Preoperative risk factors for ileostomy-associated kidney injury in colorectal tumor surgery following ileostomy formation.

Purpose: Diverting ileostomy is related to postoperative high-output stoma (HOS) leading to kidney injury. The purpose of our study was to clarify the risk factors for ileostomy-associated kidney injury, which is kidney injury starting after the first operation to ileostomy closure after colorectal tumor surgery with diverting ileostomy.

Methods: Between January 2013 and December 2020, 442 patients who underwent colorectal tumor surgery (cancer, neuroendocrine tumor, and leiomyosarcoma) following diverting ileostomy formation were included. We used the KDIGO (Kidney Disease Improving Global Outcomes) guidelines, which defines the acute kidney injury (AKI) to classify patients with ileostomy-associated kidney injury. The definition of AKI was (i) serum creatinine (sCr) ≥ 0.3 mg/dL or (ii) sCr ≥1.5-fold the preoperative level. Multivariate analyses were performed to identify the independent risk factors for kidney injury.

Results: Kidney injury developed in 99/442 eligible patients (22.4%). Patients in the kidney injury group were older age, male sex, high American Society of Anesthesiologists Physical Status Classification System (ASA-PS) score, hypertension, cardiovascular diseases, diabetes. The preoperative hemoglobin, albumin, prognostic nutritional index (PNI), and creatinine clearance (CCr) were lower, and the maximum wound length was more extended than the non-kidney injury group. The median highest daily stoma output was significantly higher in the kidney injury group. The postoperative white blood cell (WBC) and C-reactive protein (CRP) levels were also high in the kidney injury group. The univariate analysis showed older age, male sex, high ASA-PS score, hypertension, cardiovascular diseases, and diabetes were the risk factors for kidney injury. The multivariate analysis revealed that age 70 or older, ASA-PS III/IV, hypertension, and HOS ≥2000 ml/day were independent risk factors for kidney injury.

Conclusions: Surgeons should consider diverting colostomy creation for patients with risk factors such as age 70 or older, ASA-PS III/IV, and hypertension.