Endocrine Abstracts

Background: In a previous study, we retrospectively analysed a group of patients with high insulin growth factor 1 (IGF1) but normal growth hormone (GH) suppression, identifying among them a subgroup of “micromegalic” patients presenting with clinical features of acromegaly and high rate of comorbidities. We therefore expanded our cohort of patients, extended the follow-up time and collected preliminary data on treatment response aiming to better characterize this condition.

Patients and methods: We enrolled 86 patients (53 included in our previous study, mean age 48±17 years, 56 females and 30 males) referred to our Endocrinology Unit between 2008 and 2022, presenting with persistently high IGF1 and adequate GH nadir after glucose load (<0.4 ng/ml according to most recent guidelines). We divided them in two groups: with (G1, “micromegaly”, n=28/86) or without (G2, 58/86) clinical features of acromegaly. We performed systematic clinical-instrumental screening of acromegaly-related comorbidities (arterial blood pressure and glucose metabolism evaluation, thyroid ultrasound for goitre, colonoscopy and/or faecal occult blood for colonic polyposis, echocardiography for cardiopathy, polysomnography and ESS questionnaire for OSAS). We recorded biochemical and clinical data from diagnosis to the last available follow-up. Finally, we collected preliminary data of a small subgroup of patients who underwent medical or surgical treatment.

Results: In G1 group (“micromegaly”) we confirmed a higher prevalence of comorbidities vs G2 (median comorbidities for each patient 4 vs 3, P=0.001), especially goitre (P=0.009), carpal tunnel (P=0.003) and malignant neoplasms (P=0.03). During a mean follow-up time of 6±3 years, IGF1 and GH nadir levels did not significantly change, whilst we observed an increase in random GH values in G1 vs G2 patients (P=0.03). Four patients with highly suggestive clinical features of acromegaly and typical comorbidities were selected for treatment: two were treated with somatostatin analogues and two underwent transsphenoidal surgery (1 micro and 1 macroadenoma, both histologically proven GH+). All treated patients showed normalization of IGF1 values and referred subjective improvement in clinical symptoms.

Conclusions: Our preliminary data suggest that “micromegalic” patients present typical comorbidities of acromegaly and can benefit from either medical or surgical therapy.