Evaluation of Hospital-Based Hematuria Diagnosis and Subsequent Cancer Risk Among Adults in Denmark

IMPORTANCE: Data on the long-term risk of urologic and nonurologic cancer after hematuria diagnosis are sparse. Such data can improve understanding of hematuria and cancer and can provide insight into the clinical course of patients with hematuria. OBJECTIVE: To assess the risk of urologic or nonurologic cancer after a hospital-based diagnosis of hematuria. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used population-based, nationwide health care databases covering all hospitals in Denmark. The data set included records of all adults (n = 134 173) with an inpatient, outpatient, or emergency department diagnosis of hematuria. The study was conducted from January 1, 1995, to December 31, 2013. Follow-up ended on December 31, 2013. Data analysis was performed from January 16, 2017, to September 18, 2018. MAIN OUTCOMES AND MEASURES: Cumulative risk of cancer was computed, and observed cancer incidence was compared with incidence expected in the general population, using standardized incidence ratios. RESULTS: Of the 134 173 patients included, 52 367 (39.0%) were women, 81 806 (61.0%) were men, and the median (interquartile range) age was 59 (44-72) years. Within 3 months after hematuria diagnosis, 2647 patients (1.9%) received an invasive bladder cancer diagnosis, 1077 (0.8%) a noninvasive bladder cancer diagnosis, 569 (0.4%) a kidney cancer diagnosis, and 908 (1.1%) a prostate cancer diagnosis. The 3-month cumulative incidence (or absolute risk) of any cancer diagnosis was 4.81% (95% CI, 4.70%-4.93%), the 1-year risk was 6.65% (95% CI, 6.51%-6.78%), and the 5-year risk was 12.34% (95% CI, 12.15%-12.53%). The cumulative incidence of bladder cancer only increased from 1.20% (95% CI, 1.11%-1.30%) after 1 year to 1.36% (95% CI, 1.26%-1.46%) after 5 years of follow-up in women and from 2.93% (95% CI, 2.82%-3.05%) to 3.31% (95% CI, 3.19%-3.44%) in men. For noninvasive bladder cancer, the standardized incidence ratio in the 1 year to less than 5 years of follow-up was 5.39 (95% CI, 4.58-6.30) in patients without initial cystoscopy and was 0.16 (95% CI, 0.04-0.42) in patients with cystoscopy within 3 months after hospital-based diagnosis of hematuria. For kidney cancer, the standardized incidence ratio in the 1 year to less than 5 years of follow-up was 2.63 (95% CI, 2.15-3.18) in patients without cystoscopy and 1.20 (95% CI, 0.87-1.61) in patients with cystoscopy within 3 months after hospital-based diagnosis of hematuria. After 1 year, the risk of gynecologic and colorectal cancers was as expected or even lower, whereas the risk of hematologic malignant neoplasms remained slightly elevated. CONCLUSIONS AND RELEVANCE: Increased risk of bladder and kidney cancers even more than 1 year after hospital-based hematuria diagnosis, as well as the slightly elevated risk of invasive bladder cancer after 5 years, may indicate that it is a marker of greater cancer risk; these findings could inform follow-up recommendations for hematuria.