[Population screening for urinary protein loss: a sensible action]

In 2006, the Dutch Nierstichting (Kidney Foundation) provided people with urinary dipsticks to determine whether they suffered from urinary protein loss. It was suspected that 0.5% of adult inhabitants would have hidden renal disease. Within two weeks, more than one million people had applied to receive the dipsticks. They were advised to contact their general practitioner if they tested positive. Blockade of the renin-angiotensin-aldosterone system (RAAS) in subjects with known renal disease and proteinuria improves renal and cardiac survival. However, many patients currently develop end-stage renal disease without prior knowledge ofhaving chronic kidney disease. These patients can be detected by screening for proteinuria or albuminuria. Japanese studies showed that about 5% of the general population have positive dipstick tests. It is to be expected that about 1% will be truly macroalbuminuric and another 2-3% will be microalbuminuric. Macroalbuminuria is the consequence of manifest glomerular damage, while microalbuminuria is in most cases related to underlying diabetes or hypertension (which frequently are not yet diagnosed). In both conditions, treatment with RAAS blockade is indicated and is aimed at both cardiac and renal protection. There are arguments indicating that screening of the general population for urinary protein loss is cost-effective.