The clinical and cost-effectiveness of implantable cardioverter defibrillators: a systematic review

Abstract

To consider the clinical effectiveness and cost-effectiveness of implantable cardioverter defibrillators (ICDs) for arrhythmias. Electronic databases. Manufacturer submissions. A systematic review of the literature on clinical and cost-effectiveness was undertaken. The quality of selected randomised controlled trials (RCTs) was assessed using the Jadad criteria, and of selected systematic reviews using criteria developed by the NHS Centre for Reviews and Dissemination. Economic evaluations were quality assessed by their internal validity (i.e. the methods used) using a series of relevant questions, and external validity (i.e. generalisability of the economic study to the population of interest) by modified standard criteria. The clinical effectiveness and cost-effectiveness of ICDs for arrhythmias were synthesised through a narrative review with full tabulation of results of all included studies. Eight RCTs, two systematic reviews and a meta-analysis met the inclusion criteria of the review. The RCTs were of variable quality, with most trials having a Jadad quality score of 1/5 or 2/5, owing to the nature of comparing a device with drug therapy and the impossibility of double-blinding. The outcome measure of interest was mortality, which was reported as all-cause mortality in most trials and sudden cardiac death in some trials. Eleven economic evaluations of ICDs for arrhythmias were identified. None were shown to have high internal and external validity. One unpublished study relevant to the UK was identified. The evidence suggests that ICDs reduce mortality in patients with previous ventricular arrest or symptomatic sustained ventricular arrhythmias, in patients who have not had a previous sudden cardiac episode or previous ventricular arrhythmia but have reduced left ventricular function due to coronary artery disease with asymptomatic non-sustained ventricular arrhythmia and sustained tachycardia that could be induced electrophysiologically, and in some patients with severe left ventricular dysfunction (ejection fraction 30%) after myocardial infarction. QoL data are inconsistent but suggest that there is impaired QoL in patients who received numerous shocks from implanted devices. Studies show that ICDs improve survival compared with drug treatment, but with considerably increased cost. Incremental cost per life-year gained ranges from 27,000 US dollars to 213,543 Can dollars and incremental cost per quality-adjusted life-year from 71,700 US dollars to 558,000 US dollars in the published literature. The use of ICDs in the UK is increasing, but the technology is still under-utilised compared with other developed countries. Extending the current indications to patients with prior myocardial infarction and depressed heart function would impact on costs and service provision. Further research is needed on the risk stratification of patients in whom ICDs are most likely to be clinically and cost-effective. An evaluation of shock frequency on QoL is also required.