doi: 10.1161/01.CIR.0000153418.15271.99
(Circulation. 2005;111:e26.)
© 2005 American Heart Association, Inc.
Correspondence |
Letter Regarding Article by Bokhari et al, "Long-Term Comparison of the Implantable Cardioverter Defibrillator Versus Amiodarone: Eleven-Year Follow-Up of a Subset of Patients in the Canadian Implantable Defibrillator Study (CIDS)"
Institute of Cardiology, University of Bologna, Bologna, Italy
Since the implantable cardioverter defibrillator (ICD) was introduced into clinical practice, the prospect of its widespread use has been perceived as a financial threat by many healthcare systems.1,2 The interesting study by Bokhari et al3 of the long-term efficacy of ICDs in clinical practice has relevant economic implications that the authors did not discuss.
The follow-up periods reported for randomized trials on the efficacy of ICDs in secondary prevention of sudden death have been restricted previously to 3 to 5 years at most.1,4 The long-term follow-up study by Bokhari et al of Canadian Implantable Defibrillator Study (CIDS) patients at St. Michael’s Hospital in Toronto,3 who for the most part continued taking the treatment to which they were originally randomized, shows how the long-term efficacy at up to 11 years (mean 5.9 years) may be higher than at mid-term, with a reduction in the relative risk of mortality of 43%, as compared with 20% at 3 years in the original CIDS study.5 We calculate that such an increase in long-term efficacy would reduce the number needed to treat to save one life from 27 patients at 3 years to just 5 patients (at the long-term follow-up of the recent substudy). Such considerations suggest that modeling studies, in which long-term cost-effectiveness was estimated only from extrapolating the available data on ICD efficacy,4 may have been overly pessimistic because of an underestimation of ICD’s long-term efficacy.
Although long-term studies of randomized groups of patients such as that reported by Bokhari et al are unlikely to be replicated,3 long-term assessment of the efficacy and cost-effectiveness of ICDs should remain a priority, especially when viewed from the perspective of a wider use of ICDs for primary prevention of sudden death in patients with an expected long-term survival once sudden arrhythmic death has been prevented by the ICD. Valuable information on long-term efficacy and cost-effectiveness could also come from registries involving a large number of patients in primary and secondary prevention of sudden death.
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1. Boriani G, Biffi M, Martignani C, Gallina M, Branzi A. Cost-effectiveness of implantable cardioverter-defibrillators. Eur Heart J. 2001; 22: 990–996.
2. Boriani G, Biffi M, Martignani C, Camanini C, Grigioni F, Rapezzi C, Branzi A. Cardioverter-defibrillators after MADIT-II: the balance between weight of evidence and treatment costs. Eur J Heart Fail. 2003; 5: 419–425.[CrossRef][Medline] [Order article via Infotrieve]
3. Bokhari F, Newman D, Greene M, Korley V, Mangat I, Dorian P. Long-term comparison of the implantable cardioverter defibrillator versus amiodarone: eleven-year follow-up of a subset of patients in the Canadian Implantable Defibrillator Study (CIDS). Circulation. 2004; 110: 112–116.
4. Lynd LD, O’Brien BJ. Cost-effectiveness of the implantable cardioverter defibrillator: a review of current evidence. J Cardiovasc Electrophysiol. 2003; 14: S99–S103.[Medline] [Order article via Infotrieve]
5. Connolly SJ, Gent M, Roberts RS, Dorian P, Roy D, Sheldon RS, Mitchell LB, Green MS, Klein GJ, O’Brien B. Canadian Implantable Defibrillator Study (CIDS): a randomized trial of the implantable cardioverter defibrillator against amiodarone. Circulation. 2000; 101: 1297–1302.
Response
Terrence Donnelly Heart Center, Department of Medicine, St. Michael’s Hospital, Toronto, Ontario, Canada, dorianp{at}smh.toronto.on.ca
Boriani and colleagues provide interesting insight into the financial implications of defibrillator implantation for long-term prevention of sudden cardiac death. Although the efficacy of the implantable cardioverter defibrillator (ICD) to treat ventricular fibrillation is unquestionable, its application for the primary prevention of sudden cardiac death is currently under considerable scrutiny. The "upfront" costs associated with defibrillator implantation have raised the question of cost-effectiveness.
We agree that an optimal assessment of ICD cost efficacy requires long-term follow-up beyond the usual 3 to 5 years in most randomized trials. Boriani and colleagues suggest that the survival advantage in our study1 makes ICD implantation significantly more cost-effective by reducing the number of patients needed to treat to save one life. Given that current defibrillator life does not approach 11 years and more reasonably approximates 5 years, however, the cost of the device would have to be doubled during the follow-up to account for a minimum of 2 implantation procedures. Conversely, our data imply that the alternative to defibrillator implantation leads universally to either patient morbidity or mortality because of failure of, intolerance to, or inefficacy of amiodarone therapy.
In 2005, the major challenge is the application of the ICD in a primary prophylaxis environment, where patients who are deemed to be at high risk for sudden death receive an implanted defibrillator before the identification of sustained ventricular arrhythmias. In this patient population, as Boriani and colleagues suggest, cost-effectiveness is of the utmost importance because our ability to deliver this therapy to all potentially eligible patients is significantly limited. Further studies to elucidate the exact patient population that benefits most and ongoing efforts to make defibrillator technology less costly will be instrumental in optimizing the cost-effectiveness of this already "effective" therapy.
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1. Bokhari F, Newman D, Greene M, Korley V, Mangat I, Dorian P. Long-term comparison of the implantable cardioverter defibrillator versus amiodarone: eleven-year follow-up of a subset of patients in the Canadian Implantable Defibrillator Study (CIDS). Circulation. 2004; 110: 112–116.
Related Article:
Circulation 2005 111: 245.
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