How does COVID-19 impact the kidneys?

Kidneys perform vital functions and are crucial organs in the body. Impairment of kidney functions manifests as kidney disease. Throughout the course of the pandemic, individuals with kidney disease are at increased risk if exposed to COVID-19. The virus has also tremendously impacted the kidneys of COVID-infected patients.

Baylor College of Medicine experts Dr. David Sheikh-Hamad and Dr. Rajeev Raghavan explain the risks and effects of coronavirus on the kidneys.

“The kidney is a filter for our body and is responsible for removing toxins and fluid, by producing urine. As kidney function diminishes, the build-up of toxins and fluids begins to affect other organs such as the brain, heart and lungs. Some of the most critically ill patients with COVID even required temporary dialysis,” Raghavan said. “The kidneys often take weeks to recover; hence, COVID survivors may present to our clinic with lingering  aftereffects of their disease. This manifests as blood or protein in the urine, or a reduction in the percent of kidney function, known as the glomerular filtration rate.”

“There are a variety of reasons for kidney failure, some of which have to do with inflammation. Patients with cystic disease also develop kidney failure and would require dialysis or transplantation at some point in their lives,” Sheikh-Hamad said. “Patients with diabetes or hypertension are most at-risk for kidney failure, as well as going on dialysis and needing transplantation. Over a long period of time, poorly controlled high blood pressure will damage the kidneys. In about 50% of patients with diabetes, kidney disease will develop within 10 to 15 years.”

While nephrologists continue to learn about the correlation between COVID-19 and kidneys, preliminary observations show that patients with kidney disease are at higher risk of contracting the virus due to a weakened immune system. Patients who receive dialysis in a center are at even higher risk, due to the frequent exposure to dialysis staff, transportation personnel and other patients.

“Nephrologists have faced many challenges during the pandemic. We have co-managed critically ill patients in the ICU and have converted our clinic encounters to tele-visits. We have fielded frantic questions from our vulnerable patients, such as kidney transplant recipients. As medical directors in dialysis clinics, we have helped establish new protocols to keep our patients and staff safe. The COVID experience has been humbling,” Raghavan said.

COVID-19 can directly target and enter the cells in the kidneys. The lack of oxygen from lung injury or shock reduces kidney function. The virus can also cause blood clots to form, which can lead to stroke, heart attacks, clogging of the kidneys, and impact normal function.

Patients at high risk for the development of severe lung manifestations from COVID-19 infection tend to develop kidney failure in the course of their infection; patients at risk include elderly patients, patients with hypertension, patients with heart disease, and other patients who are immune-compromised for a variety of reasons. Many of them develop kidney failure and require dialysis while in the ICU.

“The majority of patients we see in the ICU on ventilators with kidney failure requiring continuous dialysis treatments are Hispanic, which raises questions about genetic susceptibility for lung disease in Hispanics and whether there are preexisting comorbid conditions within this population that predispose them to COVID,” Sheikh-Hamad said.

Experts are continuously learning more about the virus and its impact on the organs. While they have faced hurdles, they have also made advances in critical care.

Sheikh-Hamad is a professor of medicine-nephrology at Baylor. Raghavan is an associate professor of medicine-nephrology at Baylor.

-By Homa Shalchi