Abstract
Introduction: The specificity of cortisol after 1 mg dexamethasone (cortisolDST) ≥50 nmol/l as a criterion for mild autonomous cortisol secretion (MACS) is approximately 80% in patients with adrenal incidentalomas (AI). The aim was to study the associations of cortisolDSTto age, BMI, and renal function. We used machine learning models to uncover potential non-linear associations.
Methods: We studied 1129 patients with AI examined from 2005 to 2015 at Skåne University Hospital and Helsingborg Hospital. CortisolDSTwas ln-transformed in the analyses. The covariates studied were gender, age, BMI, 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). Various machine learning models were trained to fit the data and examined using feature importance analysis and partial dependence plots. Partial dependence plots show the marginal effect on cortisolDSTof a covariate averaging over other covariates.
Results: CortisolDST was strongly associated to the size of the AI but had weaker associations to age, BMI, and eGFR according to permutation importance. The partial dependence plots indicated relatively linear relationships for cortisolDSTto age (positively) and eGFR (negatively). There was a negative relationship to BMI at levels below 30 kg/m2. Using linear regression, we found that cortisolDST increased 10% (95% CI, 7–14%) for each 10-year increase in age. In patients with BMI below 30 kg/m2, cortisolDSTdecreased 19% (95% CI, 14–23%) for each 5 kg/m2 increase in BMI. We found no association at BMI levels above 30 kg/m2. CortisolDST increased 9% (95% CI, 6–11%) for each 10 ml/min/1.73m2 decrease in eGFR.
Conclusions: CortisolDST is positively associated to age, negatively to BMI if below 30 kg/m2, and negatively to eGFR. These associations should be considered before diagnosing MACS.
Methods: We studied 1129 patients with AI examined from 2005 to 2015 at Skåne University Hospital and Helsingborg Hospital. CortisolDSTwas ln-transformed in the analyses. The covariates studied were gender, age, BMI, 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). Various machine learning models were trained to fit the data and examined using feature importance analysis and partial dependence plots. Partial dependence plots show the marginal effect on cortisolDSTof a covariate averaging over other covariates.
Results: CortisolDST was strongly associated to the size of the AI but had weaker associations to age, BMI, and eGFR according to permutation importance. The partial dependence plots indicated relatively linear relationships for cortisolDSTto age (positively) and eGFR (negatively). There was a negative relationship to BMI at levels below 30 kg/m2. Using linear regression, we found that cortisolDST increased 10% (95% CI, 7–14%) for each 10-year increase in age. In patients with BMI below 30 kg/m2, cortisolDSTdecreased 19% (95% CI, 14–23%) for each 5 kg/m2 increase in BMI. We found no association at BMI levels above 30 kg/m2. CortisolDST increased 9% (95% CI, 6–11%) for each 10 ml/min/1.73m2 decrease in eGFR.
Conclusions: CortisolDST is positively associated to age, negatively to BMI if below 30 kg/m2, and negatively to eGFR. These associations should be considered before diagnosing MACS.
| Original language | English |
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| Publication date | 2022 |
| DOIs | |
| Publication status | Published - 2022 |
| Event | European Congress of Endocrinology 2022 - Milano, Italy Duration: 21 May 2022 → 24 May 2022 |
Conference
| Conference | European Congress of Endocrinology 2022 |
|---|---|
| Country/Territory | Italy |
| City | Milano |
| Period | 21/05/2022 → 24/05/2022 |