Sense and sensitivity: assessing inhaled corticosteroid effects on the hypothalamic-pituitary-adrenal axis

Inhaled Corticosteroids and Endocrine Effects in Childhood

Asthma is the most common chronic inflammatory disease of children, and inhaled corticosteroids (ICSs) are the most effective and commonly used treatment of persistent asthma. ICSs currently approved for and commonly used by children with asthma include beclomethasone dipropionate, budesonide, fluticasone propionate, mometasone furoate, ciclesonide, and triamcinolone acetonide. This article reviews 4 areas critical to understanding potential adverse endocrine outcomes of ICSs and placing them in proper perspective: (1) influence of drug/delivery device properties on systemic steroid burden; (2) adrenal insufficiency during ICS treatment; (3) growth effects of ICS and asthma itself; and (4) bone mineral accretion during ICS therapy.

Oral steroid-sparing effect of high-dose inhaled corticosteroids in asthma

BACKGROUND

The proportion of the efficacy of high-dose inhaled corticosteroids (ICS) in oral corticosteroid-dependent asthma that is due to systemic effects is uncertain. This study aimed to estimate the ICS dose-response relationship for oral corticosteroid-sparing effects in oral corticosteroid-dependent asthma, and to determine the proportion of oral corticosteroid-sparing effects due to their systemic effects, based on the comparative dose-response relationship of ICS versus oral corticosteroids on adrenal suppression.

METHODS

Systematic review and meta-analysis of randomised controlled trials reporting oral corticosteroid-sparing effects of high-dose ICS in oral corticosteroid-dependent asthma. In addition, reports of oral corticosteroid to ICS dose-equivalence in terms of adrenal suppression were retrieved. The primary outcome was the proportion of the oral corticosteroid-sparing effect of ICS that could be attributed to systemic absorption, per 1000 µg increase of ICS, expressed as a ratio. This ratio estimates the oral corticosteroid sparing effect of ICS due to systemic effects.

RESULTS

11 studies including 1283 participants reporting oral corticosteroid-sparing effects of ICS were identified. The prednisone dose decrease per 1000 µg increase in ICS varied from 2.1 mg to 4.9 mg, depending on the type of ICS. The ratio of the prednisone-sparing effect due to the systemic effects per 1000 µg of fluticasone propionate was 1.02 (95% CI 0.68-2.08) and for budesonide was 0.93 (95% CI 0.63-1.89).

CONCLUSION

In patients with oral corticosteroid-dependent asthma, the limited available evidence suggests that the majority of the oral corticosteroid-sparing effect of high-dose ICS is likely to be due to systemic effects.

Effect of long term inhaled corticosteroid therapy on adrenal suppression, growth and bone health in children with asthma

BACKGROUND

Inhaled corticosteroids (ICS) are the most effective treatment for children with persistent asthma. However adverse effects of ICS on Hypothalamo Pituitary Adrenal (HPA) axis, growth and bone metabolism are a concern. Hence the primary objective of this study was to describe the effects of long term inhaled corticosteroid therapy (ICS) on adrenal function, growth and bone health in children with asthma in comparison to an age and sex matched group of children with asthma who were not on long term ICS. Describing the association between the dose of ICS and duration of therapy on the above parameters were secondary objectives.

METHOD

Seventy children with asthma on ICS and 70 controls were studied. Diagnosis of asthma in selected patients was reviewed according to the criteria laid down by GINA 2018 guidelines. The estimated adult heights were interpreted relative to their Mid Parental Height (MPH) range. Serum calcium, alkaline phosphatase and vitamin D levels were analyzed in both groups and cortisol value at 30 min following a low dose short synacthen test was obtained from the study group. The average daily dose of ICS (Beclamethasone) was categorized as low, medium and high (100-200, 200-400, > 400 μg /day) respectively according to published literature.

RESULTS

Heights of all children were within the MPH range. There was no statistically significant difference in the bone profiles and vitamin D levels between the two groups (Ca: p = 0.554, vitamin D: p = 0.187) but vitamin D levels were insufficient (< 50 nmol/l) in 34% of cases and 41% of controls. Suppressed cortisol levels were seen in 24%. Doses of ICS were low, medium and high in 56, 32 and 12% of children respectively. The association between adrenal suppression with longer duration of therapy (p < 0.01) and with increasing dose of ICS (p < 0.001) were statistically significant.

CONCLUSION

ICS had no impact on the growth and bone profiles but its dose and duration were significantly associated with adrenal suppression.

Effects of inhaled steroids on growth, bone metabolism and adrenal function

Inhaled corticosteroids are a first-line therapy for persistent asthma in children. Major safety concerns of long-term inhaled corticosteroid therapy include suppression of adrenal function, growth and bone development. Proper interpretation of inhaled corticosteroid safety studies requires knowledge of the differences among various inhaled corticosteroid drug/delivery device systems. Dosage, type of inhaler device used, patient technique and characteristics of the individual drug influence the systemic effects of inhaled corticosteroids. Systemic side effects can occur when continuous high-dose treatment is required for severe asthma or when the dosage prescribed is excessive and compliance unusually good. Overall, however, recent studies confirm that benefits of inhaled corticosteroids, properly prescribed and used, clearly outweigh not only their potential adverse effects, but also the risks associated with poorly controlled asthma.

Evaluation of tests of hypothalamic-pituitary-adrenal axis function used to measure effects of inhaled corticosteroids

OBJECTIVES

To review the evidence supporting the evaluation of hypothalamic-pituitary-adrenal (HPA) axis function as a measure of systemic exposure and clinical adverse events, discuss factors that affect systemic exposure to inhaled corticosteroids (ICSs), and review the effects of various ICSs that are currently available or under development on HPA axis function from a therapeutic perspective.

DATA SOURCES

Randomized published clinical trials and review articles on the topic of HPA axis suppression were retrieved in MEDLINE. Searches dating back to 1988 were restricted to human studies published in English.

STUDY SELECTION

Studies that evaluated HPA axis function and the methods used to measure its activities and the effects of ICSs (fluticasone propionate, budesonide, beclomethasone dipropionate, mometasone furoate, and ciclesonide) were selected.

RESULTS

Factors that influence adverse events caused by ICSs include pharmacokinetic and pharmacodynamic properties, delivery devices, and therapeutic dose and duration. Basal measurements of blood and urinary cortisol levels, reflecting basal HPA axis function, are the most sensitive markers for assessing systemic ICS bioavailability but, compared with dynamic stimulation tests, are poor clinical predictors of adrenal dysfunction.

CONCLUSIONS

Basal serologic and urinary cortisol tests provide the best measures of assessing and comparing systemic ICS exposure. Long-term clinical studies are needed to determine whether such tests are predictive of ICS toxicity.

The systemic safety of inhaled corticosteroid therapy: a focus on ciclesonide

OBJECTIVE

To review the potential systemic activity of ciclesonide and its active metabolite, desisobutyryl-ciclesonide, by evaluation of the effects on hypothalamic-pituitary-adrenal (HPA) axis function.

DATA SOURCES

EMBASE and MEDLINE searches using the keyword ciclesonide, without date restrictions, were conducted to identify published articles that related to clinical trials that included ciclesonide.

STUDY SELECTION

The primary articles that reported systemic safety data for ciclesonide were reviewed.

RESULTS

Ciclesonide (320-1,280 microg/d) demonstrated no detectable, clinically relevant effect on HPA axis function as evaluated by basal cortisol excretion measurements and dynamic stimulation tests. Furthermore, ciclesonide had no effect on the normal diurnal rhythm of endogenous cortisol secretion while simultaneously improving pulmonary function and reducing bronchial hyperresponsiveness. These results suggest that ciclesonide has a low systemic activity that may be attributable to unique pharmacologic properties, including a high degree of serum protein binding, a low oral bioavailability, and rapid systemic elimination, that reduce the level of systemically available pharmacologically active drug.

CONCLUSIONS

Even at the higher doses used to treat more severe cases of asthma, ciclesonide was observed to have no effect on HPA axis function. These data, in conjunction with the observed clinical efficacy, suggest that ciclesonide may have an improved therapeutic margin compared with some other currently available inhaled corticosteroid treatments and, therefore, the potential to improve therapeutic outcomes.

Effects of inhaled steroids on growth, bone metabolism, and adrenal function

For children who have persistent asthma of any degree, ICS treatment is recommended. Although topical airway corticosteroid therapy has improved the control of asthma markedly while lessening the risk of corticosteroid side effects, the use of ICS continues to be accompanied by a fear of potential adverse systemic effects. Unfortunately, these fears result in some children being deprived of appropriate and effective treatment or even exposed to a greater risk of periodic oral corticosteroid treatment. Nevertheless, because these agents may be used for long periods of time in a large number of children, safety issues are paramount. Important overall conclusions seem well supported by the literature. First, ICS used in small doses present no significant risk for systemic side effects. When ICS are used at higher dosages and continuously for long periods of time, important differences in drug characteristics, in particular the efficiency of inactivation of swallowed drug (which does not exert a therapeutic effect prior to gaining access to the systemic circulation), affect the ratio of therapeutic to systemic effect of individual ICS. From a practical viewpoint, the long-term clinical history of ICS therapy is informative. Clinically significant suppression of the HPA axis resulting from ICS therapy alone is rare. Detectable suppression of childhood growth can occur when ICS with relatively poor first-pass inactivation are administered at doses greater than or equal to 400 microg per day; this effect on 1-year growth is reduced when clinically equivalent doses of ICS with improved first-pass inactivation of swallowed drug are used. Administration of ICS alone, however, is not associated with any detectable effects on final adult height. Harmful effects of ICS on bone metabolism, although not yet studied adequately, are not expected with the use of an ICS dosage that does not suppress basal HPA axis function or childhood growth. An important caveat to these conclusions is that they refer to the use of ICS used alone and in recommended doses, not in combination with intranasal or other topical corticosteroids. Differences in safety profiles among the available ICS exist, but there are few direct comparative studies attempting to establish rank in benefit-to-risk ratios. The safety profile of all ICS preparations, which focus anti-inflammatory effects on the lung, is markedly better than that of oral glucocorticoids. Risk of adverse effects is minimized by using the lowest effective dosage, by limiting systemic availability of the drug through careful selection of the inhalation device and proper technique, by the adjunct use of alternative anti-inflammatory agents, and, when higher doses are required, by choice of ICS medication. Monitoring growth in children is a sensitive method of detecting significant ICS systemic effects and can enhance a family's confidence in the safety of the medication. When long-term, high-dose therapy is required, periodic evaluations of adrenal function and bone density may be advisable. ICS are highly effective and, because their benefits clearly exceed potential risks, can be used safely in children who have persistent asthma.

Inhaled steroids for children: effects on growth, bone, and adrenal function

Inhaled corticosteroids are the first-line therapy for persistent asthma in children. Major safety concerns of long-term inhaled corticosteroid therapy include suppression of adrenal function and impaired growth and bone development. Proper interpretation of inhaled corticosteroid safety requires knowledge of differences among various drug devices. Dosage, type of inhaler device used, patient technique, and characteristics of the individual drug influence systemic effects of inhaled corticosteroids. Systemic side effects can occur when continuous high-dose treatment is required for severe asthma or when prescribed dosage is excessive and compliance is unusually good. Recent studies confirm that benefits of inhaled corticosteroids outweigh potential adverse effects and the risks associated with poorly controlled asthma.

Long-term effect of budesonide on hypothalamic-pituitary-adrenal axis function in children with mild to moderate asthma

OBJECTIVE

To determine the safety of long-term (36 months) administration of an inhaled corticosteroid (budesonide) on hypothalamic-pituitary-adrenal (HPA) axis function in children with mild to moderate asthma.

METHODS

This was an ancillary study of the Childhood Asthma Management Program (CAMP). Sixty-three children who had mild to moderate asthma and were enrolled in CAMP underwent evaluation of HPA axis function before and 12 and 36 months after receiving continuous therapy with either an inhaled anti-inflammatory agent (budesonide 400 microg/day or nedocromil 16 mg/day) or placebo. HPA axis function was assessed by serum cortisol levels 30 and 60 minutes after 0.25 mg of adrenocorticotrophic hormone (ACTH) and 24-hour urinary free cortisol excretion.

RESULTS

There were no differences in serum cortisol levels after ACTH stimulation between treatment groups, regardless of time after ACTH administration or months of follow-up. Urinary cortisol excretion per body surface area was similar in both treatment groups at 36 months, after adjusting for age at randomization, race, gender, and clinic. Cumulative inhaled corticosteroid exposure did not influence serum cortisol response to ACTH or urinary free cortisol excretion at 36 months.

CONCLUSIONS

We found no effects of chronic budesonide treatment at a dose of 400 micro g/day on HPA axis function in children with mild to moderate asthma and demonstrated the absence of a cumulative effect on HPA axis function over a 3-year period.