#3750 SERUM AMYLOID A AS PROGNOSTIC MARKER FOR CKD AND NON-CKD COVID-19 PATIENTS ADMITTED TO THE EMERGENCY ROOM
Authors: Filev Rumen , Cankova Mila , Bogov Boris , Svinarov Dobrin , Hristova Julieta , Kalinov Krasimir , Rostaing Lionel 
Published: June 2023

Abstract

Background and Aims
Patients with chronic kidney disease (CKD) and a SARS-CoV-2 infection are at higher risk of developing acute kidney injury (AKI) and of mortality after hospital admission. Herein, we assessed whether serum amyloid A (SAA) was associated with outcomes (AKI and/or death).

Method
The study group included 160 patients: 70 Covid-19-positive CKD patients (eGFR &lt;60 mL/min), 50 Covid-19-positive patients with no history of kidney disease, 20 Covid-19-negative CKD patients, and 20 healthy controls. We collected data on patients’ gender, age, co-morbidities, and laboratory results from blood and urine samples taken at admission into the ER, and from healthy volunteers. All participants gave their informed consent for trial with protocol №12/31.05.2022 approved by the ethical committee KENIMUS of the Medical University of Sofia, Bulgaria. Laboratory values included calculated eGFR (by the CKD-EPI 2021 formula), highly sensitive inflammatory markers, D-dimer, blood-cell counts, and changes in urine parameters. Co-morbidities included hypertension, obesity, diabetes mellitus, vascular disease, and CKD. All patients had been treated by the official protocol of the Republic of Bulgaria for SARS-CoV-2. We determined the levels of SAA across the four groups to assess if this biomarker could predict AKI, risk of mortality, and if there was a significant difference between the CKD and non-CKD patients.

Results
Overall, median age of Covid-19 patients was 56.4 years; gender ratio was 50% M/F in all groups. Median duration of symptoms before hospitalization was 6 days. Of the 160 patients, 30% were febrile with temperatures &gt;38oC. Overall, creatinine level on admission was elevated in 40% of cases; eGFR was &lt;60 mL/min/1.73 m2 in 37.5% of patients. Mean value of eGFR on admission was 82.3 mL/min/1.73 m2 for the non-CKD Covid-19-positive group, 49.5 mL/min/1.73 m2 for the CKD Covid-19-positive group, 62.3 mL/min/1.73 m2 for the CKD patients without COVID-19, and 111.1 mL/min/1.73 m2 for the healthy control group. In total, three Covid-19 patients needed renal-replacement therapy: two patients from the CKD group and one from the non-CKD group. AKI occurred in 38 Covid-19 patients (23.7%). Of these, 31 had CKD (44.3% of the Covid-19 positive CKD patients). Overall, within our cohort of 160 patients, in-hospital mortality was 14.3% (23 patients): of these, 82.6% had AKI (19 patients). Overall, 100% of patients that did not survive Covid-19 also had CKD. We analyzed the levels of SAA across the groups. The reference limits considered for negative results were &lt;7 pg/mL; the ELISA could measure values up to 300 pg/mL. Of the 23 patients that died, 19 had levels &gt;300 pg/ml (82.6%), whilst the remainder had results &gt;250 pg/mL. The other patients who survived the infection in our cohort had levels well below 200 pg/ml. When the patients with AKI and without AKI were compared on the basis of SAA, patients with AKI had significantly higher biomarker values (p- = 0.02). When compared across the four groups, no significant differences were found except when comparing the healthy control group with the other three groups, where there was significance of p&lt;0.0001 in each comparison.

Conclusion
We confirm that SAA was a reliable biomarker for predicting AKI in Covid-19 patients. It also acted as a predictor for a fatal outcome in patients with severely Covid-19 infection. In conclusion, SAA is a reliable marker, highly informative in the emergency department setting, enabling us to have an early prognosis for the outcome of the Covid-19 infection for the patients in our cohort.