Diminishing proportional risk of sudden death with advancing age: implications for prevention of sudden death

BACKGROUND: Advances in primary and secondary prevention of sudden death have led to a wide array of potentially beneficial therapies. Identification of patients most likely to benefit would be of use when considering costly interventions such as an implantable defibrillator. We sought to determine the effect of advancing age on the mode of death in the Amiodarone Trialists Metanalysis. METHODS AND RESULTS: Patients (n = 6252; age, 61.2+/-10.5 years; 83% men) were included in an analysis of predictors of sudden death (SD) and all-cause death (ACD), based on baseline variables at enrollment. Patients were divided into 5 age groups: < or =50 years, 51 to 60 years, 61 to 70 years, 71 to 80 years, and >80 years. During a mean of 16.8+/-10.3 months of follow-up, there were 1023 deaths, with an annual overall mortality rate of 11.7%. Both sudden death and nonsudden death rates increased with age, although the increase of nonsudden death with age was more dramatic. The overall proportion of death that was sudden (SD/ACD ratio) was 0.41, falling from 0.51 before age 50 years to 0.26 after age 80 years (P =.002 for trend). The SD/ACD ratio was not affected by sex, New York Heart Association Class, or left ventricular ejection fraction. CONCLUSIONS: Although the incidence of sudden death increases with age, the proportion of death that is sudden diminishes markedly. This finding may influence the yield of interventions targeted at prevention of sudden death.