Why is this important?
Adrenal insufficiency or cortisol deficiency is a situation that can be life-threatening for an individual. Taking corticosteroids or opiates or the occurrence of infectious diseases can expose to the risk of adrenal insufficiency. The dosage of basal cortisol in the blood at 8 a.m., following ACTH stimulation is still today the reference test for diagnosing an adrenal function disorder. However, it requires a consultation and a blood sample. The salivary cortisone test helps simplify the procedure by reflecting free serum cortisol. The sample taken at home is then sent to the laboratory for analysis.
Methodology
This prospective study was carried out in patients at high risk of adrenal insufficiency. After taking a saliva sample when they woke up, at home, the patients then went to a care facility to perform an ACTH stimulation test. This study evaluates the effectiveness of the saliva test versus the standard test for diagnosing adrenal insufficiency.
Principle results
Two hundred and twenty patients were recruited for this study. The average age of the population was 55.1 years and 49% were women. In the population as a whole, the prevalence of adrenal insufficiency measured by the ACTH stimulation test was 44%. Five percent of the saliva samples were contaminated with residues of oral hydrocortisone administered the previous day and were excluded from the analyses.
The area under the curve corresponding to the use of salivary cortisone measurement upon awakening as a predictor of adrenal insufficiency was 0.95 [0,92-0,97].
The negative predictive value was 96% and the positive predictive value 95% for sensitivity and specificity thresholds of at least 95%.
In 70% of individuals, the data provided by the measurement of salivary cortisone on awakening and the stimulation of ACTH were similar.
The vast majority of patients (83%) showed a clear preference for the saliva test.
Univariate analysis showed no influence of age, sex, body mass index, smoking status or alcohol consumption on saliva test results. Multivariate analyzes showed that the use of oral corticosteroids had an impact on the saliva test result whereas inhaled, topical or nasal corticosteroids did not.
