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21st October 2021
The level of cardiopulmonary events such as symptomatic deep vein thrombosis, pulmonary embolism, myocardial infarction and ischaemic stroke are not affected by the use of antithrombotic therapy. This was the conclusion of a randomised, double-blind, placebo-controlled trial among symptomatic outpatients infected with COVID-19 undertaken by a group from the Brigham and Women’s Hospital, Boston, Massachusetts, US. The risks of thromboembolic events in patients with covid-19 are high and associated with a greater risk of death. While there is some evidence indicating that the use of heparins among non-critically ill hospitalised patients with Covid-19 increases the probability of survival, there is a paucity of data on the use of antithrombotic therapy among symptomatic outpatients.
The ACTIV-4B COVID-19 Outpatient Thrombosis Prevention Trial was designed to explore whether patients infected with COVID-19 but who were not sufficiently unwell to require hospitalisation, could benefit from anti-platelet or anticoagulant (i.e., antithrombotic) therapy, as a means of slowing disease progression. Patients aged between 40 and 80 years of age with a PCR or antigen confirmed diagnosis of COVID-19 were eligible for inclusion in the study. All were randomised in a 1:1:1:1 fashion to aspirin 81 mg daily (and matching placebo), apixaban 2.5 mg twice daily, apixaban 5 mg twice daily or placebo twice daily for a period of 45 days. The primary outcome of interest was a composite of cardiopulmonary outcomes including symptomatic deep vein thrombosis, pulmonary embolism, arterial thromboembolism, myocardial infarction, ischaemic stroke, hospitalisation for cardiovascular or pulmonary events and all-cause mortality, for up to 45 days.
In total, 657 patients with a median age of 54 years (59.1% women) were randomised to one of the four arms and the median time from diagnosis to randomisation was 7 days and 3 days between randomisation and the start of therapy. During this period of time, some patients were hospitalised and complete follow-up were available for only 556 individuals. Unfortunately, the incidence of cardiopulmonary events was low, with only 5 events; 1 deep vein thrombosis in the aspirin group, 3 cardiopulmonary events (all hospitalisations), 2 in the apixaban 5 mg group, 1 in apixaban 2.5 mg group) and one hospitalisation in the placebo group. While the event rate was very low, the authors also noted that there were no major bleeding events reported during the trial and there were no deaths. However, there were 4 suspected non-major bleeds in the aspirin group with 6 and 4 in the low and high apixaban groups respectively.
The authors reported that the trial was terminated early due to the low event rate. They concluded that while among clinically stable symptomatic outpatients, treatment with aspirin or apixaban did not reduce the rate of clinical outcomes. However, the generalisability of this conclusion is limited because of the low incidence of primary events.
Connors JM et al. Effect of Antithrombotic Therapy on Clinical Outcomes in Outpatients With Clinically Stable Symptomatic COVID-19. The ACTIV-4B Randomized Clinical Trial. JAMA 2021
18th January 2021
The risk-benefit ratio for the use of aspirin in older adults is still unclear though some secondary analyses of randomised trials have indicated that aspirin can reduce the incidence and mortality due to colorectal cancer. Given this uncertainty, a team from the Division of Cancer Prevention, National Cancer Institute, Maryland, US, decided to focus their investigation on a post hoc analysis of older individuals in the prostate, lung, colorectal and ovarian cancer screening trial (PLCO).
PLCO was a large trial to determine the effects of screening on cancer-related mortality and secondary endpoints in people aged 55 to 74 years of age. The researchers limited their analysis to individuals at least 65 years of age after enrolment and whose baseline questionnaire contained information on aspirin use. Individuals who had a history of any of the cancers studied were excluded. The use of aspirin was then categorised as either less than or more than three-times/week. The aim of the study was to evaluate whether use of aspirin had an impact on the incidence and survival from bladder, breast, oesophageal, gastric, pancreatic and uterine cancers among individuals 65 years of age and older. The original PLCO data collection was completed in 2009 after 13 years of follow-up but for the current study, data collection continued until 2014, among individuals who consented to further follow-up or 2009 in those unwilling to be followed.
The eligible study population included 139,896 individuals with a mean age at baseline of 66.4 years (51.4% female). A total of 32,580 incident cancers were recorded during the follow-up period. The use of aspirin at least three times per week not associated with the incident risk of any of the included cancers. However, the researchers did find that after adjustment for co-morbidities, aspirin use (i.e., at least three times per week) was associated with a significantly increased survival compared to no use of the drug for bladder (hazard ratio, HR = 0.67, 95% CI 0.51–0.88, p = 0.003) and breast cancer (HR = 0.75, 95% CI 0.59–0.96, p = 0.02) only. In addition, any use of aspirin was also associated with a reduced risk of death from both bladder (HR = 0.75, 95% CI 0.58 – 0.98) and breast cancer (HR = 0.79, 95% CI 0.63–0.99) but again, not for any of the other cancers.
Unfortunately, the authors were unable to account for their findings and concluded that further work is needed to consider the relative benefits and harms associated with longterm use of aspirin.
Loomans-Kropps HA, Pinksky P, Umar A. Evaluation of aspirin use with cancer incidence and survival among older adults in the prostate, lung, colorectal, and ovarian cancer screening trial. JAMA Netw Open 2021
20th November 2020
Thus any intervention that is able to reduce disability by reducing a subsequent ischaemic stroke is a major objective of immediate therapy. Although the use of aspirin in combination with clopidogrel has been shown to reduce the risk of further stroke and myocardial infarction, to date, evidence for a beneficial effect from adding ticagrelor to aspirin in terms of a reduction in the burden of disability after a stroke is lacking.
In an analysis, researchers from the Department of Neurology and Stroke Center, University of Paris, France, sought to examine whether combing both drugs reduced the 30-day risk of disabling stroke or death. Disability was measured using the modified Rankin Scale (mRS) which ranges from 0 to 6, in which 0-1 represents no disability, 2-5 increasing disability and 6, death. Patients were enrolled if they were 40 years of age and older, with a non-cardioembolic acute ischaemic stroke and a stroke scale score of 5 or less (higher scores indicate more severe stroke). They were randomised to ticagrelor or matching placebo 1:1 and a loading dose of 180mg was given as soon as possible after randomisation, followed by a daily dose of 180mg (90mg twice daily). In addition, all patients received 300 to 325 mg of aspirin on the first day, followed by 75 to 100mg until day 30. The main outcome measure was the time to the occurrence of disabling stroke or death within 30 days, measured by the mRS scale.
A total of 11,016 patients with a mean age of 68.1 years (42.6% female) were included in the study. A primary end point with a mRS > 1 at day 30 (that is. disabling stroke or death) occurred in 221 (4.0%) of patients taking ticagrelor and in 260 (4.7%) of those taking placebo. This provided a number needed to treat of 133. In other words, treating 133 patients with ticagrelor and aspirin for 30 days, avoided 1 disabling stroke or death at day 30. Furthermore, disability burden (based on the mRS scale) was reduced by 23%.
Amarenco P et al. Ticagrelor added to aspirin in acute ischemic stroke
or transient ischemic attack in prevention of disabling stroke: A randomized clinical trial. JAMA Neurol doi:10.1001/jamaneurol.2020.4396