# The Epidemiology and Outcomes of Acute Kidney Injury in Patients With Chronic Kidney Disease: A Single-Center Retrospective Cohort Study

## TL;DR

This study finds that CKD patients with heart disease and lower kidney function are more likely to develop kidney injury after surgery.

## Contribution

Identifies ischemic heart disease and lower eGFR as novel risk factors for postoperative AKI in CKD patients.

## Key findings

- 24% of CKD patients developed postoperative AKI, all classified as Stage 1.
- Ischemic heart disease and lower eGFR significantly increased AKI risk.
- AKI patients were more likely to require ongoing dialysis than non-AKI patients.

## Abstract

Background: Previous studies have highlighted the association between chronic kidney disease (CKD) and the increased incidence of postoperative acute kidney injury (AKI). However, the risk factor and incidence of postoperative AKI in patients with CKD undergoing elective surgery remained unclear. This retrospective study aimed to evaluate the perioperative predictors of postoperative AKI in patients with CKD.

Methods: Data from 137 patients with CKD, defined by an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2, who underwent elective surgery under general or regional anesthesia between November 2018 and October 2023, were retrospectively reviewed. Patients were placed on a peripheral arterial catheter, and dual arterial blood gas analysis was performed within 30 min before and after surgery. Patients undergoing cardiac surgery, emergency surgery, preoperative renal replacement therapy, as well as those with missing data, were excluded from the study. Both general and local anesthesia modalities were included in the analysis.

Results: The incidence of postoperative AKI was 24%. All cases of AKI were classified as Stage 1. Preoperative ischemic heart disease (odds ratio: 2.660, 95% CI: 1.16–6.10, p=0.00207) and lower eGFR (odds ratio: 0.947, 95% CI: 0.915–0.980, p=0.00181) were associated with increased risk of postoperative AKI. More patients who developed postoperative AKI converted to maintained dialysis compared to patients who did not develop AKI (15% vs. 2.1%, p=0.0021).

Conclusions: History of ischemic heart disease and preoperative lower eGFR and may serve as risk factors for postoperative AKI in CKD patients.