RESUMO
AIMS: Patients with atrial fibrillation (AF) treated with oral anticoagulants (OACs) have an increased risk of bleeding including haematuria. In the general population, gross haematuria is associated with urinary tract cancer. Consequently, we aimed to investigate the potential association between gross haematuria and urinary tract cancer in anticoagulated patients with AF. METHODS AND RESULTS: Using Danish nationwide registers, we included Danish AF patients treated with OACs between 2001 and 2015. Non-parametric estimation and semi-parametric absolute risk regression were used to estimate the absolute risk of urinary tract cancer in patients with and without gross haematuria. We included 125 063 AF patients with a median age of 74 years (interquartile range 65-80) and a majority of males (57%). The absolute risk of gross haematuria 12 months after treatment initiation increased with age ranging from 0.37% [95% confidence interval (CI) 0.31-0.42] to 0.85% (95% CI 0.75-0.96) in the youngest and oldest age groups of ≤70 and >80 years of age, respectively. The 1-year risk of urinary tract cancer after haematuria ranged from 4.2% (95% CI 2.6-6.6) to 6.5% (95% CI 4.6-9.0) for patients in age group >80 and 71-80 years, respectively. Gross haematuria conferred large risk ratios of urinary tract cancer when comparing patients with and without haematuria across all age groups. CONCLUSION: Gross haematuria was associated with clinically relevant risks of urinary tract cancer in anticoagulated patients with AF. These findings underline the importance of meticulously examining anticoagulated patients with haematuria.