Relative and absolute risks of all-cause and cause-specific deaths attributable to atrial fibrillation in middle-aged and elderly community dwellers

Abstract

Background: The relative and absolute risks of outcomes other than all-cause death (ACD) attributable to atrial fibrillation (AF) stratified age have not been sufficiently investigated.

Methods: A prospective study of 23,634 community dwellers aged 40 years or older without organic cardiovascular disease (AF=335, non-AF=23,299) was conducted. Multivariate-adjusted rates, rate ratios (RRs) and excess deaths (EDs) for ACD, cardiovascular death (CVD) and non-cardiovascular death (non-CVD), and sex- and age-adjusted RR and ED in middle-aged (40 to 69) and elderly (70 years or older) for ACD, CVD, non-CVD, sudden cardiac death (SCD), stroke-related death (Str-D), neoplasm-related death (NPD), and infection-related death (IFD) attributable to AF were estimated using Poisson regression.

Results: Multivariate-adjusted analysis revealed that AF significantly increased the risk of ACD (RR [95% confidence interval]:1.70 [1.23-2.95]) and CVD (3.86 [2.38-6.27]), but not non-CVD. Age-stratified analysis revealed that AF increased the risk of Str-D in middle-aged (14.5 [4.77-44.3]) and elderly individuals (4.92 [1.91-12.7]), SCD in elderly individuals (3.21 [1.37-7.51]), and might increase the risk of IFD in elderly individuals (2.02 [0.80-4.65], p=0.098). The RR of CVD was higher in middle-aged versus elderly individuals (RRs, 6.19 vs. 3.57) but the absolute risk difference was larger in elderly individuals (EDs: 7.6 vs. 3.0 per 1000 person-years).

Conclusions: Larger absolute risk differences for ACD and CVD attributable to AF among elderly people indicate that the absolute burden of AF is higher in elderly versus middle-aged people despite the relatively small RR.

Keywords: Absolute risk difference; Atrial fibrillation; Cardiovascular death; Non-cardiovascular death; Relative risk; Sudden cardiac death.