Effectiveness and efficiency of different guidelines on statin treatment for preventing deaths from coronary heart disease: modelling study

Resveratrol-mediated cardioprotection against myocardial ischemia-reperfusion injury was revoked by statin-induced mitochondrial alterations

Resveratrol is well known for its antioxidant potential and ability to preserve mitochondrial function, reported attenuating ischemia-reperfusion (IR) injury in the heart. The present study investigates resveratrol on IR injury in rat hearts treated with statin for 14 days. Male Wistar rats were used in this study, and statin-induced cardiac metabolic alterations were monitored after the administration of simvastatin (80 mg/kg). IR was instigated by the Langendroff perfusion system and measured the physiological and biochemical changes. The basal level changes in ECG, ANP, and BNP expression and CoenzymeQ₁₀ level were altered in statin-treated animals compared to the normal rat heart. The animals treated with statin demonstrated higher IR injury (measured via low rate pressure product (88.4%), increased histological alterations, prominent mitochondrial dysfunction (NQR: IR-72%, Stat IR-67%; SQR: IR-71%, Stat IR-74%; COX: IR-58%, Stat IR-52%) than the normal rat heart underwent similar protocols. Administration of heart with resveratrol recovered the IR associated hemodynamic indices in normal heart subjected to IR but failed to impart a similar effect in the statin-treated heart. Our results demonstrated that resveratrol failed to reverse the IR-associated cardiac injury and functional abnormalities in statin-treated rat hearts subjected to IR but effective in IR challenged normal heart.

Performance of the Net Reclassification Improvement for Nonnested Models and a Novel Percentile-Based Alternative

The net reclassification improvement (NRI) is a widely used metric used to assess the relative ability of 2 risk models to distinguish between low- and high-risk individuals. However, the validity and usefulness of the NRI have been questioned. Criticism of the NRI focuses on its use comparing nested risk models, whereas in practice it is often used to compare nonnested risk models derived from distinct data sources. In this study, we evaluated the performance of the NRI in a nonnested context by using it to compare competing cardiovascular risk-prediction models. We explored the NRI's sensitivity to variations in risk categories and to the calibration of the compared models. We found that the NRI was very sensitive to changes in the definition of risk categories, especially when at least 1 model was miscalibrated. To address these shortcomings, we describe a novel alternative to the usual NRI that uses percentiles of risk instead of cutoffs based on absolute risk. This percentile-based NRI demonstrates the relative ability of 2 models to rank patient risk. It displays more stable behavior, and we recommend its use when there are no established risk categories or when models are miscalibrated.

Hypercholesterolaemia - practical information for non-specialists

Hypercholesterolaemia is amongst the most common conditions encountered in the medical profession. It remains one of the key modifiable cardiovascular risk factors and there have been recent advances in the risk stratification methods and treatment options available. In this review, we provide a background into hypercholesterolaemia for non-specialists and consider the merits of the different risk assessment tools available. We also provide detailed considerations as to: i) when to start treatment, ii) what targets to aim for and iii) the role of low density lipoprotein cholesterol.

Moderate-intensity statin therapy seems ineffective in primary cardiovascular prevention in patients with type 2 diabetes complicated by nephropathy. A multicenter prospective 8 years follow up study

BACKGROUND

Although numerous studies and metanalysis have shown the beneficial effect of statin therapy in CVD secondary prevention, there is still controversy such the use of statins for primary CVD prevention in patients with DM. The purpose of this study was to evaluate the occurrence of total major adverse cardio-vascular events (MACE) in a cohort of patients with type 2 diabetes complicated by nephropathy treated with statins, in order to verify real life effect of statin on CVD primary prevention.

METHODS

We conducted an observational prospective multicenter study on 564 patients with type 2 diabetic nephropathy free of cardiovascular disease attending 21 national outpatient diabetes clinics and followed them up for 8 years. 169 of them were treated with statins (group A) while 395 were not on statins (group B).

RESULTS

Notably, none of the patients was treated with a high-intensity statin therapy according to last ADA position statement. Total MACE occurred in 32 patients from group A and in 68 patients from group B. Fatal MACE occurred in 13 patients from group A and in 30 from group B; nonfatal MACE occurred in 19 patients from group A and in 38 patients from group B. The analysis of the Kaplan-Meier survival curves showed a not statistically significant difference in the incidence of total (p 0.758), fatal (p 0.474) and nonfatal (p 0.812) MACE between the two groups. HbA1c only showed a significant difference in the incidence of MACE between the two groups (HR 1.201, CI 1.041-1.387, p 0.012).

CONCLUSIONS

These findings suggest that, in a real clinical setting, moderate-intensity statin treatment is ineffective in cardiovascular primary prevention for patients with diabetic nephropathy. Trial registration ClinicalTrials.gov Identifier NCT00535925. Date of registration: September 24, 2007, retrospectively registered.

Short-term predictive ability of selected cardiovascular risk prediction models in a rural Bangladeshi population: a case-cohort study

Background

Prediction of absolute risk of cardiovascular diseases (CVDs) has important clinical and public health significance, but the predictive ability of the available tools has not yet been tested in the rural Bangladeshi population. The present study was undertaken to test the hypothesis that both laboratory-based (Framingham equation and WHO/ISH laboratory-based charts) and non-laboratory-based tools may be used to predict CVDs on a short-term basis.

Methods

Data from a case-cohort study (52989 cohort and 439 sub-cohort participants), conducted on a rural Bangladeshi population, were analysed using modified Cox PH model with a maximum follow-up of 2.5 years. The outcome variable, coronary heart diseases (CHDs), was assessed in 2014 using electrocardiography, and it was used as a surrogate marker for CVDs in Bangladesh. The predictive power of the models was assessed by calculating C-statistics and generating ROC curves with other measures of diagnostic tests.

Results

All the models showed high negative prediction values (NPVs, 84 % to 92 %) and these did not differ between models or gender. The sensitivity of the models substantially changed based on the risk prediction thresholds (between 5–30 %); however, the NPVs and PPVs were relatively stable at various threshold levels. Hypertension and dyslipidaemia were significantly associated with CHD outcome in males and ABSI (a body shape index) in females. All models showed similar C-statistics (0.611–0.685, in both genders). Overall, the non-laboratory-based model showed better performance (0.685) in women but equal performance in men.

Conclusions

Existing CVD risk prediction tools may identify future CHD cases with fairly good confidence on a short-term basis. The non-laboratory-based tool, using ABSI as a predictor, may provide better predictive accuracy among women.

Cost-effectiveness of natriuretic peptide-based screening and collaborative care: a report from the STOP-HF (St Vincent's Screening TO Prevent Heart Failure) study

AIMS

Prevention of cardiovascular disease and heart failure (HF) in a cost-effective manner is a public health goal. This work aims to assess the cost-effectiveness of the St Vincent's Screening TO Prevent Heart Failure (STOP-HF) intervention.

METHODS AND RESULTS

This is a substudy of 1054 participants with cardiovascular risk factors [median age 65.8 years, interquartile range (IQR) 57.8:72.4, with 4.3 years, IQR 3.4:5.2, follow-up]. Annual natriuretic peptide-based screening was performed, with collaborative cardiovascular care between specialist physicians and general practitioners provided to patients with BNP levels >50 pg/mL. Analysis of cost per case prevented and cost-effectiveness per quality-adjusted life year (QALY) gained was performed. The primary clinical endpoint of LV dysfunction (LVD) with or without HF was reduced in intervention patients [odds ratio (OR) 0.60; 95% confidence interval (CI) 0.38-0.94; P = 0.026]. There were 157 deaths and/or emergency hospitalizations for major adverse cardiac events (MACE) in the control group vs. 102 in the intervention group (OR 0.68; 95% CI 0.49-0.93; P = 0.01). The cost per case of LVD/HF prevented was €9683 (sensitivity range -€843 to €20 210), whereas the cost per MACE prevented was €3471 (sensitivity range -€302 to €7245). Cardiovascular hospitalization savings offset increased outpatient and primary care costs. The cost per QALY gain was €1104 and the intervention has an 88% probability of being cost-effective at a willingness to pay threshold of €30 000.

CONCLUSION

Among patients with cardiovascular risk factors, natriuretic peptide-based screening and collaborative care reduced LVD, HF, and MACE, and has a high probability of being cost-effective.

TRIAL REGISTRATION

NCT00921960.

Statin prescribing according to gender, age and indication: what about the benefit-risk balance?

RATIONALES, AIMS AND OBJECTIVES

The increasing dispensing of statins has raised concern about the appropriateness of prescribing to various population groups. We aimed to (1) investigate incident and prevalent statin prescribing according to indication, gender and age and (2) relate prescribing patterns to evidence on beneficial and adverse effects.

METHODS

A cohort of Danish inhabitants (n = 4 424 818) was followed in nationwide registries for dispensed statin prescriptions and hospital discharge information. We calculated incidence rates (2005-2009), prevalence trends (2000-2010) and absolute numbers of statin users according to register proxies for indication, gender and age.

RESULTS

In 2010, the prevalence became highest for ages 75-84 and was higher in men than women (37% and 33%, respectively). Indication-specific incidences and prevalences peaked at ages around 65-70, but in myocardial infarction, the prevalence was about 80% at ages 45-80. Particularly, incidences tended to be lower in women until ages of about 60 where after gender differences were negligible. In asymptomatic individuals (hypercholesterolaemia, presumably only indication) aged 50+, dispensing was highest in women. The fraction of statin dispensing for primary prevention decreased with age: higher for incident than prevalent prescribing. Independent of age, this fraction was highest among women, e.g. 60% versus 45% at ages 55-64. The fraction for potential atherosclerotic condition (PAC, e.g. heart failure) increased with age.

CONCLUSION

Prevalence of statin utilization was highest for ages 75-84, although indication-specific measures were relatively low. Despite inconclusive evidence for a favourable risk-benefit balance, statin prescribing was high among people aged 80+, asymptomatic women and PAC patients.

Cardiovascular Disease Population Risk Tool (CVDPoRT): predictive algorithm for assessing CVD risk in the community setting. A study protocol

INTRODUCTION

Recent publications have called for substantial improvements in the design, conduct, analysis and reporting of prediction models. Publication of study protocols, with prespecification of key aspects of the analysis plan, can help to improve transparency, increase quality and protect against increased type I error. Valid population-based risk algorithms are essential for population health planning and policy decision-making. The purpose of this study is to develop, evaluate and apply cardiovascular disease (CVD) risk algorithms for the population setting.

METHODS AND ANALYSIS

The Ontario sample of the Canadian Community Health Survey (2001, 2003, 2005; 77,251 respondents) will be used to assess risk factors focusing on health behaviours (physical activity, diet, smoking and alcohol use). Incident CVD outcomes will be assessed through linkage to administrative healthcare databases (619,886 person-years of follow-up until 31 December 2011). Sociodemographic factors (age, sex, immigrant status, education) and mediating factors such as presence of diabetes and hypertension will be included as predictors. Algorithms will be developed using competing risks survival analysis. The analysis plan adheres to published recommendations for the development of valid prediction models to limit the risk of overfitting and improve the quality of predictions. Key considerations are fully prespecifying the predictor variables; appropriate handling of missing data; use of flexible functions for continuous predictors; and avoiding data-driven variable selection procedures. The 2007 and 2009 surveys (approximately 50,000 respondents) will be used for validation. Calibration will be assessed overall and in predefined subgroups of importance to clinicians and policymakers.

ETHICS AND DISSEMINATION

This study has been approved by the Ottawa Health Science Network Research Ethics Board. The findings will be disseminated through professional and scientific conferences, and in peer-reviewed journals. The algorithm will be accessible electronically for population and individual uses.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT02267447.

Antioxidant effects of statins in the management of cardiometabolic disorders

Redox systems are key players in vascular health. A shift in redox homeostasis-that results in an imbalance between reactive oxygen species (ROS) generation and endogenous antioxidant defenses has the potential to create a state of oxidative stress that subsequently plays a role in the pathogenesis of a number of diseases, including those of the cardiovascular and metabolic system. Statins, which are primarily used to reduce the concentration of low-density lipoprotein cholesterol, have also been shown to reduce oxidative stress by modulating redox systems. Studies conducted both in vitro and in vivo support the role of oxidative stress in the development of atherosclerosis and cardiovascular diseases. Oxidative stress may also be responsible for various diabetic complications and the development of fatty liver. Statins reduce oxidative stress by blocking the generation of ROS and reducing the NAD+/NADH ratio. These drugs also have effects on nitric oxide synthase, lipid peroxidation and the adiponectin levels. It is possible that the antioxidant properties of statins contribute to their protective cardiovascular effects, independent of the lipid-lowering actions of these agents. However, possible adverse effects of statins on glucose homeostasis may be related to the redox system. Therefore, studies investigating the modulation of redox signaling by statins are warranted.

Who needs laboratories and who needs statins?: comparative and cost-effectiveness analyses of non-laboratory-based, laboratory-based, and staged primary cardiovascular disease screening guidelines

BACKGROUND

Early detection and treatment of cardiovascular disease (CVD) risk factors produces significant clinical benefits, but no consensus exists on optimal screening algorithms. This study aimed to evaluate the comparative and cost-effectiveness of staged laboratory-based and non-laboratory-based total CVD risk assessment.

METHODS AND RESULTS

We used receiver operating characteristic curve and cost-effectiveness modeling methods to compare strategies with and without laboratory components and used single-stage and multistage algorithms, including approaches based on Framingham risk scores (laboratory-based assessments for all individuals). Analyses were conducted using data from 5998 adults in the Third National Health and Nutrition Examination Survey without history of CVD using 10-year CVD death as the main outcome. A microsimulation model projected lifetime costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios for 60 Framingham-based, non-laboratory-based, and staged screening approaches. Across strategies, the area under the receiver operating characteristic curve was 0.774 to 0.780 in men and 0.812 to 0.834 in women. There were no statistically significant differences in area under the receiver operating characteristic curve between multistage and Framingham-based approaches. In cost-effectiveness analyses, multistage strategies had incremental cost-effectiveness ratios of $52,000/QALY and $83,000/QALY for men and women, respectively. Single-stage/Framingham-based strategies were dominated (higher cost and lower QALYs) or had unattractive incremental cost-effectiveness ratios (>$300,000/QALY) compared with single-stage/non-laboratory-based and multistage approaches.

CONCLUSIONS

Non-laboratory-based CVD risk assessment can be useful in primary CVD prevention as a substitute for laboratory-based assessments or as the initial component of a multistage approach. Cost-effective multistage screening strategies could avoid 25% to 75% of laboratory testing used in CVD risk screening with predictive power comparable with Framingham risks.

Appraisal tools for clinical practice guidelines: a systematic review

INTRODUCTION

Clinical practice guidelines can improve healthcare processes and patient outcomes, but are often of low quality. Guideline appraisal tools aim to help potential guideline users in assessing guideline quality. We conducted a systematic review of publications describing guideline appraisal tools in order to identify and compare existing tools.

METHODS

Among others we searched MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews from 1995 to May 2011 for relevant primary and secondary publications. We also handsearched the reference lists of relevant publications. On the basis of the available literature we firstly generated 34 items to be used in the comparison of appraisal tools and grouped them into thirteen quality dimensions. We then extracted formal characteristics as well as questions and statements of the appraisal tools and assigned them to the items.

RESULTS

We identified 40 different appraisal tools. They covered between three and thirteen of the thirteen possible quality dimensions and between three and 29 of the possible 34 items. The main focus of the appraisal tools were the quality dimensions "evaluation of evidence" (mentioned in 35 tools; 88%), "presentation of guideline content" (34 tools; 85%), "transferability" (33 tools; 83%), "independence" (32 tools; 80%), "scope" (30 tools; 75%), and "information retrieval" (29 tools; 73%). The quality dimensions "consideration of different perspectives" and "dissemination, implementation and evaluation of the guideline" were covered by only twenty (50%) and eighteen tools (45%) respectively.

CONCLUSIONS

Most guideline appraisal tools assess whether the literature search and the evaluation, synthesis and presentation of the evidence in guidelines follow the principles of evidence-based medicine. Although conflicts of interest and norms and values of guideline developers, as well as patient involvement, affect the trustworthiness of guidelines, they are currently insufficiently considered. Greater focus should be placed on these issues in the further development of guideline appraisal tools.

Adherence to preventive statin therapy according to socioeconomic position

AIM

To explore whether long-term adherence to preventive statin therapy depends on socioeconomic position (SEP).

METHODS

A cohort of individuals without established cardiovascular disease (CVD) or diabetes initiating preventive statin therapy during 2002-2005 was followed in the individual-level Danish registries for 4 years or until censoring events (death, emigration, CVD or diabetes). Only individuals aged 40-84 years for whom information was available on the SEP indicators, education and income were included (N = 76,038). Two different aspects of poor adherence were applied as outcome measures: (1) Proportion of days covered (PDC) with medication below 80 %, assuming a daily dose of one tablet (continuity); (2) Discontinuation defined as a gap between two consecutive prescriptions exceeding 365 days (persistence). Stratum-specific logistic regression analyses were applied to estimate the odds ratio (OR) for PDC <80 % across SEP, adjusting for age and hypertension. Hazard ratio (HR) for discontinuation was estimated by Cox regression analyses.

RESULTS

Adjusting mutually for income and education, the OR for PDC <80 % decreased with increasing income. Comparing the highest income quintile with the lowest, the OR were 0.64 (95 % Confidence Interval 0.64-0.65) and 0.73 (0.73-0.74) in men aged 40-64 and 65-84 years, respectively; in women, the figures were 0.79 (0.79-0.79) and 0.95 (0.94-0.95), respectively. While observed increases in adherence with longer education in unadjusted analyses were attenuated after adjustment for income among men, the potential inverse relationship between length of education and adherence was enhanced among women. Applying discontinuation as outcome, analogous differences were demonstrated.

CONCLUSION

Adherence to preventive statin therapy in Denmark decreases with decreasing income-especially in men aged 40-64 years.

Statins for the primary prevention of cardiovascular disease

BACKGROUND

Reducing high blood cholesterol, a risk factor for cardiovascular disease (CVD) events in people with and without a past history of CVD is an important goal of pharmacotherapy. Statins are the first-choice agents. Previous reviews of the effects of statins have highlighted their benefits in people with CVD. The case for primary prevention was uncertain when the last version of this review was published (2011) and in light of new data an update of this review is required.

OBJECTIVES

To assess the effects, both harms and benefits, of statins in people with no history of CVD.

SEARCH METHODS

To avoid duplication of effort, we checked reference lists of previous systematic reviews. The searches conducted in 2007 were updated in January 2012. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2022, Issue 4), MEDLINE OVID (1950 to December Week 4 2011) and EMBASE OVID (1980 to 2012 Week 1).There were no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials of statins versus placebo or usual care control with minimum treatment duration of one year and follow-up of six months, in adults with no restrictions on total, low density lipoprotein (LDL) or high density lipoprotein (HDL) cholesterol levels, and where 10% or less had a history of CVD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion and extracted data. Outcomes included all-cause mortality, fatal and non-fatal CHD, CVD and stroke events, combined endpoints (fatal and non-fatal CHD, CVD and stroke events), revascularisation, change in total and LDL cholesterol concentrations, adverse events, quality of life and costs. Odds ratios (OR) and risk ratios (RR) were calculated for dichotomous data, and for continuous data, pooled mean differences (MD) (with 95% confidence intervals (CI)) were calculated. We contacted trial authors to obtain missing data.

MAIN RESULTS

The latest search found four new trials and updated follow-up data on three trials included in the original review. Eighteen randomised control trials (19 trial arms; 56,934 participants) were included. Fourteen trials recruited patients with specific conditions (raised lipids, diabetes, hypertension, microalbuminuria). All-cause mortality was reduced by statins (OR 0.86, 95% CI 0.79 to 0.94); as was combined fatal and non-fatal CVD RR 0.75 (95% CI 0.70 to 0.81), combined fatal and non-fatal CHD events RR 0.73 (95% CI 0.67 to 0.80) and combined fatal and non-fatal stroke (RR 0.78, 95% CI 0.68 to 0.89). Reduction of revascularisation rates (RR 0.62, 95% CI 0.54 to 0.72) was also seen. Total cholesterol and LDL cholesterol were reduced in all trials but there was evidence of heterogeneity of effects. There was no evidence of any serious harm caused by statin prescription. Evidence available to date showed that primary prevention with statins is likely to be cost-effective and may improve patient quality of life. Recent findings from the Cholesterol Treatment Trialists study using individual patient data meta-analysis indicate that these benefits are similar in people at lower (< 1% per year) risk of a major cardiovascular event.

AUTHORS' CONCLUSIONS

Reductions in all-cause mortality, major vascular events and revascularisations were found with no excess of adverse events among people without evidence of CVD treated with statins.

Potentially important considerations in choosing specific statin treatments to reduce overall morbidity and mortality

Hypercholesterolemia and dyslipidemia are independent risk factors for cardiovascular disease and death. Statins are the drugs of choice to decrease plasma cholesterol and have other beneficial actions beyond lipid-lowering leading to substantial improvements in cardiovascular morbidity and mortality. However, evaluation of the effects of statins to reduce overall morbidity and mortality must integrate metabolic consequences of statin therapy with its lipid-lowering effect. Indeed, reduction in LDL-cholesterol to target level achieved by statins does not completely eliminate risk of cardiovascular disease and may elevate metabolic risk factors that contribute to dysregulation of metabolic homeostasis. This may lead to increased incidence of diabetes and its cardiovascular complications that are explained, in part, by reciprocal relationships between insulin resistance and endothelial dysfunction. Genetic factors may determine 40-60% of total cholesterol levels and 70% of the efficacy of statin treatments. Metabolic and cardiovascular phenotypes that are either genetically determined or environmentally acquired are also important determinants of responses to specific statins. Moreover, differences between biological outcomes of specific statins or increasing dosages of statins result in differential metabolic actions due to off-target or unknown mechanism that have important implications for the use of statins to reduce overall morbidity and mortality. In this review, we discuss differential cardiovascular and metabolic pleiotropic actions of specific statins that interact in a context-dependent manner with patient phenotypes and genotypes. These important considerations may influence progression of atherosclerosis, risk of diabetes, and modulation of insulin resistance that help determine overall morbidity and mortality in patients undergoing statin therapy.

Statin utilization according to indication and age: a Danish cohort study on changing prescribing and purchasing behaviour

OBJECTIVE

Introduced to reduce mortality after myocardial infarction (MI), statins are now recommended for a range of other conditions, including asymptomatic individuals without cardiovascular disease or diabetes. The aim was to describe trends in Danish statin utilization according to indication and age during 1996-2009, and to analyse changing prescribing and purchasing behaviour during time intervals (driver periods) a priori defined by potential influential factors.

METHODS

A nationwide cohort (N=4,998,580) was followed in Danish individual-level registries. Based on a hierarchy of register markers of indications for statin prescribing, we analysed incidence and prevalence of use by age and indication (age ≥ 40). Applying Poisson regression, we calculated Incidence Rate Ratios (IRR) of statin treatment for the last year of each driver period, applying the first year as reference.

RESULTS

Treatment prevalence increased from 7/1000 to 187/1000, representing a shift towards lower-level indications and increased relatively more in individuals aged 75+. While treatment prevalence in MI-patients reached 780/1000, asymptomatic individuals represented 50% of incident statin-users in 2009. A marked increase in incidence of statin use occurred during 1999-2003 (IRR=3.05) across all indications, followed by a more moderate rise during 2003-2006 (IRR=1.29) and 2006-2008 (IRR=1.15) - most marked increases in asymptomatic individuals. A sudden decrease was observed in 2009 (IRR=0.82) for all indications and ages.

CONCLUSION

While patent expiry and lower prices most likely boosted the general increase in statin utilization, the gradually altered indication and age pattern seems to be driven by guidelines, influencing both reimbursement rules and general healthcare policies. A media debate on statin side effects may have modified the general attitudes.

Cardiovascular risk

Cardiovascular disease is a major, growing, worldwide problem. It is important that individuals at risk of developing cardiovascular disease can be effectively identified and appropriately stratified according to risk. This review examines what we understand by the term risk, traditional and novel risk factors, clinical scoring systems, and the use of risk for informing prescribing decisions. Many different cardiovascular risk factors have been identified. Established, traditional factors such as ageing are powerful predictors of adverse outcome, and in the case of hypertension and dyslipidaemia are the major targets for therapeutic intervention. Numerous novel biomarkers have also been described, such as inflammatory and genetic markers. These have yet to be shown to be of value in improving risk prediction, but may represent potential therapeutic targets and facilitate more targeted use of existing therapies. Risk factors have been incorporated into several cardiovascular disease prediction algorithms, such as the Framingham equation, SCORE and QRISK. These have relatively poor predictive power, and uncertainties remain with regards to aspects such as choice of equation, different risk thresholds and the roles of relative risk, lifetime risk and reversible factors in identifying and treating at-risk individuals. Nonetheless, such scores provide objective and transparent means of quantifying risk and their integration into therapeutic guidelines enables equitable and cost-effective distribution of health service resources and improves the consistency and quality of clinical decision making.

Is the high-risk strategy to prevent cardiovascular disease equitable? A pharmacoepidemiological cohort study

BACKGROUND

Statins are increasingly prescribed to prevent cardiovascular disease (CVD) in asymptomatic individuals. Yet, it is unknown whether those at higher CVD risk - i.e. individuals in lower socio-economic position (SEP) - are adequately reached by this high-risk strategy. We aimed to examine whether the Danish implementation of the strategy to prevent cardiovascular disease (CVD) by initiating statin (HMG-CoA reductase inhibitor) therapy in high-risk individuals is equitable across socioeconomic groups.

METHODS

DESIGN

Cohort study.

SETTING AND PARTICIPANTS

Applying individual-level nationwide register information on socio-demographics, dispensed prescription drugs and hospital discharges, all Danish citizens aged 20+ without previous register-markers of CVD, diabetes or statin therapy were followed during 2002-2006 for first occurrence of myocardial infarction (MI) and a dispensed statin prescription (N = 3.3 mill).

MAIN OUTCOME MEASURES

Stratified by gender, 5-year age-groups and socioeconomic position (SEP), incidence of MI was applied as a proxy for statin need. Need-standardized statin incidence rates were calculated, applying MI incidence rate ratios (IRR) as need-weights to adjust for unequal needs across SEP.Horizontal equity in initiating statin therapy was tested by means of Poisson regression analysis. Applying the need-standardized statin parameters and the lowest SEP-group as reference, a need-standardized statin IRR > 1 translates into horizontal inequity favouring the higher SEP-groups.

RESULTS

MI incidence decreased with increasing SEP without a parallel trend in incidence of statin therapy. According to the regression analyses, the need-standardized statin incidence increased in men aged 40-64 by 17%, IRR 1.17 (95% CI: 1.14-1.19) with each increase in income quintile. In women the proportion was 23%, IRR 1.23 (1.16-1.29). An analogous pattern was seen applying education as SEP indicator and among subjects aged 65-84.

CONCLUSION

The high-risk strategy to prevent CVD by initiating statin therapy seems to be inequitable, reaching primarily high-risk subjects in lower risk SEP-groups.

Predictive risk algorithms in a population setting: an overview

BACKGROUND

The widespread use of risk algorithms in clinical medicine is testimony to how they have helped transform clinical decision-making. Risk algorithms have a similar but underdeveloped potential to support decision-making for population health.

OBJECTIVE

To describe the role of predictive risk algorithms in a population setting.

METHODS

First, predictive risk algorithms and how clinicians use them are described. Second, the population uses of risk algorithms are described, highlighting the strengths of risk algorithms for health planning. Lastly, the way in which predictive risk algorithms are developed is discussed briefly and a guide for algorithm assessment in population health presented.

CONCLUSION

For the past 20 years, absolute and baseline risk has been a cornerstone of population health planning. The most accurate and discriminating method to generate such estimates is the use of multivariable risk algorithms. Routinely collected data can be used to develop algorithms with characteristics that are well suited to health planning and such data are increasingly available. The widespread use of risk algorithms in clinical medicine is testimony to how they have helped transform clinical decision-making. Risk algorithms have a similar but underdeveloped potential to support decision-making for population health.

Improving the cost-effectiveness of cardiovascular disease prevention in Australia: a modelling study

BACKGROUND

Cardiovascular disease is the leading cause of death worldwide. Like many countries, Australia is currently changing its guidelines for cardiovascular disease prevention from drug treatment for everyone with 'high blood pressure' or 'high cholesterol', to prevention based on a patient's absolute risk. In this research, we model cost-effectiveness of cardiovascular disease prevention with blood pressure and lipid drugs in Australia under three different scenarios: (1) the true current practice in Australia; (2) prevention as intended under the current guidelines; and (3) prevention according to proposed absolute risk levels. We consider the implications of changing to absolute risk-based cardiovascular disease prevention, for the health of the Australian people and for Government health sector expenditure over the long term.

METHODS

We evaluate cost-effectiveness of statins, diuretics, ACE inhibitors, calcium channel blockers and beta-blockers, for Australian men and women, aged 35 to 84 years, who have never experienced a heart disease or stroke event. Epidemiological changes and health care costs are simulated by age and sex in a discrete time Markov model, to determine total impacts on population health and health sector costs over the lifetime, from which we derive cost-effectiveness ratios in 2008 Australian dollars per quality-adjusted life year.

RESULTS

Cardiovascular disease prevention based on absolute risk is more cost-effective than prevention under the current guidelines based on single risk factor thresholds, and is more cost-effective than the current practice, which does not follow current clinical guidelines. Recommending blood pressure-lowering drugs to everyone with at least 5% absolute risk and statin drugs to everyone with at least 10% absolute risk, can achieve current levels of population health, while saving $5.4 billion for the Australian Government over the lifetime of the population. But savings could be as high as $7.1 billion if Australia could match the cheaper price of statin drugs in New Zealand.

CONCLUSIONS

Changing to absolute risk-based cardiovascular disease prevention is highly recommended for reducing health sector spending, but the Australian Government must also consider measures to reduce the cost of statin drugs, over and above the legislated price cuts of November 2010.

Should risky treatments be reserved for secondary prevention? Theoretical considerations regarding risk-benefit tradeoffs

OBJECTIVE

Clinical intuition suggests that risk-reducing treatments are more beneficial for patients with greater risk of disease. This intuition contributes to our rationale for tolerating greater adverse event risk in the setting of secondary prevention of certain diseases such as myocardial infarction or stroke. However, under certain conditions treatment benefits may be greater in primary prevention, even when the treatment carries harmful adverse effect potential.

STUDY DESIGN AND SETTING

We present simple decision-theoretic models that illustrate conditions of risk and benefit under which a treatment is predicted to be more beneficial in primary than in secondary prevention.

RESULTS

The models cover a spectrum of possible clinical circumstances, and demonstrate that net benefit in primary prevention can occur despite no benefit (or even net harm) in secondary prevention.

CONCLUSION

This framework provides a rationale for extending the familiar concept of balancing risks and benefits to account for disease-specific considerations of primary vs. secondary prevention.

Evidence-based use of statins for primary prevention of cardiovascular disease

Three-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, commonly known as statins, are widely available, inexpensive, and represent a potent therapy for treating elevated cholesterol. Current national guidelines put forth by the Adult Treatment Panel III recommend statins as part of a comprehensive primary prevention strategy for patients with elevated low-density lipoprotein cholesterol at increased risk for developing coronary heart disease within 10 years. Lack of a clear-cut mortality benefit in primary prevention has caused some to question the use of statins for patients without known coronary heart disease. On review of the literature, we conclude that current data support only a modest mortality benefit for statin primary prevention when assessed in the short term (<5 years). Of note, statin primary prevention results in a significant decrease in cardiovascular morbidity over the short and long term and a trend toward increased reduction in mortality over the long term. When appraised together, these data provide compelling evidence to support the use of statins for primary prevention in patients with risk factors for developing coronary heart disease over the next 10 years.

A comparative analysis of three widely used lipid management guidelines in the EPIC-Norfolk cohort

AIMS

To compare the impact of three major guidelines for the prevention of cardiovascular disease (CVD).

METHODS AND RESULTS

21,263 men and women aged 39-79 years from the EPIC (European Prospective Investigation of Cancer) Norfolk cohort were retrospectively classified at baseline by statin therapy recommendations according to the NICE, ESC and ATPIII CVD prevention guidelines. Recommendations based on baseline data were related to 10-year follow-up to calculate number of new CVD events that could be prevented by statins, number-needed-to-treat (NNT) and CVD incidence decrease. Statin therapy was recommended to 34% by the NICE guideline, 29% by ESC and 32% by ATPIII. A total of 263 events could potentially have been prevented by application of the NICE guideline, 219 by ESC and 199 by ATPIII. The NNT with statins over 10 years was 27 with the NICE guideline, 28 with ESC and 34 with ATPIII. Application of the NICE guideline could have decreased CVD incidence by 13%; using ESC guidelines the figure is 11% and with ATPIII it is 10%.

CONCLUSIONS

The NICE guideline selected greater percentages of elderly and subjects with prevalent CVD risk factors. It performed best in recommending statins and could have prevented the greatest number of CVD events. With all guidelines, nearly half the subjects who developed a CVD event were not considered eligible for statins at baseline. Less selective prevention strategies need to be explored.

Preventing falls among seniors: the way forward

There is a growing body of research about the etiology and prevention of falls. However, the persistently high incidence of falls among seniors calls for renewed efforts to develop, test, implement, and scale-up fall prevention strategies for older adults. This paper considers advances in the field and describes three priority areas for generating research and translating knowledge on fall prevention. Clinical practice guidelines, systems change approaches and environmental risk factors are discussed. Recommendations include transcending our health sector view of the fall prevention problem, supporting comparative research on system-oriented approaches to fall prevention, and examining ways to sustain and scale-up fall prevention efforts.

Value of primordial and primary prevention for cardiovascular disease: a policy statement from the American Heart Association

The process of atherosclerosis may begin in youth and continue for decades, leading to both nonfatal and fatal cardiovascular events, including myocardial infarction, stroke, and sudden death. With primordial and primary prevention, cardiovascular disease is largely preventable. Clinical trial evidence has shown convincingly that pharmacological treatment of risk factors can prevent events. The data are less definitive but also highly suggestive that appropriate public policy and lifestyle interventions aimed at eliminating tobacco use, limiting salt consumption, encouraging physical exercise, and improving diet can prevent events. There has been concern about whether efforts aimed at primordial and primary prevention provide value (ie, whether such interventions are worth what we pay for them). Although questions about the value of therapeutics for acute disease may be addressed by cost-effectiveness analysis, the long time frames involved in evaluating preventive interventions make cost-effectiveness analysis difficult and necessarily flawed. Nonetheless, cost-effectiveness analyses reviewed in this policy statement largely suggest that public policy, community efforts, and pharmacological intervention are all likely to be cost-effective and often cost saving compared with common benchmarks. The high direct medical care and indirect costs of cardiovascular disease-approaching $450 billion a year in 2010 and projected to rise to over $1 trillion a year by 2030-make this a critical medical and societal issue. Prevention of cardiovascular disease will also provide great value in developing a healthier, more productive society.

A population-based risk algorithm for the development of diabetes: development and validation of the Diabetes Population Risk Tool (DPoRT)

BACKGROUND

National estimates of the upcoming diabetes epidemic are needed to understand the distribution of diabetes risk in the population and to inform health policy.

OBJECTIVE

To create and validate a population-based risk prediction tool for incident diabetes using commonly collected national survey data.

METHODS

With the use of a cohort design that links baseline risk factors to a validated population-based diabetes registry, a model (Diabetes Population Risk Tool (DPoRT)) was developed to predict 9-year risk for diabetes. The probability of developing diabetes was modelled using sex-specific Weibull survival functions for people > 20 years of age without diabetes (N=19,861). The model was validated in two external cohorts in Ontario (N=26,465) and Manitoba (N=9899). Predictive accuracy and model performance were assessed by comparing observed diabetes rates with predicted estimates. Discrimination and calibration were measured using a C statistic and Hosmer-Lemeshow χ² statistic (χ²(H-L)).

RESULTS

Predictive factors included were body mass index, age, ethnicity, hypertension, immigrant status, smoking, education status and heart disease. DPoRT showed good discrimination (C=0.77-0.80) and calibration (χ²(H-L) < 20) in both external validation cohorts.

CONCLUSIONS

This algorithm can be used to estimate diabetes incidence and quantify the effect of interventions using routinely collected survey data.

Public health impact of statin prescribing strategies based on JUPITER

OBJECTIVE

To evaluate the public health impact of statin prescribing strategies based on the Justification for the Use of Statins in Primary Prevention: an Intervention Trial Evaluating Rosuvastatin Study (JUPITER).

METHODS

We studied 2268 adults aged 35-75 without cardiovascular disease in a population-based study in Switzerland in 2003-2006. We assessed the eligibility for statins according to the Adult Treatment Panel III (ATPIII) guidelines, and by adding "strict" (hs-CRP≥2.0 mg/L and LDL-cholesterol <3.4 mmol/L), and "extended" (hs-CRP≥2.0 mg/L alone) JUPITER-like criteria. We estimated the proportion of CHD deaths potentially prevented over 10 years in the Swiss population.

RESULTS

Fifteen percent were already taking statins, 42% were eligible by ATPIII guidelines, 53% by adding "strict," and 62% by adding "extended" criteria, with a total of 19% newly eligible. The number needed to treat with statins to avoid one CHD death over 10 years was 38 for ATPIII, 84 for "strict" and 92 for "extended" JUPITER-like criteria. ATPIII would prevent 17% of CHD deaths, compared with 20% for ATPIII+"strict" and 23% for ATPIII + "extended" criteria (+6%).

CONCLUSION

Implementing JUPITER-like strategies would make statin prescribing for primary prevention more common and less efficient than it is with current guidelines.

Comparative effectiveness of guidelines for the management of hyperlipidemia and hypertension for type 2 diabetes patients

BACKGROUND

Several guidelines to reduce cardiovascular risk in diabetes patients exist in North America, Europe, and Australia. Their ability to achieve this goal efficiently is unclear.

METHODS AND FINDINGS

Decision analysis was used to compare the efficiency and effectiveness of international contemporary guidelines for the management of hypertension and hyperlipidemia for patients aged 40-80 with type 2 diabetes. Measures of comparative effectiveness included the expected probability of a coronary or stroke event, incremental medication costs per event, and number-needed-to-treat (NNT) to prevent an event. All guidelines are equally effective, but they differ significantly in their medication costs. The range of NNT to prevent an event was small across guidelines (6.5-7.6 for males and 6.5-7.5 for females); a larger range of differences were observed for expected cost per event avoided (ranges, $117,269-$157,186 for males and $115,999-$163,775 for females). Australian and U.S. guidelines result in the highest and lowest expected costs, respectively.

CONCLUSIONS

International guidelines based on the same evidence and seeking the same goal are similar in their effectiveness; however, there are large differences in expected medication costs.

Statins for the primary prevention of cardiovascular disease

BACKGROUND

Reducing high blood cholesterol, a risk factor for cardiovascular disease (CVD) events in people with and without a past history of coronary heart disease (CHD) is an important goal of pharmacotherapy. Statins are the first-choice agents. Previous reviews of the effects of statins have highlighted their benefits in people with coronary artery disease. The case for primary prevention, however, is less clear.

OBJECTIVES

To assess the effects, both harms and benefits, of statins in people with no history of CVD.

SEARCH STRATEGY

To avoid duplication of effort, we checked reference lists of previous systematic reviews. We searched the Cochrane Central Register of Controlled Trials (Issue 1, 2007), MEDLINE (2001 to March 2007) and EMBASE (2003 to March 2007). There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials of statins with minimum duration of one year and follow-up of six months, in adults with no restrictions on their total low density lipoprotein (LDL) or high density lipoprotein (HDL) cholesterol levels, and where 10% or less had a history of CVD, were included.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion and extracted data. Outcomes included all cause mortality, fatal and non-fatal CHD, CVD and stroke events, combined endpoints (fatal and non-fatal CHD, CVD and stroke events), change in blood total cholesterol concentration, revascularisation, adverse events, quality of life and costs. Relative risk (RR) was calculated for dichotomous data, and for continuous data pooled weighted mean differences (with 95% confidence intervals) were calculated.

MAIN RESULTS

Fourteen randomised control trials (16 trial arms; 34,272 participants) were included. Eleven trials recruited patients with specific conditions (raised lipids, diabetes, hypertension, microalbuminuria). All-cause mortality was reduced by statins (RR 0.83, 95% CI 0.73 to 0.95) as was combined fatal and non-fatal CVD endpoints (RR 0.70, 95% CI 0.61 to 0.79). Benefits were also seen in the reduction of revascularisation rates (RR 0.66, 95% CI 0.53 to 0.83). Total cholesterol and LDL cholesterol were reduced in all trials but there was evidence of heterogeneity of effects. There was no clear evidence of any significant harm caused by statin prescription or of effects on patient quality of life.

AUTHORS' CONCLUSIONS

Although reductions in all-cause mortality, composite endpoints and revascularisations were found with no excess of adverse events, there was evidence of selective reporting of outcomes, failure to report adverse events and inclusion of people with cardiovascular disease. Only limited evidence showed that primary prevention with statins may be cost effective and improve patient quality of life. Caution should be taken in prescribing statins for primary prevention among people at low cardiovascular risk.

Coronary risk assessment by point-based vs. equation-based Framingham models: significant implications for clinical care

BACKGROUND

US cholesterol guidelines use original and simplified versions of the Framingham model to estimate future coronary risk and thereby classify patients into risk groups with different treatment strategies. We sought to compare risk estimates and risk group classification generated by the original, complex Framingham model and the simplified, point-based version.

METHODS

We assessed 2,543 subjects age 20-79 from the 2001-2006 National Health and Nutrition Examination Surveys (NHANES) for whom Adult Treatment Panel III (ATP-III) guidelines recommend formal risk stratification. For each subject, we calculated the 10-year risk of major coronary events using the original and point-based Framingham models, and then compared differences in these risk estimates and whether these differences would place subjects into different ATP-III risk groups (<10% risk, 10-20% risk, or >20% risk). Using standard procedures, all analyses were adjusted for survey weights, clustering, and stratification to make our results nationally representative.

RESULTS

Among 39 million eligible adults, the original Framingham model categorized 71% of subjects as having "moderate" risk (<10% risk of a major coronary event in the next 10 years), 22% as having "moderately high" (10-20%) risk, and 7% as having "high" (>20%) risk. Estimates of coronary risk by the original and point-based models often differed substantially. The point-based system classified 15% of adults (5.7 million) into different risk groups than the original model, with 10% (3.9 million) misclassified into higher risk groups and 5% (1.8 million) into lower risk groups, for a net impact of classifying 2.1 million adults into higher risk groups. These risk group misclassifications would impact guideline-recommended drug treatment strategies for 25-46% of affected subjects. Patterns of misclassifications varied significantly by gender, age, and underlying CHD risk.

CONCLUSIONS

Compared to the original Framingham model, the point-based version misclassifies millions of Americans into risk groups for which guidelines recommend different treatment strategies.

The impact of ageing and changing utilization patterns on future cardiovascular drug expenditure: a pharmacoepidemiological projection approach

PURPOSE

To develop a method for projecting the impact of ageing and changing drug utilization patterns on future drug expenditure.

METHODS

Applying nationwide registries, prescriptions of three categories of cardiovascular drugs were followed for all Danish residents from 1 January 1996 until 2006. The official Danish population forecast 2006-2015 was applied for projecting the population composition. A previously developed pharmacoepidemiological semi-Markov model was extended to apply for projection of future drug utilization. We either assumed that past trends in model parameters (incidence, discontinuation and drug user mortality) would continue during 2006-2015, or that all model parameters would remain unchanged at their values in 2005. Yearly drug expenditure per user of a particular drug was assumed to remain unchanged. Scenarios of future treatment prevalence with different drug categories were modelled by extrapolating future age- and gender-specific parameter values (treatment incidence, discontinuation and drug user mortality) from historic point estimates and their historic trend.

RESULTS

Provided a continuance of past trends, increasing utilization of ACE inhibitors, angiotensin II antagonists and statins translates into a rise in annual expenditure of 176%, mainly explained by increases in treatment incidence. Due to pharmacoepidemiological disequilibrium, unchanged model parameters would imply an increase of 64%, ageing alone 14%.

CONCLUSION

Increasing cardiovascular drug utilization may pose a substantial burden on future health care resources. However, prescribing behaviour is likely to depend on changing clinical guidelines. Despite the limited impact as cost driver, population ageing remains a challenge for future health care services.

The effectiveness of national guidelines for preventing cardiovascular disease: integrating effectiveness concepts and evaluating guidelines' use in the real world

PURPOSE OF REVIEW

Clinical guidelines historically have emphasized efficacy (intervention benefit in a controlled or experimental setting) rather than effectiveness (intervention benefit in the real world). This review examines how concepts of effectiveness currently influence the development of guidelines for prevention of cardiovascular disease, and how these concepts contribute to increased evaluation of guideline effectiveness.

RECENT FINDINGS

A growing emphasis on effectiveness in cardiovascular preventive guidelines is largely influenced by a desire for guidelines to facilitate improved quality of care. Single risk factor guidelines for cardiovascular disease are being merged, and guideline recommendations are becoming simpler and easier to implement into practice. Simultaneously, guideline programs are undertaking a wider range of development, implementation and evaluation activities. Implementation science, a supporting discipline, is rapidly maturing and resulting in increasingly sophisticated studies designed to test the effectiveness of prevention interventions and approaches to improve guideline uptake. Modelling studies are used to develop effective guideline recommendations and evaluate the overall effectiveness of guidelines for reducing cardiovascular disease.

SUMMARY

A sea change is occurring in cardiovascular guidelines toward effectiveness and prevention of multiple chronic diseases, and away from a focus on the efficacy of medical therapy for individual cardiovascular disease risk factors. The 'effectiveness sea' should eventually stretch to embrace cost-effectiveness and population effectiveness.

Genetic variation in 3-hydroxy-3-methylglutaryl CoA reductase modifies the chemopreventive activity of statins for colorectal cancer

Genetic variation in 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR), the rate-limiting enzyme in cholesterol synthesis, modifies the effect of statins on serum cholesterol levels. Long-term use of statins is associated with a reduced risk of colorectal cancer (CRC) in some, but not all, studies. We genotyped variants in 40 candidate genes important for cholesterol synthesis and metabolism in a population-based case-control study of CRC involving 2,138 incident cases and 2,049 population-based controls. We identified a single-nucleotide polymorphism in the HMGCR gene that significantly modified the protective association between statins and CRC risk. Compared with nonusers, the unadjusted odds ratio of CRC among statin users with the A/A genotype of rs12654264 in HMGCR was 0.3 (95% confidence interval, 0.18-0.51) and among statin users with the T/T genotype was 0.66 (95% confidence interval, 0.41-1.06; P-interaction = 0.0012). This genetic variant (A/A genotype of rs12654264) also was associated with lower serum levels of low-density lipoprotein among all cases and controls. In colon cancer cell lines, the reduction in cholesterol levels after statin treatment was substantially stronger in cells carrying the A/A genotype, and this difference was related to alternative splicing involving the HMGCR statin-binding domain. We anticipate that these data may advance the development of personalized statin use for reducing the risk of cancer as well as cardiovascular disease among the approximately 25 million people currently using statins worldwide.

Cardiovascular risk factor trends and potential for reducing coronary heart disease mortality in the United States of America

OBJECTIVE

To examine the potential for reducing cardiovascular risk factors in the United States of America enough to cause age-adjusted coronary heart disease (CHD) mortality rates to drop by 20% (from 2000 baseline figures) by 2010, as targeted under the Healthy People 2010 initiative.

METHODS

Using a previously validated, comprehensive CHD mortality model known as IMPACT that integrates trends in all the major cardiovascular risk factors, stratified by age and sex, we calculated how much CHD mortality would drop between 2000 and 2010 in the projected population of the United States aged 25-84 years (198 million). We did this for three assumed scenarios: (i) if recent risk factor trends were to continue to 2010; (ii) success in reaching all the Healthy People 2010 risk factor targets, and (iii) further drops in risk factors, to the levels already seen in the low-risk stratum.

FINDINGS

If age-adjusted CHD mortality rates observed in 2000 remained unchanged, some 388,000 CHD deaths would occur in 2010. First scenario: if recent risk factor trends continued to 2010, there would be approximately 19,000 fewer deaths than in 2000. Although improved total cholesterol, lowered blood pressure in men, decreased smoking and increased physical activity would account for some 51,000 fewer deaths, these would be offset by approximately 32,000 additional deaths from adverse trends in obesity and diabetes and in blood pressure in women. Second scenario: If Healthy People 2010 cardiovascular risk factor targets were reached, approximately 188,000 CHD deaths would be prevented. Scenario three: If the cardiovascular risk levels of the low-risk stratum were reached, approximately 372,000 CHD deaths would be prevented.

CONCLUSION

Achievement of the Healthy People 2010 cardiovascular risk factor targets would almost halve the predicted CHD death rates. Additional reductions in major risk factors could prevent or postpone substantially more deaths from CHD.

If cannabis caused schizophrenia--how many cannabis users may need to be prevented in order to prevent one case of schizophrenia? England and Wales calculations

BACKGROUND

We consider how many cannabis users may need to be prevented in order to prevent one case of schizophrenia or psychosis [defined as number needed to prevent (NNP)].

METHOD

Calculation for England and Wales using best available estimates of: incidence of schizophrenia; rates of heavy and light cannabis use; and risk that cannabis causes schizophrenia.

RESULTS

In men the annual mean NNP for heavy cannabis and schizophrenia ranged from 2800 [90% confidence interval (CI) 2018-4530] in those aged 20-24 years to 4700 (90% CI 3114-8416) in those aged 35-39. In women, mean NNP for heavy cannabis use and schizophrenia ranged from 5470 (90% CI 3640-9839) in those aged 25-29 to 10 870 (90% CI 6786-22 732) in 35-39-year-olds. Equivalent mean NNP for heavy cannabis use and psychosis were lower, from 1360 (90% CI 1007-2124) in men aged 20-24 and 2480 (90% CI 1408-3518) in women aged 16-19. The mean and median number of light cannabis users that would need to be prevented in order to prevent one case of schizophrenia or psychosis per year are four to five times greater than among heavy users.

CONCLUSIONS

The number of young people who need to be exposed to an intervention to generate NNP and prevent one case of schizophrenia will be even larger. The public health importance of preventing cannabis to reduce schizophrenia or psychosis remains uncertain. More attention should be given to testing the hypothesis that cannabis is related causally to psychotic outcomes, and to considering what strategies will be the most effective in reducing heavy cannabis use among young people.

Will biomedical innovation change the future of healthcare?

Healthcare costs in all industrial nations have increased and payors are starting to look at new ways to contain costs and at new funding models. The business model of pharmaceutical companies is also undergoing rapid changes - potentially disruptive new modalities, such as RNAi, therapeutic vaccines, and cell therapy are emerging, R&D costs have increased year on year, pressures on drug pricing and the efficacy and safety of medicines are mounting. Change is therefore inevitable and already ongoing in healthcare systems and pharmaceutical companies alike. This paper presents several major forces which could drive different future scenarios including: R&D costs, the source of payments for medicines and the emergence of new modalities.

Cardiovascular risk estimation and eligibility for statins in primary prevention comparing different strategies

Recommendations for statin use for primary prevention of coronary heart disease (CHD) are based on estimation of the 10-year CHD risk. It is unclear which risk algorithm and guidelines should be used in European populations. Using data from a population-based study in Switzerland, we first assessed 10-year CHD risk and eligibility for statins in 5,683 women and men 35 to 75 years of age without cardiovascular disease by comparing recommendations by the European Society of Cardiology without and with extrapolation of risk to age 60 years, the International Atherosclerosis Society, and the US Adult Treatment Panel III. The proportions of participants classified as high-risk for CHD were 12.5% (15.4% with extrapolation), 3.0%, and 5.8%, respectively. Proportions of participants eligible for statins were 9.2% (11.6% with extrapolation), 13.7%, and 16.7%, respectively. Assuming full compliance to each guideline, expected relative decreases in CHD deaths in Switzerland over a 10-year period would be 16.4% (17.5% with extrapolation), 18.7%, and 19.3%, respectively; the corresponding numbers needed to treat to prevent 1 CHD death would be 285 (340 with extrapolation), 380, and 440, respectively. In conclusion, the proportion of subjects classified as high risk for CHD varied over a fivefold range across recommendations. Following the International Atherosclerosis Society and the Adult Treatment Panel III recommendations might prevent more CHD deaths at the cost of higher numbers needed to treat compared with European Society of Cardiology guidelines.

The 2006 Canadian dyslipidemia guidelines will prevent more deaths while treating fewer people--but should they be further modified?

BACKGROUND

When clinical guidelines affect large numbers of individuals or substantial resources, it is important to understand their benefits, harms and costs from a population perspective. Many countries' dyslipidemia guidelines include these perspectives.

OBJECTIVE

To compare the effectiveness and efficiency of the 2003 and 2006 Canadian dyslipidemia guidelines for statin treatment in reducing deaths from coronary artery disease (CAD) in the Canadian population.

METHODS

The 2003 and 2006 Canadian dyslipidemia guidelines were applied to data from the Canadian Heart Health Survey (weighted sample of 12,300,000 people), which includes information on family history and physical measurements, including fasting lipid profiles. The number of people recommended for statin treatment, the potential number of CAD deaths avoided and the number needed to treat to avoid one CAD death with five years of statin therapy were determined for each guideline.

RESULTS

Compared with the 2003 guidelines, 1.4% fewer people (20 to 74 years of age) are recommended statin treatment, potentially preventing 7% more CAD deaths. The number needed to treat to prevent one CAD death over five years decreased from 172 (2003 guideline) to 147 (2006 guideline).

CONCLUSIONS

From a population perspective, the 2006 Canadian dyslipidemia recommendations are an improvement of earlier versions, preventing more CAD events and deaths with fewer statin prescriptions. Despite these improvements, the Canadian dyslipidemia recommendations should explicitly address issues of absolute benefit and cost-effectiveness in future revisions.

Against diagnosis

The act of diagnosis requires that patients be placed in a binary category of either having or not having a certain disease. Accordingly, the diseases of particular concern for industrialized countries--such as type 2 diabetes, obesity, or depression--require that a somewhat arbitrary cut-point be chosen on a continuous scale of measurement (for example, a fasting glucose level >6.9 mmol/L [>125 mg/dL] for type 2 diabetes). These cut-points do not adequately reflect disease biology, may inappropriately treat patients on either side of the cut-point as 2 homogenous risk groups, fail to incorporate other risk factors, and are invariable to patient preference. This article discusses risk prediction as an alternative to diagnosis: Patient risk factors (blood pressure, age) are combined into a single statistical model (risk for a cardiovascular event within 10 years) and the results are used in shared decision making about possible treatments. The authors compare and contrast the diagnostic and risk prediction approaches and attempt to identify the types of medical problem to which each is best suited.

The use of fluvastatin in cardiovascular risk management

BACKGROUND

Fluvastatin was the first synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) to be developed and is used in the management of dyslipidaemia in primary and secondary prevention of cardiovascular disease.

OBJECTIVE

This article reviews the properties of fluvastatin and experience accrued through its use in clinical practice and clinical trials.

METHODS

Relevant publications were identified through the PubMed database and product information held by the US Federal Drug Administration was also reviewed.

RESULTS/CONCLUSIONS

In the authors' opinion, fluvastatin exhibits a favourable safety profile in comparison to other statins, with a low incidence of adverse effects and a reduced propensity for interactions with other drugs. However, fluvastatin is a less potent cholesterol-lowering agent than newer statins on the market and its future predominant use is likely to be in niche patient groups at risk of side effects or drug interactions with other agents.