Risk of Thrombosis Following the First Dose of ChAdOx1 nCoV-19 Vaccine in Patients Undergoing Maintenance Hemodialysis: A Self-Controlled Case Series Study

Abstract

Shih-Chieh Shao,1,2 Tzu-Chi Liao,1 Kai-Cheng Chang,1,3 Hui-Yu Chen,3 Swu-Jane Lin,4 Cheng-Yang Hsieh,1,5 Edward Chia-Cheng Lai1 1School of Pharmacy, Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan; 2Department of Pharmacy, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan; 3Department of Pharmacy, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan; 4Department of Pharmacy Systems, Outcomes and Policy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA; 5Department of Neurology, Tainan Sin Lau Hospital, Tainan, TaiwanCorrespondence: Cheng-Yang Hsieh, Department of Neurology, Tainan Sin Lau Hospital, 57, Section 1, Dongmen Road, East District, Tainan, 70142, Taiwan, Tel [phone], Ext 4180, Fax [phone], Email [email protected]: The ChAdOx1 nCoV-19 vaccine is associated with vaccine-induced thrombosis and thrombocytopenia (VITT). Patients with end-stage renal disease (ESRD) under hemodialysis are at elevated risk of heparin-induced thrombocytopenia, which shares similar mechanisms with VITT. We aimed to examine the risk of VITT after the first dose of ChAdOx1 nCoV-19 vaccine using a self-controlled case series analysis (SCCS) in the hemodialyzed ESRD population.Methods: Drawing from the largest multi-center electronic medical records database in Taiwan, we identified adult patients, with or without hemodialysis, between 1st December, 2020, and 31st December, 2021, who received a first dose of ChAdOx1 nCoV-19 vaccine and had an outcome of thrombocytopenia, venous thrombosis, or arterial thrombosis. We calculated the incident rate ratios (IRRs) of outcomes in different periods at risk, compared to periods not at risk.Results: We identified 59 hemodialysis patients and 41 non-dialysis patients with an outcome. The SCCS analyses showed, for the hemodialysis group, a significantly increased risk of outcomes during the period 31 to 60 days post-exposure to ChAdOx1 nCoV-19 vaccine (IRR: 2.823; 95% CI: 1.423– 5.600). However, in non-dialysis patients there was no increase in risks during any of the post-exposure risk periods.Conclusion: For ESRD patients under hemodialysis, the first dose of ChAdOx1 nCoV-19 vaccine was associated with a 2.8-fold increase in risk of thrombosis.Keywords: thrombosis, thrombocytopenia, ChAdOx1 nCoV-19 vaccine, hemodialysis, end-stage renal disease

Keywords

• thrombosis
• thrombocytopenia
• chadox1 ncov-19 vaccine
• hemodialysis
• end-stage renal disease