RESUMO
Ageing is characterized by a progressive loss of complexity, which is an essential condition for making the organism capable of keeping homeostasis. Thus, senile loss of complexity makes old individuals frail: a syndrome characterized by the presence of shrinking (sarcopenia), weakness, poor endurance and energy, slowness, and low physical activity. Moreover, renal ageing progressively leads to a glomerular filtration rate (GFR) reduction, one of the main pharmacokinetic senile changes, which is not detectable by simply evaluating serum urea or creatinine values but measuring or calculating patient's GFR. Finally, current epidemiology has documented that detrimental social-behavioral factors such as low education level, poor financial-resource, depression, and isolation, also influence the onset and progression of chronic diseases, and even overall mortality, particularly in the elderly. Thus, we propose that these 3 variables: frailty phenotype, senile GFR, and detrimental social-behavioral factors, should be considered at time of prescribing drugs or medical procedures in the elderly. Additionally, they should also be considered for following patient's response to prescribed therapies in elderly patients suffering from chronic diseases (diabetes mellitus, chronic kidney disease, etc.), or on organ replacement treatments (dialysis and transplantation).