Inhaled anticholinergic drug therapy and the risk of acute urinary retention in chronic obstructive pulmonary disease: a population-based study.

BACKGROUND Inhaled anticholinergic medications (IACs) are widely used treatments for chronic obstructive pulmonary disease (COPD). The systemic anticholinergic effects of IAC therapy have not been extensively studied. This study sought to determine the risk of acute urinary retention (AUR) in seniors with COPD using IACs. METHODS A nested case-control study of individuals with COPD aged 66 years or older was conducted from April 1, 2003, to March 31, 2009, using population-based linked databases from Ontario, Canada. A hospitalization, same-day surgery, or emergency department visit for AUR identified cases, which were matched with up to 5 controls. Exposure to IACs was determined using a comprehensive drug benefits database. Conditional logistic regression analysis was conducted to determine the association between IAC use and AUR. RESULTS Of 565,073 individuals with COPD, 9432 men and 1806 women developed AUR. Men who just initiated a regimen of IACs were at increased risk for AUR compared with nonusers (adjusted odds ratio [OR], 1.42; 95% confidence interval [CI], 1.20-1.68). In men with evidence of benign prostatic hyperplasia, the risk was increased further (OR, 1.81; 95% CI, 1.46-2.24). Men using both short- and long-acting IACs had a significantly higher risk of AUR compared with monotherapy users (OR, 1.84; 95% CI, 1.25-2.71) or nonusers (2.69; 1.93-3.76). CONCLUSIONS Use of short- and long-acting IACs is associated with an increased risk of AUR in men with COPD. Men receiving concurrent treatment with both short- and long-acting IACs and those with evidence of benign prostatic hyperplasia are at highest risk.