Implications for present and future applications of the implantable cardioverter-defibrillator resulting from the use of a simple model of cost efficacy

Cost-effectiveness of implantable cardioverter defibrillator therapy

Cost-efficacy assessment of implantable cardioverter defibrillator (ICD) therapy has proved contentious and may have limited uptake of ICD therapy, particularly in Europe. Published modeling assessments are too inaccurate to determine clinical practice, and assessments based on clinical studies are incomplete (from the cost-efficacy viewpoint). Although ICD therapy seems certain to be most cost-effective in patients who are likely to have good longevity if their risk of sudden cardiac death is countered, the benefit of ICD therapy is not necessarily limited to such groups. Physicians and health economists need to develop a better understanding of how to assess high-technology therapy costs so that uptake of such therapy is appropriately expedited with due regard to ethical and cost constraints.

Handling uncertainty in cost-effectiveness models

The use of modelling in economic evaluation is widespread, and it most often involves synthesising data from a number of sources. However, even when economic evaluations are conducted alongside clinical trials, some form of modelling is usually essential. The aim of this article is to review the handling of uncertainty in the cost-effectiveness results that are generated by the use of decision-analytic-type modelling. The modelling process is split into a number of stages: (i) a set of methods to be employed in a study are defined, which should include a 'reference case' of agreed methods to enhance the comparability of results; (ii) the clinical and demographic characteristics of the patients the model relates to should be specified as carefully as in any experimental study; and (iii) the data requirements of the model should be estimated using the principles of Bayesian statistics, such that prior distributions are specified for unknown model parameters. Monte Carlo simulation can then be employed to sample from these prior distributions to obtain a distribution of the cost effectiveness of the intervention. Such probabilistic analyses are related to parameter uncertainty. In addition, modelling uncertainty is likely to add a further layer of uncertainty to the results of particular analyses.

The implantable cardioverter-defibrillator

Ventricular arrhythmias remain a major cause of cardiovascular mortality. Therapy for serious ventricular arrhythmias has evolved over the past decade, from treatment primarily with antiarrhythmic drugs to implanted devices. The implantable cardioverter-defibrillator (ICD) is the best therapy for patients who have experienced an episode of ventricular fibrillation not accompanied by an acute myocardial infarction or other transient or reversible cause. It is also superior therapy in patients with sustained ventricular tachycardia (VT) causing syncope or hemodynamic compromise. Controlled clinical trials have confirmed the utility of these devices. As primary prevention, the ICD is superior to conventional antiarrhythmic drug therapy in patients who have survived a myocardial infarction and who have spontaneous, nonsustained ventricular tachycardia, a low ejection fraction, inducible VT at electrophysiologic study, and whose VT is not suppressed by procainamide. The effect of the ICD on survival of other patient populations remains to be proven. The device is costly, but its price is generally accepted to be reasonable. The ICD has been a major advance in the treatment of ventricular arrhythmias.

The cost-effectiveness of automatic implantable cardiac defibrillators: results from MADIT. Multicenter Automatic Defibrillator Implantation Trial

BACKGROUND

The recently reported Multicenter Automatic Defibrillator Implantation Trial (MADIT) showed improved survival in selected asymptomatic patients with coronary disease and nonsustained ventricular tachycardia. The economic consequences of defibrillator management in this patient population are unknown.

METHODS AND RESULTS

Patients were followed up to quantify their use of healthcare services, including hospitalizations, physician visits, medications, laboratory tests, and procedures, during the trial. The costs of these services, including the costs of the defibrillator, were determined in patients randomized to defibrillator and nondefibrillator therapy. Incremental cost-effectiveness ratios were calculated by relating these costs to the increased survival associated with the use of the defibrillator. The average survival for the defibrillator group over a 4-year period was 3.66 years compared with 2.80 years for conventionally treated patients. Accumulated net costs were $97,560 for the defibrillator group compared with $75,980 for individuals treated with medications alone. The resulting incremental cost-effectiveness ratio of $27,000 per life-year saved compares favorably with other cardiac interventions. Sensitivity analyses showed that the incremental cost-effectiveness ratio would be reduced to approximately $23,000 per life-year saved if transvenous defibrillators were used instead of the older devices, which required thoracic surgery for implantation.

CONCLUSIONS

An implanted cardiac defibrillator is cost-effective in selected individuals at high risk for ventricular arrhythmias.

An economic analysis of the Survival and Ventricular Enlargement (SAVE) Study. Application to the United Kingdom

Recent studies have shown that ACE inhibitors reduce morbidity and mortality after myocardial infarction (MI). While these trials have obvious clinical implications, the widespread introduction of a new treatment for a condition as common as MI also has clear cost implications. The results of the post-MI studies with ACE inhibitors suggest that restricted use of treatment-in high-risk patients-is likely to be most cost effective, whereas treatment of all MI survivors, many of whom are at low risk, will be least cost effective. An approach somewhere in between may maximise clinical benefit at an acceptable cost. Economic analysis may help in deciding how these drugs might be best used after MI. We have conducted a cost-effectiveness and cost-utility analysis of the Survival and Ventricular Enlargement (SAVE) study, which reported the benefit of ACE inhibitors in intermediate-risk patients. Assuming all MI survivors require measurement of left ventricular function before selection for treatment (the approach used in the SAVE study), the incremental cost per life-year gained (LYG), over 4 years, using prophylactic captopril is approximately 10000 pounds sterling (Pounds) [1994 to 1995 values]. The cost per quality-adjusted life-year (QALY) is similar. These incremental cost per LYG and cost per QALY ratios compare favourably with other commonly used symptomatic and prophylactic treatments, and argue for extending post-MI use of ACE inhibitors to intermediate-as well as high-risk patients.

Cost savings with nonthoracotomy implantable cardioverter-defibrillators

We analyzed hospital and physician charges for 99 consecutive patients who underwent implantable cardioverter-defibrillator (ICD) implantation at our institution. Eighteen patients received an epicardial lead system and 81 were scheduled to receive a nonthoracotomy lead system, the generator being implanted either abdominally (n = 62) or pectorally (n = 19). The epicardial group had a significantly longer convalescent stay (11.6 +/- 2.5 days; mean +/- SEM) than the abdominal nonthoracotomy group, analyzed by intention to treat (4.6 +/- 0.5 days) or by treatment received (3.8 +/- 0.2 days; p <0.0001). Postoperative stay for the pectoral group was shorter still (2.9 +/- 0.4 days; p <0.033). Total charges for the epicardial group were $99,081 +/- $25,094, significantly higher than those for any of the nonthoracotomy groups (p <0.017). Total charges for the pectoral group were $44,128 +/- $2,465, significantly less than those for the abdominal nonthoracotomy group, analyzed by intention to treat ($59,961 +/- $1,369; p <0.05) or by treatment received ($56,679 +/- $635; p <0.05). Cost reductions in the nonthoracotomy groups were primarily due to decreased in-hospital convalescence period, lower surgeon and anesthesiologist fees, and lower procedure-day hospital charges in the pectoral group. The use of ICDs with nonthoracotomy leads can result in significantly shorter in-hospital convalescence and a reduction in total implant-related charges of 40% to 55%. The use of pectorally implanted ICDs results in further reduction in hospital stay and further cost reduction of 22% to 26%. The trend toward shorter convalescent stay without postimplant testing is likely to reduce further the overall costs of ICD implantation.

Hospital readmission in patients treated with tiered-therapy implantable defibrillators

BACKGROUND

We wished to determine the incidence, reasons, costs, and predictors of cardiac-related hospital readmission in patients with tiered-therapy implantable defibrillators. Hospital readmission in patients with defibrillators reduces their quality of life and increases the cost associated with such therapy.

METHODS AND RESULTS

We retrospectively studied 65 consecutive local patients (median age, 67 years; median ejection fraction, 0.34) who underwent tiered-therapy defibrillator implantation at this institution. Patients were followed for a median of 19 months (interquartile range, 10 to 27 months). The cause, duration, costs, and predictors of cardiac-related rehospitalizations were analyzed. There were 76 cardiac admissions for 34 patients. The rate of cardiac-related hospital readmission was 0.72 per patient-year of follow-up. Arrhythmia-related admissions accounted for 43 of such admissions in 24 patients. Actuarial freedom from cardiac-related admissions was 0.57 and 0.40 at 1 and 2 years, respectively. The median length of stay for hospital readmissions was 5 days (interquartile range, 3 to 8 days). The median cost per admission was $5842 (interquartile range, $3549 to $12 170). The time to first readmission and the total rehospitalization time per year of follow-up were associated with a poor preimplant New York Heart Association functional class. Readmission for cardiac arrhythmias was not predicted by clinical parameters.

CONCLUSIONS

Rehospitalization for cardiac reasons is common in patients receiving implantable defibrillators and is responsible for substantial resource consumption. The need for readmission for arrhythmia-related reasons cannot be predicted by clinical parameters at the time of device implantation.

Cardiac electrophysiology: a cost-effective approach

Clinical cardiac electrophysiology is a relatively new discipline, heavily dependent upon new technology that is often expensive. In cardiac pacing, no effective alternative to permanent pacing usually exists for patients with Class I indications, so cost-reduction strategies involve appropriate selection and utilization of hardware and facilities. Cost-effective utilization of radiofrequency ablation and implantable cardioverter-defibrillators requires that these techniques be compared with alternative therapies, usually antiarrhythmic drugs. Both ablation and defibrillator implantation can be shown to be cost effective in selected populations, but a cost-conscious approach to procedures and patient selection can make them cost effective in a broad range of patients.

Cost-effectiveness of implantable defibrillator as first-choice therapy versus electrophysiologically guided, tiered strategy in postinfarct sudden death survivors. A randomized study

BACKGROUND

Rising costs of health care, partly as a result of costly therapeutic innovations, are of concern to both the medical profession and healthcare authorities. The implantable cardioverter-defibrillator (ICD) is still not remunerated by Dutch healthcare insurers. The aim of this study was to evaluate the cost-effectiveness of early implantation of the ICD in postinfarct sudden death survivors.

METHODS AND RESULTS

Sixty consecutive postinfarct survivors of cardiac arrest caused by ventricular tachycardia or fibrillation were randomly assigned either ICD as first choice (n = 29) or a tiered therapy starting with antiarrhythmic drugs and guided by electrophysiological (EP) testing (n = 31). Median follow-up was 729 days (range, 3 to 1675 days). Fifteen patients died, 4 in the early ICD group and 11 in the EP-guided strategy group (P = .07). For quantitative assessment, the cost-effectiveness ratio was calculated for both groups and expressed as median total costs per patient per day alive. Because effectiveness aspects other than mortality are not incorporated in this ratio, other factors related to quality of life were used as qualitative measures of cost-effectiveness. The cost-effectiveness ratios were $63 and $94 for the early ICD and EP-guided strategy groups, respectively, per patient per day alive. This amounts to a net cost-effectiveness of $11,315 per patient per year alive saved by early ICD implantation. Costs in the early ICD group were higher only during the first 3 months of follow-up, but as a result of the high proportion of therapy changes, including arrhythmia surgery and late ICD implantation, costs in the EP-guided strategy group became higher after that. Patients discharged with antiarrhythmic drugs as sole therapy had the lowest total costs. This subset, however, showed extremely high mortality, resulting in a poor cost-effectiveness ratio ($196 per day). Invasive therapies and hospitalization were the major contributors to costs. If quality-of-life measures are taken into account, the cost-effectiveness of early ICD implantation was even more favorable. Recurrent cardiac arrest and cardiac transplantation occurred in the EP-guided strategy group only, whereas exercise tolerance, total hospitalization duration, number of invasive procedures, and antiarrhythmic therapy changes were significantly in favor of early ICD implantation.

CONCLUSIONS

In terms of cost-effectiveness, early ICD implantation is superior to the EP-guided therapeutic strategy in postinfarct sudden death survivors.