Association of anion gap and albumin corrected anion gap with acute kidney injury in patients with acute ischemic stroke

Background. Acute kidney injury (AKI) has become a common complication of acute ischemic stroke (AIS) and may have a significant impact on clinical outcomes. Anion gap (AG)/albumin corrected anion gap (ACAG) are used to assess acid-base balance status and help identify the severity of metabolic acidosis. Objectives. To explore the association of AG and ACAG with the risk of AKI in AIS patients admitted to the intensive care unit (ICU). Materials and methods. Data of AIS patients in this retrospective cohort study were extracted from the electronic ICU (eICU) databases (2014-2015). The outcome was the occurrence of AKI after ICU admission. The covariates included demographic data, vital signs, comorbidities, laboratory parameters, and medication use. The association of AG and ACAG levels with AKI risk in AIS patients was evaluated using univariate and multivariate logistic regression models with odds ratios (ORs) and 95% confidence intervals (95% CIs). The predictive performance of AG and ACAG for the risk of AKI in AIS patients was assessed with the area under the curve (AUC). To further explore the association of AG and ACAG levels with AKI risk, subgroup analyses were performed according to comorbidities. Results. Of the 1,260 AIS patients, 546 (43%) developed AKI. Elevated AG (OR = 1.73, 95% CI: 1.32-2.29) and ACAG (OR = 1.57, 95% CI: 1.21-2.04) were associated with the risk of AKI in AIS patients. The AUC of ACAG was superior to AG for predicting the risk of AKI (0.581 vs 0.558; p = 0.024). Elevated ACAG levels were associated with the risk of AKI in AIS patients without ischemic heart disease (OR = 1.60, 95% CI: 1.19-2.15), diabetes (OR = 1.58, 95% CI: 1.19-2.10) and hypertension (OR = 1.69, 95% CI: 1.24-2.30). Conclusions. Albumin corrected anion gap was a better predictor than AG for AKI risk in AIS patients, which may help clinicians identify high -risk patients for AKI.