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

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.