Metformin intake and risk of metabolic acidosis after radical cystectomy with urinary diversion: A comparative study using data from the TriNetX research network

Purpose

To investigate the association of diabetes mellitus and metformin use with metabolic acidosis risk after radical cystectomy (RC) and urinary diversion for bladder cancer.

Materials and Methods

This retrospective cohort study used TriNetX Research Network data. Patients undergoing RC with continent diversion or ileal conduit for bladder cancer were identified using International Classification of Diseases, 10th Revision (ICD-10) and ICD-10 Procedure Coding System (ICD-10-PCS) codes. The primary outcome was acidosis between 1 month and 3 years postsurgery. Risk ratios (RR) and odds ratios (OR) were calculated based on diabetes and metformin use, stratified by diversion type and chronic kidney disease stage. Propensity score matching balanced potential confounders.

Results

We identified 1,986 patients who underwent continent diversion and 11,184 who underwent ileal conduit reconstruction. In matched analyses, diabetes patients had higher acidosis risk (continent diversion: RR 1.87, 95% confidence interval [CI] 1.39–2.51; ileal conduit: RR 1.94, 95% CI 1.66–2.27). The risk was highest for diabetes patients with metformin prescription (continent diversion: RR 2.06, 95% CI 1.63–2.61; ileal conduit: RR 2.13, 95% CI 1.84–2.47). However, among patients with diabetes, metformin use did not significantly affect acidosis rates in most analyses. Continent diversion patients had higher acidosis risk than ileal conduit patients (RR 1.89, 95% CI 1.58–2.26).

Conclusion

Diabetes significantly increases metabolic acidosis risk after RC with urinary diversion, especially in continent diversion patients. While metformin may contribute to metabolic acidosis risk, its impact appears less significant than that of diabetes. Careful monitoring and appropriate metformin adjustments are crucial in this population.