Before you begin, have you completed the first two modules in this series about renal theraputics?
Part one: Introduction to the kidney
Part two: Medicines and the kidney

Chronic kidney disease (CKD) describes abnormal kidney function and/or structure that has been present for more than three months. The criteria are as follows:

• Estimated glomerular filtration rate (eGFR) less than 60mL/min/1.73m2 (on at least two occasions, 90 days apart), or
• One or more markers of kidney damage.

These markers include:

• Albuminuria (presence of albumin (protein) in the urine)  with an albumin-to-creatinine ratio greater than 3mg/mmol
• Urine sediment abnormalities
• Haematuria
• Electrolyte abnormalities due to tubular disorders
• Renal histological (tissue) abnormalities
• Structural abnormalities detected by imaging, e.g. polycystic kidney disease, reflux nephropathy
• A history of kidney transplantation.

CKD is common, with an estimated one in 10 people living with CKD. Prevalence also increases dramatically with age. A 2014 Public Health England (PHE) report, stated that 1.9 per cent of people aged 64 and under had CKD stages three to five, compared to 13.5 per cent of those aged 65-74 and 32.7 per cent of those aged 75 and over. 

Black, Asian and minority ethnic communities are five times more likely to develop CKD than other groups. The prevalence of CKD stages three to five is higher in women at 7.4 per cent, compared to 4.7 per cent in men.