[EVALUATION OF ADRENAL CORTICAL FUNCTION USING SALIVARY CORTISOL MEASUREMENTS IN CHILDREN WITH BRONCHIAL ASTHMA]

When corticosteroids are used for a long time in patients with bronchial asthma, a decrease in adrenal cortex function occurs. We investigated the use of salivary cortisol measurements as a simple, noninvasive method for the evaluation of the adrenal cortex function in pediatric asthmatic patients.

Plasma and salivary cortisol levels were measured from 8:00 am to 10:00 am in 248 pediatric asthmatic patients aged 0-18 years that were under long-term care management at the National Hospital Organization Fukuoka National Hospital in 2011-2013. We determined the correlation between plasma and salivary cortisol levels and calculated a salivary cortisol cut-off value for screening adrenocortical function.

There was a significant positive correlation between salivary cortisol levels and plasma cortisol levels in all patients, patients under age 3, and patients over age 3 (r=0.759, r=0.563, r=0.827, respectively). Salivary cortisol cut-off values were 0.015μg/dL for plasma cortisol levels below 3μg/dL (sensitivity 83%, specificity 82%), and 0.045μg/dL those below 5μg/dL (sensitivity 83%, specificity 75%). 5μg/dL or less is an abnormal value, and 3μg/dL or less is considered to be adrenal insufficiency.

Salivary cortisol levels were positively correlated with plasma cortisol levels in pediatric asthmatic patients. This is a useful method for frequently monitoring young children with adrenal dysfunction or severe asthma that are treated with high doses of inhaled corticosteroids.