TUESDAY, June 14, 2011 (HealthDay News) -- Patients with early-stage chronic kidney disease are more likely to die if they have elevated levels of a certain hormone, a new study says.
Endocrine hormone fibroblast growth factor 23 (FGF-23) regulates phosphorus metabolism. It was known that levels of FGF-23 increase as kidney function declines and that high levels of the hormone are associated with increased risk of death in patients with kidney failure. But little was known about how elevated levels of FGF-23 affect outcomes of patients with early-stage chronic kidney disease.
This study looked at 3,879 patients with early-stage chronic kidney disease. During a median follow-up of 3.5 years, 266 of the patients died and 410 progressed to kidney failure. The researchers found that median FGF-23 levels were higher in these patients than in those who remained "event-free."
Patients with the highest levels of FGF-23 were 4.3 times more likely to die than those with the lowest levels, according to the study in the June 15 issue of the Journal of the American Medical Association.
The researchers said they were surprised to find that high FGF-23 levels were more strongly associated with death than other factors, including cardiovascular disease and chronic kidney disease-specific risk factors such as reduced estimated glomerular filtration rate (GFR, a measure of the kidney's ability to filter out and remove waste products) and proteinuria (excessive protein in the urine).
The reasons for the link between elevated FGF-23 levels and increased risk of death aren't known.
"If the results of the current study are confirmed and experimental studies support the hypothesis of direct toxicity of FGF-23, future research should evaluate whether therapeutic or preventative strategies that lower FGF-23 can improve outcomes," Dr. Tamara Isakova, of the University of Miami Miller School of Medicine, and colleagues said in a news release from the journal.
The American Academy of Family Physicians has more about chronic kidney disease.