title: Moderately impaired renal function increases morning cortisol and cortisol levels at dexamethasone suppression test in patients with incidentally detected adrenal adenomas.
abstract: OBJECTIVE
  Patients with incidentally detected adrenal adenomas may have subclinical hypercortisolism. We hypothesized that impaired renal function could lead to increased cortisol levels in these patients.
  
  
  METHODS
  Descriptive retrospective study of consecutive patients.
  
  
  METHODS
  A total of 166 patients with incidentally detected unilateral adrenal adenomas were examined during 2008-2013.
  
  
  METHODS
  Levels of cortisol, ACTH and cortisol at 1 mg overnight dexamethasone suppression test (DST) were measured. The estimated glomerular filtration rate (eGFR) was calculated using the MDRD equation.
  
  
  RESULTS
  Renal function was normal, mildly impaired, moderately impaired or severely impaired (eGFR >90, 60-90, 30-60 and 15-30 ml/min/1·73 m(2)) in 34, 54, 10 and 1% of the patients, respectively. Patients with normal and mildly impaired renal function had similar cortisol levels. Patients with moderately impaired renal function, compared to all the patients with eGFR >60 ml/min/1·73 m(2), exhibited increased cortisol (541 vs 456 nmol/l, P = 0·02), increased cortisol at DST (62 vs 37 nmol/l, P = 0·001), but similar ACTH levels (4·1 vs 2·9 pmol/l, P = 0·21). Patients with moderately impaired renal function thus exhibited cortisol at DST ≥ 50 nmol/l, more often than patients with eGFR >60 ml/min/1·73 m(2) (76% vs 30%, P = 0·000), while the prevalence of ACTH below 2 pmol/l was similar (24% vs 31%, P = 0·51).
  
  
  CONCLUSIONS
  Moderately impaired renal function increases cortisol and cortisol at DST in patients with adrenal adenomas, while mildly impaired renal function has no such effect. Cortisol level at DST ≥ 50 nmol/l therefore seems to have low specificity in diagnosing subclinical adrenal hypercortisolism, and an additional criterion, for example low ACTH, is required.
authors.affiliation: Department of Internal Medicine, Helsingborg Hospital, Faculty of Medicine, Lund University, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Olsen
authors.affiliation: Department of Radiology, Helsingborg Hospital, Faculty of Medicine, Lund University, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Mjöman
mesh_terms: D018246:Adrenocortical Adenoma / Q000097:blood* / Q000188:drug therapy*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000368:Aged; D003907:Dexamethasone / Q000627:therapeutic use*; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone