Diabetes mellitus induced by somatostatin analogue therapy is not permanent in acromegalic patients

CONTEXT: Therapy with somatostatin analogues (SSAs) may have deleterious effects on glucose metabolism in patients with acromegaly, often leading to the development of diabetes mellitus (DM). AIM: The aim of the study was to evaluate whether DM, developed during therapy with SSAs, may revert after drug withdrawal and cure of acromegaly with pituitary adenomectomy. DESIGN: Retrospective cohort study, in a tertiary referral centre. PATIENTS: Eighteen acromegalic patients without DM at the diagnosis of acromegaly treated with SSAs as a primary therapy, and then cured by pituitary adenomectomy. METHODS: Endocrine status and glucose homeostasis were evaluated at diagnosis of acromegaly and at least every 6 months during SSA therapy. At each visit, patients were classified into one of the following classes: normal glucose tolerance, prediabetes, overt diabetes. RESULTS: Median follow-up after starting SSAs therapy was 69 months (IQR 54.75-132.25). During SSA therapy, all patients had controlled acromegaly defined by normal serum IGF1 concentrations for the age. Of the 13 euglycaemic patients at diagnosis, three developed prediabetes and three diabetes, whereas, of the five prediabetic patients at diagnosis, two worsened to overt diabetes and three remained in the prediabetic range (P = 0.04). After curing acromegaly with pituitary adenomectomy and subsequent SSA withdrawal, prediabetes reverted in five of six patients, and diabetes in all five patients (three reverted to euglycaemia, while two reverted to prediabetes) (P = 0.01). CONCLUSIONS: In acromegalic patients with controlled disease, changes in glycaemic status induced by SSAs are not permanent.