C-reactive protein as a predictor of acute kidney injury in ICU patients: A prospective observational cohort study.

Abstract

Objective: To evaluate baseline C-reactive protein (CRP) as a predictor of acute kidney injury (AKI) in critically ill ICU patients. Study Design: Prospective Observational Cohort study. Setting: ICU of Shifa Hospital Islamabad. Period: 1^st November 2025 to 28^th February 2026. Methods: A total of 194 patients aged 16-92 years were enrolled using consecutive sampling. Baseline CRP was measured within 12 hours of ICU admission. Mann–Whitney U test compared CRP levels between AKI and non-AKI groups. ROC curve analysis determined predictive accuracy. Binary logistic regression identified independent predictors of AKI. A p-value ≤0.05 was considered statistically significant. Results: AKI occurred in 66 patients (34.0%). Baseline CRP was significantly higher in patients who developed AKI (mean rank 116.52 vs. 88.45, U = 3002.0, p = .020). ROC analysis demonstrated acceptable discriminatory ability (AUC = 0.645). On multivariate logistic regression, age (OR = 1.034, p = .036), male gender (OR = 4.024, p = .012), APACHE II score (OR = 1.099, p = .027), and baseline CRP (OR = 1.006, p = .031) were independent predictors of AKI. AKI was significantly associated with ICU mortality (p = .003) and mechanical ventilation (p = .030), but not with length of ICU stay (p = .069). Conclusion: Elevated baseline CRP is independently associated with development of AKI in critically ill ICU patients. However, its discriminatory ability is modest (AUC 0.645), suggesting that CRP should be interpreted in conjunction with established severity scores such as APACHE II rather than used as a standalone predictor.