Correlation analysis of blood bicarbonate and short-term adverse prognosis of acute kidney injury

Objective To evaluate the relationship between serum bicarbonate（HCO₃^-）concentration and short-term adverse outcomes in acute kidney injury（AKI）patients. Methods From May 2013 to May 2018，clinical data were retrospectively reviewed for 586 hospitalized AKI patients. Allcause mortality within 28 days after a diagnosis of AKI was employed as an endpoint of adverse outcome. According to the concentration of blood HCO₃^- ，they were divided into two groups of HCO₃^- declining （blood HCO₃^-< 22. 0 mmol/L，n=279）and HCO₃^- non-declining（blood HCO₃^-≥22. 0 mmol/L，n= 307）. Results During a follow-up period of 28 days，131 patients（22. 4%）died. Kaplan-Meier survival analysis indicated that patients with lower blood HCO₃^- had a shorter median survival（Log Rank χ²= 12. 998，P<0. 001）. Multivariate COX regression analysis showed that low blood HCO₃^- was an independent risk factor for 28-day all-cause mortality in AKI patients after adjusting for age，multiple organ dysfunction syndrome（MODS），cardiac dysfunction，shock and etiology of AKI（HR=0. 917，95%CI 0. 885-0. 949，P<0. 001）. Receiver operating characteristic（ROC）curve analysis indicated that the area under the curve（AUC）of blood HCO₃^-concentration was 0. 703 in predicting 28-day mortality of AKI patients（P<0. 001）. Conclusion Blood HCO₃^- is an important influencing factor of mortality in AKI patients. And lower blood HCO₃^- has certain clinical value in predicting short-term adverse prognosis of AKI patients.