OBJECTIVE Secondary adrenal insufficiency (SAI) is an uncommon sequela following resection of pituitary adenoma. The aim of this study was to evaluate the utility of postoperative days (PODs) 1 and 2 morning cortisol levels for predicting the development of new SAI and other endocrine outcomes following pituitary adenoma resection. METHODS Patients who underwent resection of pituitary adenoma (June 2012–August 2023) with available POD1 or POD2 morning serum cortisol levels and a minimum postoperative endocrine follow-up of 1 year were included. Patients were excluded if they had preexisting Cushing’s syndrome or received steroids perioperatively. Logistic regression and receiver operating characteristic analyses were conducted to assess the performance of POD1 and POD2 morning cortisol levels for prediction of new postoperative SAI and other long-term endocrine outcomes, with optimal cutoff values determined using Youden’s index. RESULTS Of 229 patients (137 female, mean age 51.4 years), 219 (95.6%) had available POD1 morning cortisol results, 59 (25.7%) had POD2 results, and 49 (21.4%) had both POD1 and POD2 results. Eighteen patients (7.8%) developed new SAI postoperatively. Over long-term follow-up, 6.1% of patients had long-term SAI, 24.8% had persistent new hypopituitarism in one or more pituitary axes, 17.0% had new hypogonadotropic hypogonadism, 13.0% had new central hypothyroidism, 3.9% had arginine vasopressin deficiency, and 3.0% had growth hormone deficiency. The development of any SAI was significantly associated with both POD1 (OR 0.91, 95% CI 0.86–0.97; p = 0.004) and POD2 (OR 0.30, 95% CI 0.09–0.96; p = 0.041) morning cortisol levels, with POD2 levels having superior discriminative performance (POD1: area under the receiver operating characteristic curve AUC 0.719 vs POD2: AUC 0.990). POD2 morning cortisol significantly predicted development of any SAI (AUC 0.990, p < 0.001) with a cutoff of 4.95 µg/dL (sensitivity of 100% and specificity of 96.1%). Logistic regression revealed that each 1-µg/dL increase in POD1 morning cortisol was associated with reduced odds of developing any SAI by 9% (OR 0.91, 95% CI 0.86–0.97; p = 0.004). In those who underwent POD2 cortisol testing, each 1-µg/dL increase in the POD2 morning cortisol level was associated with reduced odds of developing any SAI by 70% (OR 0.30, 95% CI 0.09–0.96; p = 0.041). CONCLUSIONS Although cortisol assessment on both POD1 and POD2 was useful following pituitary adenoma resection, the POD2 morning cortisol level was a more specific predictor of new postoperative SAI while also having predictive utility for other long-term endocrinopathies.
Liu et al. (Sun,) studied this question.