The effect of growth hormone (GH) replacement on blood glucose homeostasis in adult nondiabetic patients with GH deficiency: real-life data from the NordiNet® International Outcome Study

Abstract

Objective: To assess the effect of 4 years’ growth hormone (GH) replacement on glucose homeostasis and evaluate factors affecting glycosylated haemoglobin (HbA1c) in adults with growth hormone deficiency (GHD). Design: NordiNet® International Outcome Study, a noninterventional study, monitors long-term effectiveness and safety of GH replacement [Norditropin® (somatropin), Novo Nordisk A/S] in real-life clinical practice. Patients: Nondiabetic patients (n = 245) with adult-onset GHD (age ≥20 years at GH start), ≥4 years’ GH replacement and HbA1c values at baseline and 4 years were included in the analysis. Measurements: Changes from baseline (∆) to 4 years in HbA1c, fasting plasma glucose (FPG), IGF-I, lipids (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, triglycerides), waist circumference, glycaemic (HbA1c <5·7%; HbA1c, 5·7–6·5%; HbA1c, ≥6·5%) and metabolic health status were evaluated. Effects of baseline HbA1c, gender, baseline age, average GH dose and baseline body mass index (BMI) on ΔHbA1c were investigated. The models were adjusted for concomitant medication use. Results: Mean (standard deviation) baseline HbA1c was 5·13 (0·65)% and remained at the same level at 4 years. Age at treatment start (P = 0·0094) and BMI (P = 0·0008) had a significant impact on ∆HbA1c. At 4 years, 85% of patients with HbA1c <5·7% (normal levels) at baseline and 55% of patients with HbA1c 5·7–6·5% (impaired glucose tolerance) at baseline remained in the same glycaemic health category. Nineteen patients improved from impaired glucose tolerance to normal HbA1c. Seven patients developed diabetes. Conclusions: These data demonstrate that 4 years’ GH replacement therapy did not adversely affect glucose homeostasis in the majority of adults with GHD.