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 (HbA_1c ) 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 HbA_1c values at baseline and 4 years were included in the analysis.

Measurements: Changes from baseline (∆) to 4 years in HbA_1c , fasting plasma glucose (FPG), IGF-I, lipids (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, triglycerides), waist circumference, glycaemic (HbA_1c <5·7%; HbA_1c , 5·7-6·5%; HbA_1c , ≥6·5%) and metabolic health status were evaluated. Effects of baseline HbA_1c , gender, baseline age, average GH dose and baseline body mass index (BMI) on ΔHbA_1c were investigated. The models were adjusted for concomitant medication use.

Results: Mean (standard deviation) baseline HbA_1c 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 ∆HbA_1c . At 4 years, 85% of patients with HbA_1c <5·7% (normal levels) at baseline and 55% of patients with HbA_1c 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 HbA_1c . 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.