Rec- ommendations are based on a body of evidence that includes the systematic review conducted by the ERC and are denoted by the superscript SR (eg, LOE: B-RSR ). Comorbidities included various combinations of renal disease, chronic obstructive pulmonary disease, atrial fibrillation, and heart disease, among others. Recommendation-Specific Supportive Text 1. Older age is defined as 75 years. The ERC s analyses are helpful in clearly demonstrat- ing that neither age nor comorbidities alone should be exclusions for an ICD. However, the data included in the analysis are limited. Firstly, most data are from non- randomized studies and both selection and uniden- tified confounding biases can never be fully adjusted for. It is likely that the more frail patients are already appropriately not offered ICDs and are thus not includ- ed. Secondly, because most of the studies are nonran- domized, these findings signify only an association and not causality. Also, older adults are prone to higher complication rates, shorter life expectancies (and thus, fewer years during which they could derive benefit from an ICD), and varying preferences.S10.3-2 For these reasons, it is important to take a particularly nuanced and patient- centered approach to treating these patients. 10.4. 