Risk of Bone Fractures Following Urinary Intestinal Diversion: A Population-based Study.

Purpose: Patients with bladder cancer who undergo intestinal urinary diversion may be at increased risk for bone fractures thought to be secondary to chronic metabolic acidosis and ensuing bone loss. Our main objective was to assess whether patients who undergo intestinal urinary diversion are at increased risk for fracture. Materials and Methods: Patients who underwent intestinal urinary diversion between 1994 and 2014 in Ontario, Canada were identified using linked administrative databases. Patients were categorized as undergoing diversion for bladder cancer or nonbladder cancer causes and matched 4:1 to a healthy cohort. We determined incidence rates of the incidence of fractures per 100 person-years. Multivariable Cox proportional hazards models were used to evaluate the impact of intestinal urinary diversion on the risk of fracture. Results: Overall 4,301 patients with and 907 without bladder cancer underwent intestinal urinary diversion. The fracture incidence rate was significantly greater in the bladder cancer and nonbladder cancer cohorts compared to respective matched controls. In the bladder cancer cohort vs matched controls there were 4.41 vs 2.63 fractures per 100 person-years and in the nonbladder cancer cohort vs matched controls there were 5.67 vs 3.51 fractures per 100 person-years (each p <0.001). On multivariable analysis patients who underwent intestinal urinary diversion for bladder cancer or nonbladder cancer reasons had significantly shorter fracture-free survival compared to the respective matched cohorts (HR 1.48, IQR 1.35-1.63, and HR 1.48, IQR 1.31-1.69, respectively). Conclusions: Our results demonstrated that regardless of age patients with intestinal urinary diversion are at increased risk for bone fractures compared to the general population. Our findings are in line with previous reports and support the need for bone health monitoring.