Table 4. Comparison of trials regarding predictors for survival in the elderly.

Variable	Alba, et al.[31]	Koplan, et al.[32]	Ertel, et al.[33]	Mezu, et al.[34]
COPD: chronic obstructive pulmonary disease; GFR: glomerular filtration rate; ICD: implantable cardiac defibrillators; LVEF: left ventricular ejection fraction; PAD: peripheral arterial disease;
Time of publication	2013	2006	2010	2011
Type of study	Meta-analysis	Retrospective cohort study	Retrospective cohort study	Retrospective cohort study
Patient population	ICD-patients; heart failure	ICD-patients; > 80 yrs	ICD-patients; > 80 yrs	ICD-patients; > 80 yrs; heart failure
Total number of patients	257,692	107	225	99
Predictors of mortality	age, renal function, COPD, diabetes, PAD, LVEF, ICD intervention	LVEF, renal function	LVEF, no beta-blocker treatment	Age, GFR