Evaluation of hypothalamic-pituitary-adrenal axis suppression by low-dose (0.5 microg) and standard-dose (250 microg) adrenocorticotropic hormone (ACTH) tests in asthmatic children treated with inhaled corticosteroid

Oral corticosteroids for asthma exacerbations might be associated with adrenal suppression: Are physicians aware of that?

INTRODUCTION

Oral corticosteroids (OCS) are a mainstay of treatment for asthma exacerbations, and short-term OCS courses were generally considered to be safe. Nevertheless, frequent short-term OCS courses could lead to hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Our study aimed at investigating the integrity of the HPA axis in children with persistent asthma or recurrent wheezing at the beginning of an inhaled corticosteroids (ICS) trial.

METHOD

Morning basal cortisol was assessed just before the beginning of ICS, and 30, 60, and 90 days later, using Immulite® Siemens Medical Solutions Diagnostic chemiluminescent enzyme immunoassay (Los Angeles, USA; 2006).

RESULTS

In all, 140 children (0.3-15 years old) with persistent asthma or recurrent wheezing have been evaluated and 40% of them reported short-term OCS courses for up to 30 days before evaluation. Out of these, 12.5% had biochemical adrenal suppression but showed adrenal recovery during a three-month ICS trial treatment. No significant differences were observed among children with or without adrenal suppression, neither in the number of days free of OCS treatment before cortisol evaluation (p=0.29) nor in the last OCS course duration (p=0.20). The number of short-term OCS courses reported in the year preceding the cortisol evaluation was also not different (p=0.89).

CONCLUSION

Short-term systemic courses of corticosteroids at conventional doses can put children at risk of HPA axis dysfunction. ICS treatment does not impair adrenal recovery from occurring. Health practitioners should be aware of the risk of a blunted cortisol response upon exposure to stress during the follow-up of patients with persistent asthma or recurrent wheezing.

Evidence of hypothalamic-pituitary-adrenal axis suppression during moderate-to-high-dose inhaled corticosteroid use

The possible risk of adverse effects due to regular use of inhaled corticosteroids (ICS) is a real concern. Our aim was to describe the factors that have an impact on hypothalamic-pituitary-adrenal axis suppression (HPA-AS) in children and adolescents taking ICS regularly. The HPA axis status of patients who were on moderate-to-high-dose ICS [>176 and >264 μg/day fluticasone propionate-hydrofluoroalkane (FP-HFA) for patients 0-11 and ≥12 years, respectively] was investigated. Various types of ICS were converted to FP-HFA equivalent according to National Asthma Education and Prevention Program (NAEPP) guidelines. Participants with a baseline (8 a.m.) serum cortisol <15 μg/dL underwent a low-dose ACTH stimulation test (LDAT) to diagnose HPA-AS. Among 91 patients, 60 (75.9 %) participants underwent LDAT, and seven (7.7, 95 % CI 3.5-15.3 %) were diagnosed with HPA-AS. Ciclesonide was more frequently used by the participants with HPA-AS compared to patients with a normal HPA axis (42.9 vs. 4.8 %, p = 0.009). Use of ICS at moderate-to-high doses for at least 7 months distinguished participants with HPA-AS from those with a normal HPA axis. Among the duration, type, and dose of ICS, solely the use of ICS with a body mass index (BMI)-adjusted daily dose of ≥22 μg FP was found to increase the risk for HPA-AS (odds ratio (OR) 7.22, 95 % confidence interval (CI) 1.23-42.26, p = 0.028). The receiver operating characteristics (ROC) curve analysis revealed a cutoff value of 291 μg/day FP (area under the curve (AUC) = 0.840, p = 0.003) for predicting HPA-AS Conclusion: The prevalence of HPA-AS was found to be 7.7 % in children taking not only high-dose ICS but also moderate-dose ICS. Dose alone was found to be an actual risk factor for HPA-AS.

Early morning salivary cortisol and cortisone, and adrenal responses to a simplified low-dose short Synacthen test in children with asthma

OBJECTIVE

To examine serum cortisol responses to a simplified low-dose short Synacthen test (LDSST) in children treated with inhaled corticosteroids (ICS) for asthma and to compare these to early morning salivary cortisol (EMSC) and cortisone (EMSCn) levels.

DESIGN

Early morning salivary cortisol and EMSCn samples were collected for three consecutive days. On day three, Synacthen 500 ng/1·73 m(2) was administered intravenously. Samples were collected at 0, 15, 25, 35 min.

RESULTS

A total of 269 subjects (160 M: 109 F), median (range) age 10·0 (5·1-15·2) years were studied. Peak cortisol in the LDSST was <500 nmol/l in 101 subjects (37·5%) and <350 nmol/l in 12 subjects (4·5%). Basal cortisol correlated with peak cortisol: r = 0·55, (95% CI: 0·46, 0·63, P < 0·0001). Time at which peak cortisol concentration was achieved was significantly related to the value of peak cortisol (P < 0·0001), with higher cortisol peaks occurring later in the test and lower cortisol peaks occurring earlier. EMSC and EMSCn had no predictive value for the identification of patients with a peak cortisol <500 nmol/l. EMSCn was superior to EMSC in identifying patients with a peak cortisol <350 nmol/l: a minimum EMSCn cut-off value of 12·5 nmol/l gave a negative predictive value of 99·2% and positive predictive value of 30·1%.

CONCLUSION

Our data illustrate that basal measures of cortisol are likely to be of value in screening populations for patients at greatest risk of adrenal crisis. EMSCn shows promise as a screening tool for the identification of patients with severe adrenal insufficiency.

Airway and systemic effects of soluble and suspension formulations of nebulized budesonide in asthmatic children

BACKGROUND

Using cyclodextrin with budesonide enables it to be formulated in a solution for nebulization.

OBJECTIVE

To observe the effects of a Captisol-enabled budesonide solution (CBIS), 60 microg twice daily, delivered via a nebulizer (eFlow), compared with a conventional budesonide suspension (Pulmicort Respules), 250 microg twice daily, delivered via another nebulizer (LC Plus), using fraction of exhaled nitric oxide (FE(NO)) and overnight urinary cortisol to creatinine ratio as the primary outcomes for efficacy and systemic bioactivity.

METHODS

A randomized, open-label, crossover study was conducted in 12 children with mild-to-moderate persistent asthma (aged 5-12 years). Measurements were performed after a 2-week steroid washout at baseline and at the end of each 2-week randomized treatment.

RESULTS

The nebulization time was shorter (95% confidence interval [CI], 0.83-5.63 minutes; P = .03) with CBIS (mean, 1.77 minutes) than with Pulmicort Respules (mean, 5.01 minutes). The reduction in FE(NO) with CBIS from pooled baseline was 2.45-fold (95% CI, 1.87-3.21; P < .001); and with Pulmicort Respules, 3.18-fold (95% CI, 2.26-4.47; P < .001). No statistically significant changes from pooled baseline in lung function and overnight urinary cortisol to creatinine ratio were observed with either treatment.

CONCLUSIONS

The nebulization time was shorter with CBIS compared with Pulmicort Respules. Both formulations exhibited similar anti-inflammatory activity in terms of reducing FE(NO), with no detectable difference between them when used in a putative microgram nominal dose ratio of 1:4. Neither formulation produced significant adrenal suppression.

Dysregulation of the stress response in asthmatic children

The stress system co-ordinates the adaptive responses of the organism to stressors of any kind. Inappropriate responsiveness may account for increased susceptibility to a variety of disorders, including asthma. Accumulated evidence from animal models suggests that exogenously applied stress enhances airway reactivity and increases allergen-induced airway inflammation. This is in agreement with the clinical observation that stressful life events increase the risk of a new asthma attack. Activation of the hypothalamic-pituitary-adrenal (HPA) axis by specific cytokines increases the release of cortisol, which in turn feeds back and suppresses the immune reaction. Data from animal models suggest that inability to increase glucocorticoid production in response to stress is associated with increased airway inflammation with mechanical dysfunction of the lungs. Recently, a growing body of evidence shows that asthmatic subjects who are not treated with inhaled corticosteroids (ICS) are likely to have an attenuated activity and/or responsiveness of their HPA axis. In line with this concept, most asthmatic children demonstrate improved HPA axis responsiveness on conventional doses of ICS, as their airway inflammation subsides. Few patients may experience further deterioration of adrenal function, a phenomenon which may be genetically determined.

The hypothalamic-pituitary-adrenal axis in asthmatic children

Reduced responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis in patients with various chronic allergic inflammatory disorders and a blunted HPA axis response of poorly controlled asthmatics before long-term treatment with inhaled corticosteroids (ICS) have been reported. It seems that pro- and anti-inflammatory cytokines might be involved in the attenuation of cortisol and adrenocorticotropic hormone (ACTH) responses to stress in these patients. Although long-term ICS treatment might produce mild adrenal suppression in some asthmatic children, improvement of adrenal function has been detected in the majority of cases. We postulate that the anti-inflammatory effects of ICS result both in asthma remission and HPA axis improvement. Adrenal suppression of some asthmatic patients on maintenance ICS seems to be a separate phenomenon, possibly constitutionally or genetically determined.