Incidence of Acute Kidney Injury and Mortality in Critically Ill Patients: Urinary Chloride as a Prognostic Marker

Abstract Background Acute kidney injury (AKI) is characterized by a rapid decrease in renal function. It is frequent in hospitalized patients and its incidence is higher in critically ill patients. It is associated with high rates of morbidity and mortality. AKI affects over 13 million people per year globally, and results in 1.7 million deaths. It is diagnosed in up to 20% of hospitalized patients and in 30– 60% of critically ill patients. It is the most frequent cause of organ dysfunction in intensive care units and the occurrence of even mild AKI is associated with a 50% higher risk of death. Objective To investigate the association between urinary chloride concentrations, AKI and mortality. Patients and Methods This prospective observational study has been carried out in Ain Shams University ICUs and included 90 critically ill patients with acute kidney injury during a study period of 6 months. Results Our results support a statistically high significant increase in serum chloride levels among non survival cases on the first day of ICU admission, till the 9th day. The present study revealed that urinary chloride level was significantly higher among survivors’ group on all days of ICU admission. There was a significant decrease in overall survival among AKI patients as they had longer ICU stay and 48.8% mortality rate (all non-AKI patients were discharged alive by 4th day). Conclusion We found that a lower urinary chloride concentration at the time of ICU admission was associated with higher mortality and higher incidence of AKI in critically ill patients. Urinary chloride measurement may constitute an early and useful prognostic marker for assessment of patients in ICU.