Table 3.

Age at the time of ICD implantation and long-term mortality by cause of death

Age at the time of ICD implantation (years)	n	Events/100 person-years (no. of events)	Unadjusted models		Multivariable-adjusted modelsa
			Hazard ratiob (95% CI)	P-value	Hazard ratiob (95% CI)	P-value
Cardiac mortality
<65	248	1.8 (19)	Reference group	—	Reference group	—
65–75	135	4.7 (25)	2.6 (1.5–4.8)	0.001	3.1 (1.6–6.1)	0.001
>75	119	7.3 (27)	4.1 (2.3–7.4)	<0.001	4.1 (2.1–8.0)	<0.001
Non-cardiac mortality
<65	248	0.9 (10)	Reference group	—	Reference group	—
65–75	135	1.9 (10)	2.0 (0.8–4.9)	0.11	1.9 (0.7–5.1)	0.22
>75	119	4.9 (18)	5.3 (2.5–11.6)	<0.001	5.1 (2.0–12.8)	<0.001

CI, confidence interval.

^aAdjusted for sex, prior sudden cardiac death, ICD implantation indication, history of congestive heart failure, left ventricular ejection fraction≤35%, ischaemic cardiomyopathy diagnosis, prior coronary revascularization, renal disease, stroke, hypertension, dyslipidaemia, history of cigarette smoking, history of malignancy, diabetes mellitus, and chronic obstructive pulmonary disease.

^bUsing Wald tests to assess the overall associations, age was strongly associated with cardiac mortality in unadjusted (P < 0.001) and adjusted models (P < 0.001) and non-cardiac mortality in unadjusted (P < 0.001) and adjusted models (P = 0.001).