#2317 Did acute kidney injury confer greater mortality in COVID-19 hospitalized patients? A Portuguese hospital experience in the third COVID wave
Authors: Martins Fábio , Almeida Ana Rita , De Almeida Edgar A F 
Published: May 2024

Abstract

Background and Aims
The outbreak of coronavirus disease 2019 (COVID-19) pandemic, which originated in December 2019, had a huge impact on healthcare worldwide. Numerous studies have reported alterations in kidney function among hospitalized patients with COVID-19, such as hematuria, proteinuria, and acute kidney injury (AKI). Histopathology exams in autopsies have identified various potential causes for the presence of AKI in these patients, with reports linking AKI to unfavorable outcomes across multiple countries. However, additional data concerning hospitalized COVID patients in Portugal are essential to further understand this aspect.

Method
Retrospective cohort study enrolling adult patients, who attended the Emergency Department and recorded positive polymerase chain reaction (PCR) results for SARS-CoV-2 from January 1 to January 31, 2021. AKI was diagnosed using the Kidney Disease Improving Global Outcome (KDIGO) classification based on serum creatinine (sCr) criteria and using a background creatinine available in the patient record. We performed an analysis of incidence, lethality, and possible risk factors of AKI in COVID-19 patients.

Results
The study encompassed a cohort of 239 patients, of whom 62 (25.94%) received a diagnosis of Acute Kidney Injury (AKI) based on KDIGO criteria. Within this subgroup, the average age was 77.65 years (±12.07), with a total of 29 male patients (46.78%). Notably, 30 deaths (48.39%) occurred during the hospital stay in this group. Regarding the AKI classification, 39 patients (62.9%) were classified as KDIGO-AKI stage 1, 14 patients (22.58%) as stage 2, and 9 patients (14.52%) as stage 3. Regarding the timing of the diagnosis of AKI, 54 (87%) occurred in the moment of admission, 7 patients (11.3%) were diagnosed within the first 48 hours and a solitary case (1.6%) was diagnosed after 7 days of hospitalization. In the non-AKI group, the mean age was 69.86 years (±15.95), and approximately 55% were male. Within this group, 49 deaths (27.7%) were recorded during hospitalization. Significantly higher mortality rates were observed in the AKI group, demonstrating a statistically significant difference (p &lt; 0.01) and a relative risk of 1.75 or mortality during hospitalization for AKI patients. Furthermore, the duration of hospitalization was notably prolonged in the AKI group (p &lt; 0.01), with a disparity of approximately three days. Individuals who developed AKI exhibited lower scores on the Barthel-dependence scale, indicative of higher dependence (p &lt; 0.01), and were significantly older (p &lt; 0.01) comparing with the ones that did not develop acute kidney injury. Additionally, it was remarkable that the leukocyte count at admission was more elevated in the AKI group (p = 0.03) compared to non-AKI patients with a difference of approximately 1.62×109/L.

Conclusion
Respiratory infections, including COVID-19, frequently lead to emergency department admissions and hospitalizations. This study validates an elevated prevalence of acute kidney injury (AKI) both at admission and during the hospital stay in such cases. The presence of AKI is linked to adverse outcomes, including mortality and extended hospital stays, underscoring the critical importance of promptly diagnosing AKI. Larger-scale studies are warranted in this field to enhance our understanding of this entity and therefore improve the outcomes related to this prevalent condition.