#4589 hypochloremia as a marker of all-cause mortality and unplanned dialysis starts in a cohort of acute kidney injury: a 4-year follow-up study

Abstract Background and Aims Serum chloride is an emerging marker of mortality in patients with hypertension, heart failure, sepsis, and chronic kidney disease. The relationship between hyperchloremia and acute kidney injury is well known, especially in critically ill patients. However, the role of baseline hypochloremia in the prognosis of hospitalized patients with acute kidney injury (AKI) remains poorly understood. Method Retrospective cohort type study. We included n=243 patients with AKI stage 3 from consultations received by the nephrology department of our hospital between January 1, 2017, to December 31, 2017. The sample was divided into two groups considering baseline serum chloride (Cl−) levels. Hypochloremia was considered if Cl−< 98 mEq/L. The primary endpoint was a composite variable for unplanned dialysis starts and all-cause mortality. Results The mean age was 68 years. Females accounted for 39.5%. The mean baseline sodium was 137±7.2 mEq/l, and the mean baseline chloride was 98.9±7.05 mEq/l (Table 1). The mean follow-up of the patients was 21±19.61 months. The incidence of the primary endpoint was n=166 (68.3%). 148 (60.9%) died, of whom 78 (32%) died during their hospital stay. The causes of death were: 30.6% cardiovascular, 12.9% tumor, 44.7% infectious, and 11.8% other. Kaplan-Meier estimates showed lower survival rates in patients with chloride levels below 98 mEq/l (p=0.006, log-rank test) (Figure 1). Conclusion Patients with AKI stage 3 with lower baseline chloride levels (<98 mEq/L) were more likely to have higher overall mortality and unplanned dialysis starts.