Thursday, April 07, 2022

BMJ: Elevated Risk Of Blood Clots Up To 6 Months After COVID Infection

 

https://twitter.com/KartikSehgal_MD/status/1281695760879202304


#16,677

Although originally billed as primarily producing a SARS-like viral pneumonia, COVID-19 has repeatedly shown that pneumonia is only part of its extensive repertoire (see Nature Med. Review: Extrapulmonary manifestations of COVID-19)

 A few, of many, non-pulmonary impacts of SARS-CoV-2 infection include:

Nat. Comms: Neuropathology and Virus in Brain of SARS-CoV-2 Infected Non-human Primates

Diabetologia: Incidence of Newly Diagnosed Diabetes After Covid-19

American Heart Assoc: Stroke Risk Among Older Adults Highest in First 3 Days After COVID-19 Diagnosi

Nature: Long-term Cardiovascular Outcomes of COVID-19

Often, thrombotic events (blood clots, strokes, etc.) have been associated with COVID-19 infection, including:

The evidence has been so strong that nearly a year ago researchers at the FIOCRUZ Institute made the case that COVID-19 Should Be Considered A `Thrombotic Viral Fever'

Today we've got a Swedish study, published in the BMJ, that finds a highly elevated risk of blood clots up to 6 months following COVID infection, a risk that extends to even those who experienced mild illness. 

This is a long, and detailed study, so I've just reproduced the abstract, a few excerpts, and the link to a press release.  Many will undoubtedly want to take the time to read the full report. 

But in short, the authors found: a five-fold increase in the risk of DVT (deep vein thrombosis), a 33-fold increase in risk of a PE (pulmonary embolism), and an almost doubled risk of bleeding in the first month following infection.   

BMJ 2022; 377 doi: https://doi.org/10.1136/bmj-2021-069590 (Published 06 April 2022)
Cite this as: BMJ 2022;377:e069590

Abstract


Objective 

To quantify the risk of deep vein thrombosis, pulmonary embolism, and bleeding after covid-19.

Design 

Self-controlled case series and matched cohort study.

Setting 

National registries in Sweden.

Participants 

1 057 174 people who tested positive for SARS-CoV-2 between 1 February 2020 and 25 May 2021 in Sweden, matched on age, sex, and county of residence to 4 076 342 control participants.

Main outcomes measures 

Self-controlled case series and conditional Poisson regression were used to determine the incidence rate ratio and risk ratio with corresponding 95% confidence intervals for a first deep vein thrombosis, pulmonary embolism, or bleeding event. In the self-controlled case series, the incidence rate ratios for first time outcomes after covid-19 were determined using set time intervals and the spline model. The risk ratios for first time and all events were determined during days 1-30 after covid-19 or index date using the matched cohort study, and adjusting for potential confounders (comorbidities, cancer, surgery, long term anticoagulation treatment, previous venous thromboembolism, or previous bleeding event).

Results 

Compared with the control period, incidence rate ratios were significantly increased 70 days after covid-19 for deep vein thrombosis, 110 days for pulmonary embolism, and 60 days for bleeding. In particular, incidence rate ratios for a first pulmonary embolism were 36.17 (95% confidence interval 31.55 to 41.47) during the first week after covid-19 and 46.40 (40.61 to 53.02) during the second week.

Incidence rate ratios during days 1-30 after covid-19 were 5.90 (5.12 to 6.80) for deep vein thrombosis, 31.59 (27.99 to 35.63) for pulmonary embolism, and 2.48 (2.30 to 2.68) for bleeding. Similarly, the risk ratios during days 1-30 after covid-19 were 4.98 (4.96 to 5.01) for deep vein thrombosis, 33.05 (32.8 to 33.3) for pulmonary embolism, and 1.88 (1.71 to 2.07) for bleeding, after adjusting for the effect of potential confounders.
The rate ratios were highest in patients with critical covid-19 and highest during the first pandemic wave in Sweden compared with the second and third waves. In the same period, the absolute risk among patients with covid-19 was 0.039% (401 events) for deep vein thrombosis, 0.17% (1761 events) for pulmonary embolism, and 0.101% (1002 events) for bleeding.

Conclusions 

The findings of this study suggest that covid-19 is a risk factor for deep vein thrombosis, pulmonary embolism, and bleeding. These results could impact recommendations on diagnostic and prophylactic strategies against venous thromboembolism after covid-19.
          (SNIP)


Conclusions and policy implications

The present findings have major policy implications. Our findings arguably support thromboprophylaxis to avoid thrombotic events, especially for high risk patients,23 and strengthens the importance of vaccination against covid-19. It remains to be established whether SARS-CoV-2 infection increases the risk of venous thromboembolism or bleeding more than it does for respiratory infections, such as influenza, but also whether the period of thromboprophylaxis after covid-19 should be extended. Future clinical research would be beneficial in this context.


For a plain-language summary of this report, you may wish to refer to the press release (below).
NEWS RELEASE 

BMJ

Despite the recent arrival of a `milder' Omicron variant, the more we learn about the post-acute phase of COVID, the more apparent it becomes that you really, really, don't want to get infected if you can help it (see Preprint: Results of the Danish AFTER-COVID Survey).