# Impact of Renin‐Angiotensin System Inhibitors on Renal Function During Temporary Ileostomy Period in Rectal Cancer Patients: A Retrospective Cohort Study

## TL;DR

This study finds that using RASIs is linked to worsened kidney function in rectal cancer patients with temporary ileostomies.

## Contribution

The study is the first to investigate RASIs' impact on renal function during ileostomy in rectal cancer patients.

## Key findings

- RASIs were associated with significantly lower eGFR levels a month after surgery.
- RASIs were a significant risk factor for CKD classification worsening post-surgery.
- Renal function recovery remained slow until stoma closure in RASI users.

## Abstract

This study aims to elucidate the effects of renin‐angiotensin system inhibitors (RASIs) on renal function throughout the stoma period in patients undergoing ileostomy formation and subsequent stoma closure following rectal cancer surgery.

In this single‐center retrospective study, patients who underwent rectal resection with temporary ileostomy between January 2010 and December 2020 were divided into two groups based on RASI use. Renal function was assessed using the estimated glomerular filtration rate (eGFR) at pre‐surgery (T0), a month post‐surgery (T1), and pre‐stoma closure (T2). The eGFR, its change at each point, and the chronic kidney disease (CKD) classification were used to assess early and subsequent changes in renal function.

Nineteen of 101 patients were using RASI. The RASI and control groups both exhibited eGFR decline at T1, with the former group showing a significantly lower median eGFR (56.2 mL/min/1.73m2 vs. 68.7; p = 0.007). Although a slight improvement in eGFR was observed, neither group returned to baseline levels by T2. The RASI group showed lower eGFR values at both time points. Multivariate analyses indicated that RASI use was a significant risk factor for renal function impairment in terms of a worse CKD classification at T1 (OR: 9.099; 95% CI: 3.015–27.460; p < 0.001).

Our findings suggest that the use of RASIs is associated with early perioperative renal function impairment in patients undergoing ileostomy and stoma closure, with relatively slow recovery. These results indicate the impact of RASIs on eGFR and the importance of careful renal function management.

This retrospective study explored the potential impact of renin–angiotensin system inhibitors (RASIs) on renal function during the ileostomy period in patients undergoing rectal cancer surgery. RASI use was associated with early postoperative renal impairment, and relatively slow recovery of renal function was observed until stoma closure. These findings suggest that careful monitoring of renal function is warranted in patients receiving RASIs after ileostomy.