ABSTRACT
Background: IgA nephropathy (IgAN) flairs with gross hematuria after COVID-19 vaccination have been recently reported as adverse events of immunization, but no study to date has examined the incidence and clinical course of IgAN patients with gross hematuria following vaccination. Method(s): A single-center retrospective observational study included 301 patients with biopsy-proven IgAN and followed-up for more than 6 months with therapeutic intervention and received at least one dose of COVID-19 vaccination. We examined from medical records the incidence of gross hematuria following vaccination and also evaluated the clinical course of eGFR, spot urine protein/Cr ratio (UPCR), urinary erythrocyte count (URBC) /hpf among IgAN patients with gross hematuria following COVID-19 vaccination. Result(s): We identified 7 (3.0 %) patients with gross hematuria following COVID-19 vaccination. 6 patients were female. The median age was 42 (range, 33 to 48). Median time to develop gross hematuria after vaccination was 1 (range, 0 to 4) day and gross hematuria resolved within 3 (range, 1 to 7) days. 6 patients presented gross hematuria after the second dose. Mean baseline eGFR and UPCR before vaccination were 73.7 (IQR, 61.3 to 86.0) ml/min/1.73m2 and 0.23 (range, 0.01 to 0.70) g/g Cr, respectively, and median grade of hematuria was URBC 10-19/hpf. With mean follow up of 238.7 (range, 184 to 282) days after the onset of gross hematuria, 4 patients were introduced steroid therapy. Within one month after the onset of gross hematuria, mean eGFR decreased -13 (range, -29.2 to -5.2) % and UPCR increased +0.70 (range, +0.02 to + 2.59) g/gCr from baseline, and median grade of hematuria increased to URBC 50- 99/hpf as compared to baseline. At 6 months, mean eGFR and UPCR improved to 73.9 (IQR, 60.2 to 88.0) ml/min/1.73m2 and 0.30 (range, 0.06 to 0.74) g/g Cr, respectively, and median grade of hematuria decreased to URBC 5-9/hpf. Conclusion(s): Our study revealed the incidence of gross hematuria following vaccination in IgAN patients and also suggested that eGFR, proteinuria and hematuria may transiently worsen but improve almost to baseline with appropriate therapeutic intervention or careful follow-up.