Medication persistence among patients with asthma/COPD drugs

Objective To determine medication possession ratio (MPR) of patients with asthma/COPD drugs. Method Individual patient's volumes of asthma/COPD drugs (ATC-code R03) for 2000-2004 were obtained from a pharmacy record database. For each patient the MPR was calculated as the percentage of the treatment time that the patient had drugs available. Main outcome measure Medication possession ratio (MPR). Results A total of 1,812 patients, 20 years and older, with dispensed asthma/COPD drugs were registered in the database, 928 patients (51%) had acquired drugs less than once per year (68% for 20-29 years old) during the 5-year study. Only 13% of the patients had steroids and steroid combinations available to allow continuous treatment. Eight percent of the patients 20-29 years old had MPR >= 80% of all the included drugs and 5% when only steroids and steroid combinations were considered. About 25% of the patients had acquired 80% of the total volume of asthma/COPD drugs. Conclusion The majority of the patients, and particularly those in the youngest age group used asthma/COPD drugs only sporadically. This may indicate undermedication which is likely to have a negative impact on patient outcome.