Association between use of antithrombotic medication and hematuria-related complications

IMPORTANCE: Antithrombotic medications are among the most commonly prescribed medications. OBJECTIVE: To characterize rates of hematuria-related complications among patients taking antithrombotic medications. DESIGN, SETTING, AND PARTICIPANTS: Population-based, retrospective cohort study including all citizens in Ontario, Canada, aged 66 years and older between 2002 and 2014. The final follow-up date was December 31, 2014. EXPOSURES: Receipt of an oral anticoagulant or antiplatelet medication. MAIN OUTCOMES AND MEASURES: Hematuria-related complications, defined as emergency department visit, hospitalization, or a urologic procedure to investigate or manage gross hematuria. RESULTS: Among 2 518 064 patients, 808 897 (mean [SD] age, 72.1 [6.8] years; 428 531 [53%] women) received at least 1 prescription for an antithrombotic agent over the study period. Over a median follow-up of 7.3 years, the rates of hematuria-related complications were 123.95 events per 1000 person-years among patients actively exposed to antithrombotic agents vs 80.17 events per 1000 person-years among patients not exposed to these drugs (difference, 43.8; 95% CI, 43.0-44.6; P < .001, and incidence rate ratio [IRR], 1.44; 95% CI, 1.42-1.46). The rates of complications among exposed vs unexposed patients (80.17 events/1000 person-years) were 105.78 for urologic procedures (difference, 33.5; 95% CI, 32.8-34.3; P < .001, and IRR, 1.37; 95% CI, 1.36-1.39), 11.12 for hospitalizations (difference, 5.7; 95% CI, 5.5-5.9; P < .001, and IRR, 2.03; 95% CI, 2.00-2.06), and 7.05 for emergency department visits (difference, 4.5; 95% CI, 4.3-4.7; P < .001, and IRR, 2.80; 95% CI, 2.74-2.86). Compared with patients who were unexposed to thrombotic agents, the rates of hematuria-related complications were 191.61 events per 1000 person-years (difference, 117.3; 95% CI, 112.8-121.8) for those exposed to both an anticoagulant and antiplatelet agent (IRR, 10.48; 95% CI, 8.16-13.45), 140.92 (difference, 57.7; 95% CI, 56.9-58.4) for those exposed to anticoagulants (IRR, 1.55; 95% CI, 1.52-1.59), and 110.72 (difference, 26.5; 95% CI, 25.9-27.0) for those exposed to antiplatelet agents (IRR, 1.31; 95% CI, 1.29-1.33). Patients exposed to antithrombotic agents, compared with patients not exposed to these drugs, were more likely to be diagnosed as having bladder cancer within 6 months (0.70% vs 0.38%; odds ratio, 1.85; 95% CI, 1.79-1.92). CONCLUSIONS AND RELEVANCE: Among older adults in Ontario, Canada, use of antithrombotic medications, compared with nonuse of these medications, was significantly associated with higher rates of hematuria-related complications (including emergency department visits, hospitalizations, and urologic procedures to manage gross hematuria).