Treatment persistence with leukotriene receptor antagonists and inhaled corticosteroids

Background. Leukotriene receptor antagonists (LTRAs) and inhaled corticosteroids (ICSs) must be taken continuously to control persistent asthma. We compared the use of LTRAs and ICSs in patients with similar level of asthma control at treatment initiation with particular attention to treatment persistence. Methods. Two cohorts of 15 to 45 year old patients with asthma were selected from the Quebec Health Insurance Plan Database between January 1, 1998, and December 31, 2000. We first identified new users of LTRAs and from the remaining patients, we selected new users of ICSs. The ICS patients were then one-to-one matched to LTRA patients on the use of short-acting beta(2)-agonists and oral corticosteroids in the year prior to the date of the first LTRA or ICS dispensation ( index date). We compared compliance to initial therapies using Cox proportional hazards models. Results. Each of the LTRA and ICS cohorts included 2200 patients. Multivariate model showed that compliance was significantly better for LTRAs than for ICSs [ adjusted rate ratio of treatment discontinuation (aRR), 0.46; 95% confidence interval (CI), 0.42 - 0.49]. If in both groups all medications filled were taken at the prescribed dose, the annual percent of days on therapy for LTRA users would have been twice that for ICS users (38% vs. 19%; p < 0.0001). Conclusion. The findings of this observational study indicate a far from optimal persistence to LTRAs and ICSs in asthmatic patients. The superior persistence to LTRAs might result in better effectiveness.