Randomised trial of prophylactic daily aspirin in British male doctors

Migraine history, nonsteroidal anti-inflammatory drug use, and risk of postmenopausal endometrial cancer

Endometrial cancer is primarily a hormonally mediated disease. As such, factors that mediate or reflect exposure to estrogens, or that mediate response to such exposure, may plausibly be associated with endometrial cancer risk. History of migraines, another hormonally mediated condition, has recently been associated with a reduced risk of hormone receptor-positive breast cancer; however, the relationship between migraines and endometrial cancer has not previously been explored. We evaluated the relationship between migraine history and endometrial cancer risk in postmenopausal women, considering also the potential impact of nonsteroidal anti-inflammatory drug (NSAID) use, given the relationship of NSAIDs to hormones and to migraine history. We identified 93,384 women participating in the Women's Health Initiative prospective cohort who had an intact uterus at the time of study entry. Using Cox proportional hazards regression, we assessed risk of endometrial cancer during study follow-up according to history of migraines and according to current NSAID use at the time of study entry, adjusting for age, study arm, race, and hormone therapy use. We also evaluated interaction in these associations by body mass index. Having a history of migraines was not associated with endometrial cancer risk [hazard ratio (HR) = 0.91, 95% confidence interval (CI) = 0.75-1.11], regardless of body mass index (BMI) or NSAID use status. Similarly, current NSAID use was not associated with endometrial cancer risk (HR = 1.01, 95% CI = 0.88-1.16), regardless of BMI. Migraine history and NSAID use do not appear to be associated with risk of endometrial cancer.

Inducing apoptosis in rolling cancer cells: a combined therapy with aspirin and immobilized TRAIL and E-selectin

Though metastasis is considered an inefficient process, over 90% of cancer related deaths are attributed to the formation of secondary tumors. Thus, eliminating circulating cancer cells could lead to improved patient survival. This study was aimed at exploiting the interactions of cancer cells with selectins under flow to selectively kill captured colon cancer cells. Microtubes functionalized with E-selectin and TRAIL were perfused with colon cancer cell line Colo205 either treated with 1 mM aspirin or untreated for 1 or 2 h. Cells were collected from the microtube and analyzed by flow cytometry. Aspirin treatment alone killed only 3% cells in culture. A 95% difference in the number of cells killed between control and TRAIL + ES surfaces was seen when aspirin treated cells were perfused over the functionalized surface for 2 h. We have demonstrated a novel biomimetic method to capture and neutralize cancer cells in flow, thus reducing the chances for the formation of secondary tumors.

Aspirin in the primary prevention of cardiovascular disease in the Women's Health Study: effect of noncompliance

Randomized evidence for aspirin in the primary prevention of cardiovascular disease (CVD) among women is limited and suggests at most a modest effect for total CVD. Lack of compliance, however, can null-bias estimated effects. We used marginal structural models (MSMs) to estimate the etiologic effect of continuous aspirin use on CVD events among 39,876 apparently healthy female health professionals aged 45 years and older in the Women's Health Study, a randomized trial of 100 mg aspirin every other day versus placebo. As-treated analyses and MSMs controlled for time-varying determinants of aspirin use and CVD. Predictors of aspirin use differed by randomized group and prior use and included medical history, CVD risk factors, and intermediate CVD events. Previously reported intent-to-treat analyses found small non-significant effects of aspirin on total CVD (hazard ratio (HR) = 0.91, 95 % confidence interval (CI) = 0.81-1.03) and CVD mortality (HR = 0.95, 95 % CI = 0.74-1.22). As-treated analyses were similar for total CVD with a slight reduction in CVD mortality (HR = 0.88, 95 % CI = 0.67-1.16). MSMs, which adjusted for non-compliance, were similar for total CVD (HR = 0.93; 95 % CI: 0.81, 1.07) but suggested lower CVD mortality with aspirin use (HR = 0.76; 95 % CI: 0.54, 1.08). Adjusting for non-compliance had little impact on the estimated effect of aspirin on total CVD, but strengthened the effect on CVD mortality. These results support a limited effect of low-dose aspirin on total CVD in women, but potential benefit for CVD mortality.

Should more patients continue aspirin therapy perioperatively?: clinical impact of aspirin withdrawal syndrome

OBJECTIVE

To provide an evidence-based focused review of aspirin use in the perioperative period along with an in-depth discussion of the considerations and risks associated with its preoperative withdrawal.

BACKGROUND

For patients with established cardiovascular disease, taking aspirin is considered a critical therapy. The cessation of aspirin can cause a platelet rebound phenomenon and prothrombotic state leading to major adverse cardiovascular events. Despite the risks of aspirin withdrawal, which are exacerbated during the perioperative period, standard practice has been to stop aspirin before elective surgery for fear of excessive bleeding. Mounting evidence suggests that this practice should be abandoned.

METHODS

We performed a PubMed and Medline literature search using the keywords aspirin, withdrawal, and perioperative. We manually reviewed relevant citations for inclusion.

RESULTS/CONCLUSIONS

Clinicians should employ a patient-specific strategy for perioperative aspirin management that weighs the risks of stopping aspirin with those associated with its continuation. Most patients, especially those taking aspirin for secondary cardiovascular prevention, should have their aspirin continued throughout the perioperative period. When aspirin is held preoperatively, the aspirin withdrawal syndrome may significantly increase the risk of a major thromboembolic complication. For many operative procedures, the risk of perioperative bleeding while continuing aspirin is minimal, as compared with the concomitant thromboembolic risks associated with aspirin withdrawal. Those cases where aspirin should be stopped include patients undergoing intracranial, middle ear, posterior eye, intramedullary spine, and possibly transurethral prostatectomy surgery.

Migraine: possible role of shear-induced platelet aggregation with serotonin release

BACKGROUND

Migraine patients are at an increased risk for stroke, as well as other thromboembolic events. This warrants further study of the role of platelets in a proportion of migraine patients.

OBJECTIVE

To extend the "platelet hypothesis" using literature data and observations made in a rat model of shear stress-induced platelet aggregation. Such aggregation causes release of serotonin, leading to vasoconstriction during sufficiently strong aggregation and to long-lasting vasodilation when aggregation diminishes. This vasodilation also depends on nitric oxide and prostaglandin formation.

RESULTS

A role for platelet aggregation in a number of migraineurs is indicated by reports of an increased platelet activity during attacks and favorable effects of antiplatelet medication. We hypothesize that in those patients, a migraine attack with or without aura may both be caused by a rise in platelet-released plasma serotonin, albeit at different concentration. At high concentrations, serotonin may cause vasoconstriction and, consequently, the neuronal signs of aura, whereas at low concentrations, it may already stimulate perivascular pain fibers and cause vasodilation via local formation of nitric oxide, prostaglandins, and neuropeptides. Platelet aggregation may be unilaterally evoked by elevated shear stress in a stenotic cervico-cranial artery, by reversible vasoconstriction or by other cardiovascular abnormality, eg, a symptomatic patent foramen ovale. This most likely occurs when a migraine trigger has further enhanced platelet aggregability; literature shows that many triggers either stimulate platelets directly or reduce endogenous platelet antagonists like prostacyclin.

CONCLUSION

New strategies for migraine medication and risk reduction of stroke are suggested.

Effect of daily aspirin on risk of cancer metastasis: a study of incident cancers during randomised controlled trials

BACKGROUND

Daily aspirin reduces the long-term incidence of some adenocarcinomas, but effects on mortality due to some cancers appear after only a few years, suggesting that it might also reduce growth or metastasis. We established the frequency of distant metastasis in patients who developed cancer during trials of daily aspirin versus control.

METHODS

Our analysis included all five large randomised trials of daily aspirin (≥75 mg daily) versus control for the prevention of vascular events in the UK. Electronic and paper records were reviewed for all patients with incident cancer. The effect of aspirin on risk of metastases at presentation or on subsequent follow-up (including post-trial follow-up of in-trial cancers) was stratified by tumour histology (adenocarcinoma vs other) and clinical characteristics.

FINDINGS

Of 17,285 trial participants, 987 had a new solid cancer diagnosed during mean in-trial follow-up of 6·5 years (SD 2·0). Allocation to aspirin reduced risk of cancer with distant metastasis (all cancers, hazard ratio [HR] 0·64, 95% CI 0·48-0·84, p=0·001; adenocarcinoma, HR 0·54, 95% CI 0·38-0·77, p=0·0007; other solid cancers, HR 0·82, 95% CI 0·53-1·28, p=0·39), due mainly to a reduction in proportion of adenocarcinomas that had metastatic versus local disease (odds ratio 0·52, 95% CI 0·35-0·75, p=0·0006). Aspirin reduced risk of adenocarcinoma with metastasis at initial diagnosis (HR 0·69, 95% CI 0·50-0·95, p=0·02) and risk of metastasis on subsequent follow-up in patients without metastasis initially (HR 0·45, 95% CI 0·28-0·72, p=0·0009), particularly in patients with colorectal cancer (HR 0·26, 95% CI 0·11-0·57, p=0·0008) and in patients who remained on trial treatment up to or after diagnosis (HR 0·31, 95% CI 0·15-0·62, p=0·0009). Allocation to aspirin reduced death due to cancer in patients who developed adenocarcinoma, particularly in those without metastasis at diagnosis (HR 0·50, 95% CI 0·34-0·74, p=0·0006). Consequently, aspirin reduced the overall risk of fatal adenocarcinoma in the trial populations (HR 0·65, 95% CI 0·53-0·82, p=0·0002), but not the risk of other fatal cancers (HR 1·06, 95% CI 0·84-1·32, p=0·64; difference, p=0·003). Effects were independent of age and sex, but absolute benefit was greatest in smokers. A low-dose, slow-release formulation of aspirin designed to inhibit platelets but to have little systemic bioavailability was as effective as higher doses.

INTERPRETATION

That aspirin prevents distant metastasis could account for the early reduction in cancer deaths in trials of daily aspirin versus control. This finding suggests that aspirin might help in treatment of some cancers and provides proof of principle for pharmacological intervention specifically to prevent distant metastasis.

FUNDING

None.

Short-term effects of daily aspirin on cancer incidence, mortality, and non-vascular death: analysis of the time course of risks and benefits in 51 randomised controlled trials

BACKGROUND

Daily aspirin reduces the long-term risk of death due to cancer. However, the short-term effect is less certain, especially in women, effects on cancer incidence are largely unknown, and the time course of risk and benefit in primary prevention is unclear. We studied cancer deaths in all trials of daily aspirin versus control and the time course of effects of low-dose aspirin on cancer incidence and other outcomes in trials in primary prevention.

METHODS

We studied individual patient data from randomised trials of daily aspirin versus no aspirin in prevention of vascular events. Death due to cancer, all non-vascular death, vascular death, and all deaths were assessed in all eligible trials. In trials of low-dose aspirin in primary prevention, we also established the time course of effects on incident cancer, major vascular events, and major extracranial bleeds, with stratification by age, sex, and smoking status.

RESULTS

Allocation to aspirin reduced cancer deaths (562 vs 664 deaths; odds ratio [OR] 0·85, 95% CI 0·76-0·96, p=0·008; 34 trials, 69,224 participants), particularly from 5 years onwards (92 vs 145; OR 0·63, 95% CI 0·49-0·82, p=0·0005), resulting in fewer non-vascular deaths overall (1021 vs 1173; OR 0·88, 95% CI 0·78-0·96, p=0·003; 51 trials, 77,549 participants). In trials in primary prevention, the reduction in non-vascular deaths accounted for 87 (91%) of 96 deaths prevented. In six trials of daily low-dose aspirin in primary prevention (35,535 participants), aspirin reduced cancer incidence from 3 years onwards (324 vs 421 cases; OR 0·76, 95% CI 0·66-0·88, p=0·0003) in women (132 vs 176; OR 0·75, 95% CI 0·59-0·94, p=0·01) and in men (192 vs 245; OR 0·77, 95% CI 0·63-0·93, p=0·008). The reduced risk of major vascular events on aspirin was initially offset by an increased risk of major bleeding, but effects on both outcomes diminished with increasing follow-up, leaving only the reduced risk of cancer (absolute reduction 3·13 [95% CI 1·44-4·82] per 1000 patients per year) from 3 years onwards. Case-fatality from major extracranial bleeds was also lower on aspirin than on control (8/203 vs 15/132; OR 0·32, 95% CI 0·12-0·83, p=0·009).

INTERPRETATION

Alongside the previously reported reduction by aspirin of the long-term risk of cancer death, the short-term reductions in cancer incidence and mortality and the decrease in risk of major extracranial bleeds with extended use, and their low case-fatality, add to the case for daily aspirin in prevention of cancer.

FUNDING

None.

Primary and secondary prevention of cardiovascular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline focuses on long-term administration of antithrombotic drugs designed for primary and secondary prevention of cardiovascular disease, including two new antiplatelet therapies.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We present 23 recommendations for pertinent clinical questions. For primary prevention of cardiovascular disease, we suggest low-dose aspirin (75-100 mg/d) in patients aged > 50 years over no aspirin therapy (Grade 2B). For patients with established coronary artery disease, defined as patients 1-year post-acute coronary syndrome, with prior revascularization, coronary stenoses > 50% by coronary angiogram, and/or evidence for cardiac ischemia on diagnostic testing, we recommend long-term low-dose aspirin or clopidogrel (75 mg/d) (Grade 1A). For patients with acute coronary syndromes who undergo percutaneous coronary intervention (PCI) with stent placement, we recommend for the first year dual antiplatelet therapy with low-dose aspirin in combination with ticagrelor 90 mg bid, clopidogrel 75 mg/d, or prasugrel 10 mg/d over single antiplatelet therapy (Grade 1B). For patients undergoing elective PCI with stent placement, we recommend aspirin (75-325 mg/d) and clopidogrel for a minimum duration of 1 month (bare-metal stents) or 3 to 6 months (drug-eluting stents) (Grade 1A). We suggest continuing low-dose aspirin plus clopidogrel for 12 months for all stents (Grade 2C). Thereafter, we recommend single antiplatelet therapy over continuation of dual antiplatelet therapy (Grade 1B).

CONCLUSIONS

Recommendations continue to favor single antiplatelet therapy for patients with established coronary artery disease. For patients with acute coronary syndromes or undergoing elective PCI with stent placement, dual antiplatelet therapy for up to 1 year is warranted.

Antiplatelet drugs: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

The article describes the mechanisms of action, pharmacokinetics, and pharmacodynamics of aspirin, dipyridamole, cilostazol, the thienopyridines, and the glycoprotein IIb/IIIa antagonists. The relationships among dose, efficacy, and safety are discussed along with a mechanistic overview of results of randomized clinical trials. The article does not provide specific management recommendations but highlights important practical aspects of antiplatelet therapy, including optimal dosing, the variable balance between benefits and risks when antiplatelet therapies are used alone or in combination with other antiplatelet drugs in different clinical settings, and the implications of persistently high platelet reactivity despite such treatment.

Aspirin and non-aspirin non-steroidal anti-inflammatory drug use and risk of lung cancer

There is evidence that aspirin and non-aspirin non-steroidal anti-inflammatory drug (NSAID) have anti-carcinogenic properties, but their effect on lung cancer, in particular in never-smokers, is unclear. Information on past or current use of anti-inflammatory medication was obtained in 398 Chinese female primary lung cancer cases and 814 controls in a hospital-based study in Singapore. 65% of cases and 88% of controls were never-smokers. Controls were excluded if they had been admitted for conditions associated with aspirin or NSAID use (n=174). Regular aspirin use (twice a week or more, for a month or more) was associated with a reduced risk of lung cancer (adjusted odds ratio [OR] 0.50, 95% confidence intervals [95%CI] 0.31-0.81 in non-smokers; OR 0.38, 95%CI 0.16-0.93 in smokers). Regular use of non-aspirin NSAID, paracetamol, steroid creams and steroid pills was uncommon and no association with lung cancer was detected. Our results suggest that aspirin consumption may reduce lung cancer risk in Asian women and are consistent with current understanding of the role of cyclooxygenase in lung carcinogenesis.

Balancing the risk and benefits of low-dose aspirin in clinical practice

Antiplatelet agents are widely used in primary and secondary prevention of cardiovascular events. The scientific evidence has provided strong support for the benefits of aspirin in decreasing the risk of cardiovascular events in a wide range of pathologies. The relatively rare occurrence of major bleeding complications should not be underestimated, mainly due to its high morbi-mortality. The assessment of both gastrointestinal risk and cardiovascular benefits of low-dose aspirin for any individual patient may be difficult in clinical practice. In this review, we summarize the evidence supporting the efficacy of aspirin and the risks of side effects due to hemorrhagic complications. This article proposes a unifying framework for application to help the clinician in the decision making process of individuals who have different risk of cardiovascular and bleeding events with different examples. Finally, new developments in the field directed towards individualized risk assessment strategies are described.

Role of ASA in the primary and secondary prevention of cardiovascular events

Cardiovascular disease, which includes coronary heart disease, cerebrovascular disease and peripheral artery disease, is the leading cause of death in developed countries. Evidence from basic research, clinical investigations, observational epidemiologic studies and randomized clinical trials has provided strong support for the benefits of aspirin in decreasing the risk of cardiovascular events in a wide range of pathologies in secondary prevention. Data in primary prevention have far more uncertainties. An overview for the evidence supporting the efficacy of aspirin in primary and secondary prevention of cardiovascular disease is discussed, including the relative and absolute benefit and the risks of side effects. Finally, future developments in the field directed towards individualized treatment strategies and novel antiplatelet agents are examined.

Aspirin in primary and secondary prevention in elderly adults revisited

Despite the frequency and long duration of aspirin use, its role in primary and secondary prevention in older adults is not well studied. This review takes a critical look at the available literature on aspirin efficacy in elderly adults, and some relevant guidelines for practicing physicians are suggested.

The role of low-dose aspirin in the prevention of colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is a prevalent disease that is associated with considerable morbidity and mortality. The progression of normal mucosa through adenomatous polyps to overt cancer can span for 10 - 15 years, making early detection, as well as the use of chemopreventive agents such as aspirin, an attractive option. The effects of aspirin in reducing CRC incidence and mortality have consistently been demonstrated in a number of studies. However, a greater understanding of how aspirin exerts its anti-cancer effects is warranted.

AREAS COVERED

The aim of this non-systematic review, which was developed using published randomized and epidemiological studies, as well as key references known to the authors, was to consider the role of aspirin in CRC prevention. Areas covered include the effects of aspirin on cardiovascular disease, CRC and colorectal adenoma (CRA) prevention, mode of action of aspirin and the benefit-to-risk of aspirin in disease prevention.

EXPERT OPINION

Incorporating CRC and CRA benefits into coronary heart disease (CHD) risk scores would be particularly useful for determining the benefit-to-risk ratio for aspirin use in borderline cases. For instance, patients with an annual CHD risk around 0.7 - 1.4%, but with a high risk of colorectal neoplasm may benefit from aspirin. The strong association between CRC and age may also be useful for re-examining the benefit-to-risk ratio for aspirin use in older patients. However, it has to be noted that a cancer prevention indication for aspirin is not approved regulatory-wise anywhere.

Aspirin in the chemoprevention of colorectal neoplasia: an overview

Considerable evidence supports the effectiveness of aspirin for chemoprevention of colorectal cancer (CRC) in addition to its well-established benefits in the prevention of vascular disease. Epidemiologic studies have consistently observed an inverse association between aspirin use and risk of CRC. A recent pooled analysis of a long-term posttrial follow-up of nearly 14,000 patients from four randomized, cardiovascular disease prevention trials showed that daily aspirin treatment for about five years was associated with a 34% reduction in 20-year CRC mortality. A separate metaanalysis of nearly 3,000 patients with a history of colorectal adenoma or cancer in four randomized adenoma prevention trials showed that aspirin reduced the occurrence of advanced adenomas by 28% and any adenoma by 17%. Aspirin has also been shown to be beneficial in a clinical trial of patients with Lynch syndrome, a hereditary CRC syndrome; in those treated with aspirin for at least two years, there was a 50% or more reduction in the risk of CRC commencing five years after randomization and after aspirin had been discontinued. A few observational studies have shown an increase in survival among patients with CRC who use aspirin. Taken together, these findings strengthen the case for consideration of long-term aspirin use in CRC prevention. Despite these compelling data, there is a lack of consensus about the balance of risks and benefits associated with long-term aspirin use, particularly in low-risk populations. The optimal dose to use for cancer prevention and the precise mechanism underlying aspirin's anticancer effect require further investigation.

Diabetes and the risk for colorectal cancer

Diabetes mellitus has been reported to be associated with an increased risk for colorectal cancer. The review analyzes current epidemiological data on the association of diabetes and the risk for colorectal cancer. Hyperinsulinemia, hyperglycemia, and inflammation are suggested to play a key role in the pathophysiology of cancer in diabetes. Data regarding potential treatment-related risks, particularly in conjunction with the use of insulin and insulin analogues, are also presented. Furthermore, the impact of glycemic control and cardiorespiratory fitness on cancer prognosis is considered. Finally, the preventive potential of aspirin and other nonsteroidal anti-inflammatory drugs, and the recommendations concerning colonoscopy-screening are presented.

Primary prevention of ischaemic cardiovascular disorders with antiplatelet agents

In those who have already survived myocardial infarction (MI) or stroke, or have had a transient ischaemic episode (TIA), daily low dose aspirin (ASA) reduces the risk of recurrences by an amount that greatly exceeds the risk of serious bleeding (secondary prevention). ASA is therefore recommended for these people. However, in primary prevention-reducing risk in those so far free of clinically manifest episodes-the benefit is of the same order as the bleeding hazard, (which is much the same in both primary and secondary prevention contexts). The use of other effective agents such as statins further emphasises the even balance between benefit and hazard in primary prevention. Six primary prevention trials are reviewed, first singly and then in a meta-analysis based on individual patient data. ASA reduced non-fatal myocardial infarction by about 25%. However, death from coronary heart disease (CHD) was not significantly reduced (by 5%), nor was any vascular death (3%). There was a non- significant reduction in strokes of 5%, this being the net result of an 8% reduction in non-fatal stroke and a 21% increase in stroke death (mainly from haemorrhagic events), both effects being non-significant. Serious vascular events (MI, stroke or vascular death) were significantly reduced by 12%, mainly due to the large effect on non-fatal MI. About 1650 people would need to be treated with ASA for a year to avoid one serious vascular event, which contrasts with the 10-20 events avoided in secondary prevention by treating 1,000 patients for a year. Other primary prevention trials not included in the meta-analysis have also reported no benefits in MI or stroke, but the findings of still unpublished trials are awaited. Recently, however, encouraging results have come from meta-analyses of the effects of ASA on cancer incidence and mortality and on its effects on cancer metastasis, particularly for adenocarcinomas. Typically, reductions in these measures have been around 30% following treatment for four or five years, but more in several instances. These results alter the balance in primary prevention between benefit and hazard as it appears for arterial events alone, tipping it towards the use of ASA. Consequently, new guidelines on advice and decisions on ASA in primary prevention are now needed. Low dose ASA, eg. 75 mg daily is as effective as higher doses for all the vascular and cancer benefits established in the meta-analyses, and it causes less serious bleeding than higher doses.

Antiplatelet agents and anticoagulants for hypertension

BACKGROUND

Elevated systemic blood pressure results in high intravascular pressure but the main complications, coronary heart disease (CHD), ischaemic strokes and peripheral vascular disease (PVD), are related to thrombosis rather than haemorrhage. Some complications related to elevated blood pressure, heart failure or atrial fibrillation, are themselves associated with stroke and thromboembolism. Therefore it is important to investigate if antithrombotic therapy may be useful in preventing thrombosis-related complications in patients with elevated blood pressure.

OBJECTIVES

To conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with high blood pressure, including those with elevations in both systolic and diastolic blood pressure, isolated elevations of either systolic or diastolic blood pressure, to address the following hypotheses: (i) antiplatelet agents reduce total deaths and/or major thrombotic events when compared to placebo or other active treatment; and (ii) oral anticoagulants reduce total deaths and/or major thromboembolic events when compared to placebo or other active treatment.

SEARCH METHODS

Electronic databases (MEDLINE, EMBASE, DARE, CENTRAL, Hypertension Group specialised register) were searched up to January 2011. The reference lists of papers resulting from the electronic searches and abstracts from national and international cardiovascular meetings were hand-searched to identify missed or unpublished studies. Relevant authors of studies were contacted to obtain further data.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with elevated blood pressure were included if they were of at least 3 months in duration and compared antithrombotic therapy with control or other active treatment.

DATA COLLECTION AND ANALYSIS

Data were independently collected and verified by two reviewers. Data from different trials were pooled where appropriate.

MAIN RESULTS

Four trials with a combined total of 44,012 patients met the inclusion criteria and are included in this review. Acetylsalicylic acid (ASA) did not reduce stroke or 'all cardiovascular events' compared to placebo in primary prevention patients with elevated blood pressure and no prior cardiovascular disease. In one large trial ASA taken for 5 years reduced myocardial infarction (ARR 0.5%, NNT 200), increased major haemorrhage (ARI 0.7%, NNT 154), and did not reduce all cause mortality or cardiovascular mortality. In one trial there was no significant difference between ASA and clopidogrel for the composite endpoint of stroke, myocardial infarction or vascular death. In two small trials warfarin alone or in combination with ASA did not reduce stroke or coronary events. The ATC meta-analysis of antiplatelet therapy for secondary prevention in patients with elevated blood pressure reported an absolute reduction in vascular events of 4.1% as compared to placebo. Data on the 10,600 patients with elevated blood pressure from the 29 individual trials included in the ATC meta-analysis was requested but could not be obtained.

AUTHORS' CONCLUSIONS

Antiplatelet therapy with ASA for primary prevention in patients with elevated blood pressure provides a benefit, reduction in myocardial infarction, which is negated by a harm of similar magnitude, increase in major haemorrhage.The benefit of antiplatelet therapy for secondary prevention in patients with elevated blood pressure is many times greater than the harm.Benefit has not been demonstrated for warfarin therapy alone or in combination with aspirin in patients with elevated blood pressure. Ticlopidine, clopidogrel and newer antiplatelet agents such as prasugrel and ticagrelor have not been sufficiently evaluated in patients with high blood pressure. Newer antithrombotic oral drugs such as dabigatran, rivaroxaban, apixaban and endosaban are yet to be tested in patients with high blood pressure.Further trials of antithrombotic therapy including with newer agents and complete documentation of all benefits and harms are required in patients with elevated blood pressure.

Clinical use of aspirin in treatment and prevention of cardiovascular disease

Cardiovascular disease (CVD), principally heart disease and stroke, is the leading cause of death for both males and females in developed countries. Aspirin is the most widely used and tested antiplatelet drug in CVD, and it is proven to be the cornerstone of antiplatelet therapy in treatment and prevention of CVD in clinical trials in various populations. In acute coronary syndrome, thrombotic stroke, and Kawasaki's disease, acute use of aspirin can decrease mortality and recurrence of cardiovascular events. As secondary prevention, aspirin is believed to be effective in acute coronary syndrome, stable angina, revascularization, stroke, TIA, and atrial fibrillation. Aspirin may also be used for patients with a high risk of future CVD for primary prevention, but the balance between benefits and the possibility of side effects must be considered.

Preventing bowel cancer: an insight for clinicians

Worldwide, colorectal cancer causes 610,000 deaths annually with 38,000 new cases diagnosed in the UK and 16,000 deaths each year. The prognosis is directly related to the staging of the cancer at diagnosis, with an overall 5-year survival rate of approximately 50%. However, for localized disease the figure is much higher at 90%, although unfortunately many cancers present at an advanced stage. Importantly, there is the potential to reduce the incidence because most tumours arise from premalignant adenomatous polyps, which if detected and removed interrupts the adenoma-adenocarcinoma sequence. In addition, identifying colorectal cancer at an early stage can impact on the mortality rates for this neoplasm. The current screening options for bowel cancer include analysis of stool for occult blood and endoscopic assessments of the colorectum, including flexible sigmoidoscopy and full colonoscopy. The aim of this review is to present information on the natural history of colorectal cancer, the evaluation of the different screening modalities and the current faecal occult blood screening program within the UK National Health Service, and to discuss how dietary factors and aspirin may affect aetiology.

Killing two birds with one salicylate: aspirin's dual roles in preventative health

In a recent article published in The Lancet, investigators studied the impact of daily aspirin use on subsequent cancer deaths. Utilizing data from more than 25,000 patients enrolled in 8 large trials, which were originally intended to study the impact of daily aspirin use on the incidence of cardiovascular events, the authors found a substantial decrease in risk of fatal solid organ malignancies. In particular, the risk reduction was specific to adenocarcinomas. The findings from this study are highly relevant to the thoracic surgeon, with adenocarcinomas of the lung and esophagus among those tumors demonstrating the most profound risk reduction.

Effect of aspirin dose on mortality and cardiovascular events in people with diabetes: a meta-analysis

OBJECTIVES

Pharmacologic evidence suggests adequate antiplatelet activity in diabetic patients requires >100 mg aspirin daily, yet recent trials have used ≤100 mg daily. This meta-analysis explored the relationship between aspirin dose and prevention of cardiovascular events.

DATA SOURCES

Six electronic databases were searched using database-appropriate terms for aspirin, diabetes, and comparative study from inception until February 2010.

REVIEW METHODS

Randomized controlled trials and cohort studies comparing aspirin to no antiplatelet therapy were included if they reported cardiovascular events as pre-specified outcomes, aspirin dose, and number of diabetic patients. Studies were stratified by daily aspirin dose (≤100 mg; 101-325 mg; >325 mg) and pooled risk ratios (RR) were calculated using random effects models. All-cause mortality was the primary outcome of interest. Cardiovascular-related mortality, myocardial infarction, and stroke were secondary outcomes.

RESULTS

Data for diabetic patients were available from 21 studies (n = 17,522). Overall, 1,172 (15.4%) of 7,592 aspirin users and 1,520 (18.4%) of 8,269 controls died (p = 0.31). The pooled RRs were 0.89 (95% CI: 0.72-1.10; p = 0.27) from 13 studies using ≤100 mg (I(2) = 64%); 0.89 (95% CI: 0.61-1.30; p = 0.55) from four studies using 101-325 mg (I(2) = 83%); and 0.96 (95% CI: 0.85-1.08; p = 0.50) from eight studies using >325 mg (I(2) = 0%). Aspirin use was associated with a significantly lower risk of mortality (RR: 0.82; 95% CI: 0.69-0.98; p = 0.03) in 13 secondary prevention studies (I(2) = 27%), whereas aspirin use in seven primary prevention studies (I(2) = 0%) was not (RR: 1.01; 95% CI 0.85-1.19; p = 0.94). A substantial amount of heterogeneity was observed amongst studies in all outcomes. Although inclusion of cohort studies was a major source of heterogeneity, stratification by study design did not reveal a significant dose-response relationship.

CONCLUSIONS/INTERPRETATION

This summary of available data does not support an aspirin dose-response effect for prevention of cardiovascular events in diabetic patients. However, the systematic review identified an important gap in randomized controlled trial evidence for using 101-325 mg aspirin daily in diabetes.

Aspirin and NSAID use and lung cancer risk: a pooled analysis in the International Lung Cancer Consortium (ILCCO)

PURPOSE

To investigate the hypothesis that non-steroidal anti-inflammatory drugs (NSAIDs) lower lung cancer risk.

METHODS

We analysed pooled individual-level data from seven case-control and one cohort study in the International Lung Cancer Consortium (ILCCO). Relative risks for lung cancer associated with self-reported history of aspirin and other NSAID use were estimated within individual studies using logistic regression or proportional hazards models, adjusted for packyears of smoking, age, calendar period, ethnicity and education and were combined using random effects meta-analysis.

RESULTS

A total of 4,309 lung cancer cases (mean age at diagnosis 65 years, 45% adenocarcinoma and 22% squamous-cell carcinoma) and 58,301 non-cases/controls were included. Amongst controls, 34% had used NSAIDs in the past (81% of them used aspirin). After adjustment for negative confounding by smoking, ever-NSAID use (affirmative answer to the study-specific question on NSAID use) was associated with a 26% reduction (95% confidence interval 8 to 41%) in lung cancer risk in men, but not in women (3% increase (-11% to 30%)). In men, the association was stronger in current and former smokers, and for squamous-cell carcinoma than for adenocarcinomas, but there was no trend with duration of use. No differences were found in the effects on lung cancer risk of aspirin and non-aspirin NSAIDs.

CONCLUSIONS

Evidence from ILCCO suggests that NSAID use in men confers a modest protection for lung cancer, especially amongst ever-smokers. Additional investigation is needed regarding the possible effects of age, duration, dose and type of NSAID and whether effect modification by smoking status or sex exists.

Meta-analysis on the association between nonsteroidal anti-inflammatory drug use and lung cancer risk

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs), especially aspirin, have emerged as the most potential chemopreventive agents. However, epidemiologic studies reported a controversial association between NSAID use and lung cancer risk. We conducted a meta-analysis to summarize the evidence for such relationship.

METHODS

Eligible studies were identified by searching the electronic literature PubMed, Medline, Embase, and ScienceDirect databases for relevant reports and bibliographies. Studies were included if they designed as cohort study, case-control study, or clinical trial on the NSAID exposure and lung cancer with sufficient raw data to analyzes. Relative risk (RR) or odds ratio (OR) was used to evaluate the association between NSAIDs and lung cancer. Stratified analysis was also performed.

RESULTS

A total of 19 studies including 20,266 lung cancer cases met the inclusion criteria. To the effect of aspirin on lung cancer, the combined RR for cohort studies was 0.96 (95%confidence interval [CI]: 0.78-1.19) and OR for case-control studies was 0.87 (95%CI: 0.69-1.09). When restricted in exposure of aspirin use to 7 tablets per week, the OR was 0.80 (95%CI: 0.67-0.95). The summary risk estimates showed no significant association between non-aspirin NSAID or overall NSAID use and lung cancer risk.

CONCLUSIONS

Aspirin use with a dose of 7 tablets per week can significantly reduce lung cancer risk, whereas non-aspirin NSAIDs showed no chemopreventive value. Greater attention should be paid to identifying appropriate individuals for this new indication of aspirin and the optimal dose and duration as a chemopreventive agent.

Aspirin for the prevention of colorectal cancer

Over 600,000 people worldwide die of colorectal cancer (CRC) annually, highlighting the importance of developing effective prevention strategies. Among proposed chemopreventive interventions, aspirin is perhaps the agent with the strongest body of evidence that supports wider spread use to significantly reduce the population burden of CRC. Several epidemiological studies, four randomized controlled trials (RCTs) of colorectal polyp recurrence, and RCTs in patients with hereditary colorectal cancer syndromes, have shown that aspirin reduces incidence of colorectal neoplasia. Recently, in a pooled analysis of five cardiovascular-prevention RCTs linked to cancer outcomes, daily aspirin use at any dose reduced the risk of CRC by 24% and of CRC-associated mortality by 35% after a delay of 8-10 years. In an expanded meta-analysis of 8 cardiovascular-prevention RCTs, daily aspirin use at any dose was associated with a 21% lower risk of all cancer death, including CRC, with benefit only apparent after 5 years. In this review, we will summarize human studies of aspirin in CRC prevention as well as discuss the safety profile and mechanism of aspirin in CRC prevention.

Effect of aspirin on mortality in the primary prevention of cardiovascular disease

OBJECTIVE

The lack of a mortality benefit of aspirin in prior meta-analyses of primary prevention trials of cardiovascular disease has contributed to uncertainty about the balance of benefits and risks of aspirin in primary prevention. We performed an updated meta-analysis of randomized controlled trials of aspirin to obtain best estimates of the effect of aspirin on mortality in primary prevention.

METHODS

Eligible articles were identified by searches of electronic databases and reference lists. Outcomes of interest were all-cause mortality, cardiovascular mortality, myocardial infarction, stroke, and bleeding. Data were pooled from individual trials using the DerSimonian-Laird random-effects model, and results are presented as relative risk (RR) and 95% confidence intervals (CIs).

RESULTS

Nine randomized controlled trials enrolling 100,076 participants were included. Aspirin reduced all-cause mortality (RR 0.94; 95% CI, 0.88-1.00), myocardial infarction (RR 0.83; 95% CI, 0.69-1.00), ischemic stroke (RR 0.86; 95% CI, 0.75-0.98), and the composite of myocardial infarction, stroke, or cardiovascular death (RR 0.88; 95% CI, 0.83-0.94), but did not reduce cardiovascular mortality (RR 0.96; 95% CI, 0.84-1.09). Aspirin increased the risk of hemorrhagic stroke (RR 1.36; 95% CI, 1.01-1.82), major bleeding (RR 1.66; 95% CI, 1.41-1.95), and gastrointestinal bleeding (RR 1.37; 95% CI, 1.15-1.62). A lack of availability of patient-level data precluded exploration of benefits and risks of aspirin in key subgroups.

CONCLUSION

Aspirin prevents deaths, myocardial infarction, and ischemic stroke, and increases hemorrhagic stroke and major bleeding when used in the primary prevention of cardiovascular disease.

Cost-effectiveness analysis: cardiovascular benefits of proton pump inhibitor co-therapy in patients using aspirin for secondary prevention

BACKGROUND

Many patients with cardiovascular (CV) disease will stop aspirin (ASA) because of ASA-related dyspepsia. Proton pump inhibitor (PPI) co-therapy may reduce ASA-related dyspepsia, enhancing ASA adherence and improving CV outcomes.

AIM

To explore the impact of PPI co-therapy on CV outcomes in long-term, low-dose ASA users.

METHODS

We modified a previously published Markov model to assess the long-term impact of PPI co-therapy on CV and upper gastrointestinal bleeding (UGIB) outcomes among patients using ASA for secondary CV prevention. UGIB events, recurrent myocardial infarctions (MIs) and incremental cost-effectiveness ratios (ICERs) were measured. The perspective taken was that of a long-term payer.

RESULTS

Compared with ASA alone, ASA plus PPI resulted in fewer lifetime UGIB events (3.4% vs. 7.2%) and increased ASA adherence (74% vs. 71%). Increased ASA adherence resulted in fewer recurrent MIs (26 fewer events per 10000 patients). On average, the ASA plus PPI strategy resulted in 38 additional days of life per patient, with the majority of this benefit (61%) because of a reduction in CV mortality (rather than UGIB-related mortality). ASA plus PPI was also more costly than ASA alone, with an ICER of $19000 per life-year saved. Results were sensitive to cost of PPI and impact of PPI on ASA adherence.

CONCLUSIONS

Proton pump inhibitor co-therapy has the potential to impact not only GI, but also CV outcomes in patients with CV disease using ASA and such co-therapy is likely to be cost-effective. Future studies should better quantify the CV benefits of PPI co-therapy.

Aspirin for the prevention of cardiovascular events in patients without clinical cardiovascular disease: a meta-analysis of randomized trials

BACKGROUND

The benefit of aspirin to prevent cardiovascular events in subjects without clinical cardiovascular disease relative to the increased risk of bleeding is uncertain.

METHODS

A meta-analysis of randomized trials of aspirin versus placebo/control to assess the effect of aspirin on major cardiovascular events (MCEs) (nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death), individual components of the MCE, stroke subtype, all-cause mortality, and major bleeding. Nine trials involving 102,621 patients were included: 52,145 allocated to aspirin and 50,476 to placebo/control.

RESULTS

Over a mean follow-up of 6.9 years, aspirin was associated with a reduction in MCE (risk ratio [RR] 0.90, 95% CI 0.85-0.96, P < .001). There was no significant reduction for myocardial infarction, stroke, ischemic stroke, or all-cause mortality. Aspirin was associated with hemorrhagic stroke (RR 1.35, 95% CI 1.01-1.81, P = .04) and major bleeding (RR 1.62, 95% CI 1.31-2.00, P < .001). In meta-regression, the benefits and bleeding risks of aspirin were independent of baseline cardiovascular risk, background therapy, age, sex, and aspirin dose. The number needed to treat to prevent 1 MCE over a mean follow-up of 6.9 years was 253 (95% CI 163-568), which was offset by the number needed to harm to cause 1 major bleed of 261 (95% CI 182-476).

CONCLUSIONS

The current totality of evidence provides only modest support for a benefit of aspirin in patients without clinical cardiovascular disease, which is offset by its risk. For every 1,000 subjects treated with aspirin over a 5-year period, aspirin would prevent 2.9 MCE and cause 2.8 major bleeds.

Reconsidering low-dose aspirin therapy for cardiovascular disease: a study protocol for physician and patient behavioral change

Background

There are often disparities between current evidence and current practice. Decreasing the gap between desired practice outcomes and observed practice outcomes in the healthcare system is not always easy. Stopping previously recommended or variably recommended interventions may be even harder to achieve than increasing the use of a desired but under-performed activity. For over a decade, aspirin has been prescribed for primary prevention of cardiovascular disease and for patients with the coronary artery disease risk equivalents; yet, there is no substantial evidence of an appropriate risk-benefit ratio to support this practice. This paper describes the protocol of a randomized trial being conducted in six primary care practices in the Denver metropolitan area to examine the effectiveness of three interventional strategies to change physician behavior regarding prescription of low-dose aspirin.

Methods

All practices received academic detailing, one arm received clinician reminders to reconsider aspirin, a second arm received both clinician and patient messages to reconsider aspirin. The intervention will run for 15 to 18 months. Data collected at baseline and for outcomes from an electronic health record will be used to assess pre- and post-interventional prescribing, as well as to explore any inappropriate decrease in aspirin use by patients with known cardiovascular disease.

Discussion

This study was designed to investigate effective methods of changing physician behavior to decrease the use of aspirin for primary cardiovascular disease prevention. The results of this study will contribute to the small pool of knowledge currently available on the topic of ceasing previously supported practices.

Trial Registration

ClinicalTrials.gov: NCT01247454

The use of antiplatelet therapy in the outpatient setting: Canadian Cardiovascular Society Guidelines Executive Summary

Antiplatelet agents are a cornerstone of therapy for patients with atherosclerotic vascular disease. There is presently a lack of comprehensive guidelines focusing on the use of antiplatelet drugs in patients currently manifesting or at elevated risk of cardiovascular disease. The Canadian Antiplatelet Therapy Guidelines Committee reviewed existing disease-based guidelines and subsequently published literature and used expert opinion and review to develop guidelines on the use of antiplatelet therapy in the outpatient setting. This Executive Summary provides an abbreviated version of the principal recommendations. Antiplatelet therapy appears to be generally underused, perhaps in part because of a lack of clear, evidence-based guidance. Here, we provide specific guidelines for secondary prevention in patients discharged from hospital after acute coronary syndromes, percutaneous coronary intervention, or coronary artery bypass grafting; patients with a history of transient cerebral ischemic events or strokes; and patients with peripheral arterial disease. Issues related to primary prevention are also addressed, in addition to special clinical contexts such as diabetes, heart failure, chronic kidney disease, pregnancy or lactation, and perioperative management. Recommendations are provided regarding pharmacologic interactions that may occur during combination therapy with warfarin, clopidogrel, and proton-pump inhibitors, or aspirin and nonsteroidal anti-inflammatory drugs, as well as for the management of bleeding complications. The complete guidelines document is published as a supplementary issue of the Canadian Journal of Cardiology and is available at http://www.ccs.ca/.

Five-year analysis of the prevention of colorectal sporadic adenomatous polyps trial

OBJECTIVES

Subjects in the Prevention of Colorectal Sporadic Adenomatous Polyps (PreSAP) trial (PRESAP/NCT00141193/www.clinicaltrials.gov) were studied to determine efficacy and safety at a year 5 assessment.

METHODS

In this randomized, placebo-controlled, double-blind trial, 1,561 subjects with diagnosed colorectal adenomas removed within 3 months of the study's initiation were assessed after ~ 3 years on celecoxib followed by 2 years off. Studied in 107 primary and secondary care settings, subjects were stratified by cardioprotective aspirin use and randomized to receive orally 400 ng celecoxib (933 subjects) or placebo (628 subjects) once daily. Efficacy was measured by colonoscopy at years 1, 3, and 5, and safety was measured by investigators for the on-treatment period and collected by subject self-report over 2 years post-treatment.

RESULTS

At year 5, the primary outcome measure was the rate of new adenomas measured cumulatively from baseline. This rate was statistically significantly lower in the celecoxib group (51.4%) than in the placebo group (57.5%; P<0.001). Similarly, the cumulative rate of new advanced adenomas was significantly lower in the celecoxib group (10.0%) than in the placebo group (13.8%; P=0.007). However, the year 5 interval measure, which was not cumulative and did not take the rates of previous years into account, showed that after 2 years off treatment, the celecoxib group (27.0%) was 1.66 times more likely to have new adenomas than the placebo group (16.3%; P<0.0001). Similarly, the percentage of patients with new advanced adenomas was significantly higher in the celecoxib group (5.0%) than in the placebo group (3.8%) (P=0.0072). The evaluation of safety from baseline through year 5 indicated that the risks of serious cardiac disorders (relative risk (RR) 1.66; 95% confidence interval (CI) 1.01-2.73), selected renal/hypertension events (RR 1.35; 95% CI 1.09-1.68), and general vascular (RR 1.34; 95% CI 1.08-1.68) and cardiac disorders (RR 1.59; 95% CI 1.12-2.26) were higher in those taking celecoxib than in those on placebo.

CONCLUSIONS

The year 5 cumulative measures of the incidence of new and advanced adenomas were significantly lower in the celecoxib group than in the placebo group, but the year 5 interval rates of these measures were significantly lower in the placebo group than the celecoxib group, perhaps suggesting a release of cyclooxygenase-2 inhibition. Consistent with what has been previously reported, increased risk of renal/hypertension events and cardiac disorders associated with celecoxib therapy mandates caution in patient selection.

Antiplatelet therapy and vascular disease: an update

Atherosclerosis is a diffuse, systemic disorder of the large and medium-sized arterial vessels, affecting the coronary, cerebral and peripheral circulation. Chronic inflammatory processes are the central pathophysiological mechanism largely driven by lipid accumulation, and provide the substrate for occlusive thrombus formation. The clinical sequelae of acute arterial thrombosis, heart attack and stroke, are the most common causes of morbidity and mortality in the industrialized world. Such acute events are characterized by rupture or erosion of the atherosclerotic plaque leading to acute thrombosis. The atherosclerotic process and associated thrombotic complications are collectively termed atherothrombosis. The platelet is a pivotal mediator of various endothelial, immune, thrombotic and inflammatory responses and therefore a key player in the initiation and progression of atherothrombosis. A robust evidence base supports the clear clinical benefits of antiplatelet agents in the primary and secondary therapy of atherothrombotic disorders. Percutaneous coronary and peripheral interventions have an established central role in the management of atherothrombotic disease and demand a greater understanding of platelet biology. In this article, we provide a clinically orientated overview of the pathophysiology of arterial thrombosis and the evidence supporting the use of the various established antiplatelet therapies, and discuss new and future agents.

Gender Differences in the Primary Prevention of Stroke with Aspirin

Aspirin is used to prevent ischemic stroke and other types of cardiovascular disease. Seven trials of aspirin focusing on the effectiveness of primary prevention of stroke and other cardiovascular events have been performed, but three of these did not include women. Data from these trials, and one meta-analysis, suggest that aspirin prevents myocardial infarction in men and stroke in women, although the findings in women were driven by the results of a single large study, and a subsequent meta-analysis did not find a gender difference. The reasons for the possible gender differences in aspirin's effectiveness are not entirely clear.

Aspirin use and risk for lung cancer: a meta-analysis

BACKGROUND

Aspirin has received increasing attention owing to its potential as a chemopreventive agent against lung cancer. Previous observational studies have reported inconsistent findings on this issue. We investigated the association between aspirin use and risk for lung cancer by conducting a meta-analysis.

PATIENTS AND METHODS

Relevant studies were identified by searching Medline, EMBASE, and Cochrane Library to December 2009. We also reviewed relevant bibliographies from the retrieved articles. Two authors independently extracted data and assessed study quality. Disagreements were resolved by consensus.

RESULTS

Fifteen studies (six case-control studies and nine prospective cohort studies) were included in the final meta-analysis. When all studies were pooled, the odds ratio (OR) of aspirin use for lung cancer risk was 0.86 [95% confidence interval (CI) 0.76-0.98]. In subgroup meta-analyses, there was no association between aspirin use and lung cancer risk among cohort studies (relative risk, 0.97; 95% CI 0.87-1.08), while there was a significant association among case-control studies (OR, 0.74; 95% CI 0.57-0.99). In a subgroup meta-analysis by quality of study methodology, a significant protective effect of aspirin use on lung cancer was observed only among eight low-quality studies (OR, 0.82; 95% CI 0.68-0.99), but not among seven high-quality studies (OR, 0.90; 95% CI 0.76-1.07).

CONCLUSIONS

Overall, the findings of this meta-analysis support that there was no association between aspirin use and lung cancer risk. Our findings should be confirmed in future prospective cohort studies or randomized, controlled trials.

Oral antiplatelet therapy in stroke prevention. Minireview

BACKGROUND

Antiplatelet therapy plays a crucial role in the primary and secondary prevention of noncardioembolic ischemic stroke / transient ischemic attacks (IS/TIA). Several antiplatelet agents are available. This review deals with the characteristics of particular antiplatelet agents as well as choice of antiplatelet treatment in various situations, based on the evidence and international recommendations.

METHODS

PubMed and Stroke Trials Registry on-line databases and the European Stroke Organisation Guidelines for Management of IS/TIA 2008 and update of the recommendations of the American Heart Association / American Stroke Association Council 2008 on Stroke were used.

RESULTS

Acetylsalicylic acid (ASA) is the only antiplatelet drug used in primary prevention, mainly to reduce the risk of myocardial infarction (MI), but also in women aged 45 years or more and in some patients with non-valvular atrial fibrillation to reduce risk of IS/TIA. In the secondary prevention of noncardioembolic IS/TIA, ASA in combination with long release dipyridamole (DIP) and clopidogrel (CLOP) alone are considered first choice therapies. The choice of the particular antiplatelet agent should be individualized according to the patient risk factor profiles and treatment tolerance. ASA alone or triflusal can be used alternatively in patients who cannot be treated with either ASA+DIP or CLOP. The use of indobufen should be considered only in patients in need of temporary interruption of the antiplatelet therapy. Ticlopidine (TIC) should not be newly introduced into the treatment. Currently, insufficient data are available on the use of cilostazol in IS/TIA prevention.

Low-dose aspirin therapy in patients with type 2 diabetes and reduced glomerular filtration rate: subanalysis from the JPAD trial

OBJECTIVE

Type 2 diabetes accompanied by renal damage is a strong risk factor for atherosclerotic events. The purpose of this study was to investigate the efficacy of low-dose aspirin therapy on primary prevention of atherosclerotic events in patients with type 2 diabetes and coexisting renal dysfunction.

RESEARCH DESIGN AND METHODS

The Japanese Primary Prevention of Atherosclerosis With Aspirin for Diabetes (JPAD) trial was a prospective, randomized, open-label trial conducted throughout Japan that enrolled 2,539 type 2 diabetic patients without a history of atherosclerotic diseases. Patients were assigned to the aspirin group (81 mg/day or 100 mg/day) or the nonaspirin group and followed for a median of 4.37 years. The primary end points were atherosclerotic events of fatal and nonfatal ischemic heart disease, stroke, and peripheral arterial disease.

RESULTS

The analysis included 2,523 patients who had serum creatinine measured. In 1,373 patients with baseline estimated glomerular filtration rate (eGFR) 60-89 mL/min/1.73 m(2), the incidence of primary end points was significantly lower in the aspirin group than in the nonaspirin group (aspirin, 30/661; nonaspirin, 55/712; hazard ratio 0.57 [95% CI 0.36-0.88]; P = 0.011). Low-dose aspirin therapy did not reduce primary end points in patients with eGFR ≥ 90 mL/min/1.73 m(2) (aspirin, 9/248; nonaspirin, 11/270; 0.94 [0.38-2.3]) or those with eGFR <60 mL/min/1.73 m(2) (aspirin, 29/342; nonaspirin, 19/290; 1.3 [0.76-2.4]). The Cox proportional hazard model demonstrated a significant interaction between mild renal dysfunction (eGFR 60-89 mL/min/1.73 m(2)) and aspirin (P = 0.02).

CONCLUSIONS

These results suggest a differential effect of low-dose aspirin therapy in diabetic patients with eGFR 60-89 mL/min/1.73 m(2).

Effect of daily aspirin on long-term risk of death due to cancer: analysis of individual patient data from randomised trials

BACKGROUND

Treatment with daily aspirin for 5 years or longer reduces subsequent risk of colorectal cancer. Several lines of evidence suggest that aspirin might also reduce risk of other cancers, particularly of the gastrointestinal tract, but proof in man is lacking. We studied deaths due to cancer during and after randomised trials of daily aspirin versus control done originally for prevention of vascular events.

METHODS

We used individual patient data from all randomised trials of daily aspirin versus no aspirin with mean duration of scheduled trial treatment of 4 years or longer to determine the effect of allocation to aspirin on risk of cancer death in relation to scheduled duration of trial treatment for gastrointestinal and non-gastrointestinal cancers. In three large UK trials, long-term post-trial follow-up of individual patients was obtained from death certificates and cancer registries.

RESULTS

In eight eligible trials (25 570 patients, 674 cancer deaths), allocation to aspirin reduced death due to cancer (pooled odds ratio [OR] 0·79, 95% CI 0·68-0·92, p=0·003). On analysis of individual patient data, which were available from seven trials (23 535 patients, 657 cancer deaths), benefit was apparent only after 5 years' follow-up (all cancers, hazard ratio [HR] 0·66, 0·50-0·87; gastrointestinal cancers, 0·46, 0·27-0·77; both p=0·003). The 20-year risk of cancer death (1634 deaths in 12 659 patients in three trials) remained lower in the aspirin groups than in the control groups (all solid cancers, HR 0·80, 0·72-0·88, p<0·0001; gastrointestinal cancers, 0·65, 0·54-0·78, p<0·0001), and benefit increased (interaction p=0·01) with scheduled duration of trial treatment (≥7·5 years: all solid cancers, 0·69, 0·54-0·88, p=0·003; gastrointestinal cancers, 0·41, 0·26-0·66, p=0·0001). The latent period before an effect on deaths was about 5 years for oesophageal, pancreatic, brain, and lung cancer, but was more delayed for stomach, colorectal, and prostate cancer. For lung and oesophageal cancer, benefit was confined to adenocarcinomas, and the overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR 0·66, 0·56-0·77, p<0·0001). Benefit was unrelated to aspirin dose (75 mg upwards), sex, or smoking, but increased with age-the absolute reduction in 20-year risk of cancer death reaching 7·08% (2·42-11·74) at age 65 years and older.

INTERPRETATION

Daily aspirin reduced deaths due to several common cancers during and after the trials. Benefit increased with duration of treatment and was consistent across the different study populations. These findings have implications for guidelines on use of aspirin and for understanding of carcinogenesis and its susceptibility to drug intervention.

FUNDING

None.