Department of Clinical Sciences in Lund, Lund University, Lund, Sweden.
Department of Internal Medicine, Ängelholm Hospital, Ängelholm, Sweden.
Front Endocrinol (Lausanne). 2023 Jan 16;13:1055298. doi: 10.3389/fendo.2022.1055298. eCollection 2022.
The specificity of cortisol after 1 mg dexamethasone (cortisol) ≥50 nmol/L as a criterion for mild autonomous cortisol secretion (MACS) is approximately 85% in patients with adrenal incidentalomas (AI). The aim was to study the associations of cortisol to age, BMI, and renal function.
We studied 1,129 patients with AI examined from 2005 to 2015 at Skåne University Hospital and Helsingborg Hospital. The covariates studied were gender, age, BMI, estimated glomerular filtration rate (eGFR), treatment with inhalation steroids, size of the AI, and size of the smallest AI in patients with bilateral AI (set to 0 in unilateral AI). We used machine learning models to uncover potential nonlinear associations. They were trained to fit the data and examined using feature importance analysis and partial dependence plots. Partial dependence plots show the marginal effect on cortisol of a covariate averaging over other covariates.
Cortisol was strongly associated with the size of the AI and weakly associated with age, BMI, and eGFR according to the feature importance analysis. The partial dependence plots indicated relatively linear relationships for cortisol to age (positively) and eGFR (negatively). The association between cortisol and BMI was nonlinear. At BMI below 30 kg/m, cortisol was negatively associated with BMI, but it was unchanged at higher BMI levels. Using linear regression, we found that cortisol increased by 11% (95% CI, 7%-14%) for each 10-year increase in age. In patients with a BMI below 30 kg/m, cortisol increased by 23% (95% CI, 16%-31%) for each 5 kg/m decrease in BMI. We found no association at BMI levels above 30 kg/m. Cortisol increased by 9% (95% CI, 6%-11%) for each 10 ml/min/1.73m decrease in eGFR.
Cortisol is positively associated with age, negatively with BMI if below 30 kg/m, and negatively with eGFR. These associations should be considered before diagnosing MACS.
在患有肾上腺意外瘤（AI）的患者中，1 毫克地塞米松（皮质醇）后皮质醇特异性≥50nmol/L 作为轻度自主皮质醇分泌（MACS）的标准，其特异性约为 85%。目的是研究皮质醇与年龄、BMI 和肾功能的关系。
我们研究了 2005 年至 2015 年在斯科讷大学医院和赫尔辛堡医院检查的 1129 名 AI 患者。研究的协变量为性别、年龄、BMI、估算肾小球滤过率（eGFR）、吸入性类固醇治疗、AI 大小以及双侧 AI 中最小 AI 的大小（单侧 AI 中设置为 0）。我们使用机器学习模型来揭示潜在的非线性关联。它们被训练来拟合数据，并使用特征重要性分析和偏依赖图进行检查。偏依赖图显示了协变量对皮质醇的边际效应，平均值为其他协变量。
根据特征重要性分析，皮质醇与 AI 的大小密切相关，与年龄、BMI 和 eGFR 弱相关。偏依赖图表明皮质醇与年龄（正相关）和 eGFR（负相关）呈相对线性关系。皮质醇与 BMI 的关系是非线性的。在 BMI 低于 30kg/m 时，皮质醇与 BMI 呈负相关，但在较高的 BMI 水平下则不变。使用线性回归，我们发现皮质醇每增加 10 岁，增加 11%（95%CI，7%-14%）。在 BMI 低于 30kg/m 的患者中，皮质醇每降低 5kg/m，增加 23%（95%CI，16%-31%）。在 BMI 水平高于 30kg/m 时则没有关联。皮质醇每降低 10ml/min/1.73m，增加 9%（95%CI，6%-11%）。
皮质醇与年龄呈正相关，与 BMI（如果低于 30kg/m）呈负相关，与 eGFR 呈负相关。在诊断 MACS 之前，应考虑这些关联。
