Potential Association of Hypernatremia With Mortality in Patients With Acute Kidney Injury and COVID-19.

Background The outcome of acute kidney injury (AKI) in patients with COVID-19 and the factors associated with its outcome, including mortality, are understudied among the Indian population. Objective The objective of this study is to determine the outcome of AKI in a cohort of patients with COVID-19 admitted to medical wards and associated intensive care unit (ICU) and the factors associated with its outcome, including mortality. Method This is a retrospective study of patients with COVID-19 and AKI admitted to a tertiary care hospital. A total of 1765 patients were admitted to a hospital with COVID-19 between March 23, 2021, and June 30, 2021, during the second wave of the pandemic chiefly attributed to SARS-Co-V-2 lineage B.1.617. Patients with AKI for whom a nephrology call was sought for management (N=60) were included. Measurements carried out were the stage of AKI, co-morbidities, ICU admission, mechanical ventilation, lab parameters, and mortality. We classified AKI by comparing the highest to lowest recorded serum creatinine in hospital and staged AKI based on the Kidney Disease: Improving Global Outcomes (KDIGO) system. We further developed stepwise logistic regression models to find independent factors associated with mortality.  Results Out of the 1765 patients hospitalized with COVID-19, a total of 60 (3.4%) patients with AKI were referred to nephrology for management. The observed mortality in this cohort was 41/60 (68.3%). AKI stage 3 was observed to be the most common (78.3%). Based on a univariate analysis of association, age, chronic kidney disease, admission to ICU, the requirement for vasopressor and ventilation, lactate dehydrogenase (LDH) DH, liver function tests (LFT), hypernatremia, and leucocytosis were associated with the mortality of patients (p<0.05) with AKI and COVID-19 infection. Multivariate analysis using logistic regression led to the identification of hypernatremia (OR 5.24 {0.95-42.31}) and multiple co-morbidities (OR 2.59 {1.03-8.75}, p<0.07) as potential factors independently associated with mortality. Conclusion The study indicates the potential association of hypernatremia with mortality in AKI, along with the simultaneous presence of multiple co-morbidities with COVID-19. As the statistical power of the association is weak, we are claiming the association as potential only. It needs to be confirmed in other larger studies.