Pre- and Post-surgical Prevalence of Hyperglycemia in Patients with Subclinical Cushing's Syndrome Secondary to Adrenal Incidentaloma

Abstract

Background Subclinical Cushing's syndrome (SCS) is a common subtype of adrenal incidentaloma. There are few reports on the correlation between hyperglycemia and hypercortisone secretion and its postoperative change in SCS patients. Objective To assess the pre- and post-surgical prevalence of hyperglycemia in patients with SCS secondary to adrenal incidentaloma. Methods The data of 202 patients who consulted in respiratory department of endocrinology, renhe hospital affiliated to shanghai university (shanghai baoshan district renhe hospital). Participants included 36 SCS patients, 41 patients with Cushing's syndrome due to adrenal tumor (CSA), 47 with nonfunctional adrenal tumor (NAT), and 53 controls. OGTT was performed in all of them, and based on the results, HOMA-IR, the area under the curve of blood glucose (AUCGlu) and insulin (AUCIns) were calculated, and plasma cortisol and urinary free cortisol and plasma ACTH were measured, then the values of the parameters were compared between controls and patients. Surgical treatment was given to SCS and CSA patients. The association of hormone and glucose metabolism parameters was assessed using Pearson correlation analysis. Results The prevalence of hyperglycemia in SCS, CSA and NAT patients before surgery and in controls was 41.7%, 51.2%, 25.5%, and 24.5%, respectively. The HbA1c, 2-hour post-load insulin (2 hPIN), AUCGlu and AUCIns in SCS patients were higher than those of controls (P<0.05). CSA patients had higher fasting insulin, AUCIns and HOMA-IR than SCS patients, NAT patients and controls (P<0.05). CSA patients had higher HbA1c, fasting plasma glucose (FPG), 2-hour post-load plasma glucose (2 hPPG), 2 hPIN and AUCGlu than NAT patients and controls (P<0.05). After controlling for sex and age, in SCS patients, HbA1c was positively associated with cortisol measured at 8: 00 and 16: 00 on the day after admission, and 24-hour urinary free cortisol (r=0.68, 0.657, 0.522, P<0.05), and so was 2 hPPG (r=0.569, 0.544, 0.369, P<0.05) ; FPG was positively associated with cortisol measured at 8: 00 on the day after admission (r=0.434, P<0.05) ; AUCGlu was positively associated with cortisol measured at 8: 00 and 16: 00 on the day after admission (r=0.397, 0.409, P<0.05). In CSA group, HbA1c was positively associated with cortisol measured at 8: 00 on the day after admission (r=0.748, P<0.05), and so was FPG, 2 hPPG, AUCGlu, and 2 hPIN (r=0.631, 0.669, 0.602, 0.319, P<0.05). HbA1c was also positively associated with cortisol measured at 16: 00 on the day after admission (r=0.674, P<0.05), and so was FPG, 2 hPPG, AUCGlu, (r=0.655, 0.640, 0.624, P<0.05). Plasma cortisol and 24-hour urinary free cortisol decreased in SCS and CSA patients after surgery (P<0.05). 2 hPIN and AUCIns decreased in SCS patients after surgery (P<0.05). FIN, 2 hPIN, AUCGlu, AUCIns and HOMA-IR decreased in CSA patients after surgery (P<0.05). The postsurgical prevalence of hyperglycemia SCS and CSA patients was 33.3% and 39.0%, respectively. Conclusion The high prevalence of hyperglycemia may be related to high secretion of glucocorticoid in SCS patients, and the hyperglycemic condition was improved after surgical treatment.

Keywords

• cushing syndrome|subclinical cushing&apos;s syndrome|adrenal incidentaloma|hyperglycemia