Department of Research & Evaluation News

Kidney dialysis patients should take extra precautions to avoid being infected with COVID-19. A new Kaiser Permanente Southern California study found patients on dialysis have 18 times higher risk of hospitalization and death from COVID-19 than people who do not have end-stage kidney disease.

Intuitively, the physicians and researchers knew that these patients may be at higher risk because they often have other chronic conditions, such as diabetes. But there was some hope that they might avoid the COVID-19’s cytokine storm, the body’s immune response to COVID-19 that can have devastating effects, because of their immunocompromised condition.

“Yet, what they saw when they pulled together the data was that the patients on dialysis were being hospitalized and dying from COVID-19 at a much higher rate than the general population,” said John J. Sim, MD, the lead researcher on the study, a clinician researcher with the Department of Research & Evaluation, and a nephrologist with the Kaiser Permanente Los Angeles Medical Center. “In fact, they are dying at an exponential rate. It’s a sobering thing.”

The study was published in Kidney Medicine on Nov. 24, 2020.

End-stage kidney disease patients often require dialysis to survive

In end-stage kidney disease, a person’s kidneys can no longer filter out body waste and keep them alive. The most common causes are diabetes and high blood pressure.

When kidneys get to that point, patients often need dialysis or a new kidney. Dialysis options include hemodialysis, which is done at a clinic, or peritoneal dialysis, which is done at home. In hemodialysis, blood is pumped through an artificial kidney machine and returned to the body, while in peritoneal dialysis, the inside lining of a person’s belly acts as a filter.

Kaiser Permanente Southern California has patients at over 300 dialysis facilities throughout the region. Dialysis patients are screened for COVID-19 before every treatment and tested regularly if there are clinical indications for COVID-19.

Study cohort included more than 100 dialysis patients with COVID-19

Among 7,533 end-stage kidney disease patients, 133 (16 peritoneal and 117 hemodialysis) patients were diagnosed with COVID-19 between March 1 and June 30, 2020.

Researchers found:

• While the overall COVID-19 rates were low among those on dialysis during the study period, researchers observed high mortality among patients with COVID-19 (23% vs. 1.3% of all Kaiser Permanente Southern California members who tested positive for COVID-19).
• Overall, 76 (57%) of the patients who tested positive for coronavirus required hospitalization with a median length of hospitalization of 10 days.
• There were 30 (23%) patient deaths, with a median survival of 16 days after diagnosis
• Patients who died were older (68 vs. 64 years of age) and had more chronic illnesses, including diabetes (93%), heart failure (33%), and ischemic heart disease (57%).
• There appeared to be no differences in mortality by race/ethnicity and socioeconomic status.

Rate of COVID-19 positive cases rises

The rate of COVID-19 positive results rose among those on dialysis after the study period, while it remained steady among Kaiser Permanente Southern California members. During the study period, 1.7% of those on dialysis tested positive. However, between July 1 and November 15 it climbed to 5.3%, while the positive rate remained steady for those tested among general membership at about 2.5%.

One of the reasons that patients on dialysis may be contracting the disease at a higher rate is because they must leave their homes regularly to go to dialysis appointments.

“These patients don’t have the option of sheltering in place,” Dr. Sim said. “They put themselves at risk of exposure at least 3 times a week to get their life-sustaining therapy, and since they are immunocompromised, they have a greater risk of getting infected.”

Study highlights the vulnerability of dialysis patients

“This study raises awareness and stresses the deadly consequences for people on dialysis,” Dr. Sim said. “It also makes clear the need for these patients to be even more careful about taking COVID precautions. These messages are important for them, their caregivers, and their physicians.”

As the researchers get more cases, they may look at specific aspects, including whether end-stage kidney disease patients are less or more susceptible to COVID-19’s cytokine storm and whether the renin angiotensin system-inhibiting medications ACEI and ARB may be protective for them against COVID-19 hospitalization and death.

Team effort was key to quick study turnaround

Dr. Sim noted that this was the fastest he’s ever completed a study, and it couldn’t have been done without the help of his co-authors.

“They dropped everything they were doing and helped us pull this through,” he said. “We were able to crank out this project in a few weeks’ time because we all understood the importance of what we were doing, and because we worked together as a team.”

Other authors on this study: Cheng-Wei Huang, MD, Kaiser Permanente Los Angeles Medical Center; David C. Selevan, PMP, Kaiser Permanente Southern California Renal Business Group, Pasadena, Calif.; Joanie Chung, MS, Kaiser Permanente Southern California Department of Research & Evaluation, Pasadena, Calif.; Mark P. Rutkowski, Kaiser Permanente Southern California Renal Business Group, Pasadena, Calif.; Hui Zhou, PhD, Kaiser Permanente Southern California Department of Research & Evaluation, Pasadena, Calif.

Image: Dr. Sim taken pre-pandemic