“…Six studies [14,19,24,37,39,41] based their criteria of frailty, at least in part, on functional limitation degree as measured by activities of daily living (ADL) and instrumental activities of daily living; disability in executing ADLs was the principal criteria for two of them [39,41]. Performance in some functional fitness tests was the most utilized criteria to define frailty, being present in at least 19 articles [14, 15, 19-28, 31-34, 36, 37, 40], while physiological measures were found to characterize frailty in nine studies [14,19,20,22,25,26,[34][35][36] and fall-related aspects in six studies [24,28,[31][32][33]38]. Nutritional status and metabolic aspects contributed to define a frail elderly population in six articles [16-18, 20, 29, 38], and a low physical activity level participated in ten definitions [16-18, 20, 22, 25, 26, 29, 34, 36].…”