The nadir platelet count in the first 48 hours after ICU admission is a potential predictor of acute kidney injury in hemorrhagic shock patients

Abstract Background Whether the nadir platelet count in the first 48 hours after intensive care unit (ICU) admission could be a potential predictor of acute kidney injury (AKI) in hemorrhagic shock patients has not been determined. The purpose of this study was to investigate the relationship between the nadir platelet count in the first 48 hours after ICU admission and the occurrence of AKI caused by hemorrhagic shock. Methods This dual-center, observational retrospective study included hemorrhagic shock patients hospitalized in Maoming People's Hospital and Guangdong Medical University Affiliated Hospital from January 2019 to May 2022. The nadir platelet count was defined as the lowest value in the first 48 hours after ICU admission. Multivariate logistic regression was used to assess the independent risk factors for AKI. The area under the receiver operating characteristic curve (AUC) was analyzed to compare the diagnostic accuracy of the studied markers. The primary outcome was the occurrence of AKI within the first 7 days of ICU stay diagnosed according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria. In addition, serum cystatin C (sCysC) date were collected to explore the relationship with the nadir platelet count. Results A total of 124 patients were included for analysis, including 72 patients with AKI. Compared with patients without AKI, patients with AKI caused by hemorrhagic shock had a significantly the lower nadir platelet count, with the odds ratio (OR) of 0.980 (95% confidence interval [95% CI]: 0.973–0.987, p < 0.001). Multivariate logistic analysis showed that the nadir platelet count was an independent risk factor for AKI (OR = 0.988, 95% CI: 0.978–0.999, p = 0.035). The sensitivity and specificity for the nadir platelet count predicting AKI were 83% and 79%, respectively (AUC = 0.862, 95% CI: 0.795–0.929). Moreover, combining the nadir platelet count with sCysC increased the receiver operating characteristic (ROC) curve to 0.922 (95% CI: 0.870–0.973), and this performance was statistically significantly better than either the individual the nadir platelet count ( p = 0.018) or sCysC ( p < 0.001). Conclusions The nadir platelet count in the first 48 hours after ICU admission was independently associated with the incidence of AKI in hemorrhagic shock patients and could be a potential predictor of AKI in this patient population.