PB0469 - Frequency of INR monitoring and their impact on INR control during the COVID-19 pandemic

Sunday, June 25, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Tessa Elling, MD

PhD student
Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
Groningen, Groningen, Netherlands

Co-Author(s)

NV

Nic Veeger

PhD, Clinical epidemiologist
Department of Epidemiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
Groningen, Groningen, Netherlands
DH

Derk Hardeman

Md PhD, Clinical chemist
Thrombosis Service Zuid-West Friesland, Sneek, The Netherlands
Sneek, Friesland, Netherlands
AK

Adrian Kruit

MD PhD, clinical chemist
Thrombosis Service v.h. Med. Diagn. Centrum, Drachten, The Netherlands
Drachten, Friesland, Netherlands
JP

Jos G. J. Pouwels

MD, clinical chemist
Thrombosis Service Treant Zorggroep, Emmen, the Netherlands
Emmen, Drenthe, Netherlands
VT

Vladimir Y. I. G. Tichelaar

MD PhD, Physician researcher
Department of Hematology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
Groningen, Groningen, Netherlands
Karina Meijer, MD, PhD (she/her/hers)

MD, PhD, Internist-haematologist, Professor
Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
Groningen, Groningen, Netherlands

Background: International normalized ratio (INR) monitoring is needed to maintain optimal anticoagulation intensity in patients treated with a vitamin K antagonist (VKA). The COVID-19 pandemic may have reduced the INR testing frequency. Whether the COVID-19 pandemic had an impact on INR monitoring as well as on INR control is however not clear.

Aims: To evaluate whether there is a difference in INR testing frequency and INR control between the COVID-19 pandemic and the pre-pandemic period.

Methods: All patients managed by one of the four Thrombosis services located in the northern region of the Netherlands were included using a dynamic cohort design. The study period (i.e. December 23, 2018 to December 23, 2020) was divided into eight quartiles, and patient inclusion was evaluated at the start of each quartile. The INR return interval and the time in therapeutic range (TTR) were calculated during each quartile and compared between the pandemic and pre-pandemic period. Comparison are made to the same period of the previous year.

Results: In each quartile ~20.000 patients were included; 55% were male and mean age was 80 years (table 1). In each quartile, the majority of the patients had a TTR above 70%. INR return interval increased during the COVID-19 pandemic, especially at the start of the pandemic (28.0 [IQR 19.3-38.5] vs. 25.1 [IQR 16.3-32.7] days, p-value < 0.01). There was no decrease in TTR, even a small numerical increase in TTR was seen (72.8 [IQR 51.1-100.0] vs. 75.0 [IQR 54.4-100.0], p-value < 0.01). (figure 1).

Conclusion(s): Compared to the pre-pandemic period, the frequency of INR monitoring decreased during the COVID-19 pandemic. However, the increase in INR return interval did not affect TTR. Therefore, we conclude that VKA therapy is not immediately compromised when circumstance mandate a reduced frequency of INR monitoring.