Effects of beclomethasone and factors related to asthma on the growth of prepubertal children

Normal growth variance by Z scores should be considered when interpreting the growth inhibitory effect of inhaled corticosteroids

BACKGROUND

Randomized clinical trials suggest that long-term inhaled corticosteroid (ICS) treatment significantly inhibits growth velocity (GV) assessed by centimeters/year (cm/year) in primarily prepubescent, mild asthmatics. However, several observational studies measuring normal growth variance by Z score suggest the absence of the ICS inhibitory effect.

OBJECTIVE

To demonstrate the generalizability of ICS growth inhibition in cm/year by establishing whether this measure exceeds the expected normal changes in GV by Z score for similar age and sex.

METHODS

This was a retrospective, observational study comparing height and GV across a 2 year period in asthmatics aged 2-10 years, receiving ICS therapy (Group 3) with non-asthmatics, and non-ICS asthmatics (Groups 1 and 2), respectively. Generalized linear model procedure compared GV measures after adjustment for age, gender, and dependence of group differences on the age of the child.

RESULTS

Before initiation of ICS therapy at baseline, Group 3 patients (n = 22) were shorter than Groups 1 (n = 67) and 2 (n = 44) by mean height in cm, and height for age Z score in the adjusted model (p < .05). GV was also significantly reduced in Group 3 after initiation of ICS therapy versus Groups 1 and 2 by 1.0-1.5 cm/year, respectively, p < .05, but not significantly in comparison to expected normal GV variance determined by Z score, p ≥ .05.

CONCLUSION

Our findings suggest the need to consider normal growth variance by Z scores in addition to absolute changes (cm/year) when interpreting the inhibitory effect of ICS on GV. Larger sample size studies will be necessary to confirm our findings.

Intranasal triamcinolone and growth velocity

BACKGROUND

Inadequate designs and conflicting results from previous studies prompted the US Food and Drug Administration to publish guidelines for the design of clinical trials evaluating the effects of orally inhaled and intranasal corticosteroids on the growth of children. This study conformed to these guidelines to evaluate the effect of triamcinolone acetonide aqueous nasal spray (TAA-AQ) on the growth of children with perennial allergic rhinitis (PAR).

METHODS

This randomized, double-blind, placebo-controlled, parallel-group, multicenter study evaluated the effect of once-daily TAA-AQ (110 μg) on the growth velocity (GV) of children aged 3-9 years with PAR by using stadiometry at baseline (4-6 months), during treatment (12 months), and at follow-up (2 months). Hypothalamus-pituitary-adrenal (HPA) axis function was assessed by measuring urinary cortisol levels. Details of adverse events were recorded.

RESULTS

Of 1078 subjects screened, 299 were randomized, and 216 completed the study (placebo, 107; TAA-AQ, 109). In the primary analysis (modified intent-to-treat: placebo, 133; TAA-AQ, 134), least-squares mean GV during treatment was lower in the TAA-AQ group (5.65 cm/year) versus placebo (6.09 cm/year). The difference (-0.45 cm/year; 95% confidence interval: -0.78 to -0.11; P = .01), although clinically nonsignificant, was evident within 2 months of treatment and stabilized thereafter. At follow-up, the GV approached baseline (6.70 cm/year) in the TAA-AQ group (6.59 cm/year) and decreased slightly in the placebo group (5.89 cm/year vs 6.06 cm/year at baseline). No HPA axis suppression was observed.

CONCLUSIONS

By using rigorous Food and Drug Administration-recommended design elements, this study detected a small, statistically significant effect of TAA-AQ on the GV of children with PAR.

The effects of inhaled corticosteroids on growth in children

Inhaled corticosteroids (ICS) are recommended as the first-line therapy for children with persistent asthma. These agents are particularly effective in reducing underlying airway inflammation, improving lung function, decreasing airway hyper-reactivity, and reducing intensity of symptoms in asthmatics. Chronic diseases, such as asthma, have growth-suppressing effects independent of the treatment, which inevitably complicates growth studies. One year studies showed a small, dose-dependent effect of most ICS on childhood growth, with some differences across various ICS molecules, and across individual children. Some ICS at the doses studied did not affect childhood growth when rigorous study designs were used. Most studies did not conform completely with the FDA guidance. The data on effects of childhood ICS use on final adult height are conflicting, but one recent well-designed study showed such an effect, clearly warranting additional studies. In spite of these measurable effects of ICS on childhood growth, it is important to understand that the safety profile of all ICS preparations, with focal anti-inflammatory effects on the lung, is significantly better than oral glucocorticoids.

From knemometry to final adult height: inhaled corticosteroids and their effect on growth in childhood

Growth impairment in children with asthma, as a consequence of inhaled corticosteroids (ICS), is a major issue. Adverse systemic effects of ICS have been reviewed extensively, but no clinically relevant effects are reported if they are used in an appropriate dose as advocated in most guidelines. Growth studies can be divided into knemometry studies, intermediate term studies, and long term studies up to final adult height. These different studies provide different information. Knemometry demonstrates a dose dependent systemic effect, while all intermediate term studies demonstrate growth reduction of approximately one cm after one year of treatment. Most reassuring is that this delay seems to be temporary. The one study with a follow-up to final height shows no differences between the ICS and non-ICS treated children. The studies suggest that the use of ICS with respect to growth is safe if these drugs are used in a low to medium dose.

Childhood asthma in low income countries: an invisible killer?

Bacterial pneumonia has hitherto been considered the key cause of the high respiratory morbidity and mortality in children under five years of age (under-5s) in low-income countries, while asthma has not been stated as a significant reason. This paper explores the definitions and concepts of pneumonia and asthma/wheezing/bronchiolitis and examines whether asthma in under-5s may be confused with pneumonia. Over-diagnosing of bacterial pneumonia can be suspected from the limited association between clinical pneumonia and confirmatory test results such as chest x-ray and microbiological findings and poor treatment results using antibiotics. Moreover, children diagnosed with recurrent pneumonia in infancy were often later diagnosed with asthma. Recent studies showed a 10-15% prevalence of preschool asthma in low-income countries, although under-5s with long-term cough and difficulty breathing remain undiagnosed. New studies demonstrate that approximately 50% of acutely admitted under-5s diagnosed with pneumonia according to Integrated Management of Childhood Illnesses could be re-diagnosed with asthma or wheezing when using re-defined diagnostic criteria and treatment. It is hypothesised that untreated asthma may contribute to respiratory mortality since respiratory syncytial virus (RSV) is an important cause of respiratory death in childhood, and asthma in under-5s is often exacerbated by viral infections, including RSV. Furthermore, acute respiratory treatment failures were predominantly seen in under-5s without fever, which suggests the diagnosis of asthma/wheezing rather than bacterial pneumonia. Ultimately, underlying asthma may have contributed to malnutrition and fatal bacterial pneumonia. In conclusion, preschool asthma in low-income countries may be significantly under-diagnosed and misdiagnosed as pneumonia, and may be the cause of much morbidity and mortality.