Protein loss in urine predicts effectiveness of hypertension medication

Cornelis Boersma, pharmacist and PhD student at the University of Groningen, has analysed the medical data of over 8,500 Groningers and discovered that preventive measures work better if the amount of protein loss is higher. This has important consequences for future prevention programmes. The results of this research were published on 30 January 2008 in the British Journal of Clinical Pharmacology.

The kidneys filter urea from the blood. This occurs in the millions of capillaries (very thin blood vessels) which make up a kidney. If the filtering does not work properly, protein is released into the urine – an indication that the capillaries are not functioning properly. At the same time, this can be a sign that the rest of the blood vessels in the body are not functioning properly either.

PREVEND study
The PREVEND study was set up in order to investigate whether people with protein loss in the urine have an increased risk of kidney and cardiovascular diseases (PREVEND = Prevention of REnal and Vascular ENd-stage Disease). To this end, over 8,500 Groningers submitted urine in 1997 and the protein levels in these samples were carefully measured in the laboratory. The Groningers were then tracked for years, particularly concerning their medicine use and the occurrence of cardiovascular disease.
ACE inhibitor
A recent analysis of the Groningen data by Cornelis Boersma has revealed that people with high blood pressure only have an increased risk of cardiovascular disease if they also have protein loss in the urine. What is more important is the discovery that the effectiveness of antihypertensives depends on the level of protein loss in the urine: the greater the protein loss, the more effective the hypertension medications are against cardiovascular disease. A GP has to treat 111 people with hypertension in order to prevent 1 instance of stroke or heart attack if there is no protein loss, but only 8 if there is protein loss. In addition, these new data suggest that – if you want to prevent cardiovascular disease – the best medication for people with more protein loss is perhaps a so-called ACE inhibitor (a specific antihypertensive).
Screening
These results will have important consequences for any large-scale prevention programme: by screening for albuminuria, people with hypertension, and thus a greater risk of cardiovascular disease, can be more quickly identified. In addition, it is now possible to determine which people can best be prescribed antihypertensives. In such a prevention programme, for example, people's urine could be tested in a laboratory once every four years and when anomalous values are discovered medication can be prescribed. The researchers now want to investigate which would be the most beneficial and cost-effective screening programme for which groups of people.