The COVID-19 pandemic has had widespread effects on various aspects of health, and new research has highlighted its impact on IgA nephropathy (IgAN), the most common form of glomerulonephritis worldwide. A recent study conducted by researchers from Shenzhen Second People’s Hospital and Shenzhen People’s Hospital reveals a notable increase in the incidence of IgAN during the pandemic.
Between January 2016 and May 2023, the researchers analyzed kidney biopsy results from two medical institutions, finding the incidence of IgAN rose from 39.9% before the pandemic to 46.3% during it. This significant increase of 6.4% (P < 0.001) indicates the potential association between the virus and exacerbated kidney pathology, raising concerns about the long-term health impacts for affected patients.
IgAN typically manifests through symptoms such as hematuria, which is blood present in urine, and can lead to significant morbidity and mortality if not managed effectively. Some studies suggest COVID-19 could trigger or worsen kidney conditions, possibly due to heightened immune responses resulting from the viral infection.
Researchers sought to understand the role of SARS-CoV-2, the virus causing COVID-19, on the incidence of IgAN and other glomerular diseases by employing statistical analyses guided by the Oxford Classification (MEST-C), which assesses pathological changes. This classification evaluates key features of kidney biopsies, including mesangial hypercellularity—denoted as M lesions—and endocapillary hypercellularity—denoted as E lesions.
The study's results indicate pronounced pathological changes during the pandemic, with observable increases in pathological features categorized as M1 and E1 lesions, signaling impaired renal function. The proportions of patients showing M1 lesions rose significantly from 73.3% before the pandemic to 97.9% during it, reflecting the heightened risk of renal damage linked to COVID-19 infection.
"Our results indicate the incidence of IgAN has risen during the COVID-19 pandemic, along with exacerbated renal damage and elevated proportions of M1 and E1," noted the authors of the article. This alarming trend implies urgent clinical attention is needed for managing IgAN patients.
Over the same study period, the overall incidence of glomerular diseases remained relatively stable, except for minimal changes observed. The trends indicate notable deviations following the pandemic's onset, particularly the marked increase of IgAN diagnoses as the infection rates surged.
Investigators also gathered extensive clinical data, assessing demographics, symptoms, and laboratory indicators of disease activity among IgAN patients. The findings revealed no significant changes to the clinical manifestations, which included hypertension and various forms of hematuria, across the two study periods. While many laboratory parameters remained constant, the pathological changes suggest active inflammatory processes intensified during the pandemic.
Notably, with the introduction of COVID-19 vaccinations, the incidence of IgAN continued to rise, reflecting potential new interactions between viral infection, vaccination, and the immune system's response. According to the researchers, the mechanisms behind this association might involve alterations to the body's mucosal immune responses, which are particularly sensitive to both COVID-19 infection and its vaccines.
"Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can trigger excess IgA secretion, which may relate to IgAN," the authors explained, highlighting the vulnerabilities introduced during the pandemic. Although serologic findings showed no significant increase of IgA levels overall, the local immune response within the kidneys appears to have been pertinent.
Overall, the study presents compelling evidence of the pandemic's influence on kidney pathology and supports the need for close monitoring and timely intervention for IgAN patients. It highlights the importance of increasing clinical awareness of kidney-related complications and advancing research to improve patient outcomes during and beyond the pandemic. The findings point to pressing questions for future investigations, including how long these trends may last, and whether new treatment protocols might mitigate the observed risks associated with COVID-19 and IgAN.