Endocrine Abstracts

Background: The long-term prevalence of adrenal insufficiency after transsphenoidal surgery for GH secreting pituitary adenomas was unknown. However, recently a single study reported a high prevalence of adrenal insufficiency after surgical and/or medical treatment without postoperative radiotherapy in acromegalic patients.

Aim: To assess the prevalence and incidence rate of adrenal insufficiency in consecutive patients during long-term follow-up after successful transsphenoidal surgery for acromegaly.

Methods: In 91 consecutive patients in remission after transsphenoidal surgery, we retrospectively reviewed insulin tolerance tests, CRH stimulation tests, metyrapone tests and ACTH stimulation tests used to assess corticotrope function.

Results: Early postoperatively, insufficient adrenal function was observed in 18% of patient (n=16), which was transient in 8 and irreversible in 8 other patients in the first year of postoperative follow-up. Therefore, after the first year, the prevalence of adrenal insufficiency was 9%. Late, new-onset adrenal insufficiency developed in only 3 patients, 13, 18 and 24 years postoperatively, resp. The incidence rate of late adrenal insufficiency after successful surgery was 2/1000 person years.

After long-term follow-up, with a mean duration of 17.7±8.1 years, the prevalence of secondary adrenal insufficiency was 12% in patients in remission after surgery for acromegaly.

Conclusion: The prevalence of adrenal insufficiency 1 year after surgery was 9%, whereas during prolonged follow-up the incidence rate of adrenal insufficiency was only 2/1000 person years in patients in remission after surgery. Therefore, development of late onset adrenal insufficiency is a very infrequent complication in patients with acromegaly in remission after transsphenoidal surgery only.