To answer this question, the authors used administrative databases in Ontario, Canada – leveraging the strength of a fully government-run healthcare system – to identify all patients who underwent a urinary intestinal diversion between 1994 and 2014. Patients were categorized as being diverted for BC or non-BC (other malignancy, benign etiologies) and matched 4:1 to a control cohort (4x as many controls at their tested cohort) who had no history of malignancy or urinary diversion. Diversion in the setting of BC and non-BC were assessed independently to distinguish pathologic fractures from bone metastases versus acidosis-induced fractures, respectively.
- Patients were matched on age, gender, Charlson comorbidity score, neighborhood income quartile, area of residency, history of chemotherapy, CKD, prior fractures, era and type of urinary diversion
On multivariable analysis, patients that had undergone a urinary diversion (be it for BC or non-BC reasons) had significantly shorter fracture-free survival compared to their respective matched-cohorts [HR:1.6 (1.4-1.8) and HR:1.36 (1.1-1.7), respectively].
Based on this, the authors conclude that patients who underwent a urinary intestinal diversion are at increased risk of bone fractures compared to the general population. However, it should be noted that association doesn’t mean causation – other confounders may account for increased risk of pathologic fractures. Unknown confounders, which may not have been matched for, may contribute.
Regardless, as preventative measures such as calcium and Vit D supplementation, carry minimal risk, it is worth improving patient and physician education in patients undergoing intestinal diversion.
Limitations / Discussion Points:
1. Patients in the non-BC category had diversions for many causes – including non-BC malignancy. Therefore, these patients may also have had pathologic fractures from other diseases, which can’t be accounted for.
Presented by: Patrick O. Richard, the University of Toronto and University of Sherbrooke, Canada
Co-Authors: Shaheena Bashir, Amit Gupta, Neil Fleshner, Alexandre Zlotta, Roselyne Choinière, Aza Mohammed, Girish Kulkarni
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, @tchandra_uromd at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA