[Decline in renal function in old age : Part of physiological aging versus age-related disease].

The incidence and prevalence of chronic renal disease (CKD) in elderly patients are continuously increasing worldwide. Loss of renal function is not only considered to be part of the aging process itself but also reflects the multimorbidity of many geriatric patients. Calculating the glomerular filtration rate using specific algorithms validated for the elderly population and measuring the amount of proteinuria allow an estimation of renal function in elderly patients with high accuracy. Chronic renal failure has many clinical consequences and not only results in a delayed excretion of toxins cleared by the kidneys but also affects hematogenesis, water and electrolyte balance as well as mineral bone metabolism. Furthermore, CKD directly leads to and aggravates geriatric syndromes and in particular the onset of frailty. Therapeutic strategies to halt progression of CKD not only comprise treatment of the underlying disease but also efficient blood pressure and diabetic control and the avoidance of nephrotoxic medications.