Aspirin for primary prevention of cardiovascular events in people with diabetes: meta-analysis of randomised controlled trials

Differential effect of low-dose aspirin for primary prevention of atherosclerotic events in diabetes management: a subanalysis of the JPAD trial

OBJECTIVE

Recent reports showed that low-dose aspirin was ineffective in the primary prevention of cardiovascular events in diabetic patients overall. We hypothesized that low-dose aspirin would be beneficial in patients receiving insulin therapy, as a high-risk group.

RESEARCH DESIGN AND METHODS

This study is a subanalysis of the Japanese Primary Prevention of Atherosclerosis With Aspirin for Diabetes (JPAD) trial-a randomized, controlled, open-label trial. We randomly assigned 2,539 patients with type 2 diabetes and no previous cardiovascular disease to the low-dose aspirin group (81 or 100 mg daily) or to the no-aspirin group. The median follow-up period was 4.4 years. We investigated the effect of low-dose aspirin on preventing atherosclerotic events in groups receiving different diabetes management.

RESULTS

At baseline, 326 patients were treated with insulin, 1,750 with oral hypoglycemic agents (OHAs), and 463 with diet alone. The insulin group had the longest history of diabetes, the worst glycemic control, and the highest prevalence of diabetic microangiopathies. The diet-alone group had the opposite characteristics. The incidence of atherosclerotic events was 26.6, 14.6, and 10.4 cases per 1,000 person-years in the insulin, OHA, and diet-alone groups, respectively. In the insulin and OHA groups, low-dose aspirin did not affect atherosclerotic events (insulin: hazard ratio [HR] 1.19 [95% CI 0.60-2.40]; OHA: HR 0.84 [0.57-1.24]). In the diet-alone group, low-dose aspirin significantly reduced atherosclerotic events, despite the lowest event rates (HR 0.21 [0.05-0.64]).

CONCLUSIONS

Low-dose aspirin reduced atherosclerotic events predominantly in the diet-alone group and not in the insulin or OHA groups.

Screening for type 2 diabetes and dysglycemia

Type 2 diabetes mellitus (T2DM) and dysglycemia (impaired glucose tolerance and/or impaired fasting glucose) are increasingly contributing to the global burden of diseases. The authors reviewed the published literature to critically evaluate the evidence on screening for both conditions and to identify the gaps in current understanding. Acceptable, relatively simple, and accurate tools can be used to screen for both T2DM and dysglycemia. Lifestyle modification and/or medication (e.g., metformin) are cost-effective in reducing the incidence of T2DM. However, their application is not yet routine practice. It is unclear whether diabetes-prevention strategies, which influence cardiovascular risk favorably, will also prevent diabetic vascular complications. Cardioprotective therapies, which are cost-effective in preventing complications in conventionally diagnosed T2DM, can be used in screen-detected diabetes, but the magnitude of their effects is unknown. Economic modeling suggests that screening for both T2DM and dysglycemia may be cost-effective, although empirical data on tangible benefits in preventing complications or death are lacking. Screening for T2DM is psychologically unharmful, but the specific impact of attributing the label of dysglycemia remains uncertain. Addressing these gaps will inform the development of a screening policy for T2DM and dysglycemia within a holistic diabetes prevention and control framework combining secondary and high-risk primary prevention strategies.

[Antiplatelet agents and diabetes mellitus]

Diabetes and more specially type 2 diabetes are a major cardiovascular risk factor. The high incidence of cardiovascular thromboischemic events in type 2 diabetic patients is explained by the development of atherothrombotic lesions and by their high rate of recurrence after angioplasty but also by their high thrombogenic potential due to the association of platelet hyperactivity, hypercoagulability and hypofibrinolysis. Platelets are involved at two different levels: their hyperreactiviy but also their lower sensitivity to antiplatelets agents and specially the two main aspirin and clopidogrel. That focuses the interest of the newer antiplatelet agents (prasugrel and ticagrelor) whose efficacy seems to be less affected in the sub-group of diabetics. Besides the increased thrombo-ischemic risk in diabetics: they are also characterized by an increased hemorrhagic risk (global hemorrhagic risk and risk conferred by anti-thrombotic treatments). Sub-group analysis clearly evidenced this increased hemorrhagic risk for aspirin and clopidogrel but seems to be much less for the newer antiplatelet agents (prasugrel and ticagrelor). Specific trials of primary and secondary prevention with these new agent are particularly awaited in the high risk populations specially diabetics.

Individual and population benefits of daily aspirin therapy: a proposal for personalizing national guidelines

BACKGROUND

Clinical practice guidelines that help clinicians and patients to understand the magnitude of expected individual risks and benefits would help with patient-centered decision-making and prioritization of care. We assessed the net benefit from taking daily aspirin to estimate the individual and public health implications of a more individualized decision-making approach.

METHODS AND RESULTS

We used data from the National Health and Nutrition Examination Survey representing all US persons aged 30 to 85 years with no history of myocardial infarction and applied a Markov model based on randomized evidence and published literature to estimate lifetime effects of aspirin treatment in quality-adjusted life years (QALYs). We found that treatment benefit varies greatly by an individual's cardiovascular disease (CVD) risk. Almost all adults have fewer major clinical events on aspirin, but for most, events prevented would be so rare that even a very small distaste for aspirin use would make treatment inappropriate. With minimal dislike of aspirin use (disutility, 0.005 QALY per year), only those with a 10-year cardiac event risk >6.1% would have a net benefit. A disutility of 0.01 QALY moves this benefit cut point to 10.6%. Multiple factors altered the absolute benefit of aspirin, but the strong relationship between CVD risk and magnitude of benefit was robust.

CONCLUSIONS

The benefits of aspirin therapy depend substantially on an individual's risk of CVD and adverse treatment effects. Understanding who benefits from aspirin use and how much can help clinicians and patients to develop a more patient-centered approach to preventive therapy.

The role of antiplatelets in hypertension and diabetes mellitus

Cardiovascular disease (CVD) remains the main cause of mortality and morbidity in patients with diabetes. Prevention of CVD in diabetes involves a multifactorial approach that aims to treat the cluster of risk factors including hyperglycemia, dyslipidemia, obesity, hypertension, and hypercoagulation associated with this condition. Antiplatelets reduce the prothrombotic environment in diabetes, but complications of this therapeutic approach include a general risk of bleeding, specifically intracranial hemorrhage, the risk of which increases in the presence of hypertension. Current guidelines recommend the use of antiplatelet agents after tight control of blood pressure, which, in clinical practice, is not always possible. In this review, the evidence for antiplatelet use in diabetes with particular emphasis on patients with associated hypertension is examined. Safe levels of blood pressure with antiplatelet therapy, various studies, and general recommendations for diabetes patients, in light of current evidence, are explored.

Aspirin effect on the incidence of major adverse cardiovascular events in patients with diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Aspirin has been recommended for the prevention of major adverse cardiovascular events (MACE, composite of non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death) in diabetic patients without previous cardiovascular disease. However, recent meta-analyses have prompted re-evaluation of this practice. The study objective was to evaluate the relative and absolute benefits and harms of aspirin for the prevention of incident MACE in patients with diabetes.

METHODS

We performed a systematic review and meta-analysis on seven studies (N=11,618) reporting on the use of aspirin for the primary prevention of MACE in patients with diabetes. Two reviewers conducted a systematic search of electronic databases (MEDLINE, EMBASE, the Cochrane Library, and BIOSIS) and hand searched bibliographies and clinical trial registries. Reviewers extracted data in duplicate, evaluated the quality of the trials, and calculated pooled estimates.

RESULTS

A total of 11,618 participants were included in the analysis. The overall risk ratio (RR) for MACE was 0.91 (95% confidence intervals, CI, 0.82-1.00) with little heterogeneity among trials (I2 0.0%). Secondary outcomes of interest included myocardial infarction (RR, 0.85; 95% CI, 0.66-1.10), stroke (RR, 0.84; 95% CI, 0.64-1.11), cardiovascular death (RR, 0.95; 95% CI, 0.71-1.27), and all-cause mortality (RR, 0.95; 95% CI, 0.85-1.06). There were higher rates of hemorrhagic and gastrointestinal events. In absolute terms, these relative risks indicate that for every 10,000 diabetic patients treated with aspirin, 109 MACE may be prevented at the expense of 19 major bleeding events (with the caveat that the relative risk for the latter is not statistically significant).

CONCLUSIONS

The studies reviewed suggest that aspirin reduces the risk of MACE in patients with diabetes without cardiovascular disease, while also causing a trend toward higher rates of bleeding and gastrointestinal complications. These findings and our absolute benefit and risk calculations suggest that those with diabetes but without cardiovascular disease lie somewhere between primary and secondary prevention patients on the spectrum of benefit and risk. This underscores the importance of considering individual risk in clinical decision making regarding aspirin in those with diabetes.

Peri-operative management of antiplatelet therapy in patients with coronary artery disease: joint position paper by members of the working group on Perioperative Haemostasis of the Society on Thrombosis and Haemostasis Research (GTH), the working group on Perioperative Coagulation of the Austrian Society for Anesthesiology, Resuscitation and Intensive Care (ÖGARI) and the Working Group Thrombosis of the European Society for Cardiology (ESC)

An increasing number of patients suffering from cardiovascular disease, especially coronary artery disease (CAD), are treated with aspirin and/or clopidogrel for the prevention of major adverse events. Unfortunately, there are no specific, widely accepted recommendations for the perioperative management of patients receiving antiplatelet therapy. Therefore, members of the Perioperative Haemostasis Group of the Society on Thrombosis and Haemostasis Research (GTH), the Perioperative Coagulation Group of the Austrian Society for Anesthesiology, Reanimation and Intensive Care (ÖGARI) and the Working Group Thrombosis of the European Society of Cardiology (ESC) have created this consensus position paper to provide clear recommendations on the perioperative use of anti-platelet agents (specifically with semi-urgent and urgent surgery), strongly supporting a multidisciplinary approach to optimize the treatment of individual patients with coronary artery disease who need major cardiac and non-cardiac surgery. With planned surgery, drug eluting stents (DES) should not be used unless surgery can be delayed for ≥12 months after DES implantation. If surgery cannot be delayed, surgical revascularisation, bare-metal stents or pure balloon angioplasty should be considered. During ongoing antiplatelet therapy, elective surgery should be delayed for the recommended duration of treatment. In patients with semi-urgent surgery, the decision to prematurely stop one or both antiplatelet agents (at least 5 days pre-operatively) has to be taken after multidisciplinary consultation, evaluating the individual thrombotic and bleeding risk. Urgently needed surgery has to take place under full antiplatelet therapy despite the increased bleeding risk. A multidisciplinary approach for optimal antithrombotic and haemostatic patient management is thus mandatory.

O uso da Aspirina na Prevenção Primária da doença cardiovascular: novas atualizações

Muitas vezes os Médicos de Família têm de tomar a decisão de iniciar ou não o uso de aspirina nos seus pacientes. Embora os benefícios do tratamento com aspirina na redução do risco de enfarte do miocárdio (EM), acidente vascular cerebral (AVC) ou morte de causa vascular entre homens e mulheres com doença cardiovascular (DCV) pré-existente estejam bem estabelecidos, o papel da aspirina na prevenção primária é menos claro. Assim, o objetivo deste estudo foi determinar as indicações para o uso da aspirina na prevenção primária da DCV no adulto, baseadas na melhor evidência disponível. O autor pesquisou revisões baseadas em evidência, normas de orientação clínica, meta-análises, revisões sistemáticas e ensaios clínicos controlados e aleatorizados, na base de dados Medline e sites de Medicina Baseada na Evidência, utilizando os termos MeSH: Primary Prevention e Aspirin, publicados desde janeiro de 2000 até dezembro de 2009 em inglês, espanhol e português. Para avaliar o nível de evidência, foi utilizada a escala de Strength of Recommendation Taxonomy (SORT) da American Family Physician. As conclusões são: no homem entre os 45 e os 79 anos de idade deve ser encorajado o uso da aspirina quando o potencial benefício cardiovascular, prevenção de EM, ultrapassa o potencial dano de hemorragia gastrointestinal (GI) (SOR A); na mulher entre os 55 e os 79 anos de idade deve ser encorajado o uso da aspirina quando o potencial benefício cardiovascular, prevenção de AVC, ultrapassa o potencial dano de hemorragia GI (SOR A); a aspirina pode reduzir o risco de EM no diabético do sexo masculino (SOR B); ponderar o uso da aspirina como prevenção primária da DCV nos diabéticos tipo 1 e tipo 2 com risco cardiovascular aumentado, incluindo aqueles com >40 anos ou que têm fatores de risco adicionais (história familiar de DCV, HTA, fumantes, dislipidemia, ou albuminúria) (SOR B).

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).

Antiplatelet combinations for prevention of atherothrombotic events

Antiplatelet therapy plays a fundamental role in reducing atherothrombotic events by several pathways. The present work reviews available evidence on antiplatelet therapy both for primary prevention and in the presence of established peripheral, cerebral, or cardiac ischemic disease. Due to the importance of adherence to therapy to achieve optimal effects, special attention is given to the use of fixed-dose oral formulations in the clinical subset of patients in whom double antiplatelet therapy has proven indications.

Cardiovascular morbidity and mortality in patients with rheumatoid arthritis: vascular alterations and possible clinical implications

Mortality in patients with rheumatoid arthritis (RA) is higher than in the general population, which is due mainly to premature cardiovascular disease. Traditional cardiovascular risk factors cannot entirely explain the higher level of cardiovascular complications, and there is growing evidence that chronic inflammation is the main culprit. The aims of this review of the literature are to (i) summarize aspects of vascular alterations found in the cardiovascular system of RA patients and to relate them to the clinically relevant cardiovascular morbidity and mortality and (ii) evaluate what these abnormalities and complications might in the end imply for clinical management. A number of abnormalities in the cardiovascular system of RA patients have been identified, on the molecular level, in endothelial function, arterial stiffness, arterial morphology and, finally, in the clinical presentation of cardiovascular disease. Cardiovascular risk assessment should be part of the care of RA patients. While a great deal of data is published demonstrating abnormalities in the cardiovascular system of these patients, it is much less clear what specific interventions should be performed to reduce the incidence of cardiovascular complications. Cardiovascular care should be delivered in accordance with recommendations for the general population. Whether specific drugs (e.g. statins, aspirin) are of particular benefit in RA patients needs further investigation. Control of inflammation appears to be of benefit. Methotrexate and tumor necrosis factor-α blocking agents might reduce the number of cardiovascular events. Leflunomide, cyclosporine, non-steroidal anti-inflammatory drugs and cyclo-oxygenase-2 inhibitors may worsen cardiovascular outcome. The role of glucocorticoids in active RA remains to be determined.

Effect of platelet turnover on whole blood platelet aggregation in patients with coronary artery disease

BACKGROUND

Previous studies have demonstrated considerable variation in the antiplatelet effect of aspirin.

OBJECTIVES

To investigate the impact of platelet turnover on the antiplatelet effect of aspirin in patients with stable coronary artery disease (CAD) and to identify determinants of platelet turnover.

METHODS

Platelet turnover was evaluated by measurements of immature platelets and thrombopoietin in 177 stable CAD patients on aspirin monotherapy, including 85 type 2 diabetics and 92 non-diabetics. Whole blood platelet aggregation was determined using the VerifyNow(®) Aspirin test and multiple electrode aggregometry (MEA, Multiplate(®) ) induced by arachidonic acid (AA) (1.0 mm), adenosine diphosphate (ADP) (10 μm) and collagen (1.0 μg mL(-1) ).

RESULTS

Immature platelet levels significantly correlated with MEA (r = 0.31-0.36, P-values < 0.0001) and the platelet activation marker sP-selectin (r = 0.19, P = 0.014). Contrary to the VerifyNow(®) test, MEA significantly correlated with variations in platelet count (r = 0.45-0.68, P-values < 0.0001). Among patients with residual platelet reactivity according to AA, there were significantly more diabetics (61% vs. 41%, P = 0.027) and higher levels of sP-selectin (77.7 ± 29 vs. 70.2 ± 25 ng mL(-1) , P = 0.070) and serum thromboxane B(2) (0.81 [0.46; 1.70] vs. 0.56 [0.31; 1.12] ng mL(-1) , P = 0.034). In a multivariate regression analysis, immature platelet levels were determined by thrombopoietin levels (P < 0.001), smoking (P = 0.020) and type 2 diabetes (P = 0.042).

CONCLUSIONS

The antiplatelet effect of aspirin was reduced in CAD patients with an increased platelet turnover. Once-daily dosing of aspirin might not suffice to adequately inhibit platelet aggregation in patients with an increased platelet turnover.

The diabetic CKD patient--a major cardiovascular challenge

The diabetic patient with chronic kidney disease (CKD) is at very high risk of cardiovascular disease (CVD). Primary and secondary CVD prevention is of major importance and should be targeted at both traditional cardiovascular risk factors and risk factors specific for patients with CKD, such as albuminuria, anaemia and CKD--mineral and bone disorder. However, treatment goals have largely been derived from clinical trials including patients with no or only mild CKD and may not be generalizable to patients with advanced renal disease. Moreover, in patients on renal replacement therapy, the association between traditional CVD risk factors and the incidence of CVD may be reversed, and pharmaceutical interventions that are beneficial in the general population may be ineffective or even harmful in this high-risk population. Those involved in the delivery of care to patients with diabetes and CKD need to be aware of these issues and should adopt an individualised approach to treatment.

Antiplatelet drug interactions

Both laboratory studies in healthy volunteers and clinical studies have suggested adverse interactions between antiplatelet drugs and other commonly used medications. Interactions described include those between aspirin and ibuprofen, aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and the thienopyridine, clopidogrel, and drugs inhibiting CYP2C19, notably the proton pump inhibitors (PPI) omeprazole and esomeprazole. Other interactions between thienopyridines and CYP3A4/5 have also been reported for statins and calcium channel blockers. The ibuprofen/aspirin interaction is thought to be caused by ibuprofen blocking the access of aspirin to platelet cyclo-oxygenase. The thienopyridine interactions are caused by inhibition of microsomal enzymes that metabolize these pro-drugs to their active metabolites. We review the evidence for these interactions, assess their clinical importance and suggest strategies of how to deal with them in clinical practice. We conclude that ibuprofen is likely to interact with aspirin and reduce its anti-platelet action particularly in those patients who take ibuprofen chronically. This interaction is of greater relevance to those patients at high cardiovascular risk. A sensible strategy is to advise users of aspirin to avoid chronic ibuprofen or to ingest aspirin at least 2 h prior to ibuprofen. Clearly the use of NSAIDs that do not interact in this way is preferred. For the clopidogrel CYP2C19 and CYP3A4/5 interactions, there is good evidence that these interactions occur. However, there is less good evidence to support the clinical importance of these interactions. Again, a reasonable strategy is to avoid the chronic use of drugs that inhibit CYP2C19, notably PPIs, in subjects taking clopidogrel and use high dose H2 antagonists instead. Finally, anti-platelet agents probably interact with other drugs that affect platelet function such as selective serotonin reuptake inhibitors, and clinicians should probably judge patients taking such combination therapies as at high risk for bleeding.

Aspirin for primary prevention of cardiovascular disease in diabetes mellitus

Aspirin is effective for the prevention of cardiovascular events in patients with a history of vascular disease, as so-called secondary prevention. In general populations with no history of previous myocardial infarction or stroke, aspirin also seems useful for primary prevention of cardiovascular events, although the absolute benefits are smaller than those seen in patients with previous cardiovascular disease. Patients with diabetes mellitus are at an increased risk of cardiovascular events, but new trials have raised questions about the benefit of aspirin for primary prevention in patients with this disorder. This Review comprehensively examines the basic pharmacology of aspirin and provides an overview of the randomized, controlled trials of aspirin therapy that have included patients with diabetes mellitus. On the basis of currently available evidence from primary prevention trials, aspirin is estimated to reduce the relative risk of myocardial infarction and stroke by about 10% in patients with diabetes mellitus; however, aspirin also increases the risk of gastrointestinal bleeding. As such, low-dose aspirin therapy (75-162 mg) is reasonable for patients with diabetes mellitus and a 10-year risk of cardiovascular events >10%. Results from upcoming large trials will help clarify the effects of aspirin with greater precision, including whether the benefits differ between men and women.

The missing men: high risk of disease in men of Mexican origin

The present study sought to determine gender- and age-specific prevalences of chronic diseases in an urban Mexican American border community. The Cameron County Hispanic Cohort (CCHC; n = 2,000) was selected using a multistaged cluster design. Sociodemographics, anthropometric measures, and blood samples were collected on each participant. More women were obese (55.1%) than men (44.8%). Men had significantly higher rates of diabetes (20.4% for men vs. 15.8% for women, p < .05) and undiagnosed diabetes (6.2% for men vs. 2.4% for women, p < .01); the prevalence of diabetes rose steeply between the ages of 40 and 49 years. Men were significantly more likely to have serum cholesterol levels of 200 mg/dL and elevated low-density lipoprotein levels (22.6% vs. 26.1%, p < .01). Mexican American males in the U.S./Mexico border region have a high prevalence of obesity in younger men and higher overall rates of diabetes, including undiagnosed diabetes, and significantly higher serum cholesterol levels than women.

Coagulation and fibrinolysis in diabetes

Atherothrombotic complications are the main cause of mortality in subjects with diabetes. Premature atherosclerosis, increased platelet reactivity and activation of coagulation factors with associated hypofibrinolysis all contribute to increased cardiovascular risk in this population. Blood clot formation represents the last step in the atherothrombotic process, and the structure of the fibrin network has a role in determining predisposition to cardiovascular disease. In this review, we discuss alterations in coagulation factor plasma levels and/or activity in diabetes and clarify their role in predisposition to cardiovascular events. The effect of diabetes on fibrin network structure/fibrinolysis is reviewed and potential mechanisms that modify clot properties are discussed. Finally, modulation of clotting potential by the various therapeutic agents used in diabetes is examined. Understanding the mechanisms by which diabetes influences the coagulation pathway will help to develop more effective treatment strategies to reduce thrombotic events in subjects with this condition.

Antithrombotic therapy in patients with diabetes mellitus and coronary artery disease

Currently approved antiplatelet treatment strategies have proved successful for reducing cardiovascular adverse events in patients with CAD. However, despite the use of recommended antiplatelet treatment strategies, the presence of DM has been consistently associated with a negative impact on outcomes and a high rate of adverse cardiovascular events continue to occur in patients with DM. The elevated prevalence of low response to standard oral antiplatelet agents contribute to these impaired outcomes. Thus, the search for more potent antiplatelet treatment strategies is warranted in high-risk patients, such as those with DM. The present manuscript provides an overview on the current status of knowledge on currently available antiplatelet agents, focusing on the benefits and limitations of these therapies in DM patients, and evaluating the potential role of new antithrombotic agents and treatment strategies currently under development to overcome these limitations.

Aspirin resistance: Fact or fiction? A point of view

Aspirin is a wonder drug that has been used for well over 100 years for its analgesic and antipyretic effects. For the past three decades, it has increasingly been used for the prevention of primary and secondary cardiovascular events. Lately, it has been suggested that a significant number of individuals taking aspirin have become resistant to this drug. The phenomenon of "aspirin resistance" is based on the observation of clinical events in some patients taking aspirin, and/or a diminished platelet aggregation inhibitory response to aspirin therapy. Unfortunately, laboratory assays used to monitor the efficacy of aspirin are far from accurate and the results are not reproducible. Furthermore, results of different platelet function tests are often not congruent. In addition, platelet aggregation studies show marked inter-individual and intra-individual variability. Patients with coronary heart disease take many drugs that interfere with the effect of aspirin on platelet aggregation. Besides inhibiting formation of thromboxane A(2) from arachidonic acid, aspirin has a host of platelet-independent effects that complement its platelet inhibitory effects. Laboratory assays designed to measure platelet function do not take into account these pleiotropic effects of aspirin. In our view, use of the term "aspirin resistance" based on inadequate knowledge of imperfect laboratory tests does a disservice to physicians and patients.

Aspirin use in elderly women receiving medication therapy management services

INTRODUCTION

Cardiovascular disease is the largest single cause of death among women in the US. The American Heart Association guidelines recommend aspirin use in women > or = 65 years of age if blood pressure is controlled and the benefits of cardiovascular risk reduction likely outweigh the risk of bleeding. The objective of this study is to determine the prevalence of aspirin use in elderly women and factors associated with use.

METHODS

This retrospective study evaluated aspirin use in women aged > or = 65 years based on cardiovascular and gastrointestinal bleeding risk using a medication therapy management database within a large mid-Atlantic managed care organization. Logistic regression was used to analyze patient-related variables associated with aspirin use. Variables included clinical coronary heart disease (CHD), number of CHD risk factors, diabetes diagnosis, number of chronic medications and presence of contraindications to aspirin.

RESULTS

Aspirin use was reported in 50% of patients: 68.0% in the secondary prevention group and 46.3% in the primary prevention group. The percentage of patients using aspirin or with relative aspirin contraindications increased to 84% for the secondary prevention group and 65.9% for the primary prevention group. Patients with clinical CHD and those with diabetes and without clinical CHD were 5.88 (P=0.008) and 7.54 (P=0.012) times more likely to utilize aspirin, respectively, than patients with only one CHD risk factor of age. Patients with relative contraindications to aspirin were less likely to use aspirin (P<0.001).

CONCLUSION

The high use of aspirin in patients at higher CHD risk supports national recommendations. Clinical practitioners need to carefully assess the value of aspirin in patients at low CHD risk and those 80 years of age and beyond where evidence of benefit should be weighed against risk.

Use of Evidence-Based Therapy for the Prevention of Cardiovascular Events Among Older people

Evidence-based therapies (EBTs) for the prevention of cardiovascular disease (CVD) are reportedly underutilized in older people. The primary purpose of this study was to evaluate the use of EBTs for the prevention of CVD events in older people and secondarily whether a Home Medicines Review (HMR) service by pharmacists’ predicts the use of these medicines. A retrospective cross-sectional audit of HMR reports pertaining to 608 community-dwelling older people (≥65 years) was conducted. EBTs considered for this audit included four guideline-recommended therapies for CVD: antithrombotic therapy (warfarin ± antiplatelet therapy), β-blockers, statins, and angiotensin agents (angiotensin-converting enzyme inhibitors [ACEI] ± angiotensin II receptor blockers [ARBs]). The prevalence of EBT use among the older people, mean age (SD) 75.6 (7.5) years, was: 73% for antithrombotic therapy, 75% for statins, 74% for angiotensin therapy, and 35% for β-blockers. CVD risk factors warranting treatment with these EBTs were frequently associated with use of EBTs. EBTs were least likely to be used in those with coronary interventions like coronary artery bypass grafting (CABG)/stent insertion (all EBTs except angiotensin agents) and angiotensin agents in those with a history of myocardial infarction or chronic heart failure. A pharmacist-led HMR service was significantly associated with the prescribing of all 4 EBTs. The results from this study show good adherence to evidence-based guidelines in general, although there is still room for improvement to further optimize clinical outcomes in these complex patients. The study also adds to the available literature on the effectiveness of pharmacists’ collaborative contribution to the care of these high-risk patients.

Cost-effectiveness of aspirin use among persons with newly diagnosed type 2 diabetes

OBJECTIVE

To assess the long-term cost-effectiveness of aspirin use among adults aged >or=40 years with newly diagnosed type 2 diabetes.

RESEARCH DESIGN AND METHODS

We used a validated cost-effectiveness model of type 2 diabetes to assess the lifetime health and cost consequences of use or nonuse of aspirin. The model simulates the progression of diabetes and accompanying complications for a cohort of subjects with type 2 diabetes. The model predicts the outcomes of type 2 diabetes along five disease paths (nephropathy, neuropathy, retinopathy, coronary heart disease, and stroke) from the time of diagnosis until age 94 years or until death.

RESULTS

Over a lifetime, aspirin users gained 0.31 life-years (LY) or 0.19 quality-adjusted LYs (QALYs) over nonaspirin users, at an incremental cost of $1,700; the incremental cost-effectiveness ratio (ICER) of aspirin use was $5,428 per LY gained or $8,801 per QALY gained. In probabilistic sensitivity analyses, the ICER was <$30,000 per QALY in all of 2,000 realizations in two scenarios.

CONCLUSIONS

Regular use of aspirin among people with newly diagnosed diabetes is cost-effective.

Critical Overview on the Benefits and Harms of Aspirin

Aspirin is widely used internationally for a variety of indications, with the most prominent one being that of cardiovascular disease. However, aspirin has also been proposed as a treatment option in a diverse range of conditions such as diabetes mellitus, cancer prevention, and obstetrics. In our overview, we critically appraise the current evidence from recent systematic reviews and meta-analyses covering the benefits of aspirin across these conditions. We also look at evidence that some patients may not derive benefit due to the concept of aspirin resistance. Aspirin is also associated with the potential for significant harm, principally from haemorrhagic adverse events. We critically appraise the threat of haemorrhagic complications, and weigh up these risks against that of any potential benefit.

Is Aspirin Really Effective for Primary Cardiovascular Prevention?

Aspirin is widely used for the prevention of cardiovascular events. Although the evidence supporting the use of aspirin for secondary prevention is strong, its role in primary prevention in less clear. Nonetheless, recommendations from the US Preventive Services Task Force (USPSTF) continue to support the use of aspirin for primary cardiovascular prevention in select patients. This article will review current recommendations for primary prevention with aspirin, recent studies that have generated considerable controversy, and implications for clinical practice.