Ask the Doctor
Questions about kidney disease? Risk factors? Signs and symptoms? Are you concerned about yourself, a friend or family member? Ask Dr. Spry.
New York, NY (March 21, 2013) – Pee in a cup and you might get a clue as to how much longer you will live. A new report published online today in the National Kidney Foundation's American Journal of Kidney Diseases shows a strong correlation between levels of protein in the urine, or proteinuria, and mortality.
"Our report shows that both men and women with higher levels of proteinuria had substantially reduced life expectancy in comparison to people with relatively low levels of proteinuria," said the report's lead author, Dr. Tanvir Chowdhury Turin of the University of Calgary.
According to the National Kidney Foundation, healthy people have very little protein in the urine since the kidneys act as filters to keep protein in the body. Proteinuria is an early indication that the kidneys have been damaged in some way, allowing protein to leak out.
The study analysis was based on lab values from over 810,000 patients in Alberta, Canada who had undergone proteinuria testing in an outpatient setting.
Across the board, results showed that mild or heavy amounts of proteinuria was tied to shorter life spans in men and women between 30 and 85 years of age. For example, the life expectancies of 40-year-old men and women with no proteinuria were 15.2 and 17.4 years longer, respectively, than those with heavy proteinuria. Proteinuria-free men and women also outlived those with mild proteinuria by 8.2 years and 10.5 years, respectively.
"There is a striking reduction in life expectancy associated with the severity of proteinuria," said Dr. Turin. "We already know that severity of chronic kidney disease is associated with increased risk of adverse outcomes including mortality risk, but the effect of proteinuria on life expectancy has not been estimated before."
"The patients in this study did not have end-stage kidney failure, but there was some reason why proteinuria testing was considered appropriate for each individual," said Dr. Turin. "The correlation can be extrapolated across Canada or the U.S. among similar patient populations."
Importance of Screening
Proteinuria levels could be a barometer for a patient's wellbeing and life expectancy, especially for those at risk of kidney disease. According to Thomas Manley, Director of Scientific Activities for the National Kidney Foundation, the report sends a clear message that screening for proteinuria can help prolong lives.
"This report makes it easier to understand and communicate the importance of urine testing to patients, health providers, and policy makers." he said. "Given that proteinuria is a key marker of adverse outcomes, strategies for improving the identification of patients with proteinuria should become a priority among physicians."
"Recent studies on current practice indicate that primary care physicians could more routinely use inexpensive readily available testing for protein in the urine, for people at risk for kidney disease," said Joseph Vassalotti, MD, National Kidney Foundation Chief Medical Officer. "It is our goal to encourage primary care physicians to screen all those with diabetes, high blood pressure and a family history of kidney failure,"
Proteinuria Facts from the National Kidney Foundation:
The National Kidney Foundation (NKF) is the leading organization in the U.S. dedicated to the awareness, prevention and treatment of kidney disease for hundreds of thousands of healthcare professionals, millions of patients and tens of millions of Americans at risk. For more information, visit www.kidney.org