Endocrine Abstracts

Study objective: We investigated prevalence of impaired glucose homeostasis in a large cohort of adult patients with GH deficiency (GHD), not treated with GH after more than 10 years of follow-up.

Design: Seventy-one adult GHD patients (30 males, 41 females; mean age 48.3±2.0 years, mean BMI 28.8±0.7 kg/m², GH deficient for 10.2±1.2 years) were evaluated. Ninety percent of patients had multiple pituitary hormone deficiencies which were replaced. Fasting plasma glucose, HbA1c and oral glucose tolerance test (OGTT) were analyzed at baseline and after additional 2 years of follow-up. Peak glucose and insulin levels during OGTT, area under the curve (AUC) for glucose and insulin during OGTT, index of basal insulin resistance (HOMA-IR) and the whole body insulin sensitivity index (WBISI) were analyzed.

Results: At baseline, 58 unreplaced (with GH) GHD patients exhibited no abnormalities in glucose metabolism, 10 patients (14%) had impaired glucose tolerance and 3 patients (4%) had diabetes mellitus (1 patient treated with insulin, 2 patients treated with oral agents). After additional 2 years of follow-up, there were an increase in body weight (from 80.4±2.5 to 83.2±2.5 kg, P=0.006) BMI (from 28.8±0.7 to 30.3±0.84 kg/m², P=0.004), basal insulin level (from 13.8±1.1 to 18.6±2.3 mIU/l, P=0.001), peak insulin level during OGTT (from 103.5±10.7 to 120.3±11.8 mIU/l, P=0.05) and AUCinsulin (from 6622±654 to 8558±879 mIU/l per 120 min, P=0.004). HOMA-IR increased after 2 years (from 2.8±0.2 to 3.7±0.4, P=0.003), while WBISI decreased (from 6.7±0.7 to 2.4±0.3, P=0.001), indicating the significant increase in insulin resistance.

Conclusion: Prevalence of impaired glucose tolerance after 10 years of follow-up of adult GHD patients without GH therapy was 14%, while 4% had overt diabetes mellitus. During additional 2 years of follow-up, insulin sensitivity decreased due to an increase in body weight and ageing.