Scientists from the Michigan State University, USA, have conducted a systematic review and meta-analysis to compare mortality rate in coronavirus disease 2019 (COVID-19) patients who are aspirin users or non-users. The Findings reveal that the use of aspirin is associated with a significant reduction in overall and in-hospital mortality rates. The study is currently available on the medRxiv* preprint server.
As of July 13, 2021, globally, there have been 186 million confirmed COVID-19 cases, including 4 million deaths, registered to the World Health Organization. Although a significant proportion of COVID-19 patients remain asymptomatic or mildly symptomatic, the disease can cause severe complications in susceptible individuals, including older adults and persons with comorbidities. In severely affected in-hospital COVID-19 patients, an estimated mortality rate of 11.5% has been reported in a recent study.
According to available literature, the pathogenesis of severe COVID-19 is associated with immune dysfunction, excessive inflammation, hypercoagulation, and cardiopulmonary thrombosis. Given these observations, the scientists in the current study have hypothesized that intake of aspirin may reduce the severity of COVID-19 through its anti-inflammatory, anti-thrombotic, and immunomodulatory effects.
In the meta-analysis, the scientists included recently published as well as unpublished studies from the PubMed, MEDLINE, EMBASE, and Cochrane databases that reported the effect of low-dose aspirin consumption on COVID-19 related mortality. The studies that specifically compared aspirin use with no aspirin use in COVID-19 patients and reported events of mortality were included in the meta-analysis. The primary aim of the analysis was to determine all-cause and in-hospital mortality rates.
The scientists used Newcastle-Ottawa Scale to assess the quality of included studies. For each study, the scale provides a maximum of 9 points. A study with a score of 6 or higher is considered a high-quality publication with a low risk of bias.
From more than 900 initially included studies, the scientists finally selected five studies for the final qualitative and quantitative analyses. All selected studies were retrospective cohort studies, with four were on in-hospitalized COVID-19 patients, and one was on non-hospitalized patients. Based on the Newcastle-Ottawa Scale scores, four out of five studies were high quality, and one was low quality.
In the final five studies, there were 6,797 participants in the aspirin group and 7,268 participants in the non-aspirin group. The pooled data from 5 studies revealed that aspirin intake is associated with a 53% reduction in all-cause mortality in COVID-19 patients. In the case of hospitalized COVID-19 patients, the analysis revealed that the use of aspirin is associated with a 49% reduction in in-hospital mortality.
The study highlights the potential importance of aspirin intake in reducing mortality risk among hospitalized and non-hospitalized COVID-19 patients. Apart from anti-inflammatory and anti-platelet effects, aspirin is known to have antiviral effects against seasonal and pathogenic coronaviruses, such as human coronavirus-229E and Middle East respiratory syndrome coronavirus (MERS-CoV). Moreover, aspirin has been used as one of the therapeutic interventions in COVID-19 patients.
As mentioned by the scientists, the current study has some limitations. Because of the non-availability of clinical trial data on aspirin, the current analysis has included only observational studies. Moreover, the majority of selected studies are single-centered studies conducted in the USA and China. Thus, the findings may not be generalized to the global population.
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.