Diagnostic value of salivary cortisol in end stage renal disease.
OBJECTIVE
Salivary cortisol has been proposed a surrogate marker for free serum cortisol measurements. The aim of this study was to ascertain the diagnostic value of basal and stimulated salivary cortisol for the detection of adrenal insufficiency (AI) in hypotensive end stage renal disease (ESRD) patients. Basal salivary cortisol and basal total serum cortisol were studied in order to determine the accuracy of both biomarkers in predicting AI.


METHODS
Twenty-nine ESRD patients with sustained hypotension were investigated for possible AI. Salivary cortisol was assessed at baseline and 30min after 25microg ACTH i.m. (LDTs). The dosage of salivary aldosterone was performed in salivary cortisol hypo-responders. Basal blood samples were drawn for steroids, renin and ACTH measurements.


RESULTS
A clear separation between patients with normal and impaired adrenal function was obtained through salivary cortisol levels at 30min after ACTH. AI was detected in six cases (21%) through impaired salivary cortisol responses; stimulated salivary aldosterone helped to differentiate primary (n=3) from secondary AI (n=3). ROC curves showed that cutoff values for basal SAF < or =4.4nM and serum cortisol < or =232.0nM suggest AI (sensitivities: 93% and 69%; specificities: 86.4% and 91%, respectively).


CONCLUSIONS
We conclude that ACTH stimulated SAF is an accurate biomarker for the diagnosis of AI in hypotensive ESRD patients. Neither basal salivary cortisol nor serum cortisol showed 100% sensitivities for the detection of AI.
Arregger
Alejandro L
AL
Endocrine Research Department, Instituto de Investigaciones Médicas A. Lanari, School of Medicine, University of Buenos Aires, Argentina.
Cardoso
Estela M L
EM
Tumilasci
Omar
O
Contreras
Liliana N
LN
D000309:Adrenal Insufficiency / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000494:pharmacology; D000450:Aldosterone / Q000378:metabolism; D015415:Biomarkers / Q000097:blood / Q000378:metabolism*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism*; D007676:Kidney Failure, Chronic / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism; D011237:Predictive Value of Tests; D012463:Saliva / Q000187:drug effects / Q000378:metabolism*; D012680:Sensitivity and Specificity
D015415:Biomarkers; D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone