Old age and the kidney
Advancing age is often associated with a slow reduction in GFR (glomerular filtration rate), but also with a reduction in muscle mass, so that there is little change in serum creatinine. In the frail elderly, significant renal impairment can therefore be concealed by normal or slightly high serum creatinine levels. eGFR reporting has led to much greater recognition of subclinical CKD in the elderly. The fall in average GFR with age is probably not ‘normal’; it probably reflects increasing incidence of diseases affecting the kidney. In developed societies, vascular disease is probably a major contributor.
Rise in incidence of ESRF
The rate of ESRF rises dramatically with age, mainly through an increase (in the developed world) in renovascular disease/ atherosclerosis, and in ‘etiology unknown’. However some important reversible causes of renal failure are particularly common in the elderly, including:
Old age itself is not a bar to doing well on dialysis, though the very elderly are usually excluded from transplantation because of increased risk of the procedure and of immunosuppression. Survival on dialysis is adversely affected by age, and also by comorbid disease, so that the prognosis for elderly patients with two major comorbid conditions (e.g. diabetes and peripheral vascular disease) may be relatively short. Such patients often tolerate dialysis poorly and so may elect to have conservative care.