Cost-Effectiveness of Treatments Reducing Coronary Heart Disease Mortality in Ireland, 2000 to 2010
ABSTRACT
Objective: Coronary heart disease (CHD) is associated with a large burden of disease in Ireland and is responsible for more than 6000 deaths annually. This study examined the cost-effectiveness of specific CHD treatments in Ireland.
Methods: Irish epidemiological data on patient numbers and median survival in specific groups, plus the uptake, effectiveness, and costs of specific interventions, all stratified by age and sex, were incorporated into a previously validated CHD mortality model, the IMPACT model. This model calculates the number of life-years gained (LYGs) by specific cardiology interventions to generate incremental cost-effectiveness ratios (ICERs) per LYG for each intervention.
Results: In 2000, medical and surgical treatments together prevented or postponed approximately 1885 CHD deaths in patients aged 25 to 84 years, and thus generated approximately 14,505 extra life-years (minimum 7270, maximum 22,475). In general, all the cardiac interventions investigated were highly cost-effective in the Irish setting. Aspirin, beta-blockers, ACE inhibitors, spironolactone, and warfarin for specific conditions were the most cost-effective interventions (<€3000/LYG), followed by the statins for secondary prevention (<€6500/LYG). Revascularization for chronic angina and primary angioplasty for myocardial infarction, although still cost-effective, had the highest ICER (between €12,000 and €20,000/LYG).
Conclusions: Using a comprehensive standardized methodology, cost-effectiveness ratios in this study clearly favored simple medical treatments for myocardial infarction, secondary prevention, angina, and heart failure.
Introduction
Expenditure on health care in Ireland has increased from approximately €3.7 billion in 1997 to more than €11.3 billion in 2005 [1]. Not surprisingly, the issue of value for money arises and a number of reports including the 2003 Commission on Financial Management and Control Systems in the Health Service (Brennan report) recommended that a review be undertaken to ensure such expenditure provides good value for money [2]. New technologies including, but not limited to, pharmaceuticals are increasingly being subjected to Health Technology Assessment (HTA). The Irish National Health Strategy 2001 proposed a system of HTA which would enable the health-care system to: 1) introduce technologies speedily with proven, significant health benefits; 2) prevent the introduction of technologies which fail to meet requirements of evidence-based analysis; and 3) continuously monitor the effect of technologies after their introduction [3].
The 2006 agreement between the Irish Pharmaceutical Healthcare Association (IPHA) and the Health Service Executive (HSE) facilitated the introduction of HTA. The agreement confirms that “the HSE reserves the right to assess new and existing technologies (pharmaceuticals, diagnostics, and devices) that may have a high unit cost or a significant budget impact on the Irish health care system”[4]. Cardiovascular medications accounted for approximately 25% (€318.5 million) of spending under the Community Drugs Schemes in 2005. This is not surprising as coronary heart disease (CHD) remains a leading cause of death and disability in Ireland, and mortality rates are still among the highest in Europe. Nevertheless, CHD mortality rates have fallen since the mid-1980s with steeper falls in younger age groups. Between 1985 and 2000 mortality rates in Ireland fell by 47% in those aged 25 to 84 years. Some 43.6% of the observed decrease in mortality was attributed to treatment effects [5]. In this study we determine the cost-effectiveness of the principal CHD treatments over the 10-year period between 2000 and 2010.
Methods
We identified and analyzed the following conditions: acute myocardial infarction (AMI), secondary prevention after AMI or revascularization, unstable angina, chronic angina, heart failure in hospital and in the community, plus primary prevention using statins (HMG-CoA reductase inhibitor). The specific medical and surgical therapies considered included aspirin, thrombolysis, beta-blockers, ACE inhibitors, statins, cardiac rehabilitation, warfarin, heparin, glycoprotein IIb/IIIa inhibitors, coronary artery bypass graft (CABG) surgery, and angioplasty.
The IMPACT CHD Mortality Model
This previously validated cell-based IMPACT CHD mortality model has been described in detail elsewhere [6]. In brief, the model utilizes a very large Microsoft Excel spreadsheet to integrate data on: CHD patient numbers, uptake of specific medical and surgical treatments, effectiveness of specific treatments, and median survival in patients with and without CHD. It includes data for men and women aged 25 to 84 years. The model was developed using extensive data describing the population in Ireland for the year 2000 [5]. The complete IMPACT CHD mortality model also includes the mortality consequences of population trends in major risk factors; however, these were not the focus of this analysis. The effectiveness estimates for each therapy were based on recent meta-analyses and large randomized controlled trials. The complete list of such trials and meta-analyses, the base-case effectiveness estimates, and all the other underlying assumptions have been published previously [6–9] and can also be accessed on the IMPACT website (http://www.liv.ac.uk/PublicHealth/sc/bua/impact.html), as well as detailed in appendices I to III (http://www.ispor.org/publications/value/ViHsupplementary.asp).
Estimating the Number of Deaths Prevented or Postponed (DPPs) in Ireland in 2000
The number of CHD deaths prevented or postponed by each treatment group was based on the relative mortality reduction reported in published trials and meta-analyses applied to the case fatality observed in unselected patient cohorts. This was calculated based on the product of four variables: number of eligible patients for each age–sex-specific cardiology intervention (e.g., number of AMI patients for secondary prevention following AMI), treatment uptake levels, compliance rate (patients' adherence), and absolute risk reduction due to the particular intervention (which is a product of relative risk and case-fatality rates). To avoid double counting, adjustments were first made for overlaps between different treatment groups, by subtracting the overlapping subgroup from the main group. For instance, the postmyocardial infarct (MI) survivors total was reduced by 25%, to allow for those post-MI patients who subsequently developed heart failure.
Sources of the Irish data and detailed technical appendices can be found on the IMPACT website (http://www.liv.ac.uk/PublicHealth/sc/bua/impact.html). The website also provides details on operational definitions of the six cardiovascular risk factors studied, on the polypharmacy issues, how double counting of patients are adjusted for, as well as an in-depth calculation of the numbers of DPPs, with examples.
Median Survival Data
For each treatment category, median survival was obtained from the best available population-based data. Estimates of survival after coronary surgery were obtained from the Irish Cardiac Surgery Register [10] plus a recent cohort study in Scotland [11]. Angioplasty for angina was assumed to have a similar survival benefit [12]. Because other survival data in Ireland are limited [13], most age-specific median survival data were obtained from large cohort studies of unselected patients with AMI or heart failure in the United Kingdom [14,15]. The data for Ireland are likely to be very similar to the UK pattern, as Ireland has followed similar CHD mortality and treatment trends since the mid-1980s. Median survival estimates for patients treated for hypertension were based on the Glasgow Blood Pressure Clinic cohort [16].
The following assumptions were also made
- 1
In patients with recognized CHD, median survival was assumed to be very similar to that in age-matched myocardial infarction survivors.
- 2
In asymptomatic individuals, median survival was based on age-specific life expectancy for the general population (calculated from Irish life-tables) [17].
- 3
In subjects with symptomatic but unrecognized CHD, the median survival was assumed to lie midway between the values for myocardial infarction survivors and the general population.
- 4
The IMPACT CHD mortality model default assumptions for compliance were 100% in hospital patients, 70% in symptomatic community patients, and 50% in asymptomatic community patients [18]. In short, we looked at patients' adherence to therapeutically effective levels of medication for the general calculation of the number of DPPs due to treatments. All of these assumptions were tested in subsequent robust sensitivity analyses.
Estimation of Life-Years Gained (LYGs)
The number of LYGs in 2000 for each treatment category and for each risk factor change was estimated across sex and age groups. Each LYG estimate was calculated as the number of DPPs in 2000 from the IMPACT CHD mortality model, multiplied by the age-specific median survival for the age–sex group [5,19]. The LYG total was then obtained by summing individual LYG values across every age and sex category for each specific treatment group. Our LYG estimates were not explicitly adjusted for the influence of other competing causes of mortality such as cancer. Nevertheless, these are generally modest, amounting to less than one extra year of life [20,21]. Interaction was not tested in this model.
For this study, the 1985/2000 Irish IMPACT CHD mortality model was extended to follow each cohort of patients who received specific treatments for up to 10 years, over the time period 2000 to 2010. For example, we have estimated DPPs for a particular age group for a specific intervention in 2000, and then based on the case-fatality rates and treatment efficacy for this particular treatment-case group, the incremental DPPs without and with treatments were calculated. The difference of the estimated DPPs between treatment and without treatment gives the incremental DPPs, and when these incremental DPPs were discounted using a discount rate of 3.5% from year 1, namely, from 2001 onward, the discounted DPPs are calculated yearly for each treatment-case group. The details are explained in the tabular example attached (Tables 1 and 2).
| Year | C/F | C/E | DPPs without Rx (Rx−) | DPPs with Rx (Rx+) | Estimated DPPs | Discounted DPPs |
|---|---|---|---|---|---|---|
| 2000 | x | y | Rx−2000[5,19] | Rx+2000[5,19] | Rx+2000 − Rx−2000 | 0 |
| 2001 | x | y | Rx−2000 − (Rx−2000* x) | Rx+2000 − (Rx+2000* x) (1 − y) | Rx+2001 − Rx−2001 | DPP2001 − Discounted Yr1 |
| 2002 | x | y | Rx−2001 − (Rx−2001* x) | Rx+2001 − (Rx+2001* x) (1 − y) | Rx+2002 − Rx−2002 | DPP2002 − Discounted Yr2 |
| 2003 | x | y | Rx−2002 − (Rx−2002* x) | Rx+2002 − (Rx+2002* x) (1 − y) | Rx+2003 − Rx−2003 | DPP2003 − Discounted Yr3 |
| 2004 | x | y | Rx−2003 − (Rx−2003* x) | Rx+2003 − (Rx+2003* x) (1 − y) | Rx+2004 − Rx−2004 | DPP2004 − Discounted Yr4 |
| 2005 | x | y | Rx−2004 − (Rx−2004* x) | Rx+2004 − (Rx+2004* x) (1 − y) | Rx+2005 − Rx−2005 | DPP2005 − Discounted Yr5 |
| 2006 | x | y | Rx−2005 − (Rx−2005* x) | Rx+2005 − (Rx+2005* x) (1 − y) | Rx+2006 − Rx−2006 | DPP2006 − Discounted Yr6 |
| 2007 | x | y | Rx−2006 − (Rx−2006* x) | Rx+2006 − (Rx+2006* x) (1 − y) | Rx+2007 − Rx−2007 | DPP2007 − Discounted Yr7 |
| 2008 | x | y | Rx−2007 − (Rx−2007* x) | Rx+2007 − (Rx+2007* x) (1 − y) | Rx+2008 − Rx−2008 | DPP2008 − Discounted Yr8 |
| 2009 | x | y | Rx−2008 − (Rx−2008* x) | Rx+2008 − (Rx+2008* x) (1 − y) | Rx+2009 − Rx−2009 | DPP2009 − Discounted Yr9 |
| 2010 | x | y | Rx−2009 − (Rx−2009* x) | Rx+2009 − (Rx+2009* x) (1 − y) | Rx+2010 − Rx−2010 | DPP2010 − Discounted Yr10 |
- We assumed DPPs with and without treatment for the baseline year (2000) to be equal for comparisons, and the values are derived from the original Irish IMPACT Model estimation [5,19].
- C/E: clinical effectiveness of individual treatment categories (reported as relative risk), and the values are all given in Appendix III; C/F: case fatality; CHD, coronary heart disease; DPP, death prevented or postponed.
| Year | Discounted DPPs | Median survival (MS) | LYG = Discounted DPPs * MS |
|---|---|---|---|
| 2001 | DPP2001 − Discounted Yr1 | MS2005 + (MS2005 − MS2010) * 4/5 | DPP2001 * MS2001 |
| 2002 | DPP2002 − Discounted Yr2 | MS2005 + (MS2005 − MS2010) * 3/5 | DPP2002 * MS2002 |
| 2003 | DPP2003 − Discounted Yr3 | MS2005 + (MS2005 − MS2010) * 2/5 | DPP2003 * MS2003 |
| 2004 | DPP2004 − Discounted Yr4 | MS2005 + (MS2005 − MS2010) * 1/5 | DPP2004 * MS2004 |
| 2005 | DPP2005 − Discounted Yr5 | MS2005 | DPP2005 * MS2005 |
| 2006 | DPP2006 − Discounted Yr6 | MS2005 − (MS2005 − MS2010) * 1/5 | DPP2006 * MS2006 |
| 2007 | DPP2007 − Discounted Yr7 | MS2006 − (MS2005 − MS2010) * 1/5 | DPP2007 * MS2007 |
| 2008 | DPP2008 − Discounted Yr8 | MS2007 − (MS2005 − MS2010) * 1/5 | DPP2008 * MS2008 |
| 2009 | DPP2009 − Discounted Yr9 | MS2008 − (MS2005 − MS2010) * 1/5 | DPP2009 * MS2009 |
| 2010 | DPP2010 − Discounted Yr10 | (MS2005 + MS2005 of immediate next age group)/2 | DPP2010 * MS2010 |
- Discounted LYG = sum (LYG2001 + LYG2002 +. . . . . . LYG2010).
- DPP, death prevented or postponed; LYG, life-year gained.
Furthermore, the median survival for a specific treatment-pair group was estimated, as shown in the tabular example attached herewith. Finally, the discounted LYG for each treatment-case group is the summation of the yearly products of the median survival and the discounted DPPs for the 10-year period. The ratios of the calculated cost and the estimated LYG were then used in cost-effectiveness ratio calculations. Results were then stratified by age and sex. The detailed results for men are presented; the results for women were very similar and are detailed on the website.
The objective of this study was to compare all available treatments in CHD for a given year (2000) to analyze the efficiency of cost allocation in the health system. In this analysis, we aimed to provide a snap shot of the health system for the defined period (and on the basis of real prescriptions), and we did not further analyze the prescription trends for each treatment–disease pair. Therefore, we compared the effectiveness of the intervention to another treatment or the best available treatment. In the few remaining cases, for example, cardiac rehabilitation, it was treatment versus no treatment.
Costing Methodology
Unit costs for health technologies were estimated using the Irish case-mix model of Diagnostic-Related Groups for inpatient surgical procedures such as angioplasty and CABG. This case-mix model uses Hospital In-Patient Enquiry data from the Economic and Social Research Institute covering more than 90% of public hospitals and a few private and voluntary hospitals across Ireland [22]. The costs for the year 2001 were used. Such an analysis also includes other costs (dispensing costs, hospital costs, overhead costs, etc.) for medical procedures.
For drugs, the unit costs were derived from actual prescribing data available from the HSE-Primary care reimbursement services (PCRS, formerly General Medical Services [GMS] scheme). This pharmacy claims database is a major resource of drug prescription data in Ireland. The HSE-PCRS population coverage is approximately 30%; however, it accounts for more than 65% of all prescribing. The WHO Anatomical Therapeutic Chemical classification was used for classifying drugs, for example, statins (C10AA) and the four main types of statins prescribed to HSE-PCRS patients in 2000: atorvastatin (C10AA05), fluvastatin (C10AA04), pravastatin (C10AA03), and simvastatin (C10AA01). The GMS prescribing database was used to identify the common drugs within each of the drug classes (statins, ACE inhibitors, beta-blockers, etc.) and associated formulations prescribed (tablets, capsules, etc.). The defined daily dose (DDD), the average recommended daily adult dose, of each of the drug classes was calculated. A weight based on the percentage distribution of DDDs for individual drugs within a drug class was then calculated. Individual drug acquisition ingredient costs were obtained from the Irish Monthly Index of Medical Specialties (July 2000). The total ingredient cost incurred for each drug class was then calculated by multiplying the annual cost of each drug by the weight for that drug and then by summing over all drugs within the drug class. This was repeated for each of the drug classes.
Cost of cardiac rehabilitation was taken from the published literature. Gray et al. [23] in 1997 showed that the cost of cardiac rehabilitation for the British setting is £370, which was converted to Euros for the Irish setting. In addition, a recent study by Beswick et al. published in 2004 [24] did not show much change in the costs of cardiac rehab since 1997, ranging from £350 to £490.
Only drug costs and intervention costs were included in this analysis. Incremental cost-effectiveness ratios (ICERs) were calculated in terms of incremental cost per additional LYG. Costs, LYGs, and the numbers of DPPs for each age group were discounted on an annual incremental basis for the 10-year study period, using a discount rate of 3.5%. The methods used here are similar to those explained for England and Wales [25].
Time Frame
All costs and effects were estimated for 10-year age bands and for both men and women. The very small number of patients aged below 35 years was excluded from the analysis, as were those aged more than 85 years [5]. Interventions for AMI and acute coronary syndrome were evaluated over a 1-year scenario. Cardiac rehabilitation benefits were assumed to last for 2 years [26].
Cost-effectiveness ratios were calculated on the basis of a 10-year time horizon for continuous drug interventions in all chronic conditions except heart failure. Given the severely reduced life expectancy in heart failure, costs and benefits were calculated over 2 years for patients admitted to hospital, and over 5 years for heart failure patients treated only in the community [27].
Sensitivity Analyses
Sensitivity analyses were performed using multiway analysis of extremes method [28]. This systematically addressed the uncertainties surrounding the key variables (treatment costs, patient numbers, treatment uptake, treatment efficiency, median survival, and the overlap between different treatment categories). Base-case ICERs were calculated using the best estimates for costs and effectiveness. In other words, the minimum and maximum estimates of LYGs were applied to the reference cost in sensitivity analyses. Minimum and maximum mortality reductions were generated using 95% confidence intervals from meta-analyses for treatment efficacy, and minimum and maximum plausible values for patient numbers, treatment and uptake and adherence. This method does not involve any probabilistic interpretation as in confidence interval estimation, nor does this contain details on the statistical variations around the estimates. Illustrative examples of specific analyses and calculations are shown in the appendices of the recent England and Wales model publication [6], and also on the IMPACT website.
Results
Specific medical and surgical treatments for CHD patients prevented or postponed approximately 1885 deaths in Ireland in the year 2000 (Table 3). The combined effect of all the relevant treatments generated a total of approximately 14,505 additional life-years (minimum estimate 7270, maximum estimate 22,470). The largest contributions came from secondary prevention following myocardial infarction (22%), secondary prevention following revascularization (20%), and heart failure (10%). CABG surgery and angioplasty procedures in angina patients together accounted for approximately 18% of the total discounted LYG.
| Intervention | Patients eligible | Number of deaths prevented/postponed | LYGs Best estimate | % of total LYGs |
|---|---|---|---|---|
| Acute myocardial infarction | 3,970 | 166 | 1,086 | 7.5 |
| Secondary prevention | ||||
| Post myocardial infarction | 37,245 | 580 | 3,180 | 21.9 |
| Post coronary surgery or angioplasty | 24,438 | 229 | 2,912 | 20.1 |
| Angina | ||||
| CABG surgery | 18,990 | 144 | 2,054 | 14.2 |
| Angioplasty | 11,023 | 45 | 631 | 4.3 |
| Unstable angina | 2,432 | 33 | 208 | 1.4 |
| Angina in community | 100,598 | 241 | 2,061 | 14.2 |
| Heart failure | ||||
| Hospital treatment | 1,715 | 150 | 237 | 1.6 |
| Community treatment | 12,940 | 190 | 1,219 | 8.4 |
| Hypertension treatments | 705,648 | 59 | 545 | 3.8 |
| Statins for primary prevention | 915,169 | 46 | 371 | 2.6 |
| Total treatment effects in 2000 | 1,883 | 14,504 | 100 | |
- CABG, coronary artery bypass graft; LYG, life-year gained.
In general, all the cardiac interventions in the Irish settings could be considered cost-effective (Table 4). Nevertheless, aspirin, beta-blockers, ACE inhibitors, spironolactone, and warfarin for specific disease conditions offered the best value for money (<€3000/LYG). Statins for secondary prevention were also very cost-effective (<€7000/LYG). Revascularization for chronic angina (CABG surgery €12,968 and angioplasty €14,864/LYG) and the use of statins in primary prevention were relatively less cost-effective (€11,442/LYG). The overall cost-effectiveness of primary angioplasty for myocardial infarction was €19,206/LYG reaching to €26,006/LYG in men aged 75 to 84 years (Table 4). In Table 4, there was an age gradient across all the interventions studied. For example, primary angioplasty for AMI was least cost-effective among the elderly (75–84 years) as compared to the younger populations. A similar pattern was observed for statins in secondary prevention and IIb/IIIa inhibitors for unstable angina.
| Age group (year) | All | 45–54 | 55–64 | 65–74 | 75–84 |
|---|---|---|---|---|---|
| Acute myocardial infarction | |||||
| Cardiopulmonary resuscitation | 303 | 159 | 293 | 1,040 | 1,571 |
| Thrombolysis | 2,164 | 2,192 | 2,048 | 1,979 | 2,980 |
| Primary angioplasty | 19,206 | 19,129 | 17,870 | 17,272 | 26,006 |
| ACE inhibitors | 2,698 | 3,430 | 2,687 | 2,497 | 2,407 |
| Secondary prevention post-acute myocardial infarction | |||||
| Aspirin | 1,144 | 1,027 | 1,126 | 1,339 | 1,674 |
| Beta-blockers | 1,077 | 974 | 1,067 | 1,267 | 1,576 |
| ACE inhibitors | 2,295 | 2,074 | 2,272 | 2,698 | 3,356 |
| Statins | 4,741 | 4,340 | 4,753 | 5,635 | 6,982 |
| Warfarin | 1,392 | 1,245 | 1,364 | 1,623 | 2,029 |
| Cardiac rehabilitation | 7,679 | 6,886 | 7,543 | 8,946 | 11,100 |
| Secondary prevention post-CABG surgery or angioplasty | |||||
| Aspirin | 755 | 743 | 737 | 686 | 848 |
| Beta-blockers | 715 | 706 | 698 | 650 | 804 |
| ACE inhibitors | 1,523 | 1,504 | 1,487 | 1,384 | 1,711 |
| Statins | 3,193 | 3,147 | 3,109 | 2,894 | 3,578 |
| Warfarin | 916 | 903 | 893 | 831 | 1,028 |
| Cardiac rehabilitation | 5,029 | 4,993 | 4,934 | 4,593 | 5,679 |
| Revascularization | |||||
| CABG surgery | 12,968 | 10,804 | 11,759 | 13,059 | 20,973 |
| Angioplasty | 14,864 | 13,555 | 14,219 | 15,712 | 19,430 |
| Community angina | |||||
| Aspirin | 1,695 | 1,786 | 1,541 | 1,494 | 1,807 |
| Statins | 6,318 | 8,026 | 5,684 | 4,163 | 5,834 |
| Unstable angina | |||||
| Aspirin | 862 | 757 | 883 | 1,080 | 1,161 |
| IIb/IIIa inhibitors | 6,394 | 5,904 | 6,887 | 8,438 | 9,085 |
| Heart failure (severe, i.e., those admitted to hospital) | |||||
| ACE inhibitors | 3,922 | 2,648 | 3,575 | 4,402 | 5,374 |
| Beta-blockers | 1,227 | 859 | 1,138 | 1,361 | 1,627 |
| Spironolactone | 2,750 | 1,787 | 2,394 | 2,917 | 3,533 |
| Aspirin | 2,341 | 1,509 | 2,078 | 2,638 | 3,291 |
| Statins | 8,854 | 6,233 | 8,368 | 10,223 | 12,406 |
| Heart failure (community patients) | |||||
| ACE inhibitors | 1,668 | 1,466 | 1,697 | 1,699 | 1,673 |
| Beta-blockers | 548 | 483 | 558 | 558 | 550 |
| Spironolactone | 1,135 | 999 | 1,155 | 1,156 | 1,139 |
| Aspirin | 941 | 822 | 955 | 957 | 940 |
| Statins | 3,941 | 3,465 | 4,008 | 4,013 | 3,953 |
| Primary prevention | |||||
| Statins | 11,442 | 18,170 | 10,565 | 6,763 | 5,888 |
| Hypertension | 351 | 711 | 430 | 250 | 160 |
- CABG, coronary artery bypass graft; LYG, life-year gained.
Variation of the parameters in the model in a series of multiway sensitivity analyses is presented which does not show substantial change to the cost/LYG ratios (Table 5).
| Min | Best | Max | ||
|---|---|---|---|---|
| AMI | Hospital CPR | 205 | 303 | 410 |
| PTCA | 11,550 | 19,206 | 23,085 | |
| Thrombolysis | 1,316 | 2,164 | 2,629 | |
| ACE inhibitors | 1,613 | 2,698 | 3,223 | |
| Post-MI | Aspirin | 687 | 1,144 | 3,413 |
| Beta-blockers | 647 | 1,077 | 3,201 | |
| ACE inhibitors | 1,385 | 2,295 | 6,683 | |
| Statins | 2,881 | 4,741 | 13,383 | |
| Warfarin | 837 | 1,392 | 4,125 | |
| Post-revascularization | Aspirin | 671 | 755 | 861 |
| Beta-blockers | 637 | 715 | 815 | |
| ACE inhibitors | 1,356 | 1,523 | 1,736 | |
| Statins | 2,848 | 3,193 | 3,632 | |
| Warfarin | 816 | 916 | 1,046 | |
| Rehab | 4,498 | 5,029 | 5,703 | |
| Revascularization | CABG surgery | 9,801 | 12,968 | 14,815 |
| Angioplasty | 14,298 | 14,864 | 20,489 | |
| Community angina | Statins | 5,308 | 6,317 | 7,803 |
| Aspirin | 1,196 | 1,695 | 1,818 | |
| Unstable angina | Aspirin | 362 | 862 | 559 |
| Hospital HF | ACE inhibitors | 2,761 | 3,922 | 6,768 |
| Beta-blockers | 874 | 1,227 | 2,056 | |
| Aspirin | 1,624 | 2,341 | 4,191 | |
| Spironolactone | 1,931 | 2,750 | 4,773 | |
| Statins | 6,272 | 8,854 | 15,050 | |
| Community HF | ACE inhibitors | 1,343 | 1,668 | 2,199 |
| Beta-blockers | 442 | 548 | 718 | |
| Aspirin | 755 | 941 | 1,248 | |
| Spironolactone | 915 | 1,135 | 1,494 | |
| Statins | 3,177 | 3,941 | 5,191 | |
| Primary prevention | Statins | 6,989 | 11,442 | 13,880 |
| Hypertension | 221 | 351 | 434 |
- AMI, acute myocardial infarction; CABG, coronary artery bypass graft; CPR, cardiopulmonary resuscitation; HF, heart failure; LYG, life-year gained; MI, myocardial infarct; PTCA, angioplasty.
Discussion
This study demonstrates the cost-effectiveness of a wide range of cardiac interventions in the Irish health-care setting (<€20,000/LYG). Medications such as aspirin, beta-blockers, ACE inhibitors, spironolactone, and warfarin offered the best value for money. A recent study indicated that just less than 50% of the reduction in CHD mortality in Ireland could be attributed to medical treatments, particularly secondary preventative therapies and treatment of heart failure [5]. Although there is no fixed threshold for cost-effectiveness in Ireland, the ICERs reported in this study are comparable to that of a previous study on statins for primary prevention of cardiovascular events in Ireland (ICERs range from €17,900 to €33,800/LYG) [29]. This study confirms the cost-effectiveness of statins in the secondary prevention of CHD with ICERs varying from €4340 to €6982/LYG. These figures are slightly higher than a previous study where the cost-effectiveness of statin therapy in secondary prevention ranged from €1272 to €3900 per quality-adjusted life-year (QALY). The studies are not comparable as the outcome measure differs between the two studies [30]. The difference may be explained, in part, because of differing methodologies particularly the duration of therapy incorporated into the economic models. Not surprisingly, the ICERs for statin therapy in primary prevention were higher as the risk of a coronary event is lower and ranged from €5,888 to €18,170/LYG, similar to another study investigating the cost-effectiveness of statins for the primary prevention of CHD in Ireland [29]. Although generic statin prescribing was included in the costs, prescribing is very low in Ireland (approximately 7%) and would therefore not have had a large effect.
The role of beta-blockers in the management of patients with heart failure is now well established and a previous study indicated the cost-effectiveness of carvedilol at €1560/LYG [31]. In our study the cost-effectiveness of beta-blockers for the treatment of heart failure ranged from €483 to €558/LYG. Spironolactone has also been shown to be cost-effective in the treatment of severe heart failure in previous studies and was confirmed here with ICERs ranging from €999 to €1156/LYG in the community setting.
In the United Kingdom, the benchmark for maximum acceptable cost-effectiveness ratios has been set by the National Institute for Clinical Excellence (NICE) appraisals consistently around £20,000 to £30,000/QALY. This figure is around €45,000/QALY if converted to euros in Ireland. Although no formal benchmarks have been set for cost per LYG, similar values are also used for cost per LYG (these would be slightly lower, because quality-of-life weights are always much lower than 1.0 in CHD patients, often just 0.6 or 0.7).
Limitations of This Study
The primary aim of this article was to compare a range of therapies using a standard methodology. This study therefore focused on average net treatment costs for each LYG. It did not explicitly capture reductions in admissions, follow-up visits, costs associated with adverse events, or potential costs avoided (such as further infarcts, or further revascularization). Employing more complex modeling techniques, while theoretically desirable, was not feasible. We did not attempt to perform a cost-effectiveness analysis of individual technologies, for example, using a Markov modeling methodology. Other evidence suggests that the inclusion of long-term cost consequences in other studies may make a surprisingly small difference [32]. Each relative risk value of treatment in the model was based on a meta-analysis comparison with placebo, or an older therapy. The perfect economic analysis would prefer a mixed treatment comparison to establish a common baseline. While not ideal, the IMPACT model produced an approximation to this, by recognizing that most patients in most groups were receiving multiple therapies.
New technologies including pharmaceuticals are increasingly being subjected to HTA in an attempt to demonstrate value for money. Pharmacoeconomic assessment is now a requirement in several European Member States including Finland, The Netherlands, Norway, and Sweden before reimbursement decisions. In Portugal and Denmark cost-effectiveness data are incorporated into the reimbursement process and the NICE evaluates the cost-effectiveness of medicines for the National Health Services (NHS) in Britain [4].
This study compares the cost-effectiveness of a wide range of cardiovascular therapies in the Irish health-care setting. The majority of the data included covered the entire adult population in Ireland and therefore avoids sampling errors. The IMPACT/CHD mortality model methodology has been replicated in a number of countries including Ireland. The demand for such cost-effectiveness data in the Irish health-care setting is set to increase following recent developments, which include the IPHA/HSE agreement, the strategy for cancer control in Ireland which recommends a cancer HTA panel with an emphasis on diagnostic and therapeutic technologies, and the strategy for science, technology, and innovation.
HTA is one of the main remits of the new Health Information and Quality Authority (HIQA). It is envisaged that HIQA will lead the system-wide HTA process in Ireland through the formation of a HTA program board, which will determine the choice of HTA with each appraisal being overseen by a HTA reference group. It is envisaged that HIQA will play a central role in developing health and personal social services in Ireland and will help ensure that quality of care is promoted throughout the health system and that patients receive the best possible outcomes within available resources.
Supplementary materials for this article can be found at: http://www.ispor.org/publications/value/ViHsupplementary.asp
Source of financial support: Irish Heart Foundation.
