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AUSTIN, Texas -- Oxidative stress markers were elevated in dialysis patients with long COVID, data from a cross-sectional cohort showed.

The study included 63 patients on hemodialysis who tested positive for COVID-19, including 31 people with persistent post-COVID sequelae at least 3 months later, reported Natalia Stepanova, MD, PhD, of the Institute of Nephrology of the National Academy of Medical Science in Kyiv, Ukraine, in a poster presentation at the National Kidney Foundation Spring Clinical Meeting.

People with persistent post-COVID sequelae had significantly higher levels of three oxidative stress markers -- malondialdehyde in serum (MDAs) and erythrocytes (MDAe), and serum catalase activity (CTs) -- compared with those who fully recovered after acute SARS-CoV-2 infection. Long COVID patients also had lower serum levels of sulfhydryl groups (SH-groups) and ceruloplasmin:

• MDAs: 282 µmol/L for long COVID patients vs 217.5 µmol/L (P=0.002)
• MDAe: 859 vs 724 µmol/L (P=0.0006)
• CTs: 129.5 vs 65.3 µkat/L (P=0.03)
• SH-groups: 1.17 vs 1.73 mmol/L (P=0.02)
• Ceruloplasmin: 0.13 vs 0.17 g/L (P=0.03)

There was no significant between-group difference in transferrin levels (2.3 vs 4.05 g/L, P=0.32).

Treatment strategies to manage post-COVID syndrome in hemodialysis patients are similar to the general population, Stepanova told MedPage Today. Beyond the usual ways to support health -- rest, exercise, healthy diet, and mental health support -- antioxidant supplements may help.

"The treatment of post-COVID syndrome has to involve a multidisciplinary approach," she said. "Patients should work closely with their healthcare providers to develop a tailored treatment plan that addresses their individual needs and concerns."

The researchers found a few independent risk factors for long COVID among this dialysis population, including temporary vascular access, low dialysis adequacy, uncontrolled hypertension, and low HDL levels prior to COVID infection, Stepanova added.

"In our opinion, monitoring and correction of the above risk factors may improve clinical outcomes of post-COVID syndrome in these patients," Stepanova suggested.

It's important to try to mitigate the myriad of far-reaching harmful effects linked with oxidative stress, she added.

"[Hemodialysis patients] are at increased risk for cardiovascular disease, and oxidative stress is a known risk factor for cardiovascular disease," Stepanova pointed out. "Oxidative stress can damage the endothelium, leading to the development of atherosclerosis and an increased risk of heart attack and stroke."

Oxidative stress can also damage erythrocytes, leading to hemolysis and anemia, she added, which can be especially problematic for patients on hemodialysis whose red cell count is already reduced due to kidney failure.

Other harmful effects of oxidative stress can include fatigue, depression, and malnutrition from damage to proteins that reduce absorption of essential nutrients. "Chronic inflammation is common in patients treated with hemodialysis and can contribute to oxidative stress. Oxidative stress, in turn, can further promote inflammation, creating a vicious cycle," Stepanova said.

Hemodialysis patients in the study had an average age of 55 and a dialysis vintage of 42 months. All participants tested positive for COVID-19 at least 3 months prior to the study. Oxidative stress markers were measured 4.7 months after acute COVID recovery.

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