Evolution of glycated haemoglobin in adults on growth hormone replacement therapy

OBJECTIVES

To evaluate the effects of GH replacement therapy (GHR) for 3 years on glycated haemoglobin (HbA1c) and on the presence of dysglycaemia at any time during follow-up in Spanish adult patients with growth hormone deficiency (GHD).

STUDY DESIGN

A retrospective study of 41 patients with GHD was conducted using baseline and long-term data. Changes in HbA1c values during the first 3 years of GHR were studied in both the overall population and patients with or without dysglycaemia during follow-up. Dysglycaemia was defined as FPG ≥ 100 mg/dl and/or HbA1c ≥ 5.7%.

RESULTS

Mean HbA1c value (5.4 ± 0.4% at baseline) increased during the first and second years of GHR (HbA1c 5.5 ± 0.4%, p=0.05, and 5.5 ± 0.4%, p=0.006 respectively). This increase was not maintained during the third year (HbA1c 5.4 ± 0.3%, p=0.107) of GHR. Twenty-eight patients (68.2%) had dysglycaemia during follow-up, 9 of them since baseline. In the 19 patients without baseline dysglycaemia, HbA1c increased during the first year and remained stable in the next 2 years (mean HbA1c 5.2 ± 0.4% at baseline; 5.5 ± 0.4% at 1 year, p<0.050; 5.4 ± 0.4% at 2 years, p=0.004, and 5.4 ± 0.4% at 3 years, p=0.016). In the 9 patients with baseline dysglycaemia, HbA1c did not significantly change during the 3 years of GHR therapy.

CONCLUSIONS

HbA1c values increased during the first 2 years of GHR therapy. In patients with no dysglycaemia before treatment, HbA1c steadily increased over the 3 years. However, it did not change in patients with baseline dysglycaemia.