# Trends in Antithrombotic Therapy Initiation Among Patients With Stroke Pre‐ and Post–COVID‐19 in Sweden—An Interrupted Time Series Study

## TL;DR

This study examines how the COVID-19 pandemic affected the use of antithrombotic drugs in stroke patients in Sweden, finding no overall change but some short-term shifts in specific medications.

## Contribution

The study provides new insights into how the pandemic affected antithrombotic therapy initiation in stroke patients using nationwide data from Sweden.

## Key findings

- The overall initiation of antithrombotic drugs remained stable during the pandemic.
- Antiplatelet use increased temporarily at the start of the pandemic.
- Long-term decreases were observed in the use of warfarin and dabigatran.

## Abstract

Antithrombotic therapy constitutes a critical part of stroke management, and its utilization serves as an important indicator in the assessment of stroke care. However, knowledge on how the pandemic influenced the antithrombotic utilization after stroke remains limited.

This study aims to investigate the impact of the COVID‐19 pandemic on the initiation of antithrombotic agents after stroke in Sweden.

Using nationwide linked Swedish health registers, we conducted an interrupted time series analysis (ITSA) using generalized linear model (binomial distribution, logit link). We estimated monthly trends in the initiation of antithrombotic drugs among new stroke patients between January 2019 and April 2024, with the pandemic intervention point set in March 2020.

The monthly number of stroke cases declined significantly by 107 cases per month. No significant changes were observed in the total antithrombotic initiation. Antiplatelets showed a significant pre‐pandemic increasing trend (OR = 1.011 per month, 95% CI: 1.003 to 1.020), an immediate level increase at onset (OR = 1.150, 95% CI: 1.067 to 1.259) and a post‐intervention decline (OR = 0.991 per month, 95% CI: 0.981 to 0.998). Factor Xa inhibitors use increased post‐intervention (OR = 1.004, 95% CI: 1.002 to 1.006), while warfarin (OR = 0.990, 95% CI: 0.981 to 0.999) and dabigatran (OR = 0.991, 95% CI: 0.986 to 0.997) decreased.

The COVID‐19 pandemic had no impact on the overall use of antithrombotic agents. However, a short‐term increase in antiplatelet initiation and long‐term changes in warfarin, dabigatran, and factor Xa initiations were observed after the COVID‐19 outbreak.

The thrombotic risk induced by COVID‐19 is studied worldwide. This study examined the pandemic’s effect on the initiation of antithrombotic medicines among patients with stroke in Sweden. Using nationwide Swedish health registers from 2019 to 2024, we found that stroke frequency was not influenced by the pandemic as hypothesized by other studies, and the overall use of antithrombotic medicines remained stable over time. However, temporary changes were observed in some of the medication classes in the early months of the pandemic.