Risk of kidney failure easier to predict

A new method helps to better measure renal function. This means that a better estimate can be made of the risk of kidney failure and death due to cardiovascular disease. The new method is more reliable in people with very little muscle mass, such as the elderly and people with chronic diseases, and people who eat very little meat, such as vegetarians. The results are part of a large international research project headed by UMCG nephrologist Dr Ron Gansevoort and were published on 5 September in the New England Journal of Medicine.

Worldwide, about 10% of the population are confronted by reduced renal function that could lead to kidney failure and death due to cardiovascular disease. Gansevoort: ‘The earlier and more reliably the reduction in renal function can be estimated, the more targeted the treatment can be, thus, for example, avoiding the need for dialysis.’

Stable

Kidney patients are used to their renal function being determined by measuring the amount of creatinine in their blood. ‘Creatinine is a waste product of muscle cells and the body can only get rid of it if the kidneys excrete it in urine. The higher the creatinine levels in the blood, the poorer the kidneys are working’, explains Gansevoort. ‘We know that the creatinine method is not as reliable in people with very little muscle mass, like the elderly and people with chronic diseases. The new method measures the amount of a different substance in the blood, cystatin C. This is a waste product produced by every cell in the body and the amount of it in the blood is much more stable than for creatinine.’

PREVEND

The researchers have for the first time proved convincingly that the new method is a better predictor of kidney failure and death from cardiovascular disease. They combined the data from 11 population studies conducted in Europe, the US and Australia. The Dutch data concerned 8,000 people taking part in the Groningen PREVEND project. All of the studies conducted their measurements in the same way, so that comparisons between the predictive value of creatinine and crystatin C were possible.

Costs

‘Before you can introduce a new test as the standard, you have to know whether the substance is a good measurement of renal function and whether it is a good risk predictor. The latter is what we have convincingly demonstrated. However, the new test does cost more’, says Gansevoort. ‘Measuring cystatin C is currently advised as an additional test for people with a slightly disrupted renal function revealed by the creatinine measurement as a way to get a more reliable estimate of their prognosis. Our results may mean that the test becomes cheaper because it will be more in demand. Hopefully what will follow is implementation for all patients with renal function disorders.’