PARIS—Short-term changes in estimated glomerular filtration rate (GFR) that exceed 25% are associated with an increased risk of death in patients with or without chronic kidney disease (CKD), British investigators reported at the 49^th Congress of the European Renal Association-European Dialysis and Transplant Association.  

“Lots of patients seen in primary care undergo repeat measurements—probably more than one or two measurements a year—of their kidney function, and primary care doctors haven't necessarily known what the results mean,” Christopher Farmer, MD, renal consultant at East Kent University Hospitals NHS Foundation Trust, said.  “What we are really saying is that individuals who have changes in their kidney function over the course of a year actually do worse and probably warrant tighter follow-up in the short-term than those who don't have changes in their kidney function. Tighter follow-up may involve more frequent blood tests or screening patients for other possible predictors of mortality.” 

Dr. Farmer and his colleagues examined the relationship between short-term changes in kidney function and mortality in 29,156 adults who had at least two serum creatinine estimations over a 12-month period with an interval of at least six months between measurements. Subjects were identified from primary care databases in Kent from 2004 to 2008.

The study was undertaken to determine whether data from an earlier province-wide registry in Alberta, Canada, could be replicated in a primary care setting in the United Kingdom. In addition to a link between short-term changes in kidney function and mortality, the Canadian analysis showed that short-term changes in kidney function predicted progression of kidney disease.

In the U.K. study, the researchers determined confirmed reductions in kidney function based on a percentage change in kidney function and change in CKD stage.

Results showed that individuals who had a 25% or greater increase or decrease in their GFR over one year with a change in CKD stage had a significant three times increased risk of dying as individuals with the same baseline CKD but no short-term changes in kidney function.

The study also found a trend towards short-term changes in kidney function and worsening kidney disease.

“The point is that wherever you are …and certainly in Europe, the States, and in the developed world, somewhere in the region of 30% of the whole population have had tests of kidney function,” study co-investigator Paul Stevens, MD, also a renal consultant at East Kent University Hospitals NHS Foundation Trust, commented. “And a significant portion of them will have repeated tests of kidney function which currently aren't used to predict what will happen to them in the future as the tests may be done in order to monitor their diabetes or hypertension. Our study found that short-term changes in kidney function in either direction—either an improvement or deterioration in kidney function—are significant in terms of predicting subsequent mortality. The finding is part of our ongoing effort to better define progression of kidney disease for physicians to use in their everyday practice.”

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