Chronic kidney disease — a refresher

摘要

CHRONIC kidney disease (CKD) affects 5-10 per cent of people in the UK and the incidence is predicted to rise in coming years as the elderly population and the number of people with diabetes and hypertension increases. The kidney is involved in a wide variety of functions and when it begins to fail, a number of problems can result. Each problem can be at least partially managed with dietary interventions or drugs and this article aims to refresh your knowledge in this area. Kidney function can be expressed as glomerular filtration rate (GFR), the volume of blood filtered at the glomeruli each minute, usually standardised for surface area. A "normal" GFR is about 100rnl/min/1.73m2. It falls slowly to about half this in old age. CKD is categorised by a sustained reduction in GFR although it is not diagnosed in the absence of other signs until GFR is below 60ml/min/1.73m~2 (when the patient is said to be in stage 3 CKD). In fact, because of the spare capacity of the kidneys, few symptoms may manifest until GFR is well below this, meaning patients often only present late in the course of the disease. The Panel on p86 recaps on the stages of CKD and estimation of renal function.