Long Covid-19 in Mild and Moderate Patients: Evaluation of Kidney Function

Abstract Background: Patients recovered from severe COVID-19, report long term sequelae which are associated with a worse quality of life. However, there are few reports evaluating long COVID-19 regarding filtration kidney function in individuals with mild and moderate symptomatology. The objective: to evaluate the filtration kidney function in patients that had mild and moderate symptomatology after 6 and 12 months from recovering COVID-19 (long COVID-19). Methods: We evaluated 253 individuals with mild (n=119) and moderate (n=134) symptomatology for COVID-19 after 6 (T6) and 12 (T12) months from the date of acute infection (T0). Serum creatinine, cystatin C, proteinuria and estimated glomerular filtration rate (eGFR) were evaluated. Results: The average of age was 44±10 and 64% were women. The serum creatinine and eGFR were not different between the groups, but cystatin C increased at T12 in moderate compared to T6 and to the mild group (p = 0.04). The cystatin C eGFR was lower to T12 in mild group than T6 (p ≤ 0.001) and creatinine eGFR decreased to T12 in moderate group than T6 (p = 0.004). The moderate group present proteinuria ≥1”+” (59% vs. 42%; p=0.02) at T6 compared with mild group and the mild group increased proteinuria in T12 (63% vs. 42%; p=0.01). Discussion: Our findings suggest that, even in individuals who have recovered from mild or moderate COVID-19, the presence of proteinuria and subtle changes in kidney filtration may serve as early warning signs, emphasizing the need for ongoing monitoring of kidney function in this population.