Randomised trial of prophylactic daily aspirin in British male doctors

Clinical decision-making: Challenging traditional assumptions

Clinical decision-making that best serves the interests of our patients requires the synthesis of evidence-based medicine, sound clinical judgment and guidelines. However, a relatively low percentage of clinical guidelines are based on well-designed prospective randomized clinical trials. Thus the foundation on which good clinical outcomes can be reasonably expected should be based on i) data derived from the most applicable and highest quality clinical studies available, and ii) 'tried and tested' clinical maxims acquired through experience that are, in turn, those ideas that are in keeping with a reasonable body of medical opinion. It follows that poor decision-making and unfavorable clinical outcomes can be linked to inappropriate or inferior quality evidence, or incorrectly conceived or implemented clinical judgment. Here we review selected areas of recent controversy in clinical cardiology, highlighting the critical role of evidence-based medicine when making informed clinical decisions to help avoid harm in our patients.

A Nomogram for the Prediction of Cessation of Migraine Among Patients With Patent Foramen Ovale After Percutaneous Closure

Objective: This study aimed to develop and validate a nomogram to predict cessation of patent foramen ovale (PFO) patients with migraine headache after percutaneous closure.

Methods: A total of 247 eligible patients with PFO and migraine after percutaneous closure between May, 2016 and May, 2018 were divided into a development cohort (n = 149) and a validation cohort (n = 98). The primary end point was cessation of migraine at follow-up of 1 year after the procedure measured by the Migraine Disability Assessment Score (MIDAS). In the development cohort, the LASSO regression was used data dimension reduction. A multivariable logistic regression analysis was used to develop the predicting nomogram. The performance of the nomogram was assessed by concordance index (C-index), calibration and clinical usefulness. The results were validated in the validation cohort.

Results: Migraine with aura, history of antiplatelet, and the right-to-left shunt (RLS) at rest were identified as significant predictors based on the analysis of multivariate logistic regression. The nomogram incorporating these variables showed good calibration and discrimination in the development cohort with C-index of 0.906 (95% CI: 0.847–0.965), which was confirmed using the validation cohort with C-index of 0.827 (95% CI: 0.751–0.903). The nomogram showed good agreement between prediction by nomogram and actual observation. Furthermore, the decision curve indicated that the novel nomogram was clinically useful.

Conclusion: The novel nomogram showed favorable predictive accuracy for cessation of migraine among patients with PFO after percutaneous closure and might provide constructive guidance in clinical decision making.

Long-term aspirin use for primary cancer prevention: An updated systematic review and subgroup meta-analysis of 29 randomized clinical trials

Background and objective: Long-term aspirin use for the primary prevention of cancer remains controversial, and variations in the effect of aspirin use on cancer outcomes by aspirin dose, follow-up duration, or study population have never been systematically evaluated. The objective of this study was to evaluate the effect of aspirin on primary cancer prevention and to determine whether the effect differed according to aspirin dose, follow-up duration, or study population.

Materials and methods: Seven electronic databases were searched from inception to September 30, 2019. Randomized clinical trials (RCTs) that compared aspirin use versus no aspirin use in participants without pre-existing cancer and reported cancer outcomes were selected. Data were screened and extracted by different investigators. Analyses were performed using Review Manager 5.3 and Comprehensive Meta-Analysis 2.0. Total cancer incidence was defined as the primary clinical endpoint. Total cancer mortality, all-cause mortality, major bleeding, and total bleeding events were the secondary outcomes. Subgroup analyses were conducted based on aspirin dose, follow-up duration, and study populations.

Results: Twenty-nine RCTs that randomized 200,679 participants were included. Compared with no aspirin, aspirin use was not associated with significant reductions in total cancer incidence (RR = 1.01, 95% CI: 0.97 to 1.04, P = 0.72), total cancer mortality (RR = 1.00, 95% CI: 0.93 to 1.07, P = 0.90), or all-cause mortality (RR = 0.98, 95% CI: 0.94 to 1.02, P =0.31); however, aspirin use was associated with a 44% increase in the risk of major bleeding (RR = 1.44, 95% CI: 1.32 to 1.57, P < 0.00001) and a 52% increase in the risk of total bleeding events (RR = 1.52, 95% CI: 1.33 to 1.74, P < 0.00001). Subgroup analyses demonstrated consistent results.

Conclusions: Long-term aspirin use in individuals without pre-existing cancer was not associated with a significant reduction in total cancer incidence, cancer mortality, or all-cause mortality; however, aspirin use was associated with a significant increase in the risk of bleeding. Therefore, aspirin is not an appropriate choice for the primary cancer prevention.

Aspirin for Primary Atherosclerotic Cardiovascular Disease Prevention as Baseline Risk Increases: A Meta-Regression Analysis

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.

Aspirin in Primary Prevention of Cardiovascular Events

Aspirin has demonstrated a clear benefit in secondary prevention of coronary syndrome, while aspirin's effect in primary prevention is unclear. This report will explore the role of aspirin as primary prevention for various vascular events. It strives to provide a clear guide for clinicians on whether or not to prescribe aspirin for their patients for primary prevention. Current guidelines and recent trials failed to show clear benefit against primary prevention, with risks outweighing benefits in moderate to high risk patients. A thoughtful discussion between patients and their doctors should be conducted before beginning aspirin use. More studies are needed to gain a better understanding of aspirin use in primary prevention.

Low-dose aspirin and risk of gastric and oesophageal cancer: A population-based study in the United Kingdom using The Health Improvement Network

There is increasing interest regarding potential protective effects of low‐dose aspirin against various gastrointestinal cancers. We aimed to quantify the association between use of low‐dose aspirin and risk of gastric/oesophageal cancer using a population‐based primary care database in the UK. Between January 2005 and December 2015, we identified a cohort of 223 640 new users of low‐dose aspirin (75‐300 mg/day) and a matched cohort of nonusers at the start of follow‐up from The Health Improvement Network. Cohorts were followed to identify incident cases of gastric/oesophageal cancer. Nested case‐control analyses were conducted and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for current vs nonuse of low‐dose aspirin using logistic regression. Current use was defined as when low‐dose aspirin lasted 0 to 90 days before the index date (event date for cases, random date for controls) and previous duration was ≥1 year. We identified 727 incident cases of gastric cancer and 1394 incident cases of oesophageal cancer. ORs (95% CIs) were 0.46 (0.38‐0.57) for gastric cancer and 0.59 (0.51‐0.69) for oesophageal cancer. The effect remained consistent with no clear change seen between previous duration of low‐dose aspirin use of 1‐3, 3‐5 or >5 years. The reduced risks was seen with 75 mg/day, and effects were consistent in lag‐time analyses. In conclusion, our results indicate that use of low‐dose aspirin is associated with a 54% reduced risk of gastric cancer and a 41% reduced risk of oesophageal cancer as supported by mechanistic data.

What's new?

Low‐dose aspirin may help protect against the development of gastric and oesophageal cancers. This population‐based study using data from primary care electronic health records in the United Kingdom lends further support to that idea. Compared with no use of low‐dose aspirin, daily use of low‐dose aspirin (75–300 mg) for at least one year was associated with a 54 percent reduction in gastric cancer risk and a 41 percent reduction in oesophageal cancer risk. No clear difference in effect was observed between low‐dose aspirin use for one to three years versus more than three years.

Streamlined mail-based methods for large randomised trials: lessons learnt from the ASCEND study

Reliable assessment of the effects of an intervention usually requires large randomised trials but such studies are becoming increasingly complex and costly to run. 'Streamlined' trials are needed in which every aspect of the trial design and conduct is simplified, retaining only those elements needed to answer the research question and ensure the safety of the individual participants. In this review we discuss how the trial 'A Study of Cardiovascular Events iN Diabetes' (ASCEND) was streamlined. The study included a two-by-two factorial design: it assessed the effects of low-dose aspirin and, separately, supplementation with n-3 fatty acids on serious vascular events in 15,480 people with diabetes but no overt cardiovascular disease. Other key streamlined design features, such as mail-based recruitment and follow-up, mainly by post, with no in-person visits and use of a run-in period, are also described. We go on to discuss the success of the study and other studies that have employed a similar mail-based approach, and the type of clinical trials that are suitable for mail-based design. Finally, we consider the limitations of the study, and how these could be circumvented in future studies. ASCEND randomised large numbers of eligible participants, achieved good adherence rates and almost complete follow-up at a fraction of the cost of traditional clinic-based trials. Such studies are necessary if researchers are to address the important clinical questions most relevant to improving health.

Aspirin in the Treatment and Prevention of Migraine Headaches: Possible Additional Clinical Options for Primary Healthcare Providers

Migraine headaches are among the most common and potentially debilitating disorders encountered by primary healthcare providers. In the treatment of acute migraine and the prevention of recurrent attacks, there are prescription drugs of proven benefit. However, for those without health insurance or high co-pays, these drugs may be neither available nor affordable and, for all patients, they may be either poorly tolerated or contraindicated. The totality of evidence, which includes data from randomized trials, suggests that high-dose aspirin, in doses from 900 to 1300 mg, taken at the onset of symptoms, is an effective and safe treatment option for acute migraine headaches. In addition, the totality of evidence, including some, but not all, randomized trials, suggests the possibility that daily aspirin, in doses from 81 to 325 mg, may be an effective and safe treatment option for the prevention of recurrent migraine headaches. The relatively favorable side effect profile of aspirin and extremely low costs compared with other prescription drug therapies may provide additional options for primary healthcare providers in the treatment of both acute and recurrent migraine headaches.

[Choosing Antithrombotic Therapy in Patients with Coronary Heart Disease and Type 2 Diabetes Mellitus: How to Reduce the Risk of Death]

This review presents prevalence of type 2 diabetes mellitus (DM) in patients with ischemic heart disease (IHD), risk factors in common, and a considerable worsening of prognosis in their combination. The authors addressed pathophysiological mechanisms of platelet dysfunction and negative changes in the coagulation system in IHD patients with type 2 DM, which predetermine activation of the prothrombotic pathway of hemostasis formation. Difficulties in optimal selection of antithrombotic therapy were demonstrated for both patients with type 2 DM without a history of cardiovascular diseases and IHD patients with type 2 DM. The authors paid attention to the fact that results of randomized clinical studies (RCS) that included patients with type 2 DM and acute coronary syndrome or after coronary revascularization cannot be extrapolated to the entire population of patients with stable IHD. At present, the preferable choice of antithrombotic therapy for patients with type 2 DM and stable IHD is a combination of rivaroxaban 2.5 mg twice a day and acetylsalicylic acid 100 mg/day. This combination provides a maximal clinical benefit compared to other strategies presented in RCS.

Clinical trials in long-term antiplatelet therapies: focus on the role of aspirin

PURPOSE OF REVIEW

The purpose of this review is to summarize the existing evidence for use of long-term antiplatelet therapies for primary and secondary prevention of adverse cardiovascular events.

RECENT FINDINGS

In the setting of primary prevention, several contemporary trials have shown a lack of net clinical benefit with use of aspirin across different patient groups, including those with diabetes mellitus, older age or high estimated cardiac risk. For secondary prevention, the addition of either ticagrelor or low-dose rivaroxaban to aspirin monotherapy significantly lowered recurrent vascular events, albeit with excess bleeding. Aspirin withdrawal did not result in excess thrombotic risk or less bleeding among patients undergoing percutaneous coronary intervention (PCI) treated with ticagrelor.

SUMMARY

In the contemporary era, routine use of aspirin is not beneficial in the majority of patients free of cardiac disease. In contrast, for secondary prevention, aspirin monotherapy is not sufficient to lower recurrent vascular risk. Antiplatelet monotherapy with ticagrelor may emerge as an alternative to lower bleeding whereas maintaining ischemic efficacy in selected patients undergoing PCI.

Aspirin decreases hepatocellular carcinoma risk in hepatitis C virus carriers: a nationwide cohort study

Background

Aspirin has been found to lower the occurrence rates of some cancers through the inhibition of the cyclooxygenase enzyme. For example, there is a well-known association between aspirin use and the occurrence of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) carriers. However, the association, if any, between aspirin use and HCC in hepatitis C virus (HCV) carriers is unknown. Therefore, this study compared the occurrence rates of HCC in HCV carriers treated with or without aspirin.

Methods

The participants in this retrospective cohort study consisted of people newly diagnosed with HCV in Taiwan from 2000 to 2012. Those who were treated with aspirin were defined as the control group, whereas those not treated with aspirin were defined as the comparison cohort. We used a 1:1 propensity score matching by age, sex, comorbidities, drugs, diagnosis year, and index year with covariate assessment.

Results

Our study sample consisted of 2980 aspirin-treated HCV carriers and 7771 non-aspirin-treated HCV carriers. After propensity score matching, each cohort consisted of 1911 HCV carriers. The adjusted hazard ratio (aHR) of HCC incidence in the aspirin users (aHR = 0.56, 95% CI = 0.43–0.72, p < 0.001) was significantly lower than that in the non-aspirin users. A Kaplan-Meier analysis showed that among the HCV carriers, the aspirin users had a lower cumulative incidence rate of HCC over the first 10 years of aspirin treatment (p < 0.0001).

Conclusions

The HCC incidence rate was lower in the aspirin-using HCV carriers than in the non- aspirin-using HCV carriers, indicating that the effects of aspirin might occur through inhibition of the cyclooxygenase enzyme pathway. Moreover, protection from HCC was provided by less than a year of aspirin treatment, while treatment with aspirin for 1 to 2 years exhibited the greatest protective effect. We therefore encourage aspirin treatment to prevent HCC in HCV carriers.

Is there a cardiovascular protective effect of aspirin in chronic kidney disease patients? A systematic review and meta-analysis

PURPOSE

To perform a systematic review and meta-analysis to evaluate the cardiovascular prevention effect of aspirin among patients with chronic kidney disease (CKD).

METHODS

A comprehensive literature search was conducted in Embase, PubMed, and Cochrane library (up to March 2019) without language limitations. Randomized control trials (RCT) and observational studies that met the inclusion and exclusion criteria were included. Two reviewers independently extracted data, and evaluated study quality using modified Jadad score for RCTs and Newcastle-Ottawa Scale for observational study. A meta-analysis was conducted in the Stata 15.0 software using the DerSimonian and Laird random-effects model.

RESULTS

1768 references were identified from literature searching. Four RCTs and four cohort studies that reported the cardiovascular prevention outcome of aspirin in CKD patients (38,341 participants) were included in this review. The pooled data revealed that aspirin had no significant prevention effect on cardiovascular events among CKD patients (RR = 0.96, 95% CI, 0.59-1.13). There was also no significant reduction in cardiovascular mortality and all-cause mortality. Although we found no significant increased risk in major bleeding events, there was a statistically significant increased risk of minor bleeding events (RR = 2.57, 95% CI, 1.60-4.13) and renal events (RR = 1.30, 95% CI, 1.02-1.65) for aspirin use.

CONCLUSION

Our review indicated that aspirin use in CKD patients had no prevention effect on cardiovascular events and no statistically significant reduction in risk of cardiovascular or all-cause mortality, with a significant increased risk of minor bleeding and renal events.

Overcoming challenges to data quality in the ASPREE clinical trial

BACKGROUND

Large-scale studies risk generating inaccurate and missing data due to the complexity of data collection. Technology has the potential to improve data quality by providing operational support to data collectors. However, this potential is under-explored in community-based trials. The Aspirin in reducing events in the elderly (ASPREE) trial developed a data suite that was specifically designed to support data collectors: the ASPREE Web Accessible Relational Database (AWARD). This paper describes AWARD and the impact of system design on data quality.

METHODS

AWARD's operational requirements, conceptual design, key challenges and design solutions for data quality are presented. Impact of design features is assessed through comparison of baseline data collected prior to implementation of key functionality (n = 1000) with data collected post implementation (n = 18,114). Overall data quality is assessed according to data category.

RESULTS

At baseline, implementation of user-driven functionality reduced staff error (from 0.3% to 0.01%), out-of-range data entry (from 0.14% to 0.04%) and protocol deviations (from 0.4% to 0.08%). In the longitudinal data set, which contained more than 39 million data values collected within AWARD, 96.6% of data values were entered within specified query range or found to be accurate upon querying. The remaining data were missing (3.4%). Participant non-attendance at scheduled study activity was the most common cause of missing data. Costs associated with cleaning data in ASPREE were lower than expected compared with reports from other trials.

CONCLUSIONS

Clinical trials undertake complex operational activity in order to collect data, but technology rarely provides sufficient support. We find the AWARD suite provides proof of principle that designing technology to support data collectors can mitigate known causes of poor data quality and produce higher-quality data. Health information technology (IT) products that support the conduct of scheduled activity in addition to traditional data entry will enhance community-based clinical trials. A standardised framework for reporting data quality would aid comparisons across clinical trials.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number Register, ISRCTN83772183. Registered on 3 March 2005.

Aspirin for primary prevention of cardiovascular disease: a meta-analysis with a particular focus on subgroups

BACKGROUND

The role of aspirin in primary prevention of cardiovascular disease (CVD) remains unclear. We aimed to investigate the benefit-risk ratio of aspirin for primary prevention of CVD with a particular focus on subgroups.

METHODS

Randomized controlled trials comparing the effects of aspirin for primary prevention of CVD versus control and including at least 1000 patients were eligible for this meta-analysis. The primary efficacy outcome was all-cause mortality. Secondary outcomes included cardiovascular mortality, major adverse cardiovascular events (MACE), myocardial infarction, ischemic stroke, and net clinical benefit. The primary safety outcome was major bleeding. Subgroup analyses involving sex, concomitant statin treatment, diabetes, and smoking were performed.

RESULTS

Thirteen randomized controlled trials comprising 164,225 patients were included. The risk of all-cause and cardiovascular mortality was similar for aspirin and control groups (RR 0.98; 95% CI, 0.93-1.02; RR 0.99; 95% CI, 0.90-1.08; respectively). Aspirin reduced the relative risk (RRR) of major adverse cardiovascular events (MACE) by 9% (RR 0.91; 95% CI, 0.86-0.95), myocardial infarction by 14% (RR 0.86; 95% CI, 0.77-0.95), and ischemic stroke by 10% (RR 0.90; 95% CI, 0.82-0.99), but was associated with a 46% relative risk increase of major bleeding events (RR 1.46; 95% CI, 1.30-1.64) compared with controls. Aspirin use did not translate into a net clinical benefit adjusted for event-associated mortality risk (mean 0.034%; 95% CI, - 0.18 to 0.25%). There was an interaction for aspirin effect in three patient subgroups: (i) in patients under statin treatment, aspirin was associated with a 12% RRR of MACE (RR 0.88; 95% CI, 0.80-0.96), and this effect was lacking in the no-statin group; (ii) in non-smokers, aspirin was associated with a 10% RRR of MACE (RR 0.90; 95% CI, 0.82-0.99), and this effect was not present in smokers; and (iii) in males, aspirin use resulted in a 11% RRR of MACE (RR 0.89; 95% CI, 0.83-0.95), with a non-significant effect in females.

CONCLUSIONS

Aspirin use does not reduce all-cause or cardiovascular mortality and results in an insufficient benefit-risk ratio for CVD primary prevention. Non-smokers, patients treated with statins, and males had the greatest risk reduction of MACE across subgroups.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019118474.

Role of aspirin in primary prevention of cardiovascular disease

The benefits of aspirin therapy for the secondary prevention of cardiovascular disease clearly outweigh the risks of bleeding, and low-dose aspirin is uniformly recommended in this setting. However, no clear consensus exists about whether, and if so in whom, aspirin therapy is appropriate for the primary prevention of cardiovascular disease. Three trials of low-dose aspirin versus placebo in three populations at increased risk of myocardial infarction or ischaemic stroke in the absence of established cardiovascular disease were reported in 2018. The ASPREE trial in elderly people was terminated early for futility because aspirin had no effect on disability-free survival but significantly increased the risk of major haemorrhage and, unexpectedly, all-cause mortality. In the ASCEND trial in patients with diabetes mellitus and no evidence of vascular disease, aspirin significantly reduced serious vascular events but increased major bleeding. In the ARRIVE trial in people with multiple risk factors for cardiovascular disease, aspirin had no effect on major cardiovascular events but increased gastrointestinal bleeding. The aim of this Review is to place these new results in the context of previous evidence on aspirin for the primary prevention of cardiovascular disease and to appraise whether the new evidence is likely to enable the more targeted use of aspirin in particular individuals for whom the net benefit is both clinically worthwhile and statistically definite.

A Meta-Analysis of Aspirin for the Primary Prevention of Cardiovascular Diseases in the Context of Contemporary Preventive Strategies

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.

Aspirin in primary prevention: the triumph of clinical judgement over complex equations

Aspirin, in 2017, has celebrated its 120th birthday. The efficacy and safety of low-dose aspirin in secondary prevention of cardiovascular disease is well supported by many studies, instead in primary prevention it remains controversial, especially in the aftermath of the publication in 2018 of three novel primary prevention randomized clinical trials, showing that the benefit of low-dose aspirin, although additive to that of statin, is counterbalanced by an excess of (mainly gastrointestinal) bleeding events. The signal for a net benefit seems to be even more controversial in the elderly starting aspirin after the age of 70 years. While international guidelines have promptly downgraded their recommendations to more conservative indications, the practicing clinician is called to make the effort to individualize the treatment, after careful evaluation of the haemorrhagic risk vis-a-vis the risk to develop, in the mid-term and long-term follow-up, major cardiovascular events or cancer. This is a particularly complex task, given the different immediate and long-term impact of diverse outcomes on health, the dynamic nature over time of the benefit/risk balance, prompting periodic re-assessments of its indication, and the interindividual variability in aspirin response. The chemopreventive properties of aspirin, anticipated by a large body of epidemiological and mechanistic evidence, are awaiting their final confirmation by the long-term follow-up of the latest trials specifically designed to assess this endpoint, with the expectation to subvert the delicate benefit/risk balance of aspirin in primary prevention. This review is intended to provide an interpretation of past and current evidence to guide clinical decision making on the contemporary patient.

The evidence strength of a meta-analysis of aspirin for primary prevention of cancer

Dr. Tarek Haykal et al. (145:1795-1809, 2019) reported a meta-analysis of aspirin for the primary prevention of cancer in individuals without known cancer. The authors found that aspirin use was not associated with significant reduction in cancer mortality or incidence, but with higher rates of bleeding. The findings of this study added some evidence to the clinical practice. However, several issues might have compromised the strength of the evidence of this systematic review. If the investigators could have further clarified the inclusion and exclusion criteria, included all eligible studies, extracted data more meticulously, and performed more necessary sensitivity analyses to confirm the robustness of their findings, the strength of evidence of this meta-analysis would have been stronger.

Antiplatelet Agents for Cancer Prevention: Current Evidences and Continuing Controversies

Over the past two decades, aspirin has emerged as a promising chemoprotective agent to prevent colorectal cancer (CRC). In 2016, the mounting evidence supporting its chemoprotective effect, from both basic science and clinical research, led the US Preventive Services Task Force to recommend regular use of low-dose aspirin in some subgroups of patients for whom the benefits are deemed to outweigh the risks. In contrast, data on the chemoprotective effect of aspirin against other cancers are less clear and remain controversial. Most data come from secondary analyses of cardiovascular prevention trials, with only a limited number reporting cancer outcomes as a prespecified endpoint, and overall unclear findings. Moreover, the potential chemoprotective effect of aspirin against other cancers has been recently questioned with the publication of 3 long-awaited trials of aspirin in the primary prevention of cardiovascular diseases reporting no benefit of aspirin on overall cancer incidence and cancer-related mortality. Data on the chemoprotective effects of other antiplatelet agents remain scarce and inconclusive, and further research to examine their benefit are warranted. In this narrative review, we summarize current clinical evidence and continuing controversies on the potential chemoprotective properties of antiplatelet agents against cancer.

Effects of Aspirin or Clopidogrel on Colorectal Cancer Chemoprevention in Patients with Type 2 Diabetes Mellitus

Background: The effect of clopidogrel, whose mechanism of action differs from that of aspirin, on CRC risk remains unknown. We investigated the effects of clopidogrel and aspirin, either as monotherapy or combined, on colorectal cancer (CRC) risk in patients with Type 2 diabetes mellitus (T2DM). Methods: We conducted a cohort study using Taiwan National Health Insurance Research Database. Four groups comprising 218,903 patients using aspirin monotherapy, 20,158 patients using clopidogrel monotherapy, 42,779 patients using dual antiplatelet therapy, and 281,840 nonuser matched controls were created using propensity score matching. Cox proportional hazards regression was used to evaluate the CRC risk during follow-up. Results: During the 13-year follow-up period, we found 9431 cases of CRC over 3,409,522 person-years. The overall incidence rates of CRC were 2.04, 3.45, 1.55, and 3.52 per 1000 person-years in the aspirin, clopidogrel, dual antiplatelet, and nonuser cohorts, respectively. The adjusted hazard ratios (aHRs) were 0.59 (95% confidence interval [CI], 0.56–0.61), 0.77 (95% CI, 0.68–0.87), and 0.37 (95% CI, 0.33–0.40) for the aspirin, clopidogrel, and dual antiplatelet cohorts, respectively. Dose- and duration-dependent chemopreventive effects were observed in the three cohorts.

The Efficacy And Safety Of Aspirin As The Primary Prevention Of Cardiovascular Disease: An Updated Meta-Analysis

Purpose

Information regarding the use of aspirin for patients with no known cardiovascular disease remains conflicting. We performed an updated meta-analysis to evaluate the efficacy and safety of aspirin for primary prevention of cardiovascular disease.

Patients and methods

PubMed, MEDLINE, and Cochrane library databases were searched for randomized controlled trials comparing aspirin with placebos or no treatment published up until November 1, 2018. The primary efficacy endpoint was all-cause death. The secondary endpoints included cardiovascular death, myocardial infarction, and stroke. The safety endpoints included major bleeding, gastrointestinal bleeding, and hemorrhagic stroke.

Results

Fourteen studies were included. Aspirin use was associated with a lower risk of myocardial infarction than placebo use or no treatment (risk ratio [RR], 0.83, 95% confidence interval [CI]: 0.73–0.95, P = 0.005). Additionally, compared with the control groups, aspirin use was not associated with a lower risk of all-cause mortality or cardiovascular mortality. In terms of safety, aspirin use was associated with a higher risk of major bleeding (RR, 1.40, 95% CI: 1.25–1.57, P = 0.000), gastrointestinal bleeding (RR, 1.58, 95% CI: 1.25–1.99, P = 0.000), and hemorrhagic stroke (RR, 1.30, 95% CI: 1.06–1.60, P = 0.011). Furthermore, the treatment effect was not significantly modified by patients’ clinical characteristics. No publication bias was present.

Conclusion

Aspirin use reduced the myocardial infarction risk in patients without known cardiovascular disease, but had no effect in terms of reducing the risk of all-cause death, cardiovascular death, and stroke, and increased the risk of major bleeding, gastrointestinal bleeding, and hemorrhagic stroke.

Aspirin for Primary Prevention of Cardiovascular Disease in Diabetes: a Review of the Evidence

PURPOSE OF REVIEW

People with diabetes are at a higher risk of atherosclerotic cardiovascular disease (ASCVD) compared with those without diabetes. Though aspirin has been shown to have an overall net clinical benefit when used for secondary prevention of ASCVD in people with and without diabetes, the evidence for primary prevention, especially in those with diabetes, remains inconsistent. In this article, we review the latest studies examining the risks and benefits of aspirin use for primary prevention of ASCVD in adults with diabetes, discuss key aspects in assessing the risk-benefit ratio of aspirin use for primary prevention of ASCVD, and summarize current guidelines from professional societies on aspirin use for primary prevention in adults with diabetes.

RECENT FINDINGS

In the general population, past studies have shown no difference in the beneficial effect of aspirin for primary cardiovascular disease prevention by diabetes status. However, several randomized controlled studies and meta-analyses in adults with diabetes have shown lack of net clinical benefit of aspirin use for primary prevention of ASCVD. The recent ASCEND trial documented cardiovascular benefit of aspirin for primary prevention in adults with diabetes but suggested that the increased risk of bleeding may outweigh the cardiovascular benefit. The decision to initiate aspirin for primary prevention of ASCVD must be considered carefully on an individual basis to balance the cardiovascular benefit and bleeding risk in all patients, especially those with diabetes. A multifactorial approach that focuses on managing ASCVD risk factors such as hypertension, dyslipidemia, dysglycemia, and smoking is recommended in all patients. More research is needed to identify subgroups of people with diabetes who are more likely to benefit from aspirin use for primary prevention of ASCVD and develop better antithrombotic strategies that shift the risk-benefit balance toward an overall net clinical benefit.

Revisiting the Role of Aspirin for the Primary Prevention of Cardiovascular Disease

Aspirin is the cornerstone of the antithrombotic management of patients with established atherosclerotic cardiovascular disease, but major guidelines provide conflicting recommendations for its use in primary prevention. Findings from recent randomized trials totaling >47 000 patients called into question the net clinical benefits of aspirin in primary prevention for 3 key populations: patients with diabetes mellitus, community-dwelling elderly individuals, and patients without diabetes mellitus who are at intermediate risk for atherosclerotic events. In the context of increasing emphasis on the use of other treatments for primary prevention in patients with moderate-high future risk of developing atherosclerotic cardiovascular disease, the efficacy and safety of aspirin for primary prevention has become uncertain. Key unresolved questions regarding the role of aspirin in primary prevention include the optimal drug formulation, dosing schedule, weight-based dose selection, and interplay between sex and treatment response. In the current era, most patients without established atherosclerotic cardiovascular disease should not be prescribed aspirin. Rather, aggressive management of comorbidities tailored to the expected cardiovascular risk needs to be emphasized. In this context, informed shared decision making between clinicians and patients regarding the use of aspirin for primary prevention of cardiovascular events is a suitable and laudable approach. In this article, we revisit the role of aspirin for the primary prevention of cardiovascular diseases by critically reviewing the key scientific literature, highlight key areas of uncertainties for future research, and propose a decisional framework for clinicians to support prescription of aspirin in primary prevention.

Aspirin for Primary Prevention of Cardiovascular Disease

Aspirin has been used for decades for the primary and secondary prevention of cardiovascular disease (CVD). The effect of aspirin in secondary prevention is well-known but is still debatable for primary prevention. Despite the controversy, aspirin is believed to have a beneficial effect in primary prevention and has been widely used. However, whether the doubts concerning the wide use of aspirin are correct has resulted in the publication of data from several large clinical trials recently. There are several clinical guidelines from various international organizations on the use of aspirin for the primary prevention of CVD, and they offer some conflicting recommendations. A reduction in the overall incidence of CVD with the development of modern prevention therapies has weakened the impact of aspirin in primary prevention. Large randomized clinical trials have found decreased or no difference in CVD events but a significant increase in the risk of bleeding. Taking aspirin for the primary prevention of CVD is no longer recommended, especially for patients who have a low to moderate risk. An assessment of the balance between the benefits and risks of aspirin use should be considered.

Frequency of Intracranial Hemorrhage With Low-Dose Aspirin in Individuals Without Symptomatic Cardiovascular Disease: A Systematic Review and Meta-analysis

Importance

Use of low-dose aspirin for the primary prevention of cardiovascular events remains controversial because increased risk of bleeding may offset the overall benefit. Among major bleeding events, intracranial hemorrhage is associated with high mortality rates and functional dependency.

Objective

To assess the risk of intracranial hemorrhage associated with low-dose aspirin among individuals without symptomatic cardiovascular disease.

Data Sources

PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched from January 1966 to October 30, 2018.

Study Selection

Randomized clinical trials that compared low-dose aspirin (daily dose ≤100 mg) vs control and recorded the end points of intracranial hemorrhage separately for active treatment and control groups were included.

Data Extraction and Synthesis

A random-effect estimate was computed based on the Mantel-Haenszel method. Relative risk with 95% CI was used as a measure of aspirin vs control on risk of intracranial hemorrhage.

Main Outcomes and Measures

The main outcomes were any intracranial hemorrhage, intracerebral hemorrhage, subdural or extradural hemorrhage, and subarachnoid hemorrhage, for aspirin vs control.

Results

The search identified 13 randomized clinical trials of low-dose aspirin use for primary prevention, enrolling 134 446 patients. Pooling the results from the random-effects model showed that low-dose aspirin, compared with control, was associated with an increased risk of any intracranial bleeding (8 trials; relative risk, 1.37; 95% CI, 1.13-1.66; 2 additional intracranial hemorrhages in 1000 people), with potentially the greatest relative risk increase for subdural or extradural hemorrhage (4 trials; relative risk, 1.53; 95% CI, 1.08-2.18) and less for intracerebral hemorrhage and subarachnoid hemorrhage. Patient baseline features associated with heightened risk of intracerebral hemorrhage with low-dose aspirin, compared with control, were Asian race/ethnicity and low body mass index.

Conclusions and Relevance

Among people without symptomatic cardiovascular disease, use of low-dose aspirin was associated with an overall increased risk of intracranial hemorrhage, and heightened risk of intracerebral hemorrhage for those of Asian race/ethnicity or people with a low body mass index.

An aspirin a day? Clinical utility of aspirin therapy for the primary prevention of cardiovascular disease

Introduction: Cardiovascular disease remains a leading cause of morbidity and mortality. Since the description of its therapeutic potential, aspirin has been a cornerstone of therapy following vascular events. However, aspirin in the primary prevention setting is controversial and major guideline groups provide inconsistent recommendations. Thus, there is variability in practice as providers are faced with a balance of therapeutic benefit and drug-induced harm. Areas covered: This article provides a critical appraisal of both past and present data for aspirin in the primary prevention setting. PubMed and Cochrane Central Register databases were searched from inception to May 1^st, 2019. Expert opinion: The decision to initiate or withdraw aspirin for primary prevention requires an understanding of the equilibrium between efficacy and safety. In adults greater than 70 years of age, low to moderate cardiovascular risk, controlled diabetes, or at high risk of bleeding, initiation of aspirin for primary prevention should generally be avoided. Instead, risk factor modification should be prioritized. The net benefit of aspirin in those at high risk for cardiovascular disease and in those with uncontrolled diabetes is largely unknown. Ultimately, initiation or withdrawal of aspirin therapy must involve discussion of the patient's wishes and treatment expectations.

Aspirin Efficacy in Primary Prevention: A Meta-analysis of Randomized Controlled Trials

INTRODUCTION

The role of aspirin as a means of primary prevention remains controversial.

AIM

We have conducted a meta-analysis of all randomized controlled trials (RCTs) to evaluate the role of aspirin in primary prevention.

METHODS

Literature search was performed via PubMed, Embase, and the Cochrane Library for all related RCTs. All-cause mortality was the primary endpoint. Secondary endpoints included major adverse cardiovascular events (MACE), myocardial infarction (MI), cardiovascular mortality, cerebrovascular events, and bleeding events. We used a random effects model to report the risk ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

Our analysis included 17 RCTs (164,862 patients; 83,309 received aspirin and 81,744 received placebo). Our study did not demonstrate any significant reduction in all-cause mortality for patients treated with aspirin when compared with placebo (RR 0.97; 95% CI 0.93-1.01; P = 0.13). Sensitivity analysis performed by excluding healthy elderly (≥ 65) showed significant reductions in all-cause mortality in the aspirin-treated patients (RR 0.94; 95% CI 0.90-0.99; P = 0.01). There were no significant differences between both groups regarding cardiovascular mortality and cerebrovascular events (P > 0.05). However, aspirin-treated patients significantly reduced MACE and MI events (RR 0.89; 95% CI 0.85-0.93; P < 0.001 and RR 0.88; 95% CI 0.78-0.98; P = 0.02, respectively), respectively. However, aspirin was associated with a significantly higher incidence of bleeding, including major bleeding and intracranial bleeding (P < 0.001).

CONCLUSIONS

Aspirin use in primary prevention has resulted in a lower incidence of MACE and MI without significantly effecting cerebrovascular events. However, aspirin was associated with a higher bleeding risk. Use of aspirin as a means of primary prevention should be thoroughly discussed with patients and pursued based on the risk of cardiovascular disease while also considering bleeding risk.

Aspirin for primary prevention of stroke in individuals without cardiovascular disease-A meta-analysis

Background

The benefits of aspirin for primary prevention of stroke are uncertain.

Methods

We performed a cumulative meta-analysis of trials investigating aspirin for primary prevention of cardiovascular disease with a focus on stroke. We assessed the effects of aspirin on non-fatal stroke, hemorrhagic stroke, non-fatal myocardial infarction, all-cause mortality, cardiovascular mortality, major gastrointestinal bleeding, and an analysis of net clinical effect, in populations without a history of clinical or subclinical cardiovascular disease.

Summary of review results

Among 11 trials (157,054 participants), aspirin was not associated with a statistically significant reduction in non-fatal stroke (odds ratio, 0.94; 95% CI, 0.85 to 1.04) but was associated with an increased risk of hemorrhagic stroke (odds ratio, 1.29; 95% CI, 1.06 to 1.56). Aspirin was not associated with a statistically significant reduction in all-cause mortality (odds ratio, 0.97; 95% CI, 0.92 to 1.03) or cardiovascular mortality (odds ratio, 0.94; 95% CI, 0.85 to 1.03). Aspirin was associated with a reduction in non-fatal myocardial infarction (odds ratio, 0.80; 95% CI, 0.69 to 0.94) and an increased risk of major gastrointestinal bleeding (odds ratio, 1.83; 95% CI, 1.43 to 2.35). Using equal weighting for non-fatal events and major bleeding, we observed no net clinical benefit with aspirin use for primary prevention.

Conclusion

Our meta-analysis reports no benefit of aspirin for primary stroke prevention.

Aspirin has potential benefits for primary prevention of cardiovascular outcomes in diabetes: updated literature-based and individual participant data meta-analyses of randomized controlled trials

Background

The clinical benefit of aspirin for the primary prevention of cardiovascular disease (CVD) in diabetes remains uncertain. To evaluate the efficacy and safety of aspirin for the primary prevention of cardiovascular outcomes and all-cause mortality events in people with diabetes, we conducted an updated meta-analysis of published randomised controlled trials (RCTs) and a pooled analysis of individual participant data (IPD) from three trials.

Methods

Randomised controlled trials of aspirin compared with placebo (or no treatment) in participants with diabetes with no known CVD were identified from MEDLINE, Embase, Cochrane Library, and manual search of bibliographies to January 2019. Relative risks with 95% confidence intervals were used as the summary measures of associations.

Results

We included 12 RCTs based on 34,227 participants with a median treatment duration of 5.0 years. Comparing aspirin use with no aspirin, there was a significant reduction in risk of major adverse cardiovascular events (MACE)0.89 (0.83–0.95), with a number needed to treat (NNT)of 95 (95% CI 61 to 208) to prevent one MACE over 5 years average follow-up. Evidence was lacking of heterogeneity and publication bias among contributing trials for MACE. Aspirin use had no effect on other endpoints including all-cause mortality; however, there was a significant reduction in stroke for aspirin dosage ≤ 100 mg/day 0.75 (0.59–0.95). There were no significant effects of aspirin use on major bleeding and other bleeding events, though some of the estimates were imprecise. Pooled IPD from the three trials (2306 participants) showed no significant evidence of an effect of aspirin on any of the outcomes evaluated; however, aspirin reduced the risk of MACE in non-smokers 0.70 (0.51–0.96) with a NNT of 33 (95% CI 20 to 246) to prevent one MACE.

Conclusions

Aspirin has potential benefits in cardiovascular primary prevention in diabetes. The use of low dose aspirin may need to be individualised and based on each individual’s baseline CVD and bleeding risk.

Systematic review registration PROSPERO: CRD42019122326

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0875-4) contains supplementary material, which is available to authorized users.

The rise and fall of aspirin in the primary prevention of cardiovascular disease

Aspirin is one of the most frequently used drugs worldwide and is generally considered effective for the secondary prevention of cardiovascular disease. By contrast, the role of aspirin in primary prevention of cardiovascular disease is controversial. Early trials evaluating aspirin for primary prevention, done before the turn of the millennium, suggested reductions in myocardial infarction and stroke (although not mortality), and an increased risk of bleeding. In an effort to balance the risks and benefits of aspirin, international guidelines on primary prevention of cardiovascular disease have typically recommended aspirin only when a substantial 10-year risk of cardiovascular events exists. However, in 2018, three large randomised clinical trials of aspirin for the primary prevention of cardiovascular disease showed little or no benefit and have even suggested net harm. In this narrative Review, we reappraise the role of aspirin in primary prevention of cardiovascular disease, contextualising data from historical and contemporary trials.

Efficacy and safety of aspirin for primary prevention of cardiovascular events: a meta-analysis and trial sequential analysis of randomized controlled trials

AIMS

The role of aspirin in the primary prevention setting is continuously evolving. Recent randomized trials have challenged the role of aspirin in the primary prevention setting.

METHODS AND RESULTS

Electronic databases were searched for randomized trials that compared aspirin vs. placebo (or control) in subjects without established atherosclerotic disease. The primary efficacy outcome was all-cause mortality, while the primary safety outcome was major bleeding. Summary estimates were reported using a DerSimonian and Laird random effects model. A total of 11 trials with 157 248 subjects were included. At a mean follow-up of 6.6 years, aspirin was not associated with a lower incidence of all-cause mortality [risk ratio (RR) 0.98, 95% confidence interval (CI) 0.93-1.02; P = 0.30]; however, aspirin was associated with an increased incidence of major bleeding (RR 1.47, 95% CI 1.31-1.65; P < 0.0001) and intracranial haemorrhage (RR 1.33, 95% CI 1.13-1.58; P = 0.001). A similar effect on all-cause mortality and major bleeding was demonstrated in diabetic and high cardiovascular risk patients (i.e. 10-year risk >7.5%). Aspirin was associated with a lower incidence of myocardial infarction (RR 0.82, 95% CI 0.71-0.94; P = 0.006); however, this outcome was characterized by considerable heterogeneity (I2 = 67%), and this effect was no longer evident upon limiting the analysis to the more recent trials. Trial sequential analysis confirmed the lack of benefit of aspirin for all-cause mortality up to a relative risk reduction of 5%.

CONCLUSION

Among adults without established cardiovascular disease, aspirin was not associated with a reduction in the incidence of all-cause mortality; however, it was associated with an increased incidence of major bleeding. The routine use of aspirin for primary prevention needs to be reconsidered.

Prevention of atherothrombotic events in patients with diabetes mellitus: from antithrombotic therapies to new-generation glucose-lowering drugs

Diabetes mellitus is an important risk factor for a first cardiovascular event and for worse outcomes after a cardiovascular event has occurred. This situation might be caused, at least in part, by the prothrombotic status observed in patients with diabetes. Therefore, contemporary antithrombotic strategies, including more potent agents or drug combinations, might provide greater clinical benefit in patients with diabetes than in those without diabetes. In this Consensus Statement, our Working Group explores the mechanisms of platelet and coagulation activity, the current debate on antiplatelet therapy in primary cardiovascular disease prevention, and the benefit of various antithrombotic approaches in secondary prevention of cardiovascular disease in patients with diabetes. While acknowledging that current data are often derived from underpowered, observational studies or subgroup analyses of larger trials, we propose antithrombotic strategies for patients with diabetes in various cardiovascular settings (primary prevention, stable coronary artery disease, acute coronary syndromes, ischaemic stroke and transient ischaemic attack, peripheral artery disease, atrial fibrillation, and venous thromboembolism). Finally, we summarize the improvements in cardiovascular outcomes observed with the latest glucose-lowering drugs, and on the basis of the available evidence, we expand and integrate current guideline recommendations on antithrombotic strategies in patients with diabetes for both primary and secondary prevention of cardiovascular disease.

Association of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis

IMPORTANCE

The role for aspirin in cardiovascular primary prevention remains controversial, with potential benefits limited by an increased bleeding risk.

OBJECTIVE

To assess the association of aspirin use for primary prevention with cardiovascular events and bleeding.

DATA SOURCES

PubMed and Embase were searched on Cochrane Library Central Register of Controlled Trials from the earliest available date through November 1, 2018.

STUDY SELECTION

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.

MAIN OUTCOMES AND MEASURES

The primary cardiovascular outcome was a composite of cardiovascular mortality, nonfatal myocardial infarction, and nonfatal stroke. The primary bleeding outcome was any major bleeding (defined by the individual studies).

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 9.2% (range, 2.6%-15.9%). Aspirin use was associated with significant reductions in the composite cardiovascular outcome compared with no aspirin (57.1 per 10 000 participant-years with aspirin and 61.4 per 10 000 participant-years with no aspirin) (hazard ratio [HR], 0.89 [95% credible interval, 0.84-0.95]; absolute risk reduction, 0.38% [95% CI, 0.20%-0.55%]; number needed to treat, 265). 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 AND RELEVANCE

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.

De vuelta a la clínica: sin justificación no existe pregunta de investigación que valga

A clinical research question requires the concurrence of clinical experience and knowledge on methodology and statistics in that who formulates it. Initially, a research question should have a structure that clearly establishes what is that which is being sought (consequence or outcome), in whom (baseline status), and by action of what (maneuver). Subsequently, its reasoning must explore four aspects: feasibility and reasonableness of the questioning, lack of a prior answer, relevance of the answer to be obtained, and applicability. Once these aspects are satisfactorily covered, the question can be regarded as being "clinically relevant", which is different from being statistically significant, which refers to the probability of the result being driven by chance, which does not reflect the relevance of the question or the outcome. One should never forget that every maneuver entails adverse events that, when serious, discredit good results. It is imperative to have the possible answer estimated from within the structure of the question. The function of clinical research is to corroborate or reject a hypothesis, rather than to empirically test to find out what the outcome is.

Aspirin for Primary Prevention of Cardiovascular Disease and Renal Disease Progression in Chronic Kidney Disease Patients: a Multicenter Randomized Clinical Trial (AASER Study)

BACKGROUND

Patients with chronic kidney disease (CKD) are at high risk for developing cardiovascular events. However, limited evidence is available regarding the use of aspirin in CKD patients to decrease cardiovascular risk and to slow renal disease progression.

STUDY DESIGN

Prospective, multicenter, open-label randomized controlled trial.

SETTING AND PARTICIPANTS

One hundred eleven patients with estimated glomerular filtration rate (eGFR) 15-60 ml/min/1.73 m² without previous cardiovascular events.

INTERVENTION

Aspirin treatment (100 mg/day) (n = 50) or usual therapy (n = 61). Mean follow-up time was 64.8 ± 16.4 months.

OUTCOMES

The primary endpoint was composed of cardiovascular death, acute coronary syndrome (nonfatal MI, coronary revascularization, or unstable angina pectoris), cerebrovascular disease, heart failure, or nonfatal peripheral arterial disease. Secondary endpoints were fatal and nonfatal coronary events, renal events (defined as doubling of serum creatinine, ≥ 50% decrease in eGFR, or renal replacement therapy), and bleeding episodes.

RESULTS

During follow-up, 17 and 5 participants suffered from a primary endpoint in the control and aspirin groups, respectively. Aspirin did not significantly reduce primary composite endpoint (HR, 0.396 (0.146-1.076), p = 0.069. Eight patients suffered from a fatal or nonfatal coronary event in the control group compared to no patients in the aspirin group. Aspirin significantly reduced the risk of coronary events (log-rank, 5.997; p = 0.014). Seventeen patients in the control group reached the renal outcome in comparison with 3 patients in the aspirin group. Aspirin treatment decreased renal disease progression in a model adjusted for age, baseline kidney function, and diabetes mellitus (HR, 0.272; 95% CI, 0.077-0.955; p = 0.043) but did not when adjusted for albuminuria. No differences were found in minor bleeding episodes between groups and no major bleeding was registered.

LIMITATIONS

Small sample size and open-label trial.

CONCLUSIONS

Long-term treatment with low-dose aspirin did not reduce the composite primary endpoint; however, there were reductions in secondary endpoints with fewer coronary events and renal outcomes. ClinicalTrials.gov Identifier: NCT01709994.

Impact of acetylsalicylic acid on primary prevention of cardiovascular diseases: A meta-analysis of randomized trials

Numerous studies have investigated use of acetylsalicylic acid (ASA) for prevention of cardiovascular deaths. The vast majority of the work in this area has focused on secondary prevention. However, underuse of ASA still remains a major issue. Fewer studies have investigated the impact of ASA on primary prevention of cardiovascular death. A meta-analysis of individual participant data from six randomized studies, published in 2009, showed decrease in serious vascular events but at the cost of causing increased bleeding and hemorrhagic stroke. Recent studies have raised a number of key questions regarding the benefits and risks of using ASA for primary prevention.

Effect of Aspirin on All-Cause Mortality in the Healthy Elderly

BACKGROUND

In the primary analysis of the Aspirin in Reducing Events in the Elderly (ASPREE) trial, now published in the Journal, we report that the daily use of aspirin did not provide a benefit with regard to the primary end point of disability-free survival among older adults. A numerically higher rate of the secondary end point of death from any cause was observed with aspirin than with placebo.

METHODS

From 2010 through 2014, we enrolled community-dwelling persons in Australia and the United States who were 70 years of age or older (or ≥65 years of age among blacks and Hispanics in the United States) and did not have cardiovascular disease, dementia, or disability. Participants were randomly assigned to receive 100 mg of enteric-coated aspirin or placebo. Deaths were classified according to the underlying cause by adjudicators who were unaware of trial-group assignments. Hazard ratios were calculated to compare mortality between the aspirin group and the placebo group, and post hoc exploratory analyses of specific causes of death were performed.

RESULTS

Of the 19,114 persons who were enrolled, 9525 were assigned to receive aspirin and 9589 to receive placebo. A total of 1052 deaths occurred during a median of 4.7 years of follow-up. The risk of death from any cause was 12.7 events per 1000 person-years in the aspirin group and 11.1 events per 1000 person-years in the placebo group (hazard ratio, 1.14; 95% confidence interval [CI], 1.01 to 1.29). Cancer was the major contributor to the higher mortality in the aspirin group, accounting for 1.6 excess deaths per 1000 person-years. Cancer-related death occurred in 3.1% of the participants in the aspirin group and in 2.3% of those in the placebo group (hazard ratio, 1.31; 95% CI, 1.10 to 1.56).

CONCLUSIONS

Higher all-cause mortality was observed among apparently healthy older adults who received daily aspirin than among those who received placebo and was attributed primarily to cancer-related death. In the context of previous studies, this result was unexpected and should be interpreted with caution. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number, NCT01038583 .).

Effect of Aspirin on Disability-free Survival in the Healthy Elderly

BACKGROUND

Information on the use of aspirin to increase healthy independent life span in older persons is limited. Whether 5 years of daily low-dose aspirin therapy would extend disability-free life in healthy seniors is unclear.

METHODS

From 2010 through 2014, we enrolled community-dwelling persons in Australia and the United States who were 70 years of age or older (or ≥65 years of age among blacks and Hispanics in the United States) and did not have cardiovascular disease, dementia, or physical disability. Participants were randomly assigned to receive 100 mg per day of enteric-coated aspirin or placebo orally. The primary end point was a composite of death, dementia, or persistent physical disability. Secondary end points reported in this article included the individual components of the primary end point and major hemorrhage.

RESULTS

A total of 19,114 persons with a median age of 74 years were enrolled, of whom 9525 were randomly assigned to receive aspirin and 9589 to receive placebo. A total of 56.4% of the participants were women, 8.7% were nonwhite, and 11.0% reported previous regular aspirin use. The trial was terminated at a median of 4.7 years of follow-up after a determination was made that there would be no benefit with continued aspirin use with regard to the primary end point. The rate of the composite of death, dementia, or persistent physical disability was 21.5 events per 1000 person-years in the aspirin group and 21.2 per 1000 person-years in the placebo group (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11; P=0.79). The rate of adherence to the assigned intervention was 62.1% in the aspirin group and 64.1% in the placebo group in the final year of trial participation. Differences between the aspirin group and the placebo group were not substantial with regard to the secondary individual end points of death from any cause (12.7 events per 1000 person-years in the aspirin group and 11.1 events per 1000 person-years in the placebo group), dementia, or persistent physical disability. The rate of major hemorrhage was higher in the aspirin group than in the placebo group (3.8% vs. 2.8%; hazard ratio, 1.38; 95% CI, 1.18 to 1.62; P<0.001).

CONCLUSIONS

Aspirin use in healthy elderly persons did not prolong disability-free survival over a period of 5 years but led to a higher rate of major hemorrhage than placebo. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number, NCT01038583 .).

Efficacy and safety of chemopreventive agents on colorectal cancer incidence and mortality: systematic review and network meta-analysis

Background

Various interventions have been tested as primary prevention of colorectal cancers (CRC), but comprehensive evidence comparing them is absent. We examined the effects of various chemopreventive agents (CPAs) on CRC incidence and mortality.

Methods

We did a network meta-analysis based on a systematic review of randomized controlled trials (RCTs) that compared at least one CPA (aspirin, antioxidants, folic acid, vitamin B6, vitamin B12, calcium, vitamin D, alone or in combination) to placebo or other CPA in persons without history of CRC. Several databases were searched from inception up to March 2017. Primary outcomes were early and long-term CRC incidence and mortality.

Results

Twenty-one RCTs comprising 281,063 participants, 9 RCTS comprising 160,101 participants, and 7 RCTs comprising 24,001 participants were included in the network meta-analysis for early risk of CRC incidence, long-term risk of CRC incidence and mortality, respectively. For early CRC incidence, no CPAs were found to be effective. For long-term CRC incidence and mortality, aspirin was the only intervention that showed protective effects with potential dose-dependent effects (risk ratio [RR], 0.74 [95% CI, 0.57–0.97] for high-dose [≥325 mg/day] and RR, 0.81 [95% CI, 0.67–0.98] for very-low-dose [≤100 mg/day]). Similar trend was found for mortality (RR, 0.43 [95% CI, 0.23–0.81] for low-dose [>100–325 mg/day] and RR, 0.65 [95% CI, 0.45–0.94] for very-low-dose). However, in net clinical benefit analysis, when combining risk estimates on mortality from CRC, cardiovascular disease, and pooled risk estimates of major gastrointestinal bleeding, low-dose aspirin provided the highest net survival gain (%) of 1.736 [95% CI, 1.010–2.434].

Conclusion

Aspirin at the dose range of 75–325 mg/day is a safe and effective primary prevention for long-term CRC among people at average risk. None of the other CPAs were found to be effective. There may potentially be differential effects among various doses of aspirin that needs further investigation.

Risk of gastrointestinal bleeding and benefit from colorectal cancer reduction from long-term use of low-dose aspirin: A retrospective study of 612 509 patients

BACKGROUND AND AIM

Aspirin, commonly used for prevention of cardiovascular and cerebrovascular diseases, is well known to protect against development of colorectal cancer (CRC) but increases risk of gastrointestinal bleeding (GIB). This cohort study aims to evaluate the benefit of low-dose aspirin to prevent CRC and its associated risk of GIB.

METHOD

A population-based dataset was used to compare incidence and mortality of CRC and GIB among patients receiving low-dose aspirin with sex-matched and age-matched controls (1:2). A total of 204 170 aspirin users taking aspirin for at least 6 months and 408 339 nonusers were analyzed. Patients' clinical outcomes were documented for up to 14 years or until death.

RESULTS

A total of 612 509 patients were included; 5118 (2.51%) out of 204 170 aspirin users were diagnosed with CRC; and 2073 (1.02%) died of the malignancy. On the other hand, 13 336 (3.27%) out of 408 339 non-aspirin users were diagnosed with CRC, and 6953 (1.70%) died. Using the competing risk regression, aspirin usage significantly reduced CRC mortality (subdistribution hazard ratio = 0.59; 95% confidence interval = 0.56 to 0.62). A total of 9483 (4.64%) aspirin users developed GIB, and 820 (0.40%) died, while 11 198 (2.74%) nonusers developed GIB, and 1488 (0.36%) died. Aspirin usage marginally increased risk of bleeding-related mortality (subdistribution hazard ratio = 1.09; 95% confidence interval = 1.00 to 1.19). Subgroup analyses showed the use of acid-secreting agents significantly reduced aspirin-induced mortality.

CONCLUSION

The long-term use of aspirin reduces both incidence and mortality of CRC and at the same time increases incidence and mortality risk of GIB. With combination use of acid-secreting agents, the bleeding risk can be reduced.

Use of aspirin to reduce risk of initial vascular events in patients at moderate risk of cardiovascular disease (ARRIVE): a randomised, double-blind, placebo-controlled trial

BACKGROUND

The use of aspirin in the primary prevention of cardiovascular events remains controversial. We aimed to assess the efficacy and safety of aspirin versus placebo in patients with a moderate estimated risk of a first cardiovascular event.

METHODS

ARRIVE is a randomised, double-blind, placebo-controlled, multicentre study done in seven countries. Eligible patients were aged 55 years (men) or 60 years (women) and older and had an average cardiovascular risk, deemed to be moderate on the basis of the number of specific risk factors. We excluded patients at high risk of gastrointestinal bleeding or other bleeding, or diabetes. Patients were randomly assigned (1:1) with a computer-generated randomisation code to receive enteric-coated aspirin tablets (100 mg) or placebo tablets, once daily. Patients, investigators, and others involved in treatment or data analysis were masked to treatment allocation. The primary efficacy endpoint was a composite outcome of time to first occurrence of cardiovascular death, myocardial infarction, unstable angina, stroke, or transient ischaemic attack. Safety endpoints were haemorrhagic events and incidence of other adverse events, and were analysed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00501059.

FINDINGS

Between July 5, 2007, and Nov 15, 2016, 12 546 patients were enrolled and randomly assigned to receive aspirin (n=6270) or placebo (n=6276) at 501 study sites. Median follow-up was 60 months. In the intention-to-treat analysis, the primary endpoint occurred in 269 (4·29%) patients in the aspirin group versus 281 (4·48%) patients in the placebo group (hazard ratio [HR] 0·96; 95% CI 0·81-1·13; p=0·6038). Gastrointestinal bleeding events (mostly mild) occurred in 61 (0·97%) patients in the aspirin group versus 29 (0·46%) in the placebo group (HR 2·11; 95% CI 1·36-3·28; p=0·0007). The overall incidence rate of serious adverse events was similar in both treatment groups (n=1266 [20·19%] in the aspirin group vs n=1311 [20·89%] in the placebo group. The overall incidence of adverse events was similar in both treatment groups (n=5142 [82·01%] vs n=5129 [81·72%] in the placebo group). The overall incidence of treatment-related adverse events was low (n=1050 [16·75%] vs n=850 [13·54%] in the placebo group; p<0·0001). There were 321 documented deaths in the intention-to-treat population (n=160 [2·55%] vs n=161 [2·57%] of 6276 patients in the placebo group).

INTERPRETATION

The event rate was much lower than expected, which is probably reflective of contemporary risk management strategies, making the study more representative of a low-risk population. The role of aspirin in primary prevention among patients at moderate risk could therefore not be addressed. Nonetheless, the findings with respect to aspirin's effects are consistent with those observed in the previously published low-risk primary prevention studies.

FUNDING

Bayer.

Oral antiplatelets in primary and secondary prevention of myocardial infarction: a review

There are a number of guidelines and articles available for the use of oral antiplatelets for primary and secondary prevention of myocardial infarction (MI). Antiplatelet medications inhibit platelet activation, aggregation, and other pathways eventually inhibiting clot formation. Aspirin and clopidogrel have been the mainstay in the management of acute coronary syndrome for about a decade. We have discussed the role of aspirin, clopidogrel, ticagrelor, and prasugrel which are the most commonly used oral antiplatelet medications in the current era. We have also considered the role of newer thrombin inhibitor vorapaxar, and dual antiplatelet therapy. In this review paper, we have summarized the continuing controversy about the use of oral antiplatelet therapy and their role in primary as well as secondary prevention of MI by describing results from major clinical trials. The safety and the efficacy of the above medications have been reviewed and described in this paper.

Racial and Ethnic Differences in the Relationship between Aspirin Use and Non-Small Cell Lung Cancer Risk and Survival

BACKGROUND

African Americans (AA) experience higher incidence and mortality of lung cancer as compared with European Americans (EA). Inflammation is associated with lung cancer, many aspects of which differ between AA and EA. We investigated whether use, frequency, and duration of the anti-inflammatory drug aspirin were associated with lung cancer risk and survival, separately among AA and EA populations.

METHODS

Using data from the Maryland Non-Small Cell Lung Cancer (NSCLC) Case-Control Study (1,220 cases [404 AA and 816 EA] and 1,634 controls [1,004 EA and 630 AA]), we estimated the adjusted odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CI) of the associations between aspirin use and NSCLC risk and survival, respectively.

RESULTS

Any aspirin use (OR: 0.66; 95% CI, 0.49-0.89), daily use of ≥ 1 tablet (OR: 0.68; 95% CI, 0.50-0.90), and use for ≥ 3 years (OR: 0.61; 95% CI, 0.44-0.85) was associated with lower NSCLC risk only among men, even after adjustment for covariates including body mass index and global genetic ancestry. These variables were also associated with improved survival, but only among AA (HR: 0.64; 95% CI, 0.46-0.91; HR: 0.61; 95% CI, 0.42-0.90; and HR: 0.60; 95% CI, 0.39-0.92, respectively). Tylenol and other NSAIDs were either associated with elevated or no NSCLC risk.

CONCLUSIONS

Aspirin use is associated with lower risk of NSCLC among men and improved survival among AA.

IMPACT

Preventive regular aspirin use could be considered among men and AA.

Effects of aspirin on risks of vascular events and cancer according to bodyweight and dose: analysis of individual patient data from randomised trials

BACKGROUND

A one-dose-fits-all approach to use of aspirin has yielded only modest benefits in long-term prevention of cardiovascular events, possibly due to underdosing in patients of large body size and excess dosing in patients of small body size, which might also affect other outcomes.

METHODS

Using individual patient data, we analysed the modifying effects of bodyweight (10 kg bands) and height (10 cm bands) on the effects of low doses (≤100 mg) and higher doses (300-325 mg or ≥500 mg) of aspirin in randomised trials of aspirin in primary prevention of cardiovascular events. We stratified the findings by age, sex, and vascular risk factors, and validated them in trials of aspirin in secondary prevention of stroke. Additionally, we assessed whether any weight or height dependence was evident for the effect of aspirin on 20-year risk of colorectal cancer or any in-trial cancer.

RESULTS

Among ten eligible trials of aspirin in primary prevention (including 117 279 participants), bodyweight varied four-fold and trial median weight ranged from 60·0 kg to 81·2 kg (p<0·0001). The ability of 75-100 mg aspirin to reduce cardiovascular events decreased with increasing weight (pinteraction=0·0072), with benefit seen in people weighing 50-69 kg (hazard ratio [HR] 0·75 [95% CI 0·65-0·85]) but not in those weighing 70 kg or more (0·95 [0·86-1·04]; 1·09 [0·93-1·29] for vascular death). Furthermore, the case fatality of a first cardiovascular event was increased by low-dose aspirin in people weighing 70 kg or more (odds ratio 1·33 [95% CI 1·08-1·64], p=0·0082). Higher doses of aspirin (≥325 mg) had the opposite interaction with bodyweight (difference pinteraction=0·0013), reducing cardiovascular events only at higher weight (pinteraction=0·017). Findings were similar in men and women, in people with diabetes, in trials of aspirin in secondary prevention, and in relation to height (pinteraction=0·0025 for cardiovascular events). Aspirin-mediated reductions in long-term risk of colorectal cancer were also weight dependent (pinteraction=0·038). Stratification by body size also revealed harms due to excess dosing: risk of sudden death was increased by aspirin in people at low weight for dose (pinteraction=0·0018) and risk of all-cause death was increased in people weighing less than 50 kg who were receiving 75-100 mg aspirin (HR 1·52 [95% CI 1·04-2·21], p=0·031). In participants aged 70 years or older, the 3-year risk of cancer was also increased by aspirin (1·20 [1·03-1·47], p=0·02), particularly in those weighing less than 70 kg (1·31 [1·07-1·61], p=0·009) and consequently in women (1·44 [1·11-1·87], p=0·0069).

INTERPRETATION

Low doses of aspirin (75-100 mg) were only effective in preventing vascular events in patients weighing less than 70 kg, and had no benefit in the 80% of men and nearly 50% of all women weighing 70 kg or more. By contrast, higher doses of aspirin were only effective in patients weighing 70 kg or more. Given that aspirin's effects on other outcomes, including cancer, also showed interactions with body size, a one-dose-fits-all approach to aspirin is unlikely to be optimal, and a more tailored strategy is required.

FUNDING

Wellcome Trust and National Institute for Health Research Oxford Biomedical Research Centre.

Aspirin Resistance and Stroke

Stroke is a leading cause of death and disability worldwide. Aspirin is the most commonly used antiplatelet drug in both primary and secondary prevention of cerebrovascular and cardiovascular diseases. A proportion of patients may have stroke recurrence while they are on treatment with aspirin, giving rise to term aspirin resistance or aspirin failure. Studies have suggested that such recurrence could partly be attributed to biochemical aspirin resistance, with an estimated prevalence ranging between 5% and 65% among patients with ischemic stroke in the published studies. Common methods to evaluate laboratory aspirin resistance include light transmission aggregometry, PFA-100, VerifyNow-Aspirin assay, serum thromboxane B2, and urinary 11-dehydrothromboxane B2. Aspirin resistance is multifactorial in origin and involves diverse environmental and genetic factors, including single-nucleotide polymorphisms, miRNAs, drug interactions, and co-morbid risk factors. The current review overviews the concept of aspirin resistance, its evaluation and relationship with stroke recurrence, its outcome, and its implications on stroke management in the future.