Anastomotic protection at a cost: the renal toll of defunctioning ileostomies in rectal cancer surgery

Abstract Introduction A defunctioning ileostomy lowers the risk of anastomotic leakage after anterior resection for rectal cancer, but may cause kidney injury. This study investigated short- and long-term kidney injuries in patients undergoing low anterior resection, comparing those with and without a stoma. Method All rectal cancer patients with tumors ≤12 centimetres from the anal verge, operated in Sweden 2007–2021, were identified through the Colorectal Cancer Database Sweden. The primary outcome was end-stage kidney disease, defined as kidney transplantation or maintenance dialysis initiation. Secondary outcomes included chronic kidney disease, acute kidney injury, and dehydration. The impact of stoma reversal and potential mediation effects through anastomotic leakage were also examined. Cox regression was used, weighted by propensity scores based on clinical and socioeconomic predictors for receiving a defunctioning ileostomy. Result Some 5,291 patients remained after exclusions; 4,625 (87%) received a defunctioning ileostomy and 666 (13%) did not. Stoma placement was not significantly associated with end-stage kidney disease (HR 1.69, 95% CI: 0.19–15.23) or chronic kidney disease (HR 1.65, 95% CI: 0.91–3.00), but was associated with acute kidney injury (HR 3.03, 95% CI: 1.62–5.68) and dehydration (HR 4.02, 95% CI: 2.33–6.95). Risks of chronic kidney disease, acute kidney injury, and dehydration declined following stoma reversal. Stomas reduced anastomotic leakage with a minor attenuating mediation effect on acute kidney injury. Discussion Long-term kidney damage from ileostomy placement during low anterior resection for rectal cancer was not observed. However, short-term effects were demonstrated. Stoma reversal appeared to have an alleviating effect, suggesting its potential role in mitigating kidney damage.