Urinary tract stone raises subsequent risk for urinary tract cancer: A population-based cohort study

Objective To evaluate the association between urinary tract stone (UTS) and urinary tract cancer (UTC) in Taiwanese patients, as the results of epidemiological studies about the relationship between UTS and the development of UTC remain inconclusive. Patients/Subjects and Methods We conducted a population-based cohort study using data from the Taiwanese National Health Insurance system. The UTS cohort included 21 862 patients, and each patient was randomly frequency-matched for age, sex, and index year with two insured members of the general population who did not have UTS. Cox proportional hazard regression analysis was performed to estimate the effect of UTS on the risk of UTC. Results Patients with UTS were at a significantly higher risk of developing UTC compared with the comparison group (adjusted hazard ratio 4.66; 95% confidence interval 2.97-7.30). Women were at higher risk than men. Further analyses showed that the level of UTC was associated with that of UTS, and that the risk for UTC became more divergent for the two groups over time. Conclusions Taiwanese patients with UTS, particularly women, had a higher risk for developing UTC than patients without UTS. The risk became more marked over time for this group.