Renal calcium, phosphorus, magnesium and uric acid handling: comparison between stage III chronic kidney disease patients and healthy oldest old

Introduction It is known that chronic kidney disease (CKD) and senescence bring about a progressive reduction in glomerular filtration rate (GFR) and that in the former this is usually associated with an increase in the fractional excretion of calcium, phosphorus, magnesium, and uric acid. However, it has not yet been explained how these substances are excreted in the healthy oldest old. Thus, in the present study, we examined the renal handling of these substances in very aged people in comparison with CKD patients with similar GFR levels (stage III—CKD).