Cholesterol-lowering therapy with pravastatin in patients with average cholesterol levels and established ischaemic heart disease: is it cost-effective?

A Systematic Review of Cardiovascular Outcomes-Based Cost-Effectiveness Analyses of Lipid-Lowering Therapies

BACKGROUND

Previous reviews have evaluated economic analyses of lipid-lowering therapies using lipid levels as surrogate markers for cardiovascular disease. However, drug approval and health technology assessment agencies have stressed that surrogates should only be used in the absence of clinical endpoints.

OBJECTIVE

The aim of this systematic review was to identify and summarise the methodologies, weaknesses and strengths of economic models based on atherosclerotic cardiovascular disease event rates.

METHODS

Cost-effectiveness evaluations of lipid-lowering therapies using cardiovascular event rates in adults with hyperlipidaemia were sought in Medline, Embase, Medline In-Process, PubMed and NHS EED and conference proceedings. Search results were independently screened, extracted and quality checked by two reviewers.

RESULTS

Searches until February 2016 retrieved 3443 records, from which 26 studies (29 publications) were selected. Twenty-two studies evaluated secondary prevention (four also assessed primary prevention), two considered only primary prevention and two included mixed primary and secondary prevention populations. Most studies (18) based treatment-effect estimates on single trials, although more recent evaluations deployed meta-analyses (5/10 over the last 10 years). Markov models (14 studies) were most commonly used and only one study employed discrete event simulation. Models varied particularly in terms of health states and treatment-effect duration. No studies used a systematic review to obtain utilities. Most studies took a healthcare perspective (21/26) and sourced resource use from key trials instead of local data. Overall, reporting quality was suboptimal.

CONCLUSIONS

This review reveals methodological changes over time, but reporting weaknesses remain, particularly with respect to transparency of model reporting.

Interpretation of the evidence for the efficacy and safety of statin therapy

This Review is intended to help clinicians, patients, and the public make informed decisions about statin therapy for the prevention of heart attacks and strokes. It explains how the evidence that is available from randomised controlled trials yields reliable information about both the efficacy and safety of statin therapy. In addition, it discusses how claims that statins commonly cause adverse effects reflect a failure to recognise the limitations of other sources of evidence about the effects of treatment. Large-scale evidence from randomised trials shows that statin therapy reduces the risk of major vascular events (ie, coronary deaths or myocardial infarctions, strokes, and coronary revascularisation procedures) by about one-quarter for each mmol/L reduction in LDL cholesterol during each year (after the first) that it continues to be taken. The absolute benefits of statin therapy depend on an individual's absolute risk of occlusive vascular events and the absolute reduction in LDL cholesterol that is achieved. For example, lowering LDL cholesterol by 2 mmol/L (77 mg/dL) with an effective low-cost statin regimen (eg, atorvastatin 40 mg daily, costing about £2 per month) for 5 years in 10 000 patients would typically prevent major vascular events from occurring in about 1000 patients (ie, 10% absolute benefit) with pre-existing occlusive vascular disease (secondary prevention) and in 500 patients (ie, 5% absolute benefit) who are at increased risk but have not yet had a vascular event (primary prevention). Statin therapy has been shown to reduce vascular disease risk during each year it continues to be taken, so larger absolute benefits would accrue with more prolonged therapy, and these benefits persist long term. The only serious adverse events that have been shown to be caused by long-term statin therapy-ie, adverse effects of the statin-are myopathy (defined as muscle pain or weakness combined with large increases in blood concentrations of creatine kinase), new-onset diabetes mellitus, and, probably, haemorrhagic stroke. Typically, treatment of 10 000 patients for 5 years with an effective regimen (eg, atorvastatin 40 mg daily) would cause about 5 cases of myopathy (one of which might progress, if the statin therapy is not stopped, to the more severe condition of rhabdomyolysis), 50-100 new cases of diabetes, and 5-10 haemorrhagic strokes. However, any adverse impact of these side-effects on major vascular events has already been taken into account in the estimates of the absolute benefits. Statin therapy may cause symptomatic adverse events (eg, muscle pain or weakness) in up to about 50-100 patients (ie, 0·5-1·0% absolute harm) per 10 000 treated for 5 years. However, placebo-controlled randomised trials have shown definitively that almost all of the symptomatic adverse events that are attributed to statin therapy in routine practice are not actually caused by it (ie, they represent misattribution). The large-scale evidence available from randomised trials also indicates that it is unlikely that large absolute excesses in other serious adverse events still await discovery. Consequently, any further findings that emerge about the effects of statin therapy would not be expected to alter materially the balance of benefits and harms. It is, therefore, of concern that exaggerated claims about side-effect rates with statin therapy may be responsible for its under-use among individuals at increased risk of cardiovascular events. For, whereas the rare cases of myopathy and any muscle-related symptoms that are attributed to statin therapy generally resolve rapidly when treatment is stopped, the heart attacks or strokes that may occur if statin therapy is stopped unnecessarily can be devastating.

Cost-effectiveness of statins revisited: lessons learned about the value of innovation

BACKGROUND

The economic evaluation of statins has undergone a development from risk-factor-based models to modeling of hard end points in clinical trials with a shift back to risk-factor models after increased confidence in their predictive power has now been established. At this point, we can look back on the historical economic data on simvastatin to see what lesson regarding reimbursement we can learn.

METHODS

Historical data on the usage and sales of simvastatin in Sweden were combined with published epidemiological and clinical data to calculate the social value of simvastatin to the present day and to make projection until projected until 2018. The distribution of the social surplus was calculated by taking the costs born by society and the producer of the drug into consideration.

RESULTS

The cost of simvastatin fell drastically following patent expiration, although the number of treated patients has continued to grow. Presently, the use of simvastatin is close to cost neutrality taking direct and indirect cost savings from reduced morbidity into account. However, the major part of the social surplus generated comes from the value of improved quality-adjusted survival. Of the social surplus generated, the producer appropriated 20-43% of the value during the on-patent period, a figure dropping to 1% following loss of exclusivity. The total producer surplus between 1987 and 2018 is 2-5% of the total social surplus.

CONCLUSION

Only a small part of the surplus value generated was appropriated by the producer. A regulatory and reimbursement approach that favors early market access and coverage with evidence development as opposed to long-term trials as a pre-requisite for launch is more attractive from both a company and social perspective.

Economic evaluation of high-dose (80 mg/day) atorvastatin treatment compared with standard-dose (20 mg/day to 40 mg/day) simvastatin treatment in Canada based on the Incremental Decrease in End-Points Through Aggressive Lipid-Lowering (IDEAL) trial

BACKGROUND

The Incremental Decrease in End-Points Through Aggressive Lipid-Lowering (IDEAL) trial demonstrated incremental cardiovascular benefit of treatment with high-dose atorvastatin (80 mg/ day) versus standard-dose simvastatin (20 mg/day to 40 mg/day) in 8888 patients with a previous myocardial infarction (MI) over a median follow-up period of 4.8 years.

OBJECTIVES

To assess the cost-effectiveness of high-dose atorvastatin versus standard-dose simvastatin treatment in patients with a history of MI from a Canadian societal perspective.

METHODS

In a within-trial analysis, end point-related events, resources used and productivity losses occurring during the IDEAL trial were aggregated by treatment arm on an intention-to-treat basis to calculate the incremental cost per event avoided. Additionally, quality-adjusted survival was projected using a lifetime Markov model. Transition probabilities, workdays lost, use of study medication and cardiovascular hospitalization rates were based on IDEAL trial data. Hospitalization, study medication and productivity costs were included. Probabilistic and deterministic sensitivity analyses were performed.

RESULTS

Compared with standard-dose simvastatin, atorvastatin 80 mg led to 0.099 fewer events per patient and cost savings over 4.8 years of treatment. Over a lifetime horizon, atorvastatin 80 mg led to 0.023 qualityadjusted life years (QALYs) gained per patient at an incremental cost of $26,795/QALY gained. The incremental cost-effectiveness ratio remained below $50,000/QALY in 78% of 1000 simulations. Exclusion of indirect costs resulted in an incremental cost-effectiveness ratio of $38,834/QALY. Results were relatively sensitive to baseline age, but robust with respect to sex, baseline low-density lipoprotein cholesterol levels, diabetes status and hospitalization costs.

CONCLUSION

From a Canadian societal perspective, high-dose atorvastatin is cost-effective compared with standard-dose simvastatin in patients with a previous MI.

The Cost-Effectiveness of Direct-to-Consumer Advertising for Prescription Drugs

In this paper we use published information to analyze the economic value of Direct to Consumer Advertising (DTCA). The reviewed research finds that DTCA leads to increased demand for the advertised drug and that the effect of the drug tends to be class-wide rather than product specific. There is weak evidence that DTCA may increase compliance and improve clinical outcomes. However, there is little research on the effect of DTCA on inappropriate prescribing or on the characteristics of patients who respond to treatment. On net, if the advertised drugs are cost effective on average and the patients using the drugs in response to the advertisement are similar to other users, DTCA is likely cost effective. Overall, the literature to date is consistent with the idea that DTCA is beneficial, but further research is needed before definitive conclusions can be drawn.

Economic evaluations of cholesterol-lowering drugs: a critical and systematic review

The wide availability of economic evaluations and their increasing importance for decision making emphasises the need for economic evaluations that are methodologically sound. The aim of this review was to provide users of economic evaluations of cholesterol-lowering drugs with an insight into the quality of these evaluations. By focusing on the most relevant studies, the gap between research and policy making may be narrowed. A systematic review was conducted. All Dutch and English publications on economic evaluations of cholesterol-lowering drugs were identified by searching PubMed, the Centre for Reviews and Dissemination database (CRD), the NHS Economic Evaluation Database (NHS EED), the Health Technology Assessment database (HTA) and the Database of Abstracts of Reviews of Effects (DARE). A search strategy was set up to identify the articles to be included. The quality of these articles was assessed using Drummond's checklists. The scoring was performed by at least two reviewers. When necessary, disagreement between these reviewers was decided upon in a consensus meeting. We calculated an average quality score for the included articles. The search identified 1390 articles, of which 23 were included. Most studies measured the costs per life-year gained. The overall score per study was disappointing and varied between 2.7 and 7.7, with an average of 5.5. Most studies scored high on the measurement of costs and consequences, whereas the establishment of effectiveness left room for improvement. Only two studies included a well performed incremental analysis. This study noted an increase of quality of economic evaluations over time, suggesting the value of cost-effectiveness studies for policy decisions increases over time. In general, piggy-back evaluations tended to score higher on quality and may therefore be more valuable in decision making.

Assessing health state utilities in elderly patients at cardiovascular risk

BACKGROUND

Health state preferences can be a crucial component of cost-effectiveness analyses, but off-the-shelf health state utilities specifically for older people are not available.

OBJECTIVES

Among participants in PROSPER, a trial of pravastatin in patients>70 years, the authors assessed utilities for the health states that were relevant for the trial's cost-utility analysis.

SUBJECTS AND METHODS

The authors cross-sectionally administered the Health Utilities Index, Mark 3 (HUI) to all PROSPER participants to assess each patient's health state at the time of interview; they then used the scale's multiattribute utility function to estimate the resulting utilities. The population was then stratified into 3 health states, and the mean utility function for each was calculated: recent myocardial infarction (MI, within 3 months), previous MI (>3 months), or no prior MI. Linear and logistic regression were used to control for potential demographic and clinical characteristics.

RESULTS

Of the 5804 patients enrolled in the trial, 4677 were administered the HUI instrument. The likelihood of having a complete HUI response set decreased with higher age (P<0.001) but not with the other variables studied. A complete utility score could be calculated for 3390 participants. Of these, 2755 (81.3%) had no history of MI, 546 (16.1%) had an MI>3 months previously, and 89 (2.6%) had an MI within 3 months. The mean (median) utilities were virtually identical for these states: 0.75 (0.84), 0.74 (0.84), and 0.74 (0.84), respectively. From multivariate analyses, utilities decreased with higher age and the presence of several other comorbidities (diabetes, stroke, peripheral vascular disease); women had lower utilities than men (all P<0.01).

CONCLUSIONS

In this large implementation of the HUI in elderly patients, the instrument did not detect any differences in estimated utilities related to having a MI. Potential causes of nondiscrimination for MI include the possibility that competing comorbidities may reduce the impact of MI on quality of life in this age group, as well as the possibility that a standard instrument derived from and validated in younger populations may not perform as well in elderly people.

Cost-effectiveness of cholesterol-lowering therapy with pravastatin in patients with previous acute coronary syndromes aged 65 to 74 years compared with younger patients: results from the LIPID study

BACKGROUND

We compared cost-effectiveness of pravastatin in a placebo-controlled trial in 5500 younger (31-64 years) and 3514 older patients (65-74 years) with previous acute coronary syndromes.

METHODS

Hospitalizations and long-term medication within the 6 years of the trial were estimated in all patients . Drug dosage, nursing home, and ambulatory care costs were estimated from substudies. Incremental costs per life saved of pravastatin relative to placebo were estimated from treatment effects and resource use.

RESULTS

Over 6 years, pravastatin reduced all-cause mortality by 4.3% in the older patients and by 2.3% in the younger patients. Older patients assigned pravastatin had marginally lower cost of pravastatin and other medication over 6 years (A dollar 4442 vs A dollar 4637), but greater cost offsets (A dollar 2061 vs A dollar 897) from lower rates of hospitalizations. The incremental cost per life saved with pravastatin was A dollar 55500 in the old and A dollar 167200 in the young. Assuming no treatment effect beyond the study period, the life expectancy to age 82 years of additional survivors was 9.1 years in the older and 17.3 years in the younger. Estimated additional life-years saved from pravastatin therapy were 0.39 years for older and 0.40 years for younger patients. Incremental costs per life-year saved were A dollar 7581 in the older and A dollar 14944 in the younger, if discounted at 5% per annum.

CONCLUSIONS

Pravastatin therapy was more cost-effective among older than younger patients, because of their higher baseline risk and greater cost offsets, despite their shorter life expectancy.

Cost-effectiveness of Different Advanced Life Support Providers for Victims of Out-of-hospital Cardiac Arrests

BACKGROUND/PURPOSE

The survival rate of out-of-hospital cardiac arrest (OHCA) is only about 1.4% in Taiwan. The best configuration to achieve optimal outcomes in OHCA is still uncertain for many communities. The purpose of this study was to investigate the cost-effectiveness of two models of providing advanced life support (ALS) services, emergency medical technicians (EMTs) vs. emergency physicians (EPs), in a two-tiered emergency medical services (EMS) system.

METHODS

This was a prospective, observational, multicenter study comparing ALS provided by EMTs vs. EPs for the management of victims of OHCA. The study population consisted of patients experiencing OHCA of non-traumatic origin in Taipei city, Taiwan, between November 1999 and December 2000, for whom ALS was activated. We performed a cost-effectiveness analysis to determine the economic attractiveness of these two ALS provider programs. The outcome measurements were aggregate costs, survival and incremental cost per life saved. Sensitivity analyses were performed on all variables.

RESULTS

The expected total cost per OHCA patient was 2,248.19 US$ and 832.07 US$ for the EMT and EP programs, respectively. The overall survival rate was 4.4%. The survival rate was 9.3% for the EMT program and 2.6% for the EP program. The incremental cost-effectiveness ratio (ICER) of EMTs vs. EPs was 21,136 US$ per life saved. The ICER was sensitive to hospital admission cost changes and the probability of survival to discharge in patients admitted to hospital in the EMT program. The increased survival rate of OHCA patients in the EMT program may be attributable to the services of the hospital and/or the EMT program.

CONCLUSION

The use of EMTs as ALS care providers for OHCA patients in the two-tiered EMS system resulted in a reasonable cost-effectiveness ratio. EMTs could be considered as the second tier of EMS systems in urban areas in Taiwan.

Cost-effectiveness of simvastatin in people at different levels of vascular disease risk: economic analysis of a randomised trial in 20,536 individuals

BACKGROUND

Statin therapy reduces the rates of heart attack, stroke, and revascularisation among a wide range of individuals. Reliable assessment of its cost-effectiveness in different circumstances is needed.

METHODS

20,536 adults (aged 40-80 years) with vascular disease or diabetes were randomly allocated 40 mg simvastatin daily (10,269) or placebo (10,267) for an average of 5 years. Comparisons were made of hospitalisation and statin costs (2001 UK prices) during the scheduled treatment period between all simvastatin-allocated versus all placebo-allocated participants. Cost-effectiveness was estimated among different categories of participant.

FINDINGS

Allocation to simvastatin was associated with a highly significant 22% (95% CI 16-27; p<0.0001) proportional reduction in hospitalisation costs for all vascular events, with similar proportional reductions in every subcategory of participant studied. During an average of 5 years, estimated absolute reductions in vascular event costs per person allocated 40 mg simvastatin daily ranged from UK 847 pounds sterling (SE 137) in the highest risk quintile studied to 264 pounds sterling (48) in the lowest. Mean excess cost of statin therapy among participants allocated simvastatin was 1497 pounds sterling (8), with similar absolute increases in every subcategory. Costs of preventing a major vascular event with 40 mg simvastatin daily ranged from 4500 pounds sterling (95% CI 2300-7400) among participants with a 42% 5-year major vascular event rate to 31,100 pounds sterling (22,900-42,500) among those with a 12% rate (corresponding to 5-year major coronary event rates of 22% and 4%, respectively).

INTERPRETATION

Statin therapy is cost effective for a wider range of individuals with vascular disease or diabetes than previously recognised (particularly with lower-priced generics). It would be appropriate to consider reducing the estimated level of vascular event risk at which statin therapy is recommended.