Systemic Inflammation and Acute Kidney Injury After Colorectal Surgery

The relative importance of systemic inflammation among other causes of acute kidney injury (AKI) was investigated in this retrospective review. The WBC on the first postoperative day (POD # 1 WBC) and the derived neutrophil-to-lymphocyte ratio (NLR) were used as measures of inflammation in 1224 consecutive patients undergoing colon procedures. AKI was determined using the Kidney Disease Improving Global Outcomes (KDIGO) criteria and AKI-related complications were documented. Patients without preoperative infection (aseptic population) and the entire population (total population) were examined. AKI occurred in 24.6% of the total population and correlated with complications: postoperative infections (P = 0.016), chronic renal insufficiency (CRI, P < 0.0001), non-infectious complications (P = 0.010), 30-day readmissions (P = 0.001), and length of stay (LOS, P < 0.0001). For the total population, there was a link between inflammation (POD # 1 WBC) and AKI (P = 0.0001), on univariate regression. Medications with anti-inflammatory properties reduced AKI: ketorolac (P = 0.047) and steroids (P = 0.038). Similarly, in an aseptic population, inflammation (POD # 1 NLR) contributed significantly to AKI (P = 0.000). On multivariable analysis, the POD #1 WBC and NLR, were independently associated with AKI (P = 0.000, P = 0.022). Inflammation, in the total or aseptic populations, was a predictor of complications: postoperative infections (P =0.002, P = 0.008), in-hospital complications (P = 0.000, P = 0.002), 30-Day readmissions (P = 0.012, P = 0.371), and LOS (P <0.0001, P = 0.006). Systemic inflammation, whether septic or aseptic, is an important cause of AKI and complications.