Results:
Clinical features
In group A, acute renal injury was the most common manifestation (35%),
followed by nephrotic syndrome (27%), characterized by
macroalbuminuria, hypoproteinemia, and edema, and also included simple
hematuria and/or microalbuminuria (19%), chronic nephritis (15%)and
lupus nephritis (4%). (Figure 1A.) Most patients in group B presented
with CKD(55%) and NS(40%); Only one patient presented with lupus
nephritis(LN) (5%).(Figure 1B.)
Pathological features
A total of 38 patients completed kidney biopsy, including 18 patients in
group A and 20 patients in group B. IgAN(39%) accounted for the largest
proportion of pathological types in Group A, followed by MN(17%),
FSGS(11%) and Endocapillary proliferative glomerulonephritis(EPGN)
(11%). (Figure 2A.) Among 20 patients in Group B, the most common renal
pathologic type was IgAN(45%), followed by FSGS(25%) and MN
(15%).(Figure 2B)(Figure 3.)
Serum C3 and the deposition of C3in kidney
The serum C3 level of 25 patients with COVID-19 associated kidney injury
was measured. 80% of them had normal C3 level. Among 38 patients with
COVID-19 associated kidney injury who performed kidney biopsy, 31.6%
presented with C3 (-), 7.9% presented with C3 (+), 28.9% presented
with C3 (++), and 31.6% presented with C3(+++).(Figure 3.)
Prognosis
Follow-up visits were conducted in 13 patients of Group A and 14
patients of Group B.Among the 13 patients in group A, 7 patients had
partial remission of proteinuria, 5 patients had no remission, and 1
patient had increased proteinuria. Hematuria was partially remission in
5 patients, stable in 4 patients, and increased in 4 patients. Four
patients had stable creatinine, three had increased creatinine, and one
had decreased creatinine.Among 14 patients in group B, 6 patients had
partial remission of proteinuria, 6 patients had no remission of
proteinuria, and 1 patient had remission of proteinuria. Hematuria was
partially alleviated in 6 patients, increased in 4 patients, and stable
in 4 patients. Five patients had reduced creatinine and four had stable
creatinine.(Table 1.)