Abstract Number: PB0213
Meeting: ISTH 2021 Congress
Theme: COVID and Coagulation » COVID and Coagulation, Clinical
Background: Excess mortality has been observed in the general population during the COVID-19 pandemic, but it is unknown whether preexisting anticoagulant treatment affects survival, given that COVID-19 associated hypercoagulability adversely impacts prognosis.
Aims: To investigate whether preexisting vitamin K antagonist (VKA) treatment is associated with lower excess mortality during the first wave of the COVID-19 pandemic in the Netherlands when compared with excess mortality in the general population.
Methods: All atrial fibrillation (AF) patients (≥60 years) receiving long-term VKA therapy before week 11, 2020 were included from three Dutch anticoagulation clinics. The corresponding patient population managed by the same clinics in 2019 (i.e., all AF patients (≥60 years) receiving long-term VKA therapy before week 11, 2019) was enrolled as a control cohort. Difference in survival within 9 weeks (i.e., week 11 to 19) between the two cohorts was evaluated by Cox regression analysis. This was compared with the difference in survival during the same time frame of the general elderly (≥60 years) Dutch populations in 2020 versus 2019.
Results: The study included 22,730 VKA users for the cohort in 2019 and 19,476 for the cohort in 2020, of which baseline characteristics were comparable. The cumulative incidences for all-cause mortality of the VKA users and the general population are presented in Table 1.
| Vitamin K antagonist users | General population | |||||||
| Cohort 2019 (N=22,730) |
Cohort 2020 (N=19,476) |
Cohort 2019 (N=5,211,956) |
Cohort 2020 (N=5,343,720) |
|||||
| Follow up time (days) | No. death | Cumulative incidence (%) (95% Cl) |
No. death | Cumulative incidence (%) (95% Cl) |
No. death | Cumulative incidence (%) (95% Cl) |
No. death | Cumulative incidence (%) (95% Cl) |
| 0-10 | 22 | 0.10 (0.06-0.14) | 19 | 0.10 (0.05-0.14) | 4,591 | 0.09 (0.09-0.09) | 4,781 | 0.09 (0.09-0.09) |
| 0-20 | 74 | 0.33 (0.25-0.40) | 67 | 0.34 (0.26-0.43) | 8,919 | 0.17 (0.17-0.17) | 10,868 | 0.20 (0.20-0.21) |
| 0-30 | 129 | 0.57 (0.47-0.67) | 132 | 0.68 (0.56-0.79) | 13,084 | 0.25 (0.25-0.26) | 18,245 | 0.34 (0.34-0.35) |
| 0-40 | 192 | 0.84 (0.73-0.96) | 209 | 1.07 (0.93-1.22) | 17,351 | 0.33 (0.33-0.34) | 24,794 | 0.46 (0.46-0.47) |
| 0-50 | 263 | 1.16 (1.02-1.30) | 268 | 1.38 (1.21-1.54) | 21,533 | 0.41 (0.41-0.42) | 30,273 | 0.57 (0.56-0.57) |
| 0-60 | 308 | 1.36 (1.20-1.51) | 312 | 1.60 (1.43-1.78) | 25,592 | 0.49 (0.49-0.50) | 34,827 | 0.65 (0.64-0.66) |
| 0-62 | 319 | 1.40 (1.25-1.56) | 321 | 1.65 (1.47-1.83) | 26,350 | 0.51 (0.50-0.51) | 35,609 | 0.67 (0.66-0.67) |
Cumulative incidences of all-cause mortality during the study period of the cohorts of Vitamin K antagonist users and general population, all aged ≥60 years, estimated by Kaplan-Meier method
After adjusting for age, sex, and clinics, all-cause mortality risk of the VKA users in 2020 was 16% higher than in 2019 (95% CI -1% to 35%). During the same time frame, the contemporaneous general elderly Dutch population saw a 30% increase in all-cause mortality risk (95% CI 28%-32%, adjusting for age, sex) (Table 2).
| Vitamin K antagonist users | General population | |||
| Cohort 2019 | Cohort 2020 | Cohort 2019 | Cohort 2020 | |
| Incidence rate (95% Cl), per 100 person-years | 8.32 (7.43-9.28) | 9.78 (8.74-10.91) | 2.99 (2.95-3.02) | 3.94 (3.90-3.98) |
| Incidence rate difference (95% CI), per 100 person-years, Crude | 0 (Reference) | 1.46 (0.06-2.87) | 0 (Reference) | 0.95 (0.90-1.01) |
| Incidence rate difference (95% CI), per 100 person-years, Age-adjusted | 0 (Reference) | 1.46 (0.06-2.87) | 0 (Reference) | 2.25 (2.10-2.39) |
| Incidence rate ratio, Crude | 1 (Reference) | 1.18 (1.01-1.37) | 1 (Reference) | 1.32 (1.30-1.34) |
| Incidence rate ratio, Age-adjusted | 1 (Reference) | 1.18 (1.01-1.37) | 1 (Reference) | 1.33 (1.31-1.36) |
| Hazard ratio, Crude | 1 (Reference) | 1.18 (1.01-1.37) | 1 (Reference) | 1.32 (1.30-1.34) |
| Hazard ratio, Model 1 (adjusting for age, sex) | 1 (Reference) | 1.16 (0.99-1.35) | 1 (Reference) | 1.30 (1.28-1.32) |
| Hazard ratio, Model 2 (Model 1 + anticoagulation clinics) | 1 (Reference) | 1.16 (0.99-1.35) | – | – |
Incidence rates and hazard ratios of all-cause mortality during the study period of the cohorts of Vitamin K antagonist users and general population, all aged ≥60 years
Conclusions: Elderly patients with AF receiving long-term VKA therapy in the Netherlands appeared to have a lower excess mortality during the first wave of the COVID-19 pandemic when compared to the general elderly population.
To cite this abstract in AMA style:
Chen Q, Toorop MMA, Visser C, van der Meer FJM, Nierman MC, Goede L, ten Cate H, Kruip MJHA, Lijfering WM, Cannegieter SC, Dutch COVID & Thrombosis Coalition . Excess Mortality in a Population of Vitamin K Antagonist Users during the First Wave of the COVID-19 Pandemic in the Netherlands Compared with Excess Mortality in the General Dutch Population [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/excess-mortality-in-a-population-of-vitamin-k-antagonist-users-during-the-first-wave-of-the-covid-19-pandemic-in-the-netherlands-compared-with-excess-mortality-in-the-general-dutch-population/. Accessed November 29, 2023.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/excess-mortality-in-a-population-of-vitamin-k-antagonist-users-during-the-first-wave-of-the-covid-19-pandemic-in-the-netherlands-compared-with-excess-mortality-in-the-general-dutch-population/