Longitudinal association between medication adherence and lung health in people with cystic fibrosis

Abstract

Background: This study examined the relationship of medication adherence to frequency of pulmonary exacerbation and rate of decline in FEV(1)% predicted (FEV(1)).

Methods: 95 CF patients aged 6 years or older and prescribed a pulmonary medication, were enrolled in a longitudinal retrospective review of medication adherence and health outcomes (the occurrence and frequency of intravenous (IV) antibiotic treatments and FEV(1)) over 12-months. Pharmacy refill records were used to calculate a medication possession ratio (MPR).

Results: Composite MPR predicted the occurrence of at least one pulmonary exacerbation requiring a course of IV antibiotics (IRR=2.34, p=0.05), but not the frequency of exacerbations, after controlling for gender, baseline FEV(1,) and regimen complexity. Composite MPR predicted baseline FEV(1) (estimate=29.81, p=.007), but not decline in FEV(1).

Conclusions: These results demonstrate a significant relation between medication adherence and IV antibiotics in CF patients, highlighting the importance of addressing adherence during clinic visits to improve health outcomes.

Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Figures

Figure 1

Medication Possession Ratio (MPR) boxplot by drug.

Figure 2

Composite MPR by age groups

Figure 3

Pulmonary Exacerbations by Composite MPR (Probability of number of pulmonary exacerbations by Composite MPR while controlling for gender, regimen complexity and baseline lung function).

Figure 4

Lung function over time by adherence category after controlling for regimen complexity and BMI.