Late-Night Salivary Cortisol: Cut-Off Definition and Diagnostic Accuracy for Cushing’s Syndrome in a Portuguese Population

Authors

  • Adriana De Sousa Lages Endocrinology, Diabetes and Metabolism Department. Coimbra Hospital and University Center. Coimbra.
  • João Gonçalo Frade Clinical Pathology Department. Coimbra Hospital and University Center. Coimbra. School of Health Sciences. Polytechnic Institute of Leiria. Leiria
  • Diana Oliveira Endocrinology, Diabetes and Metabolism Department. Coimbra Hospital and University Center. Coimbra.
  • Isabel Paiva Endocrinology, Diabetes and Metabolism Department. Coimbra Hospital and University Center. Coimbra.
  • Patrícia Oliveira Endocrinology, Diabetes and Metabolism Department. Coimbra Hospital and University Center. Coimbra.
  • Alexandre Rebelo-Marques Family Health Unit from Condeixa. Agrupamento de Centros de Saúde do Baixo Mondego, Administração Regional de Saúde do Centro. Condeixa-A-Nova. Faculty of Medicine. University of Coimbra. Coimbra.
  • Francisco Carrilho Endocrinology, Diabetes and Metabolism Department. Coimbra Hospital and University Center. Coimbra.

DOI:

https://doi.org/10.20344/amp.11265

Keywords:

Circadian Rhythm, Cushing Syndrome/diagnosis, Diagnostic Techniques, Endocrine, Hydrocortisone, Saliva

Abstract

Introduction: Diagnosis of Cushing’s syndrome remains a challenge in clinical endocrinology. Even though late-night salivary cortisol is used as screening tool, individualized cut-off levels for each population must be defined.
Material and Methods: Three groups of subjects were studied: normal subjects, suspected and proven Cushing’s syndrome. Salivary cortisol was measured using an automated electrochemiluminescence assay. The functional sensitivity of the assay is 0.018 μg/dL. The diagnostic cut-off level was defined by Receiver Operating Characteristic curve and Youden’s J index.
Results: We studied 127 subjects: 57 healthy volunteers, 39 patients with suspected and 31 with proven Cushing’s syndrome. 2.5th - 97.5th percentile of the late-night salivary cortisol concentrations in normal subjects was 0.054 to 0.1827 μg/dL. Receiver Operating Characteristic curve analysis showed an area under the curve of 0.9881 (p < 0.0001). A cut-off point of 0.1 μg/dL provided a sensitivity of 96.77% (95% CI 83.3 - 99.92%) and specificity of 91.23% (95% CI 80.7 - 97.09%). There was a significant correlation between latenight salivary cortisol and late-night serum cortisol (R = 0.6977; p < 0.0001) and urinary free cortisol (R = 0.5404; p = 0.0025) in proven Cushing’s syndrome group.
Discussion: The mean ± SD late-night salivary cortisol concentration in patients with proven Cushing’s syndrome (0.6798 ± 0.52 μg/ dL) was significantly higher (p < 0.0001). In our population, the late-night salivary cortisol cut-off was 0.1 μg/dL with high sensitivity and specificity.
Conclusion: Late-night salivary cortisol has excellent diagnostic accuracy, making it a highly reliable, noninvasive, screening tool for outpatient assessment. Given its convenience and diagnostic accuracy, late-night salivary cortisol may be added to other traditional screening tests on hypercortisolism.

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Published

2019-05-31

How to Cite

1.
Lages ADS, Frade JG, Oliveira D, Paiva I, Oliveira P, Rebelo-Marques A, Carrilho F. Late-Night Salivary Cortisol: Cut-Off Definition and Diagnostic Accuracy for Cushing’s Syndrome in a Portuguese Population. Acta Med Port [Internet]. 2019 May 31 [cited 2024 Nov. 13];32(5):381-7. Available from: https://www.actamedicaportuguesa.com/revista/index.php/amp/article/view/11265

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Section

Original