#5301 COVID-19 AND ACUTE KIDNEY INJURY IN ELDERLY PATIENTS: A COMPARATIVE COHORT STUDY BETWEEN THE FIRST AND SECOND WAVE OF THE PANDEMIC IN BRAZIL
Authors: Yuasa Bruna , Magalhães Luis , Sousa de Oliveira Paula Gabriela , Yokota Lais , Cardoso Pedro , Zamoner Welder , Balbi Andre , Ponce Daniela 
Published: June 2023

Abstract

Background and Aims
In the different waves of the pandemic caused by the SARS-CoV-2 virus, the elderly continued to be affected with more severe cases of the disease and possible progression to death. The objective of this study was to compare the incidence of acute kidney injury (AKI) in the elderly during the first and second waves of the pandemic in Brazil; the risk factors associated with its development and death.

Method
Retrospective cohort study that evaluated patients over 60 years of age admitted to a Public, Tertiary, and Reference Hospital for COVID-19 with a diagnosis of SARS-CoV-2 infection, from March to December/2020 (first wave), and from January to May/2021 (second wave), from admission to hospital outcome (discharge or death).

Results
Throughout the entire period, 434 elderly patients diagnosed with COVID-19 were admitted, 173 in the first wave and 261 patients in the second wave. These two groups of patients were similar in terms of age (71±8.41 vs 70±8.03, p = 0.3239), need for intensive care unit admission (56.1% vs 58.2%, p = 0.655), vasoactive drug use (43.9% vs 52.9%, p = 0.068), need for mechanical ventilation (43.4% vs 52.5%, p = 0.062), higher APACHE values (19±7.53 vs 17 ±5.64, p = 0.312), SOFA (9±4.07 vs 7±3.56, p = 0.332), CPK (96.5±705.74 vs 150±4830.47, p = 0.0886), the incidence of AKI (56.6% vs 58.6%, p = 0.684) and mortality (46.8% vs 55.2%, p = 0.088). However, they differed in terms of white race (77.5% vs 86.8%, p = 0.011), use of corticosteroids (56.6 vs 93.9%, p &lt; 0.001), presence of proteinuria (44.8% vs 58.2%, p = 0.031), higher values of ATN-ISS (0.76±0.23 vs 0.86±0.21, p = 0.004) and D Dimer (5098±5995.04 vs 2436.5±8398.38, p = 0.0147). The two waves were similar regarding the following factors associated with the development of AKI: higher baseline creatinine, CPK, and D-Dimer values during hospitalization, higher APACHE values, need for mechanical ventilation, use of vasoactive drugs, presence of proteinuria and hematuria in the urine 1 on hospital admission. There was a difference between the waves regarding males (47.40% vs 64.08%, p = 0.037), a relevant factor in the development of AKI in the first wave; while the presence of SAH (63.9% vs 77.8%, p = 0.0202), the use of ACEI/ARB (42.6% vs 56.2%, p 0.0412) and the filtration rate basal glomerular (91±29.61 vs 80.5±26.79, p = 0.0021) were observed as factors associated with AKI only in the second wave. In the logistic regression of both waves, mechanical ventilation remained a risk factor for the development of AKI. In the first wave, the highest baseline creatinine value was also maintained as a risk factor (OR 10.54, CI 1.22-90.61, p = 0.032); while in the second, SAH (OR 1.646, CI 1.150-1.839, p = 0.018), hematuria (OR 1.681, CI 1.124-1.822, p = 0.018) and higher value of D Dimer (OR 1.977, CI 2.000-2.003, p = 0.023) remained as relevant factors for the development of AKI. As factors associated with mortality in the first wave, the highest value of CPK (OR 1.009, CI 1.001-1.017, p = 0.042) and the need for mechanical ventilation (OR 17.71, CI 1.13-277.62, p = 0.002). In the second wave, the factors associated with death were the presence of DM (OR 4.875 CI 2.602-7.094, p = 0.001), ARF (OR 1.858, CI 1.070-1.287, p &lt; 0.001), need for dialysis (OR 1.813, CI 1.086-1.407, p &lt; 0.001), proteinuria (OR 1.968, CI 1.142-1.913, p = 0.032) and higher ATN-ISS value (OR 5865.316, CI 1.325-25967740, p = 0.043).

Conclusion
The incidence of AKI was similar between the two waves of the pandemic; however, its severity was greater in the second wave, in which it was identified as a factor associated with death. Despite the greater severity of AKI, evidenced by the higher ATN-ISS, there was no higher patient mortality during the second wave of the pandemic.