# Thrombotic Events and Stroke in the Year After COVID-19 or Other Acute Respiratory Infection

## TL;DR

This study finds that people who had COVID-19 face a higher risk of blood clots and stroke in the year after infection compared to those with other respiratory illnesses.

## Contribution

The study is the first to compare thrombotic risks beyond 30 days after COVID-19 versus other acute respiratory infections.

## Key findings

- Patients with COVID-19 had a 63% higher risk of thrombotic events in the year after infection compared to those with other ARIs.
- Nonhospitalized COVID-19 patients had a 73% increased risk of thrombotic events compared to nonhospitalized ARI patients.
- The increased risk highlights the need for stroke awareness among patients and healthcare providers following COVID-19.

## Abstract

Previous studies have documented an increased risk for thrombotic events 30 days after COVID-19 infection, but less is known about this risk beyond 30 days or compared with risk after other infectious acute respiratory illnesses (ARIs). By using PCORnet data from April 1, 2022–April 30, 2023, we compared the incidences of thrombotic events in the year after COVID-19 illness with other ARI diagnoses in hospitalized and nonhospitalized patients. Overall, the risk for any thrombotic event was higher among patients with COVID-19 compared with patients with other ARIs (incidence ratio 1.63; p<0.05). Nonhospitalized patients with COVID-19 had a 73% increased risk for a thrombotic event in the year after acute illness compared with nonhospitalized patients with ARI (p<0.05). The increased risk for thrombotic events in the year after COVID-19 emphasizes the need for stroke awareness for patients and healthcare professionals.