Integration of stress hyperglycemia ratio and c-reactive protein level improves postoperative acute kidney injury risk stratification after noncardiac surgery: A nested case-control study

Abstract

Background and Objective: The stress hyperglycemia ratio (SHR) has emerged as a potential predictor of acute kidney injury (AKI). However, its role in postoperative AKI (PO-AKI) after noncardiac surgery and interaction with systemic inflammation remains unclear. This study aimed to assess whether combining SHR with high-sensitivity C-reactive protein (hs-CRP) improves risk stratification.

Methodology: This nested case-control study used the Korean INSPIRE database (2011–2020) to match 269 PO-AKI cases 1:4 with 1003 controls by age, sex, body mass index, and baseline creatinine. Conditional logistic regression was used to estimate adjusted odds ratios (aORs). Nonlinear associations were assessed using restricted cubic splines. Model performance was evaluated using changes in the C-statistic (ΔC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

Results: SHR demonstrated a U-shaped association with PO-AKI. Compared with the middle quartiles (Q2–Q3), both low (aOR = 1.48; 95% CI, 1.03–2.12) and high SHR (aOR = 1.66; 95% CI, 1.18–2.35) were associated with increased risk. Elevated hs-CRP (≥1 mg/L) further increased PO-AKI risk across SHR categories. Incorporating SHR and hs-CRP improved model performance (ΔC = 0.019; 95% CI, 0.002–0.036; P = 0.016; NRI = 0.244; P < 0.001; IDI = 0.013; P < 0.001).

Conclusion: SHR demonstrated a U-shaped association with the PO-AKI risk, and elevated hs-CRP enhances risk stratification. Combined assessment of metabolic and inflammatory markers may improve identification of high-risk patients, supporting the integration of both biomarkers for identifying high-risk patients for intensified perioperative management.