Patients undergoing long-term dialysis were more than five times likelier to be infected with COVID-19 and nearly four times as likely to die than the general population, suggesting that they should be prioritized for vaccination, according to a Canadian study published today in CMAJ.
In the study, researchers from the Ontario Renal Network at Western University in London, Ontario, compared disease characteristics and death rate between long-term dialysis patients with and without COVID-19 infection using linked datasets from Mar 12 to Aug 20, 2020.
Of 12,501 dialysis patients, 187 (1.5%) were diagnosed as having COVID-19; 62.6% of them were hospitalized, 19.8% required intensive care, 15% received mechanical ventilation, and 28.3% died. In contrast, 27% of uninfected dialysis patients were hospitalized, and 5.8% died. Age was the only predictor of death.
Risk factors for infection included receiving dialysis in a center versus at home (odds ratio [OR], 2.54), living in a long-term care facility (OR, 7.67) or in the greater Toronto area (OR, 3.27), Indian subcontinent race (OR, 1.70), other non-white ethnicity (OR, 2.03), and low income (OR, 1.82). More than 25% of infections occurred in nursing home residents, and non-white dialysis patients bore 67% of the infection burden, despite representing only 41% of all provincial dialysis patients. Age, diabetes, or other underlying conditions did not predict infection.
Home versus in-center dialysis
The number of new COVID-19 infections among dialysis patients rose from Mar 12 to Apr 23, when they peaked at 33 per week, and then steadily declined. The 12-week average on Aug 20 was a little over one new case a week.
Nearly 80% of coronavirus infections in dialysis patients occurred in 8 of the 27 provincial dialysis centers, and there were at least three cases diagnosed in the same unit within a week at six facilities. Seven clinics reported no infections. Median age of dialysis patients with COVID-19 was 68 years, and 61.5% were men.
Of the coronavirus-infected dialysis patients, 88.8% were undergoing dialysis at a clinic versus at a home, compared with 74.4% in those without COVID-19 (standardized difference, 40%). Of the entire in-center dialysis population, 1.8% had COVID-19, versus 0.3% of home hemodialysis patients and 0.8% of home peritoneal dialysis recipients.
Over the course of the study, dialysis clinics received more personal protective equipment, increasingly required universal face coverings, and provided easier access to COVID-19 testing before patients entered the clinic. However, it was common for dialysis staff to work in more than one clinic throughout that time.
The authors noted that dialysis patients are likely to be older, have underlying conditions and different degrees of immunosuppression, and live in long-term care facilities, all of which increase their risk of COVID-19 infection and related complications. And the 74% who receive dialysis in hospital outpatient centers usually undergo three treatments each week, increasing their exposure to the virus, compared with the 26% who do home dialysis and are able to isolate.
“Therefore, as the COVID-19 pandemic proceeds, focused efforts should be made to protect this population from infection including prioritizing patients on long-term dialysis and the staff treating them for SARS-CoV-2 vaccination,” the authors wrote.
In addition to standard COVID-19 prevention precautions and vaccination, the authors called for educating dialysis patients about their risk of infection and death, giving paid sick leave to patients required to work in high-risk occupations, lowering the symptom threshold for testing this group, increasing the distance between clinic dialysis treatment stations, taking universal droplet precautions, and regularly testing people at high risk of infection, such as those living in nursing homes.
Study coauthor Rebecca Cooper said in a CMAJ podcast that the study shows that dialysis patients well enough to perform dialysis at home should be encouraged to do so.
“I think this could actually prove to be a positive outcome, in a way, since home dialysis offers patients a higher quality of life and equivalent outcomes, not to mention that it’s more cost-effective for the system, and in the context of COVID, we now know that home dialysis is safer, too,” she said.