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Patient Evidence Summary
Doctor, I heard that COVID-19 causes blood clots. I have a history of DVT or PE, what do I need to know to protect myself?
For people who have a history of DVT or PE and are diagnosed with COVID-19:
If you are on anticoagulants, continue to take them as instructed.
If you are not on anticoagulants and are diagnosed with COVID-19 infection, ask your doctor if you might benefit from taking anticoagulants temporarily.
Stay as active as you can around your home.
Study highlights
There is a lot we don't know about COVID-19. If you are asked to participate in a study, please consider doing so - we need more answers!
Review the patient-friendly document “Thrombosis and COVID-19 Information for Patients and Families” by Thrombosis Canada for additional helpful information
Watch for signs of DVT and PE
Understanding the problem
The COVID-19 virus has caused millions of people around the world to become sick. One of the complications of infection with COVID-19 for some people has been the development of blood clots.
Infection with viruses and bacteria causes inflammation which helps the body to fight against the infection. However, inflammation can also trigger the blood clotting system. This seems to be the case for COVID-19 because high rates of DVT and PE have been reported in people who required admission to hospital for COVID-19 infection.
There are two types of blood clots that occur in people with COVID-19:
1) In people who have life-threatening illness due to COVID-19 infection in their lungs, inflammation causes damage to the lining of the blood vessels within the lungs. This inflammation causes blood clots to form at the damaged sites and, along with fluid in the lungs, make it hard for the body to get enough oxygen. These clots are small but are very common in this group of extremely ill people.
2) Less commonly, people who are ill with COVID-19 can also develop larger blood clots that form in the legs (deep vein thrombosis; DVT) some of which may then travel to the lungs (pulmonary embolism; PE).
There is a lot we do not understand about the effects of COVID-19 which is why high-quality research is so important. Based on what was known at the time of writing, the researchers in this review provide suggestions to doctors on how to prevent and treat blood clots in people who are infected with COVID-19.
A summary of all studies published up to April 2020.
Who? People diagnosed with COVID-19 infection.
What? Studies that collected data on people with COVID-19 infection who were diagnosed with PE or DVT.
People with COVID-19 infection | Results | Number of studies and quality of evidence | Suggestions by Bikdeli and colleagues |
|---|---|---|---|
Required admission to hospital | 25-40% were found to have DVT or PE (most were in the ICU because they were extremely ill due to COVID) | 2 studies; total of 279 people Very-low to low quality evidence | Low-dose anticoagulants should be given to all admitted COVID patients who are not bleeding |
Well enough to stay home and have a history of DVT or PE | No reports to date | No study data available | Stay as active as possible Continue to take anticoagulants if already on them Discuss with your doctor if you should start or restart anticoagulants if you are not currently taking any |
| Well enough to stay home and do NOT have a history DVT or PE | No reports to date | No study data available | Stay as active as possible |
This Evidence Summary is based on the following article:
Bikdeli B, Madhavan MV, Jimenez D, et al. COVID-19 and Thrombotic or Thromboembolic Disease: Implications for Prevention, Antithrombotic Therapy, and Follow-Up: JACC State-of-the-Art Review. J Am Coll Cardiol. 2020 Jun 16;75(23):2950-2973. doi: 10.1016/j.jacc.2020.04.031. Epub 2020 Apr 17. PubMed
Lori-Ann Linkins, MD, MSc (Clin Epi), FRCPC
Dr. Linkins is an Associate Professor of Medicine (thrombosis) at McMaster University in Hamilton, Canada. She holds a Masters Degree in Health Research Methodology and is a Deputy Editor with the Health Information Research Unit, McMaster. She is Co-Editor of the ACP Journal Club and Co-lead on the CanVECTOR Knowledge Translation Platform.
Published: Thursday, July 30, 2020
Please note that the information contained herein is not to be interpreted as an alternative to medical advice from a professional healthcare provider. If you have any questions about any medical matter, you should consult your professional healthcare providers, and should never delay seeking medical advice, disregard medical advice or discontinue medication based on information provided here.
, McMaster University