Adequate levels of adherence with controller medication is associated with increased use of rescue medication in asthmatic children

Abstract

Background: The role of asthma controller medication adherence and the level of asthma control in children is poorly defined.

Aims: To assess the association between asthma controller medication adherence and asthma control in children using routinely acquired prescribing data.

Methods: A retrospective observational study of children aged 0-18 years prescribed inhaled corticosteroids only (ICS), leukotriene receptors antagonists (LTRA), or long-acting β2 agonists (LABA) and ICS prescribed as separate or combined inhalers, between 01/09/2001 and 31/08/2006, registered with primary care practices contributing to the Practice Team Information database. The medication possession ratio (MPR) was calculated and associations with asthma control explored. Poor asthma control was defined as the issue of prescriptions for ≥ 1 course of oral corticosteroids (OCS) and/or ≥ 6 short-acting β2 agonists (SABA) canisters annually.

Results: A total of 3172 children prescribed asthma controller medication were identified. Of these, 15-39% (depending on controller medication) demonstrated adequate MPR. Adequate MPR was associated with male gender, good socio-economic status, and oral LTRA therapy. Adequate MPR was more likely to be associated with increased use of rescue medication. However logistic regression only identified a significant relationship for ICS only (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.35-2.48; p<0.001), LTRA (OR, 2.11; 95% CI, 1.27-3.48; p = 0.004) and LABA/ICS (OR, 2.85; 95% CI, 1.62-5.02; p<0.001).

Conclusion: Poor adherence was observed for all asthma controller medications, although was significantly better for oral LRTA. In this study adequate adherence was not associated with the use of less rescue medication, suggesting that adherence is a complex issue.

Figure 1. Box plot for the distribution of Medication Possession Ratio of prescribed asthma controller medications.

Whiskers represent the extreme values, and boxes represent the 75th quartile, median, and 25th quartile. Outliers were excluded from the analysis. MPR =  Medication possession ratio; ICS = Inhaled corticosteroid; LTRA = leukotriene receptors antagonists; LABA/ICS = fixed dose long-acting β2-agonist and inhaled corticosteroids combination; LABA+ICS =  concurrent long-acting β2-agonist and inhaled corticosteroids separate inhaler.