Kidney marker for death risk in elderly

Reported by Susan Aldridge, PhD, medical journalist

A new marker of kidney function called cystatin C is a good predictor of mortality risk among the elderly.
Among older adults, reduced kidney function is often a strong factor in reduced life expectancy. Generally, levels of a substance called creatinine are used to evaluate kidney function, but results are often affected by other factors. So serum creatinine is not necessarily the best indicator of mortality risk. Researchers at the University of California may have come up with a better 'marker' of kidney function.

They describe the relationship between a substance called cystatin C and mortality in a group of over 3,000 adults. The participants were aged 70 to 79 and were followed up for six years. Mortality rates increased from 1.7 per cent per year for those in the lowest fifth of cystatin C levels to 5.4 per cent per year for those in the top fifth.

The benefit of cystatin C is that levels are independent of other factors and are strongly linked to mortality. Other work has suggested that cystatin C is also a strong predictor of heart attacks. More research is needed to see how having a high cystatin C level can be addressed.

Source
Journal of the American Society of Nephrology online 2nd November 2005