Body mass index and insulin-like growth factor 1 as risk factors for discordant growth hormone and insulin-like growth factor 1 levels following pituitary surgery in acromegaly

Abstract

Growth hormone (GH)-secreting pituitary adenoma is a chronic disease characterized by excess levels of GH and insulin-like growth factor 1 (IGF-1). Based on our clinical experience and observations, we identified discordant GH and IGF-1 levels after surgery. The risk factors for this phenomenon are unclear, and individualized cure, control criteria, and management after surgery should be considered. This study aims to investigate the factors affecting the discordant GH and IGF-1 levels after pituitary surgery in acromegalic patients. We retrospectively analyzed 146 patients diagnosed with acromegaly caused by GH-secreting pituitary adenoma who had undergone trans-sphenoidal adenectomy (TSA) at Peking Union Medical College Hospital in 2013. Medical histories were obtained for all patients. Hormone levels, biochemical measurements of liver and renal function, and tumor size were recorded before and 3months after surgery. Among the GH-cured patients who had normal GH levels after TSA, 39.2% (20 of 51) had elevated IGF-1. Acromegalic patients with elevated IGF-1 and normal GH levels after TSA had a significantly higher mean body mass index and percentage of upper limit of normal range IGF-1 than the cured patients (p<0.05). A body mass index greater than >25.0kg/m2 and a percentage of upper limit of normal range IGF-1 higher than 141.5 before TSA might predict the occurrence of hormone-level discordance after surgery. Body mass index and percentage of upper limit of normal range IGF-1 before TSA might constitute prognostic risk factors for discordance in IGF-1 and GH levels in acromegaly. Additional attention should be devoted to potential risk factors for this phenomenon, and methods for modifying the cure and control criteria for acromegaly should be developed.