were within the normal range (M/F, 179/168.5 ng/ml), whereas IGF-binding protein (BP)1 and 3 values were at the lowest limits of normal range in both sexes (M/F 1.8/3.1 μg/ml and M/F 4.1/4.2 μg/ml, respectively). A statistically significant inverse correlation was found between GH, IGF-1, and IGF-BP1-3 values and total cholesterol, LDL-cholesterol, and triglycerides values in both sexes. GH and IGF-BP1-3 values were also inversely related to waist circumference and waist/hip ratio (WHR). GH, IGF-1, and IGF-BP1 and 3 values (35 cases) increased 1 year postoperatively in both sexes, mainly after malabsorptive procedures.

Conclusions: Our results support the hypothesis that GH deficiency associated with low levels of binding proteins in obese patients may be an endocrine response to visceral fat and high levels of non-esterified fatty acids, assessable in daily clinical practice by WHR, total and LDL-cholesterol, and triglycerides. In these patients, malabsorptive procedures might be the treatment of choice due to the metabolic adaptations induced.