COVID-19 Infection Linked to Increased Risk of Kidney Disease vs Influenza in US Cohort Study

A large US cohort study of more than 3 million adults suggests that prior COVID-19 infection is associated with significantly increased risks of acute and chronic kidney disease compared with influenza, underscoring the need for ongoing renal monitoring in primary care.

Approximately one in seven US adults has kidney disease, and as many as 90% remain undiagnosed due to a lack of early symptoms, according to background data cited by investigators. Chronic kidney disease (CKD) is associated with progression to kidney failure as well as increased risk of cardiovascular events, including myocardial infarction and stroke.

“Most people aren’t diagnosed until the disease has progressed to an advanced stage. We need a better way to predict who is at risk, who is more likely to develop kidney disease so that we can detect and intervene earlier,” said Djibril Ba, assistant professor of public health sciences at Penn State College of Medicine.

Study Design and Population

The retrospective cohort study, conducted using the MarketScan database, included records from January 2020 through December 2021 and analyzed 939,241 individuals with COVID-19, 199,071 individuals with influenza, and 1,878,482 individuals with neither infection. Individuals with preexisting kidney disease were excluded.

Participants were stratified into 3 groups: COVID-19 infection, influenza without COVID-19 (positive control), and no infection (negative control). Cohorts were matched by age, sex, geographic region, and timing of infection to account for viral variants.

Patients were followed for 180 to 540 days (median follow-up, 324 days) for incident kidney outcomes, including acute kidney injury (AKI), CKD, end-stage renal disease (ESRD), and glomerular diseases. Multivariable stratified Cox proportional hazards regression analyses were performed.

Key Findings

Compared with influenza, COVID-19 infection was associated with significantly increased risks of kidney-related outcomes:

• Acute kidney injury (AKI):
  • Adjusted hazard ratio (aHR), 2.74 (95% CI, 2.61-2.87)
  • Approximately 2.3-fold higher risk vs influenza
• Chronic kidney disease (CKD):
  • aHR, 1.38 (95% CI, 1.32-1.45)
  • Approximately 1.4-fold higher risk
• End-stage renal disease (ESRD):
  • aHR, 3.22 (95% CI, 2.67-3.88)
  • Approximately 4.7-fold higher risk
• Glomerular diseases:
  • aHR, 1.28 (95% CI, 1.09-1.50)

Influenza was not associated with increased risk of CKD, ESRD, or glomerular diseases and demonstrated only mild, transient effects on kidney health.

Time-specific analyses showed that COVID-19 had stronger short-term effects on AKI but sustained long-term effects on CKD risk.

Mechanistic Considerations and Comparative Risk

The investigators noted that SARS-CoV-2 may directly affect kidney tissue. Kidney cells express high levels of receptors used by the virus for cellular entry and produce enzymes that facilitate viral invasion, potentially increasing susceptibility to injury.

“While we’re in the post-pandemic era, this shows that COVID-19 history is an important variable when considering the long-term impact of the infection on kidney function and disease,” said first author Yue Zhang, PhD.

This study is among the first large-scale analyses to compare kidney outcomes following COVID-19 with those following influenza, helping clarify whether renal risk is specific to SARS-CoV-2 or a general consequence of viral respiratory infections. Findings align with prior observational studies and case reports, particularly in hospitalized populations.

References:

1. Zhang Y, Ghahramani N, Chinchilli VM, Ba DM. The risk of kidney disease increases following SARS-CoV-2 infection compared to influenza. Commun Med (Lond). 2026 Feb 25. doi:10.1038/s43856-026-01460-6
2. Penn State Health. COVID-19 infection predicts higher risk of kidney disease, study finds. News release. March 5, 2026. Accessed March 25, 2026. https://pennstatehealthnews.org/2026/03/covid-19-infection-predicts-higher-risk-of-kidney-disease-study-finds/