Mini CAT Assignment Name – Summer Anderson
Scenario: 70yo female with a significant past medical history of HTN and 2 falls in the last year presents to the geriatric clinic. She states son’s doctor told him that aspirin is a good option for people to take every day as it will decrease the risk of cardiovascular events. She’s wondering if it is also true for someone her age.
Clinical Question: In geriatric patients, does aspirin reduce the risk of cardiovascular events?
PICO Question:
P🡪 Geriatric patients
I🡪 Aspirin
C🡪 No intervention / placebo
O🡪 Reduced risk of cardiovascular events
What type of scenario is this?
□ Therapy/ Prevention □ Diagnosis □ Etiology □ Prognosis □ Screening □ Prevalence
□ Harms
Type of study best to answer this question: (think about the level of evidence)
□ Meta-analysis □ Systematic Review □ Randomized Controlled Trial □ Cohort Study
□ Case Control Study □ Case Series/Report
Search Strategy:
PICO Search Terms
| P | I | C | O |
| Geriatric patients | Aspirin | NO aspirin | Cardiovascular event prevention |
| Patients > 65 | Acetylsalicylic acid | NO treatment | Acute coronary syndrome prevention |
| Elderly patients | Aspirin 81mg | Placebo | Cardiovascular risk reduction |
| Geriatric | Primary prevention | Control group | Reduced cardiovascular events |
Filters Applied:
- Recent publications within the past 5 years
- Recent publications within the past 10 years
- Review
- Full Article
- Journal
Databases Used:
- PubMed
- ScienceDirect
- Wiley Online Library
- Cochrane Library
- Google Scholar
- BMJ
Results:
| Database | Filter | Articles Returned | |
| PubMed | English/Last 5 years/Full Text/Full Article/ | aspirin for prevention of cardiovascular events in geriatric patients | 751 |
| ScienceDirect | English/ 2010-2021/ Research Articles | Aspirin use in geriatric patients for cardiovascular event prevention | 420 |
| Wiley Online Library | English/ 2015-2020/ Journals | geriatric patients aspirin for prevention of cardiovascular events | 1,376 |
| Google Scholar | 2010-2020/Include patents/Include Citations | Elderly patients use of aspirin for cardiovascular event prevention | 17,800 |
I narrowed down these results by looking for studies that were randomized controlled trials or meta analysis. I also looked specifically at studies that focused on elderly patients specifically, as that is the key population here. I tried to choose studies that compared aspirin to a placebo to really assess the benefits/risks of taking it daily. I wanted to make sure the bias within studies was limited, and the methodology done in the studies was well-performed. There are also quite a few studies about aspirin as secondary prevention, so I made sure to choose studies that used aspirin as the primary prevention method. I wanted to look specifically at the outcome of cardiovascular events, although many also included hemorrhagic events, which I was fine with as long as my main outcome of cardiovascular events was present.
Articles Chosen for Inclusion:
| Citation | McNeil JJ, Wolfe R, Woods RL, et al. Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly. N Engl J Med. 2018;379(16):1509-1518. doi:10.1056/NEJMoa1805819 |
| Abstract | Background: Aspirin is a well-established therapy for the secondary prevention ofcardiovascular events. However, its role in the primary prevention of cardiovascular disease isunclear, especially in older persons, who have an increased risk. Methods: From 2010 through 2014, we enrolled community-dwelling men and women inAustralia and the United States who were 70 years of age or older (or ≥65 years of age amongblacks and Hispanics in the United States) and did not have cardiovascular disease, dementia, ordisability. Participants were randomly assigned to receive 100 mg of enteric-coated aspirin orplacebo. The primary end point was a composite of death, dementia, or persistent physicaldisability; results for this end point are reported in another article in the Journal. Secondary endpoints included major hemorrhage and cardiovascular disease (defined as fatal coronary heartdisease, nonfatal myocardial infarction, fatal or nonfatal stroke, or hospitalization for heartfailure). Results: Of the 19,114 persons who were enrolled in the trial, 9525 were assigned to receiveaspirin and 9589 to receive placebo. After a median of 4.7 years of follow-up, the rate ofcardiovascular disease was 10.7 events per 1000 person-years in the aspirin group and 11.3 eventsper 1000 person-years in the placebo group (hazard ratio, 0.95; 95% confidence interval [CI], 0.83to 1.08). The rate of major hemorrhage was 8.6 events per 1000 person-years and 6.2 events per1000 person-years, respectively (hazard ratio, 1.38; 95% CI, 1.18 to 1.62; P<0.001). Conclusion: The use of low-dose aspirin as a primary prevention strategy in older adultsresulted in a significantly higher risk of major hemorrhage and did not result in a significantlylower risk of cardiovascular disease than placebo. |
| PDF Link | |
| Reason for Inclusion | I selected this article because it focused specifically on older patients – everyone within the study was > 70 years of age, or > 65 years of age if black/hispanic. It looked at patients without risk factors that would be using aspirin as their primary prevention for cardiovascular disease. I chose it because it compared aspirin to placebo, and looked at outcomes that included death, dementia, disability, hemorrhage, and cardiovascular disease – specifically myocardial infarction, fatal coronary heart disease, or stroke. . |
| Citation | Shah, R., Khan, B., Latham, S. B., Khan, S. A., & Rao, S. V. (2019). A Meta-analysis of Aspirin for the Primary Prevention of Cardiovascular Diseases in the Context of Contemporary Preventive Strategies. The American Journal of Medicine. doi:10.1016/j.amjmed.2019.05.015 |
| Abstract | Background:The role of aspirin for primary prevention of cardiovascular diseases remains controversial, particularly in the context of contemporary aggressive preventive strategies. Methods: Relevant randomized clinical trials were included, and risk ratios (RRs) were calculated using random-effects models. Additional moderator analyses were performed to compare the pooled treatment effects from recent trials (those reported after the guidelines of the National Cholesterol Education Program Third Adult Treatment Panel were published in 2001; thus, conducted on the background of contemporary preventive strategies) to the results of older trials. Results: Data from 14 randomized controlled trials involving 164,751 patients were included. Aspirin use decreased myocardial infarction risk by 16% compared with placebo (RR 0.84; 95% confidence interval [CI], 0.75-0.94); however, in the moderator analyses, aspirin was not associated with a decreased risk of myocardial infarction in recent trials, but was in older trials (P-interaction = .02). Overall, aspirin use significantly increased the occurrence of major bleeding (RR 1.49; 95% CI, 1.32-1.69) and hemorrhagic stroke (RR 1.25; 95% CI, 1.01-1.54). In moderator analyses, the risk of major bleeding (P-interaction = .12) or hemorrhagic stroke (P-interaction = .44) with aspirin was not significantly different between the older and new trials. Differences between aspirin and placebo in the risks for all-cause stroke, cardiac death, and all-cause mortality were not found. Conclusions: In the context of contemporary primary prevention guidelines, the effect of aspirin on myocardial infarction risk was significantly attenuated, whereas its major bleeding and hemorrhagic stroke complications were retained. Therefore, in contemporary practice, routine use of aspirin for the primary prevention of cardiovascular events may have a net harmful effect. |
| PDF Link | |
| Reason for Inclusion | I selected this article because it was a large meta-analysis that pulled results from 14 RCTs focused on the used of aspirin and the effect it has on myocardial events. Although not specifically labeled as “elderly”, the mean age of the patients in the majority of the studies looked at ranged from 60-70, and the studies followed patients over time, so I felt the results could be applied to a geriatric population. It also chose studies comparing aspiring to placebo, and most studies typically averaged 5 years of follow up. It looked at outcomes that included myocardial infarction, cerebrovascular events, mortality, major bleeding, and hemorrhagic stroke. |
| Citation | Nudy M, Cooper J, Ghahramani M, Ruzieh M, Mandrola J, Foy AJ. Aspirin for Primary Atherosclerotic Cardiovascular Disease Prevention as Baseline Risk Increases: A Meta-Regression Analysis. Am J Med. 2020 Sep;133(9):1056-1064. doi: 10.1016/j.amjmed.2020.04.028. Epub 2020 May 20. PMID: 32445718. |
| Abstract | Background: Aspirin has long had a role in the primary prevention of atherosclerotic cardiovascular disease (ASCVD); however, recent randomized controlled trials (RCTs) have challenged this practice. Despite this, aspirin is still commonly recommended for high-risk primary prevention. We tested the hypothesis that aspirin is more efficacious for the primary prevention of ASCVD as the baseline risk increases. Methods: RCTs that compared aspirin with control for primary prevention and evaluated ASCVD (composite of myocardial infarction and ischemic stroke) and major bleeding were included. Rate ratios (RR) and 95% confidence intervals (CI) were calculated. A regression analysis was performed using the ASCVD event rate in the control arm of each RCT as the moderator. Results: Twelve RCTs were identified with 963,829 patient-years of follow-up. Aspirin was associated with a reduction in ASCVD (4.7 vs 5.3 events per 1000 patient-years; RR 0.86; 95% CI, 0.79-0.92). There was increased major bleeding among aspirin users (2.5 vs 1.8 events per 1000 patient-years; RR 1.41; 95% CI, 1.29-1.54). Regression analysis found no relationship between the log RR of ASCVD or major bleeding and rate of ASCVD in the control arm of each RCT. Conclusion: Aspirin is associated with a reduction in ASCVD when used for primary prevention; however, it is unlikely to be clinically significant given the increase in bleeding. More importantly, aspirin’s treatment effect does not increase as ASCVD risk increases, as many hypothesize. There is no suggestion from these data that use of aspirin for higher-risk primary prevention patients is beneficial |
| PDF Link | |
| Reason for Inclusion | I selected this article because it was a meta-analysis that compared RCTs, specifically those that looked at aspirin as the primary prevention of cardiovascular events. It had studies that compared the use of aspirin to placebo or control and that had a low risk of bias. It compared outcomes of myocardial infarctions, both fatal and non fatal, as well as included major bleeding risk. This study population was on the younger end of the geriatric spectrum (median age was 62.7) but because of the large span of patients it covered, I felt it was worth including. It also focuses specifically on aspirin’s treatment effect in relation to baseline cardiovascular risk, which is unique to this study, and looks particularly at aspirin as the primary prevention method. |
| Citation | Zheng SL, Roddick AJ. Association of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis. JAMA. 2019;321(3):277–287. doi:10.1001/jama.2018.20578 |
| Abstract | Objective: To assess the association of aspirin use for primary prevention with cardiovascular events and bleeding. Methods: Randomized clinical trials enrolling at least 1000 participants with no known cardiovascular disease and a follow-up of at least 12 months were included. Included studies compared aspirin use with no aspirin (placebo or no treatment). Data Extraction and Synthesis Data were screened and extracted independently by both investigators. Bayesian and frequentist meta-analyses were performed. Results: A total of 13 trials randomizing 164 225 participants with 1 050 511 participant-years of follow-up were included. The median age of trial participants was 62 years (range, 53-74), 77 501 (47%) were men, 30 361 (19%) had diabetes, and the median baseline risk of the primary cardiovascular outcome was 10.2% (range, 2.6%-30.9%). Aspirin use was associated with significant reductions in the composite cardiovascular outcome compared with no aspirin (60.2 per 10 000 participant-years with aspirin and 65.2 per 10 000 participant-years with no aspirin) (hazard ratio [HR], 0.89 [95% credible interval, 0.84-0.94]; absolute risk reduction, 0.41% [95% CI, 0.23%-0.59%]; number needed to treat, 241). Aspirin use was associated with an increased risk of major bleeding events compared with no aspirin (23.1 per 10 000 participant-years with aspirin and 16.4 per 10 000 participant-years with no aspirin) (HR, 1.43 [95% credible interval, 1.30-1.56]; absolute risk increase, 0.47% [95% CI, 0.34%-0.62%]; number needed to harm, 210). Conclusions: The use of aspirin in individuals without cardiovascular disease was associated with a lower risk of cardiovascular events and an increased risk of major bleeding. This information may inform discussions with patients about aspirin for primary prevention of cardiovascular events and bleeding. |
| PDF Link | |
| Reason for Inclusion | This study looked at 13 randomized control trials with 164,225 patients and 1,050,511 total participant years of follow-up. The participants had a median age of 62 years who would be using aspirin as primary prevention to reduce risk of cardiovascular events. I chose this article because it specifically looked at the association of aspirin use with cardiovascular or bleeding events, specifically in patients without any cardiovascular disease. It selected RCTs enrolling at least 1000 participants with a follow-up of at least 12 months, comparing aspirin use with no aspirin (placebo or no treatment). |
Summary of the Evidence:
| Author (Date) | Level of Evidence | Sample/Setting(# of subjects/ studies, cohort definition etc. ) | Outcome(s) studied | Key Findings | Limitations and Biases |
| McNeil et al., 2019Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly. | Randomized Controlled Trial | 19,114 participants from U.S. and Australia with a median age of 74 years, double-blinded randomized groups. Patients free from any overt coronary heart disease, cerebrovascular disease, atrial fibrillation, physical disability, contraindications.Median follow-up was 4.7 years | Use of daily 100mg of enteric-coated aspirin as a primary prevention strategy in older adults and the risk of cardiovascular or cerebrovascular events | Use of low-dose aspirin as primary prevention in older adults resulted in significantly higher risk of hemorrhage Aspirin in older adults did not result in a significant reduction in cardiovascular disease risk Rates of cardiovascular disease when comparing aspirin to placebo group were not statistically significantly different – 7.8 events per 1000 person-years in aspirin group compared to 8.8 events per 1000 person-years in the placebo group Individual rates of myocardial infarction, ischemic stroke, fatal cardiovascular disease, and hospitalization for heart failure were similar in the two groups The risk of major hemorrhage, most often GI or intracranial, was constant over time and did not decline with continued aspirin use | Adherence to aspirin/placebo therapy from participants could cause underestimation of harms/benefitsA large proportion of the participants were Australian or American, which could limit the application of results to these demographics |
| Shah et al., 2019A Meta-analysis of Aspirin for the Primary Prevention of Cardiovascular Diseases in the Context of Contemporary Preventive Strategies. | Meta-Analysis | Data from 14 randomized clinical trials including 164,751 patients Mean age of patients 60-70 years with average of 5 years of follow up | The outcomes for the use of an aspirin dose of average 100mg as primary prevention for cardiovascular disease in elderly patients, including outcomes of myocardial infarction, cerebrovascular events, mortality, major bleeding, and hemorrhagic stroke | Myocardial infarction occurred in 2.1% of those in the aspirin group and in 2.3% of those in the placebo groupCardiovascular mortality was 1.5% in both the aspirin and placebo groupAspirin did not significantly decrease all-cause mortality or cardiovascular mortalityAspirin increased the major bleeding risk by 49% when compared to placebo Aspirin use in patients with known cardiovascular disease decreased risk of myocardial infarction by 16% but increased the risk of major bleeding and hemorrhagic strokeWhile aspirin use has evidence of benefit in patients for secondary prevention, there appears to be little net benefit of aspirin for primary prevention | Data was combined from various studies, all of which had their own protocols, inclusion/exclusion criteria, primary endpoints, and definitions Definition of major bleeding events and cardiovascular mortality could be different Aspirin dose, follow up duration, baseline characteristics varied Some trials were older studiesRisk of bias in studies selected |
| Nudy et al., 2020Aspirin for Primary Atherosclerotic Cardiovascular Disease Prevention as Baseline Risk Increases: A Meta-Regression Analysis | Meta Regression Analysis | 12 randomized controlled trials with 963,829 patients and 829 total years of patient follow up, median age of 62.7 yearsComparing 75-500mg daily doses aspirin to placebo as primary prevention of cardiovascular events | Is aspirin more effective for reducing ASCVD events? Compared outcomes of myocardial infarctions, both fatal and non fatal, as well as included major bleeding risk in patients using aspirin as primary prevention | Aspirin is associated with a reduction in ASCVD when used for primary prevention but is unlikely to be clinically significant, and the benefit is countered by the increased risk of major bleedingThere is no evidence that aspirin for higher risk primary prevention patients is beneficialPatients over 70 or those with an increased bleeding risk should not receive aspirinIt appears patients with the highest cardiovascular risk will have the greatest net benefit from aspirin useOverall, aspirin has limited efficacy in primary prevention of ASCVD | Older RCTs were also included which could affect the outcome / application to current practiceFrequency of aspirin use could vary throughout studies, as well as dosing measuresDefinitions are not completely standardized across all trials |
| Zheng et al., 2019Association of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis. | A systematic review and meta-analysis | 13 RCTs with 164,225 participants ages 53-74 yearsComparing 100mg of aspirin to placebo or no treatment, doses > 100mg were excluded | To assess association of aspirin use for primary prevention with cardiovascular events and bleedingPrimary cardiovascular outcome was composite of cardiovascular mortality, nonfatal myocardial infarction, and non-fatal stroke. The primary bleeding outcome was any major bleeding. Secondary cardiovascular outcomes included all-cause mortality, cardiovascular-related mortality, myocardial infarction, total stroke (ischemic, hemorrhagic, and unknown), and ischemic stroke. | The use of aspirin in individuals without cardiovascular disease was associated with a lower risk of cardiovascular events and an increased risk of major bleedingAspirin was associated with significant reductions in composite cardiovascular outcomes – absolute risk reduction 0.41%Aspirin use was associated with an increased risk of major bleeding events- absolute risk increase 0.47%The use of aspirin was not associated with reductions in all-cause mortality or cardiovascular mortality When considering the totality of evidence, cardiovascular benefits associated with aspirin were modest and equally balanced by major bleeding event risks | Some risk of bias in using RCTs from other sources with various methodsLImited availability and quality of reported data throughout various studiesDiffering definitions / endpoints in various studies Daily total doses of aspirin varied from 50mg to 500mg |
Conclusion(s):
McNeil et al. – The use of low-dose aspirin as a primary prevention strategy in older adults resulted in a significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo.
Shah et al. – Aspirin was not associated with a significant reduction in cardiovascular mortality but was associated with major bleeding and hemorrhagic stroke, thus routine use of aspirin for the primary prevention of cardiovascular events may have a net harmful effect.
Nudy et al. – Aspirin is associated with a reduction in ASCVD when used for primary prevention; however, it is unlikely to be clinically significant given the increase in bleeding. More importantly, aspirin’s treatment effect does not increase as ASCVD risk increases, as many hypothesize. There is no suggestion from these data that use of aspirin for higher-risk primary prevention patients is beneficial.
Zheng et al. – When considering the totality of evidence, cardiovascular benefits associated with aspirin were modest and equally balanced by major bleeding event risks.
Overall, all studies showed that the use of aspirin as primary prevention for cardiovascular events in geriatric patients did not have a significant enough reduction in risk to merit recommendation for daily use. Additionally, daily use of aspirin was associated with an increased risk of major bleeding.
Clinical Bottom Line:
The clinical bottom line I found from these articles is that in patients with no evidence of cardiovascular disease, the benefit of aspirin as primary prevention appears to be negligible. Its use did not have very notable effects on the rate of cardiovascular events when compared to placebo in any of the above studies. In some studies, the reduction in cardiovascular risk was not even statistically significant. Additionally, it also greatly increases the risk of bleeding, which is a big consideration especially in the geriatric population and especially those at risk for falls. In geriatric patients, it appears that aspirin may have some slight reduction in cardiovascular risk but with the increase in hemorrhagic bleeding risk, it makes the overall efficacy questionable. In addition, elderly patients are already dealing with the risk of polypharmacy, and the addition of aspirin would only negatively contribute to that. Because of the very minimal benefit that aspirin may provide, it is not worth recommending for primary prevention in geriatric patients.
Weight of Evidence:
1- Shah et al., A Meta-analysis of Aspirin for the Primary Prevention of Cardiovascular Diseases in the Context of Contemporary Preventive Strategies. (2019). I felt this study was the strongest of the studies because it was the most directly applicable to my PICO question. This is a 2019 study that included 14 RCTs with risk ratios calculated for each. It involved 164,751 total patients and compared 100mg daily aspirin directly with a placebo. In addition, it looked to directly evaluate the role of aspirin as primary prevention for cardiovascular disease. The mean age of patients was 60-70 years and all were followed over an average of 5 years, which I felt made it a very strong choice.
2- Zheng et al., Association of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis. (2019) As a systematic review and meta analysis that was published in 2019, I felt this study was very strong. It included 13 RCTs with 164,225 participants ages 53-74 years, looking directly at the comparison of 100mg of daily aspirin to placebo. It excluded any dosing found that was > 100mg. The patients in this study also included some in their 50-60s, which made it less strong to me than the study above. However, due to the large sample size and large number of RCTs, I felt it was stronger than some of the other studies I have listed.
3- Nudy et al., Aspirin for Primary Atherosclerotic Cardiovascular Disease Prevention as Baseline Risk Increases: A Meta-Regression Analysis. (2020) I felt this study was very strong, looking at 12 RCTs with 145,345 participants and 963,829 total years of follow up, It directly compared the use of 75-500mg aspirin to placebo, using RCTs to do so. Most doses were 100mg, but it did have some on the higher end of that range. However, it had a median age of 62.7 years, which I felt was on the younger end of the spectrum that I wanted to look at. However, it covered a large enough span of patients that it followed over time that I still feel it is a very strong study. It also focused on aspirin’s treatment effect in relation to baseline cardiovascular risk, which is strong but less focused directly on the outcome I was looking for.
4- Mcneil et al, Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly. (2018) This study I ranked fourth considering it is an RCT published in 2018 with a sample size of 19,114 patients. It looked at the use of 100mg enteric-coated aspirin as primary prevention of cardiovascular disease in patients 70 years and older, but the primary endpoint was death, dementia, or physical disability, whereas the secondary endpoint was major hemorrhage and cardiovascular disease. It also utilized patients in Australia and the U.S. only. I felt these reasons made it slightly less strong than the above studies, in addition to the smaller size and location being less applicable across all demographics.
Overall – The evidence presented in the above studies is strong, considering the studies were all RCTs and meta-analyses that specifically looked at the comparison between aspirin and placebo/ no treatment for primary prevention. The data used included large enough sample sizes for the data to be reasonably extrapolated across many demographics and applicable to all patients. All the studies had strong methodology that worked to eliminate bias and lurking variables where possible. These studies looked at the comparison and outcomes in question specifically, thus strongly answering the proposed question. Some weaknesses of the articles are the patient adherence to the daily treatments, which could affect the outcome. Additionally, in the meta-analyses, there are varied methods and guidelines used within each RCT assessed, which could affect the results when compiling all sources. However, there were enough total studies and participants assessed throughout all the trials that I think the evidence remains very strong.
Magnitude of Effects:
Shah et al., A Meta-analysis of Aspirin for the Primary Prevention of Cardiovascular Diseases in the Context of Contemporary Preventive Strategies. (2019). Data from 14 randomized controlled trials involving 164,751 patients were included. Aspirin use decreased myocardial infarction risk by 16% compared with placebo (RR 0.84; 95% confidence interval [CI], 0.75-0.94); however, in the moderator analyses, aspirin was not associated with a decreased risk of myocardial infarction in recent trials, but was in older trials (P-interaction = .02). Overall, aspirin use significantly increased the occurrence of major bleeding (RR 1.49; 95% CI, 1.32-1.69) and hemorrhagic stroke (RR 1.25; 95% CI, 1.01-1.54). In moderator analyses, the risk of major bleeding (P-interaction = .12) or hemorrhagic stroke (P-interaction = .44) with aspirin was not significantly different between the older and new trials.
Zheng et al., Association of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis (2019). A total of 13 trials randomizing 164 225 participants with 1 050 511 participant-years of follow-up were included. The median age of trial participants was 62 years (range, 53-74), 77 501 (47%) were men, 30 361 (19%) had diabetes, and the median baseline risk of the primary cardiovascular outcome was 10.2% (range, 2.6%-30.9%). Aspirin use was associated with significant reductions in the composite cardiovascular outcome compared with no aspirin (60.2 per 10 000 participant-years with aspirin and 65.2 per 10 000 participant-years with no aspirin) (hazard ratio [HR], 0.89 [95% credible interval, 0.84-0.94]; absolute risk reduction, 0.41% [95% CI, 0.23%-0.59%]; number needed to treat, 241). Aspirin use was associated with an increased risk of major bleeding events compared with no aspirin (23.1 per 10 000 participant-years with aspirin and 16.4 per 10 000 participant-years with no aspirin) (HR, 1.43 [95% credible interval, 1.30-1.56]; absolute risk increase, 0.47% [95% CI,0.34%-0.62%]; number needed to harm, 210).
Nudy et al., Aspirin for Primary Atherosclerotic Cardiovascular Disease Prevention as Baseline Risk Increases: A Meta-Regression Analysis. (2020). Twelve RCTs were identified with 963,829 patient-years of follow-up. Aspirin was associated with a reduction in ASCVD (4.7 vs 5.3 events per 1000 patient-years; RR 0.86; 95% CI, 0.79-0.92). There was increased major bleeding among aspirin users (2.5 vs 1.8 events per 1000 patient-years; RR 1.41; 95% CI, 1.29-1.54). Regression analysis found no relationship between the log RR of ASCVD or major bleeding and rate of ASCVD in the control arm of each RCT.
Mcneil et al, Effect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly. (2019). Of the 19,114 persons who were enrolled in the trial, 9525 were assigned to receive aspirin and 9589 to receive placebo. After a median of 4.7 years of follow-up, the rate of cardiovascular disease was 10.7 events per 1000 person-years in the aspirin group and 11.3 events per 1000 person-years in the placebo group (hazard ratio, 0.95; 95% confidence interval [CI], 0.83 to 1.08). The rate of major hemorrhage was 8.6 events per 1000 person-years and 6.2 events per 1000 person-years, respectively (hazard ratio, 1.38; 95% CI, 1.18 to 1.62; P<0.001).
Clinical Significance:
Based on the findings of these articles, clinical recommendation should be to limit the use of aspirin as primary prevention for cardiovascular events in elderly patients. Daily aspirin use should not be recommended to patients with no history of cardiovascular events as it does not significantly reduce their cardiac risk and may increase risk of bleeding. Additionally, medication reconciliation would be of use to limit the use of aspirin being taken in patients with no clinical reason to do so.
Other Considerations:
A consideration for future studies would be to evaluate specifically the low dose 81mg aspirin, as one of the limitations in these studies was the various dosing of the aspirin available. Additionally, it’s worth considering how this applies to various geriatric ages in comparison to one another. For example, the benefits/risks of aspirin could greatly differ for a 65 year old in comparison to an 85 year old, and I think it would be worth exploring this in future studies.
