COVID-19 long-haulers—even those who experienced mild cases—are at significantly increased risk for substantial declines in kidney function, such as organ damage and chronic and end-stage kidney disease (ESKD), according to a study today in the Journal of the American Society of Nephrology.
Long COVID-19 consists of lung and other organ dysfunction and symptoms for months after recovery from the initial infection.
Researchers at the Veterans Affairs St. Louis Health Care System and Washington University analyzed federal health data to gauge the risk of kidney dysfunction and disease, one of the top causes of death in the United States. Because kidney disease tends to cause no symptoms, the National Kidney Foundation estimates that 90% of the 37 million Americans who have it are unaware of their condition.
Nonhospitalized patients at triple the ESKD risk
Of more than 1.7 million healthy and coronavirus-infected US veterans analyzed from Mar 1, 2020, to Mar 15, 2021, 89,216 survived for at least 30 days after their COVID-19 diagnosis. The remainder served as study controls. While most COVID-19 patients in the study were men in their late 60s, the sample also consisted of 151,289 women (including 8,817 who were infected) and adults of all ages. Median follow-up was 164 days in COVID-19 survivors and 172 days in controls.
Compared with the control group, coronavirus survivors tended to be younger, Black, and living in long-term care facilities; were more likely to be taking prescription medications (eg, antacids, nonsteroidal anti-inflammatory drugs); and had higher rates of chronic lung disease, diabetes, and cardiovascular disease.
Relative to uninfected patients, nonhospitalized COVID-19 patients were at 15% higher risk of a major adverse kidney event (eg, chronic kidney disease), 30% higher risk for acute kidney injury, and 215% higher risk for ESKD, or more than triple the risk.
After the first 30 days of SARS-CoV-2 infection, 4,757 (5.3%) of patients experienced a decline of at least 30% in glomerular filtration rate (GFR). GFR indicates kidney function and can help determine the extent of kidney disease.
Kidney damage 'not normal anything'
Patients requiring intensive care were at three times the risk of a 30% or greater drop in GFR, while hospitalized patients not requiring intensive care were at two-fold the risk. Patients with mild illness were at 1.09 times the risk.
Of all COVID-19 patients, 12,376 (13.9%) were hospitalized, including 4,146 (4.6%) who required intensive care. Relative to patients with milder illness, critically ill patients were at seven times the risk for a major kidney event, eight times the risk for acute kidney injury, and 13 times the risk for ESKD.
"People who were hospitalized for COVID-19 or needed ICU care are at the highest risk," senior author Ziyad Al-Aly, MD, said in a Washington University press release. "But the risk is not zero for those who had milder cases. In fact, it's significant. And we need to remember that we don't yet know the health implications for long haulers in the coming years."
The kidney damage seen in COVID-19 long haulers was more than that seen as part of normal aging, Al-Aly added. "The kidney function decline we've observed in these patients is not graceful aging. It is not normal anything. It is definitely a disease state."
Al-Aly said the study underscores the importance of monitoring bloodwork in COVID-19 survivors because kidney disease identified in the early stages can often be treated with medication, while ESKD requires dialysis or kidney transplant.
"If kidney care isn't an integral part of COVID-19 post-acute care strategy, then we will miss opportunities to help potentially hundreds of thousands of people who have no idea that their kidney function has declined due to this virus," he said.