title: Reproducibility and utility of an overnight 0.25 mg dexamethasone suppression test as a marker for glucocorticoid sensitivity in children with asthma.
abstract: OBJECTIVE
  Inhaled corticosteroids (ICS) are the cornerstone of asthma treatment in children. However, there is considerable inter-individual variation in glucocorticoid sensitivity, leading to over- as well as undertreatment. A simple and fast test to predict glucocorticoid sensitivity would enable more tailored therapy in children with asthma.
  
  
  OBJECTIVE
  To study reproducibility and utility of an overnight 0.25 mg dexamethasone suppression test (DST) with salivary cortisol levels as marker for glucocorticoid sensitivity in asthmatic children.
  
  
  METHODS
  23 children with atopic asthma were recruited for two overnight 0.25 mg DST's, 1 month apart.
  
  
  RESULTS
  Baseline cortisol levels correlated well between both tests. However, cortisol levels, change in cortisol levels or fractional suppression of cortisol levels after dexamethasone did not correlate between the two tests. Bland-Altman plots showed that the difference in salivary cortisol levels between test 1 and 2 of an individual patient could go up to 12 nmol/l, which is a clinically relevant difference. ICS dose did not correlate with baseline cortisol levels, height and BMI SDS.
  
  
  CONCLUSIONS
  The low-dose salivary DST test in its current form is not suitable for use in clinical practice in children with asthma, due to low reproducibility. Therefore, studies using the 0.25 mg salivary DST should be interpreted cautiously.
authors.affiliation: Department of Paediatric Endocrinology, Erasmus MC Sophia, 3015 GJ, Rotterdam, The Netherlands. rw490@medschl.cam.ac.uk.|Department of Paediatrics, Box 116 Level 8 Addenbrooke's Hospital, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK. rw490@medschl.cam.ac.uk.
authors.forename: R H
authors.initials: RH
authors.lastname: Willemsen
authors.affiliation: Department of Paediatric Endocrinology, Erasmus MC Sophia, 3015 GJ, Rotterdam, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: van Leeuwen
authors.affiliation: Department of Paediatric Pulmonology, Erasmus MC Sophia, 3015 GJ, Rotterdam, The Netherlands.
authors.forename: T A S
authors.initials: TA
authors.lastname: Voorend-van Bergen
authors.affiliation: Diagnostic Laboratory Endocrinology, Departments of Clinical Chemistry and Internal Medicine, Erasmus MC, 3015 GJ, Rotterdam, The Netherlands.
authors.forename: Y B
authors.initials: YB
authors.lastname: de Rijke
authors.affiliation: Department of Paediatric Pulmonology, Erasmus MC Sophia, 3015 GJ, Rotterdam, The Netherlands.
authors.forename: M W
authors.initials: MW
authors.lastname: Pijnenburg
authors.affiliation: Department of Paediatric Endocrinology, Erasmus MC Sophia, 3015 GJ, Rotterdam, The Netherlands.
authors.forename: E L T
authors.initials: EL
authors.lastname: van den Akker
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy* / Q000378:metabolism; D002648:Child; D002940:Circadian Rhythm; D003907:Dexamethasone / Q000008:administration & dosage*; D003940:Diagnostic Techniques, Endocrine; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D004351:Drug Resistance; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D010865:Pilot Projects; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012463:Saliva / Q000187:drug effects / Q000378:metabolism
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone; D006854:Hydrocortisone
keywords: Asthma; Glucocorticoid sensitivity; Paediatric endocrinology