Lung function changes in asthmatic children treated with HFA-BDP

Small-particle Inhaled Corticosteroid as First-line or Step-up Controller Therapy in Childhood Asthma

BACKGROUND

Because randomized controlled trials of established pediatric asthma therapies are expensive and difficult to perform, observational studies may fill gaps in the evidence base.

OBJECTIVES

To compare the effectiveness of representative small-particle inhaled corticosteroid (ICS) with that of standard size-particle ICS for children initiating or stepping up ICS therapy for asthma (analysis 1) and to compare the effectiveness of ICS dose step-up using small-particle ICS with adding long-acting β2-agonist (LABA) to the ICS (analysis 2).

METHODS

These historical matched cohort analyses drew on electronic medical records of children with asthma aged 5 to 11 years. Variables measured during 2 consecutive years (1 baseline year for confounder definition and 1 outcome year) included risk-domain asthma control (no hospital attendance for asthma, acute oral corticosteroids, or lower respiratory tract infection requiring antibiotics) and rate of severe exacerbations (asthma-related emergency, hospitalization, or oral corticosteroids).

RESULTS

In the initiation population (n = 797 in each cohort), children prescribed small-particle ICS versus standard size-particle ICS experienced greater odds of asthma control (adjusted odds ratio, 1.49; 95% CI, 1.10-2.02) and lower severe exacerbation rate (adjusted rate ratio, 0.56; 95% CI, 0.35-0.88). Step-up outcomes (n = 206 in each cohort) were also significantly better for small-particle ICS, with asthma control adjusted odds ratio of 2.22 (95% CI, 1.23-4.03) and exacerbations adjusted rate ratio of 0.49 (95% CI, 0.27-0.89). The number needed to treat with small-particle ICS to achieve 1 additional child with asthma control was 17 (95% CI, 9-107) for the initiation population and 5 (95% CI, 3-78) for the step-up population. Outcomes were not significantly different for stepped-up small-particle ICS dose versus ICS/LABA combination (n = 185 in each cohort).

CONCLUSIONS

Initiating or stepping up the ICS dose with small-particle ICS rather than with standard size-particle ICS is more effective and shows similar effectiveness to add-on LABA in childhood asthma.

Sensitivity of different spirometric tests for detecting airway obstruction in childhood asthma

OBJECTIVE

The objective of this study was to compare different measures of airflow obstruction by spirometry in childhood asthma. The objectives were; (a) to compare sensitivity of large airway tests (FEV1 and PEFR) with tests at low lung volumes (small airways) (FEF25-75, FEF50 and FEF75); (b) compare within each group which individual tests are more sensitive.

METHODS

This was a retrospective analysis of 2307 spirometry tests performed during outpatient visits on 821 doctor-diagnosed asthma patients aged 6-18. Tests were deemed acceptable if they were acceptable and repeatable by American Thoracic Society (ATS) criteria.

RESULTS

In mild obstruction, FEV1 detected 6.8% abnormal tests while FEF75 detected 33% (p < 0.0001). In more severe obstruction, the difference was more obvious (FEV1 14.8%; FEF75 71%). Tests at low lung volumes (small airway tests) were also more sensitive than PEFR. Within groups, FEV1 was more sensitive than PEFR in the large airway tests and FEF75 was more sensitive than FEF25-75 and FEF50 among the tests at low lung volumes (small airway tests). The FEV1/FVC ratio correlated more closely with tests at low lung volumes (small airway tests), than with large airway tests.

CONCLUSIONS

(1) Tests at low lung volumes (small airway tests) are more sensitive than large airway tests; (2) Within groups, the FEV1 is better than PEFR and FEF75 is better than FEF25-75 or FEF50.