According to a meta-analysis published in the Journal of Allergy and Clinical Immunology, extrafine-particle inhaled corticosteroids (ICSs) have significantly higher odds of achieving asthma control, with lower exacerbation rates at significantly lower prescribed doses compared with fine-particle ICSs.
The analysis reviewed studies published between January 2004 and June 2016 and included those that reported odds and relative risk ratios. End-point data, including asthma control, exacerbations, and prescribed ICS dose, were pooled. More than 33,000 participants, aged 5 to 80 years, from 7 studies were included; 6 studies used extrafine beclomethasone propionate, and 1 study used extrafine beclomethasone propionate and extrafine ciclesonide as comparators with fine-particle ICSs.
The likelihood of achieving asthma control was significantly greater with extrafine-particle ICSs than with fine-particle ICSs (odds ratio [OR], 1.34; 95% CI, 1.22-1.46). Similarly, exacerbation rate ratios (OR, 0.84; 95% CI, 0.73-0.97) and ICS dose (weighted mean difference, −170 μg; 95% CI, −222 to −118 μg) were significantly lower for the extrafine-particle group than for the fine-particle group.
Limitations included the fact that the same research team performed 6 of the 7 studies, introducing potential bias. Second, the studies used a coding-based medical database, with the potential for coding errors. Furthermore, the consumption of the medication could not be verified, and as the researchers did not search for unpublished data, publication bias may exist.
Nonetheless, this analysis does suggest the greater efficacy provided by extrafine-particle ICS therapy. It remains unknown, however, whether this efficacy is a result of increased deposition in the small airways, greater distribution of the formulation throughout the airways, or some other factor. The researchers stated that these questions warrant further investigation.
Sonnappa S, McQueen B, Postma DS, et al. Extrafine versus fine inhaled corticosteroids in relation to asthma control: A systematic review and meta-analysis of observational real-life studies [published online September 20, 2017]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2017.07.032