Initiation of Anticoagulants During the COVID-19 Pandemic in Sweden: An Interrupted Time Series Analysis

The COVID-19 pandemic may have increased anticoagulant initiation due to the thrombogenic nature of the disease or decreased due to the societal impact of the pandemic. We aimed to study the effect of the COVID-19 pandemic on initiation of anticoagulants in Sweden. We conducted a single interrupted time series analysis on the monthly cumulative incidence of nonvitamin K antagonist oral anticoagulants (NOAC), warfarin, or heparins, before and after March 2020, using SCIFI-PEARL dataset. For anticoagulants in total, there were no statistically significant changes or differences in the trends of initiation after the start of the pandemic. There was a slight numerical decrease in initiation after the onset of the pandemic, particularly for NOACs. For individuals aged ≥ 65 years, however, the immediate decrease in initiation was considerable for NOACs. The prepandemic declining trend of warfarin initiation seemed to attenuate, that is, became less negative, after March 2020. We did not find any profound effect of the COVID-19 pandemic on the initiation of anticoagulants in total. However, among individuals aged ≥ 65 years, a notable immediate decrease in initiation of NOACs was observed. Furthermore, the onset of the pandemic may have attenuated the downward temporal trend in initiation of warfarin use.