Exp Clin Endocrinol Diabetes 2010; 118(3): 151-157
DOI: 10.1055/s-0029-1202275
Article

© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

The low-dose (1 μg) Cosyntropin Test (LDT) for Primary Adrenocortical Insufficiency: Defining the Normal Cortisol Response and Report on First Patients with Addison Disease Confirmed with LDT

M. Pura 1 ,  Kreze 2 A. Jr. , P. Kentoš 1 , P. Vaňuga 1
  • 1Department of Endocrinology, National Institute of Endocrinology and Diabetology, Lubochna, Slovakia
  • 2IInd Internal Department, Bulovka Faculty Hospital, Prague, Czech Republic
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Publikationsverlauf

received 22.06.2008 first decision 30.10.2008

accepted 22.01.2009

Publikationsdatum:
08. April 2009 (online)

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Abstract

Background: The validity of low-dose 1 μg cosyntropin test (LDT) is reported mainly for the assessment of secondary adrenocortical insufficiency (AI). Likewise the hypothalamic-pituitary disorders, early diagnosis of the initial or partial stages of primary AI has an important role.

Objective: The aim of study was to: 1) establish the normal cut-off level at which the stimulated plasma cortisol (FP) in LDT excludes primary AI; 2) compare the results in elderly subjects to those in younger ones; 3) compare the results between normal and obese subjects; and 4) verify the established cut-off values on the sample of patients suspected to have primary AI.

Subjects and Methods: 110 subjects (99 women and 11 men, aged 19–80 years, mean 46.2±16.1 years, without suspicion for impairment of the hypothalamo-pituitary-adrenal axis were recruited to undergo the LDT in standard conditions. Control group consists of 30 patients (22 women and 8 men, aged 7–58 years, mean 38.4±10.6 years) evaluated in whom for suspicion of primary AI as suggested by LDT was confirmed by supplemental investigations (elevated ACTH levels, positive autoantibodies against 21-hydroxylase, mutational analysis of corresponding genes).

Results: The mean peak FP level at 30 min (FP30) of the subjects was 675±85 nmol/L (95% CI=659 to 691 nmol/L), thus reference values expressed as mean±2 SD were 505–845 nmol/L. There was a significant negative correlation between basal FP values (FP0) (434±105 nmol/L) and the absolute FP incremental (FPΔ) response varying from 52 to 553 nmol/L (median 230 nmol/L) (r=–0.71; P<0.001). FP30 was higher in elderly subjects (n=27) in comparison to younger subjects (n=25) (689±88 nmol/L vs. 642±63 nmol/L, u=2.11, P<0.05) due to higher FPΔ (274±116 nmol/L vs. 175±112 nmol/L; u=4.02, P<0.01) ; FP30 levels in obese subjects (n=27) did not differ from those with normal BMI (n=33) (694±100 nmol/L vs. 667±65 nmol/L, u=1.31, P>0.05). We did not find any correlation between body weight or body surface area and FP0, FP30 or FPΔ. Post-stimulation FP30 levels in the control group varied from 0 to 354 nmol/L with median 64 nmol/L (25th percentile 10 nmol/L; 75th percentile 165 nmol/L) and were entirely distinctive from those of the subjects without adrenal impairment (P<0.001).

Conclusions: Taking the mean –2 SD result as a threshold, FP value of 500 nmol/L can be consider as cut-off at 30 min in the LDT for defining the intact adrenocortical function, independently of age and body weight, body surface area.

References

Correspondence

M. PuraMD 

Department of Endocrinology

National Institute of Endocrinology and Diabetology

034 91 Lubochna

Slovakia

Telefon: +421/44/4306 113 214

Fax: +421/44/4306 322

eMail: mikulas.pura@nedu.sk