Predicting Benefit for Implantable Cardioverter-Defibrillator UsePredicting Benefit for Implantable Cardioverter-Defibrillator UsePredicting Benefit for Implantable Cardioverter-Defibrillator Use

To the Editor: In her Editorial about disparities in the use of implantable cardioverter-defibrillators (ICDs), Dr Redberg¹ raised an important question about which Medicare beneficiaries will benefit from ICDs, an issue that concerns patients, policy makers, and ICD manufacturers. The question could be expanded to all individuals at risk of sudden cardiac death who might benefit from ICD implantation, not only Medicare patients. Therefore, the issue should be whether persons who are more likely to develop sudden cardiac death and benefit from ICD therapy as primary prevention can be identified or predicted.

Developing prediction models that better identify individuals at risk of sudden cardiac death is challenging for a number of reasons. It requires distinguishing individuals at higher risk for sudden cardiac death within a lower-risk general population. The subset of persons with sudden cardiac death (who could potentially benefit from ICD use) shares the same set of traditional risk factors with persons with coronary heart disease (who potentially could benefit from coronary revascularization rather than ICD).

In addition, meaningful risk stratification for sudden cardiac death should consider that the cost-effectiveness of ICD therapy might be lessened by consideration of nonsudden cardiac death and noncardiac death. Hence, analyzing the other modes of death at the same time as identifying specific sudden cardiac death predictors would be necessary to (1) confirm that other causes of death would not compete with and overcome the benefits gained from the ICD and (2) accurately identify specific sudden cardiac death predictors rather than those shared with predictors of the other modes of death (that could benefit from therapeutic strategies other than expensive ICD therapy). Individuals at high risk of sudden death but at low risk of nonsudden cardiac death or noncardiac death and with no correctable coronary heart disease would be the best candidates for ICD therapy.