A new study revealed that there is a higher risk of mortality faced by COVID-19 patients in intensive care who have chronic kidney disease (CKD) or those who newly develop acute kidney injury (AKI) as a result of developing COVID 19.*

CKD, AKI, and COVID-19

In CKD, kidney function declines anywhere from months to years and is common in older populations. CKD has five stages, of which the fifth stage is kidney failure and requires either dialysis or a kidney transplant. AKI is a more abrupt loss of kidney function, occurs within seven days or less, and has several causes. 

Potential causes of AKI include:

• Loss of blood flow to the kidneys
• Damage from pharmaceutical drugs or other ingested/injected substances
• Damage by anything obstructing the flow of urine in the urinary tract
• Damage and inflammation caused by COVID-19 virus

Because COVID-19 may impact kidney health, people with kidney problems are an important population to study as it relates to mortality.

What they did

The study, which was led by Sanooj Soni, Ph.D., from Imperial College London in the U.K., examined 372 patients with COVID-19, whose average age was approximately 60 years old. In addition, 72% were male and 76% were of an ethnic minority, such as Black and Asian. 

In regards to kidney status:

• 58% of the patients had some form of kidney impairment, with 45% developing AKI during their stay in the intensive care unit (ICU) and 13% with pre-existing CKD. 
• 42% had neither CKD nor AKI. 

What researchers found

• Patients without kidney injury or disease had a mortality rate of 21%.
• Those with an onset of AKI caused by COVID-19 had a mortality rate of 48%.
• Patients with pre-existing CKD (stages 1 through 4) had a mortality rate of 50%.
• In patients with stage 5 CKD and who required outpatient dialysis, mortality was 47%.
• Mortality was greatest in those patients with kidney transplants, as six out of seven (6 out of 7) patients died (86%).

The researchers also looked at the need for renal replacement therapy, a form of hospital dialysis, due to COVID-19 in ICU patients with a kidney injury. 

• 56% of patients with kidney impairment required renal replacement therapy (RRT).
• Of the 48 survivors who needed dialysis for the first time during their ICU stay, 19% had to continue with dialysis after being discharged from the ICU, which suggests that COVID-19 may lead to chronic kidney problems.

What this means

Interestingly enough, patients with kidney failure and on dialysis were found to have similar mortality rates to participants with less severe CKD and those with COVID-19-associated AKI. Since all populations have comparable mortality rates, each might benefit equally from ICU admission and should be considered ICU candidates during the COVID-19 pandemic. 

The reasons for the increased mortality in patients with kidney problems are not understood, although many theories exist, such as:

• Endotheliitis, an inflammation of the blood vessels in the kidneys known to cause the same inflamed state in the lungs in COVID-19 sufferers
• Possible direct kidney injury from the cytokine-induced immune system inflammatory response (when the body is overwhelmed by its immune response)
• Death of kidney tissue related to multi-organ failure caused by COVID-19

The authors underline the importance of enhancing care for patients with kidney dysfunction who are suffering from COVID-19 as they are a high-risk population. “Attention needs to be paid to COVID-19 patients with any form of kidney disease or injury, and every effort made to prevent progression of this disease or injury to reduce mortality in this cohort of patients,” the study concluded.

*Sanooj, S. (2020, Oct. 16). Study reveals kidney disease or injury is associated with much higher risk of mortality for COVID-19 patients in ICU. EurekAlert!. https://www.eurekalert.org/pub_releases/2020-10/a-srk101620.php