Children with nephrotic syndrome may experience disease relapse or aggravation triggered by various viral infections. Limited studies on the clinical implications of the coronavirus disease 2019 (COVID-19) pandemic in children with nephrotic syndrome have been published worldwide. Therefore, this study aimed to investigate the effects of COVID-19 on the clinical course of nephrotic syndrome in children.
The medical records of 59 patients with idiopathic nephrotic syndrome who visited our hospital between February and June 2022 were retrospectively analyzed.
Twenty of the total 59 patients with nephrotic syndrome were diagnosed with COVID-19 during the study period. The mean age at the time of the diagnosis of nephrotic syndrome and COVID-19 in all 20 patients was 4.6±3.5 and 8.9±3.9 years, respectively. Three patients (15%) were diagnosed with nephrotic syndrome relapse during COVID-19 and the relapse rate was similar to them without COVID-19 (20.5%, 8/39 patients). At the time of the COVID-19 diagnosis, fever (85%) and cough (40%) were the most common symptoms. After the diagnosis of COVID-19, all patients showed improvement with symptomatic treatment, including antipyretic analgesics and cold medicine. None of the critical patients required hospitalization or oral antiviral medications.
Despite the use of immunosuppressants, the clinical manifestations of COVID-19 in children with nephrotic syndrome were not severe and are expected to be similar to that in the general population. The relapse rate of nephrotic syndrome in children with COVID-19 was also not different from them without COVID-19.
Since its first outbreak in 2019, coronavirus disease 2019 (COVID-19) has spread rapidly worldwide, affecting millions of people differently. South Korea has also been heavily affected by COVID-19, with 23.6 million confirmed cases and 27,149 deaths reported as of September 5, 2022. Among the total number of confirmed cases, 5.67 million cases were reported in children aged <19 years, accounting for 24% of the total cases, with 46 deaths, indicating that the severity of COVID-19 in pediatric patients was significantly lower than that in adults [
The medical records of pediatric patients with idiopathic nephrotic syndrome who visited our hospital between February and June 2022 were retrospectively analyzed. Patients aged <1 year and >19 years and those with inadequate medical records were excluded. Finally, total 59 patients (20 pediatric patients diagnosed with COVID-19 and 39 pediatric patients who did not have COVID-19) were included in the study. Relapse of the nephrotic syndrome within 2 weeks of COVID-19 was defined as a relapse caused by COVID-19. The diagnosis of COVID-19 was confirmed using real-time polymerase chain reaction or rapid antigen testing performed at a public health center hospital. Student
The baseline characteristics of 59 nephrotic syndrome patients who visited our hospital during the study period are as follows: mean age at the study period, 9.3±3.7 years; mean age at diagnosis of nephrotic syndrome, 4.8±3.1 years; male, 79.7%; steroid-sensitive nephrotic syndrome, 81.4% (
Twenty of the total 59 patients with nephrotic syndrome were diagnosed with COVID-19 during the study period (
Three (15%) of the 20 patients with COVID-19 were diagnosed with nephrotic syndrome relapse while COVID-19 was ongoing (
The number of COVID-19 cases in the pediatric age group was low during the early stages of the pandemic, but it gradually increased as the unprecedented COVID-19 pandemic continued to spread worldwide [
However, this study has some limitations. First, the small number of included patients owing to the short observation period. Therefore, information on later complications could not be confirmed. Second, it cannot be ruled out that patients who were not diagnosed with COVID-19 during the study period had asymptomatic COVID-19. However, to the best of our knowledge, this study is the first study to report the clinical features of COVID-19 in Korean children with nephrotic syndrome. These findings provide valuable evidence for determining the clinical prognosis of pediatric patients with nephrotic syndrome diagnosed with COVID-19.
In conclusion, the clinical manifestations of COVID-19 in children with nephrotic syndrome were not severe in spite of receiving the immunosuppressant medications and are expected to be similar to that in the general population. Further, the relapse rate of nephrotic syndrome in children with COVID-19 was not different from them without COVID-19.
This retrospective study was conducted in accordance with the principles of the Declaration of Helsinki. This study was reviewed and approved by the Institutional Review Board of Kyungpook National University Hospital (IRB No. 2022-09-006), which waived the need for written informed consent.
No potential conflict of interest relevant to this article was reported.
None.
Conceptualization: MHC
Data curation: MJP, JKE
Formal analysis: MJP, JKE
Investigation: JKE
Methodology: MHC
Visualization: MJP
Writing-original draft: MJP, JKE
Writing-review & editing: HSB, MHC
All authors read and approved the final manuscript.
Comparison of trends in the cumulative number of confirmed coronavirus disease 2019 (COVID-19) cases in South Korea and our study subjects by month. Data from: Korea Disease Control and Prevention Agency (September 5, 2022) [
Baseline characteristics of patients with nephrotic syndrome
Characteristic | Value (n=59) |
---|---|
Age at the study period (yr) | 9.3±3.7 |
Age at diagnosis of nephrotic syndrome (yr) | 4.8±3.1 |
Male sex | 47 (79.7) |
SSNS:SRNS | 48:11 |
Frequent relapse | 31 (52.5) |
Perform a renal biopsy | 14 (23.7) |
Minimal change disease | 11 |
Focal segmental glomerulosclerosis | 3 |
Values are presented as mean±standard deviation or number (%).
SSNS, steroid-sensitive nephrotic syndrome; SRNS, steroid-resistant nephrotic syndrome.
Comparison of clinical characteristics between the patients with and without COVID-19
Characteristic | COVID-19 (+) | COVID-19 (–) | |
---|---|---|---|
No. of patients | 20 | 39 | |
Male sex | 17 (85.0) | 30 (76.9) | 0.47 |
Age at diagnosis of NS (yr) | 4.6±3.5 | 4.9±2.9 | 0.71 |
Age at the study period (yr) | 8.9±3.9 | 9.5±3.6 | 0.62 |
SSNS:SRNS | 14:6 | 34:5 | 0.11 |
Frequent relapse | 11 (55.0) | 20 (51.3) | 0.79 |
Performed renal biopsy | 5 (25.0) | 9 (23.1) | 0.87 |
Minimal change disease | 3 | 8 | |
Focal segmental glomerulosclerosis | 2 | 1 | |
History of relapse triggered by URI | 13 (65.0) | 22 (56.4) | 0.52 |
eGFR at the study period (mL/min/1.73 m2) | 117.3±21.9 | 126.2±20.0 | 0.12 |
Period from the diagnosis of NS to study (yr) | 4.6±3.1 | 4.4±3.6 | 0.83 |
Drugs being taken at the study period | |||
Corticosteroid alone | 5 (25.0) | 3 (7.7) | |
Cyclosporine alone | 4 (20.0) | 8 (20.5) | |
Corticosteroid + cyclosporine | 3 (15.0) | 0 | |
Tacrolimus alone | 1 (5.0) | 1 (2.6) | |
Corticosteroid + tacrolimus | 1 (5.0) | 0 | |
Mycophenolate mofetil + tacrolimus | 0 | 1 (2.6) | |
Rituximab (within 1 yr) | 3 (15.0) | 5 (12.8) | |
Rituximab (within 1 yr) + corticosteroid | 0 | 1 (2.6) | |
None | 3 (15.0) | 20 (51.3) | <0.01 |
Patient number with NS relapse during study period | 3 (15.0) | 8 (20.5) | 0.61 |
Values are presented as number (%) or mean±standard deviation.
COVID-19, coronavirus disease 2019; NS, nephrotic syndrome; SSNS, steroid-sensitive nephrotic syndrome; SRNS, steroid-resistant nephrotic syndrome; URI, upper respiratory infection; eGFR, estimated glomerular filtration rate.
Clinical characteristics of three patients diagnosed with nephrotic syndrome relapse during the COVID-19 illness
Characteristic | Patient 1 | Patient 2 | Patient 3 |
---|---|---|---|
Sex | Male | Male | Female |
Age at diagnosis of NS (yr) | 3.0 | 3.3 | 4.5 |
Age at the time of COVID-19 (yr) | 5.7 | 10.5 | 7.8 |
Steroid responsiveness | Steroid-resistant | Steroid-sensitive | Steroid-sensitive |
Frequent relapse | No | Yes | No |
Performed renal biopsy (result) | No | Yes (MCD) | No |
History of relapse triggered by URI | No | Yes | Yes |
Duration from the diagnosis of NS to COVID-19 (yr) | 2.7 | 7.2 | 3.3 |
Drug being taken at the time of COVID-19 (dose, mg/kg/day) | Cyclosporine (5.5) | Corticosteroid (0.4) | None |
Duration from diagnosed COVID-19 to relapse (day) | 5 | 3 | 0 |
Time to remission (day) | 9 | 6 | 12 |
Follow-up period after remission (mo) | 4 | 2 | 4 |
Relapse during follow-up after remission | None | None | None |
COVID-19, coronavirus disease 2019; NS, nephrotic syndrome; URI, upper respiratory infection; MCD, minimal change disease.