UK Study Finds That Even Mild Cases Of COVID-19 Have Higher Risk Of Venous Thromboembolism Or Clots In The Veins With Potential Fatal Outcomes!
: A new study by researchers from Queen Mary University of London – United Kingdom has found that even those who simply contracted mild SARS-CoV-2 infections had a higher risk of developing venous thromboembolism (VTE).
Venous thromboembolism (VTE), a term referring to blood clots in the veins, is an underdiagnosed and serious, yet preventable medical condition that can cause disability and death.
The study’s objective was to examine association of COVID-19 with incident cardiovascular events in 17 871 UK Biobank cases between March 2020 and 2021.
For the study, all COVID-19 cases were defined utilizing health record linkage. Each case was propensity score-matched to two uninfected controls on age, sex, deprivation, body mass index, ethnicity, diabetes, prevalent ischaemic heart disease (IHD), smoking, hypertension and high cholesterol. We included the following incident outcomes: myocardial infarction, stroke, heart failure, atrial fibrillation, venous thromboembolism (VTE), pericarditis, all-cause death, cardiovascular death, IHD death. Cox proportional hazards regression was used to estimate associations of COVID-19 with each outcome over an average of 141 days (range 32–395) of prospective follow-up.
The study findings showed that in non-hospitalized cases (n=14 304) had increased risk of incident VTE (HR 2.74 (95% CI 1.38 to 5.45), p=0.004) and death (HR 10.23 (95% CI 7.63 to 13.70), p<0.0001).
Individuals with primary COVID-19 hospitalization (n=2701) had increased risk of all outcomes considered. The largest effect sizes were with VTE (HR 27.6 (95% CI 14.5 to 52.3); p<0.0001), heart failure (HR 21.6 (95% CI 10.9 to 42.9); p<0.0001) and stroke (HR 17.5 (95% CI 5.26 to 57.9); p<0.0001).
Those hospitalized with COVID-19 as a secondary diagnosis (n=866) had similarly increased cardiovascular risk.
Interestingly, the associated risks were greatest in the first 30 days after infection but remained higher than controls even after this period.
The study team concluded that individuals hospitalized with COVID-19 have increased risk of incident cardiovascular events across a range of disease and mortality outcomes. The risk of most events is highest in the early post-infection period.
Importantly, the study findings also showed that individuals not requiring hospitalization have increased risk of VTE, but not of other cardiovascular-specific outcomes.
The study finings were published in the peer reviewed journal: Heart.
Numerous past studies had already reported a predominant pattern of COVID-19 sequelae involving debilitating fatigue and persistent cardiac, neurological, digestive, renal, pulmonary, and muscular problems. This phenomenon is commonly referred to as “long COVID” and often persists for several months following recovery from severe COVID-19.
Although numerous research has examined the cardiovascular outcomes after recovery from COVID-19, none have examined the differential risks based on the degree of COVID-19 severity.&
Also, it should be noted that many of these past studies were retrospective studies.
Hence, examining whether the increased risk of cardiovascular complications associated with COVID-19 depends on the severity of SARS-CoV-2 infections is essential.
The study team from Queen Mary University of London used data from 17,871 United Kingdom Biobank participants between the ages of 40 and 69 years to investigate associations between COVID-19 and cardiovascular outcomes and mortality sequelae. A matched uninfected group of controls was also included in the study. A baseline assessment was performed for all participants.
All COVID-19 incidence was defined based on primary care disease codes, Hospital Episode Statistics records, or a positive antigen or polymerase chain reaction (PCR) test. Propensity score variables such as age, body mass index, sex, ethnicity, Townsend deprivation index, smoking behavior, and comorbidities such as diabetes, ischemic heart disease, hypertension, and high cholesterol were included in the analysis.
In the study, all cardiovascular disease outcomes were identified from the Hospital Episode Statistics and death registration records and included stroke, myocardial infarction, thromboembolism, heart failure, pericarditis, atrial fibrillation, all-cause mortality, and mortality due to cardiovascular disease and ischemic heart disease.
All study participants were monitored from the first episode of an outcome until the end of the follow-up or death.
The correlation between COVID-19 and each outcome was estimated using Cox proportional hazard regression. The entire U.K. Biobank cohort was also used to perform a sensitivity analysis, with COVID-19 exposure considered a time-varying covariate. Four COVID-19 status levels were assessed ranging from unexposed to secondary hospital diagnosis.
Corresponding author, Dr Zahra Raisi-Estabragh from William Harvey Research Institute, NIHR Barts Biomedical Research Centre, Queen Mary University of London told COVID-19 News
journalists, “The study findings showed an increased risk of myocardial infarction, stroke, atrial fibrillation, heart failure, pericarditis, venous thromboembolism, all-cause mortality, and death due to ischemic heart disease and cardiovascular disease was associated with COVID-19 hospitalizations.”
However, in contrast, non-hospitalized COVID-19 patient or those who simply had mild outcomes were at a higher risk of only venous thromboembolisms and all-cause mortality.
While cardiovascular risks were higher in the 30 days following recovery from COVID-19 as compared to the control group, the risk remained higher beyond the month following recovery.
Also, it was noted that as compared to uninfected controls, hospitalized COVID-19 patients had a 27 times greater likelihood of developing venous thromboembolism and a 21.5 times higher risk of heart failure.
Alarmingly, severe COVID-19 requiring hospitalization increased the risk of all-cause mortality by 118 times as compared to non-hospitalized patients!
Interestingly, the observations of increased venous thromboembolism risk in hospitalized and non-hospitalized COVID-19 patients alike are similar to other studies conducted in Scotland, Sweden, and the United States.
The U.K. National Institute of Health and Care Excellence recommends a prophylactic treatment with low molecular weight heparin to hospitalized and home-isolated COVID-19 patients.
It was observed that increased incidence of myocardial infarction and stroke post-recovery among hospitalized COVID-19 patients was also consistent with previous retrospective and prospective analyses performed in Sweden and Denmark, respectively.
One past retrospective cohort study similarly reported that an increased risk of ischemic heart disease was associated with hospitalized COVID-19 patients but not with influenza cases, thus suggesting a strong correlation between COVID-19 and cardiovascular outcomes.
Past studies have hypothesized coagulopathy, vascular damage, and cytokine-mediated persistent immune responses as possible mechanisms of cardiovascular sequelae.
Interestingly, in contrast to the current study findings, a prospective analysis from the U.S. found an association between non-hospitalized COVID-19 cases and an increased risk of various cardiovascular conditions.
The study team believe that this could be due to baseline differences among the U.K. and U.S. populations. Furthermore, impaired access to healthcare in the U.S, which let non-acute cardiac symptoms like stable angina worsen into acute events such as myocardial infarctions, may also contribute to these differences.
Despite these discrepancies highlight the need for longitudinal studies monitoring the cardiovascular conditions of mild-to-moderate COVID-19 cases that do not require hospitalization.
The research findings suggest a significant association between severe COVID-19 and increased risk of cardiovascular outcomes including myocardial infarction, heart failure, stroke, venous thromboembolism, arterial fibrillation, and cardiovascular and ischemic heart disease-related mortality. In contrast, mild cases of COVID-19 not requiring hospitalization were associated with a higher risk of venous thromboembolism and all-cause mortality only.
It is strongly recommended that all individuals irrespective of their initial symptomatic conditions upon being exposed to the SARS-CoV-2 virus, go for regular health screenings and consult their doctors for necessary prophylactics against blood clots and also certain cardiovascular issues.
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