Risk of arrhythmias associated with ipratropium bromide in children, adolescents, and young adults with asthma: a nested case-control study.

Study Objective To evaluate the risk of arrhythmias associated with inhaled anticholinergic (IAC) use in young patients with asthma. Design Population-based nested case-control study. Database IMS LifeLink Health Plan Claims Database. Patients Patients 5-24 years of age who were diagnosed with asthma and were new users of asthma controller medications were identified between July 1997 and April 2010. Cases were newly diagnosed with arrhythmia and were matched with up to 10 controls based on age, gender, geographic region, and quarter and year of first controller medication dispensing. Measurements and Main Results Exposure to IACs was determined in the 180 days prior to the event date, defined as date of arrhythmia claim. Active use was defined as sufficient days' supply of a prescription to extend through the event date. Among 283,429 patients with asthma, 7656 cases were matched to 76,304 controls. Most of those included were female (58.8%) and 12 years or older (73.3%). Active exposure of IACs was observed in 0.69% of cases and 0.18% of controls. Active use was associated with a 1.56-fold increase in arrhythmia risk compared with nonactive users or nonusers (adjusted odds ratio [ORadj] 1.56, 95% confidence interval [CI] 1.08-2.25]). Risk was highest among active users of ipratropium (ORadj 1.59, 95% CI 1.08-2.33). Active high-dose users of IACs (more than 0.114 mg of ipratropium equivalents) had a 69% increase in risk (ORadj 1.69, 95% CI 1.10-2.59), whereas the added risk for active users receiving low-dose IACs (0.114 mg of ipratropium equivalents or less) was not statistically significant (ORadj 1.22, 95% CI 0.53-2.65). Conclusion Use of ipratropium bromide was associated with an increased risk of arrhythmias in 12-24-year-old patients with asthma.