High prevalence of HPA axis suppression in children taking corticosteroids

Two-thirds of asthmatic children taking corticosteroids might have hypothalamic–pituitary–adrenal (HPA) dysfunction, suggest Ekkehard Zöllner and colleagues in Pediatrics.

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“Adrenal crisis has been described in children treated with high doses of inhaled fluticasone propionate,” says Zöllner, “and it was consequently recommended that doses licensed for children should not be exceeded.” However, HPA axis suppression caused by corticosteroid treatment in children was thought to be rare.

The new study involved 143 children aged 5–18 years who were seen at Tygerberg Children's Hospital, Cape Town, South Africa. Patients were taking inhaled corticosteroids for the treatment of asthma, and most were also taking nasal steroids. Adherence to therapy was self-reported. To assess HPA axis function, fasting morning serum levels of cortisol and adrenocorticotropic hormone were measured and the overnight metyrapone test was added if morning serum cortisol levels were >83 nmol/l.

Some form of biochemical HPA axis dysfunction was observed in 65.1% (95% CI 56.5–72.9%) of the children, with suppression of both hypothalamic–pituitary and adrenal function observed in 16.3% (95% CI 9.3–23.3%) of the group. In 32.3% (95% CI 23.7–40.9%) of the patients, hypothalamic–pituitary function was normal, but adrenal function was impaired. High adherence to therapy, use of nasal steroids, and low or normal BMI were associated with higher likelihood of HPA axis dysfunction.

Zöllner highlights the importance of identifying a suitable screening test for assessment of HPA axis dysfunction in this patient group, as well as identifying genetic factors that might be protective against or predict the development of HPA axis suppression. “Every asthmatic child with a low BMI treated with both inhaled corticosteroids and nasal steroids and who is adherent to therapy should have their HPA axis function assessed,” Zöllner recommends.