Inhaled corticosteroids in children with persistent asthma: effects of different drugs and delivery devices on growth

Inhaled corticosteroids (ICS) are the most effective treatment for children with persistent asthma. Although treatment with ICS is generally considered to be safe in children, the potential adverse effects of these drugs on growth remains a matter of concern for parents and physicians.

To assess the impact of different inhaled corticosteroid drugs and delivery devices on the linear growth of children with persistent asthma.

We searched the Cochrane Airways Trials Register, which is derived from systematic searches of bibliographic databases including CENTRAL, MEDLINE, Embase, CINAHL, AMED and PsycINFO. We handsearched respiratory journals and meeting abstracts. We also conducted a search of ClinicalTrials.gov and manufacturers' clinical trial databases, or contacted the manufacturer, to search for potential relevant unpublished studies. The literature search was initially conducted in September 2014, and updated in November 2015, September 2018, and April 2019.

We selected parallel-group randomized controlled trials of at least three months' duration. To be included, trials had to compare linear growth between different inhaled corticosteroid molecules at equivalent doses, delivered by the same type of device, or between different devices used to deliver the same inhaled corticosteroid molecule at the same dose, in children up to 18 years of age with persistent asthma.

At least two review authors independently selected studies and assessed risk of bias in included studies. The data were extracted by one author and checked by another. The primary outcome was linear growth velocity. We conducted meta-analyses using Review Manager 5.3 software. We used mean differences (MDs) and 95% confidence intervals (CIs ) as the metrics for treatment effects, and the random-effects model for meta-analyses. We did not perform planned subgroup analyses due to there being too few included trials.

We included six randomized trials involving 1199 children aged from 4 to 12 years (per-protocol population: 1008), with mild-to-moderate persistent asthma. Two trials were from single hospitals, and the remaining four trials were multicentre studies. The duration of trials varied from six to 20 months.One trial with 23 participants compared fluticasone with beclomethasone, and showed that fluticasone given at an equivalent dose was associated with a significant greater linear growth velocity (MD 0.81 cm/year, 95% CI 0.46 to 1.16, low certainty evidence). Three trials compared fluticasone with budesonide. Fluticasone given at an equivalent dose had a less suppressive effect than budesonide on growth, as measured by change in height over a period from 20 weeks to 12 months (MD 0.97 cm, 95% CI 0.62 to 1.32; 2 trials, 359 participants; moderate certainty evidence). However, we observed no significant difference in linear growth velocity between fluticasone and budesonide at equivalent doses (MD 0.39 cm/year, 95% CI -0.94 to 1.73; 2 trials, 236 participants; very low certainty evidence).Two trials compared inhalation devices. One trial with 212 participants revealed a comparable linear growth velocity between beclomethasone administered via hydrofluoroalkane-metered dose inhaler (HFA-MDI) and beclomethasone administered via chlorofluorocarbon-metered dose inhaler (CFC-MDI) at an equivalent dose (MD -0.44 cm/year, 95% CI -1.00 to 0.12; low certainty evidence). Another trial with 229 participants showed a small but statistically significant greater increase in height over a period of six months in favour of budesonide via Easyhaler, compared to budesonide given at the same dose via Turbuhaler (MD 0.37 cm, 95% CI 0.12 to 0.62; low certainty evidence).

This review suggests that the drug molecule and delivery device may impact the effect size of ICS on growth in children with persistent asthma. Fluticasone at an equivalent dose seems to inhibit growth less than beclomethasone and budesonide. Easyhaler is likely to have less adverse effect on growth than Turbuhaler when used for delivery of budesonide. However, the evidence from this systematic review of head-to-head trials is not certain enough to inform the selection of inhaled corticosteroid or inhalation device for the treatment of children with persistent asthma. Further studies are needed, and pragmatic trials and real-life observational studies seem more attractive and feasible.