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BMC Nephrology

Transmission of SARS-CoV-2 considering shared chairs in outpatient dialysis: a real-world case-control study.

Ravi Thadhani, Joanna L. Willetts, Catherine Wang, John W. Larkin, Hanjie Zhang, Lemuel Rivera Fuentes, Len Usvyat, Kathleen Belmonte, Yuedong Wang, Dr. Robert Kossman, Jeffrey Hymes, Peter Kotanko, Dr. Frank Maddux

Background: SARS-CoV-2 can remain transiently viable on surfaces. We examined if use of shared chairs in outpatient hemodialysis associates with a risk for indirect patient-to-patient transmission of SARS-CoV-2.

Methods: We used data from adults treated at 2,600 hemodialysis facilities in United States between February 1st and June 8th, 2020. We performed a retrospective case-control study matching each SARS-CoV-2 positive patient (case) to a non-SARS-CoV-2 patient (control) treated in the same dialysis shift. Cases and controls were matched on age, sex, race, facility, shift date, and treatment count. For each case-control pair, we traced backward 14 days to assess possible prior exposure from a 'shedding' SARS-CoV-2 positive patient who sat in the same chair immediately before the case or control. Conditional logistic regression models tested whether chair exposure after a shedding SARS-CoV-2 positive patient conferred a higher risk of SARS-CoV-2 infection to the immediate subsequent patient.

Results: Among 170,234 hemodialysis patients, 4,782 (2.8 %) tested positive for SARS-CoV-2 (mean age 64 years, 44 % female). Most facilities (68.5 %) had 0 to 1 positive SARS-CoV-2 patient. We matched 2,379 SARS-CoV-2 positive cases to 2,379 non-SARS-CoV-2 controls; 1.30 % (95 %CI 0.90 %, 1.87 %) of cases and 1.39 % (95 %CI 0.97 %, 1.97 %) of controls were exposed to a chair previously sat in by a shedding SARS-CoV-2 patient. Transmission risk among cases was not significantly different from controls (OR = 0.94; 95 %CI 0.57 to 1.54; p = 0.80). Results remained consistent in adjusted and sensitivity analyses.

Conclusions: The risk of indirect patient-to-patient transmission of SARS-CoV-2 infection from dialysis chairs appears to be low.

About the Contributors

Hanjie Zhang, MSc, PhD

Supervisor of Biostatistics and Applied Artificial Intelligence /Machine Learning

Hanjie joined the RRI in 2014. She received a Master’s Degree in statistics from Columbia University, New York and a PhD in Medical Science from the University of Maastricht, The Netherlands. Hanjie has been involved in the design of several large cluster-randomized clinical trials and complex statistical analyses in collaboration with the Medical Office, FMCNA...

Lemuel Rivera Fuentes, MD

Supervisor of Clinical Research

Lemuel joined RRI in February 2018. He obtained his MD from Universidad La Salle in Mexico City, where he was awarded the Excellency in Medical Academic Achievement Grant by the Pfizer Scientific Institute. He then proceeded to complete his internal medicine residency at the ABC Medical Center, and a postgraduate fellowship in nephrology at INCMNSZ in Mexico City. His interest in transplantation led him to attain a high-specialization postgraduate program in transplant nephrology sponsored by the National Autonomous University of Mexico.

Dr. Peter Kotanko, MD

RRI Research Director

SVP, Corporate Research & Development

Peter Kotanko, MD, is Research Director at the Renal Research Institute (RRI), New York. Prior to joining RRI, from 1997 to 2007 he served as vice chair of a department of internal medicine at an academic teaching hospital in Graz, Austria. Prior to moving to Graz in 1989, he worked from 1982 to 1989 in the Department of Physiology and the University Clinic of Internal Medicine in Innsbruck, Austria. From 1995 to 1996 he trained in nephrology at the Hammersmith Hospital, London, United Kingdom.