Effect van therapietrouw op exacerbaties is moeilijk te schatten met beschikbare real life data voor astma en COPD

Effect of medication compliance on exacerbations is hard to estimate with available real life data for asthma and COPD BACKGROUND Effectiveness of long-acting bronchodilators and inhaled corticosteroids has been established in clinical trials. Their effectiveness in real life is not well documented. OBJECTIVE To investigate to what extent it is possible to estimate the effect of medication compliance on the risk of asthma and COPD exacerbations, using data from community pharmacies and GP practices. DESIGN AND METHODS A cohort of 2294 asthma patients and 1559 COPD patients I∗ 18 years old) was compiled from linked databases of the PHARMO Institute. They were followed 1-4 years. Two measures of compliance were applied: (1) 'actual use' on a certain day, defined as the availability of medication on that day; (2) 'long-term compliance', which was assumed if there was actual use on at least 80% of the study period. Cox proportional hazards models were used to estimate associations of compliance and exacerbations, with and without adjustment for patients' baseline characteristics lage, body mass index, gender, smoking history, disease severity). The adjusted analysis was applied on a subset of patients. RESULTS Without statistical adjustments, compliance was associated with a shorter time to exacerbations. After adjustment for baseline characteristics, the associations disappeared, but no protective effect was found. The same results were found in the subset when no adjustment was applied. CONCLUSION Registrations should be improved in order to enable the estimation of the real life effect of medication compliance on the risk of exacerbations in asthma and COPD patients.