AIMS: Patients with atrial fibrillation (AF) treated with oral anticoagulants (OAC) have an increased risk of bleeding including hematuria. In the general population gross hematuria is associated with urinary tract cancer. Consequently, we aimed to investigate the potential association between gross hematuria 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 2016. 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 hematuria. We included 125,063 AF patients with a median age of 74 years (interquartile range [IQR] 65-80) and a majority of males (57%). The absolute risk of gross hematuria 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 years and > 80 years of age, respectively. The 1-year risk of urinary tract cancer after hematuria 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 years and 71-80 years, respectively. Gross hematuria conferred large risk ratios of urinary tract cancer when comparing patients with- and without hematuria across all age groups.

CONCLUSION: Gross hematuria was associated with clinically relevant risks of urinary tract cancer in anticoagulated patients with AF. Thus, underlining the importance of meticulously examining anticoagulated patients with hematuria.