Implantable cardioverter defibrillators: arrhythmias. A rapid and systematic review.

PROPOSED SERVICE: The service proposed is the use of implantable cardioverter defibrillators (ICDs) in the management of risk factors leading to sudden cardiac death (SCD). ICDs are similar in size to a pacemaker and are intended to prevent death due to life-threatening ventricular tachyarrhythmias. EPIDEMIOLOGY AND BACKGROUND: SCD occurs in approximately 100, 000 people annually in the UK and is usually due to ventricular tachyarrhythmia. Increasing numbers of people are surviving a first episode of ventricular tachyarrhythmia and are at high risk of further episodes. Standard treatments for those at high risk have been anti-arrhythmic drugs, catheter ablation or surgery and, increasingly, vasodilating beta-blockers. METHODS: Electronic databases were searched for the period 1980-99. In addition, bibliographies of related papers were assessed for relevant studies, and experts were contacted to identify additional published and unpublished references. Studies were included if they were systematic reviews, meta-analyses or randomised controlled trials (RCTs) comparing ICDs with conventional therapy in people at high risk of SCD. NUMBER AND QUALITY OF STUDIES AND DIRECTION OF EVIDENCE: Seven RCTs on effectiveness the majority of which were of good quality, eight cost-effectiveness analyses most of which were older studies and based on non-UK data, and two good-quality literature reviews one of which was a critical appraisal of the literature of effectiveness and cost-effectiveness of ICD therapy, and the other a review of the cost-effectiveness of ICD therapy. These showed changes in absolute risk of total mortality ranging from an increase of 1. 7% to a reduction of 22. 8% (relative risk reductions of -7% to +54%). SUMMARY OF BENEFITS: Estimated benefits from RCT data are 0. 23-0. 8 additional years of life with ICD therapy compared with anti-arrhythmic drug therapy. COSTS: Unit cost of ICDs (based on 1999/2000 prices), ranges from pound 12, 500 to pound 22, 000. Total discounted costs for 3 years range from pound 20, 000 to pound 29, 000. COST-EFFECTIVENESS: Cost-effectiveness estimates in the literature identified range from 11, 000 to 146, 000 per life-year saved. Using UK cost data from three hospitals and trial survival data from one RCT, the estimate of cost-effectiveness from this review ranges between pound 20, 250 and pound 87, 000 per life-year saved. COST-UTILITY: Cost per quality-adjusted life-year is estimated by the authors of this review at pound 21, 300 to pound 108, 800 (using survival data from one trial and quality-of-life indices derived from clinical opinion). These figures remain speculative until quality-of-life data from ongoing trials are available to inform future UK cost-effectiveness/utility analyses. IMPLICATIONS: If implemented for indications supported by evidence from RCTs, ICDs may cost the NHS in excess of pound 24 million per annum. FUTURE RESEARCH: Future research should include the use of British Pacing and Electrophysiological Group registries to assess the use of different types of ICD and current service provision.