Much Higher Rate of Untreated Kidney Failure Found Among Older People
Incidence of advanced kidney disease in the elderly may be substantially underestimated by rates of treated kidney failure
June 19, 2012 - A study involving
almost 2 million adults in Canada to determine whether age is associated with the
likelihood of treatment for kidney failure found the rate of progression to untreated kidney failure was considerably higher among older
adults – the elderly in particular.
In the report to be published in the June 20 issue of the Journal of the American Medical Association (JAMA), the
study authors explain what led to their study.
“Studies of the association among age, kidney function, and clinical outcomes have reported that elderly patients are
less likely to develop end-stage renal disease (ESRD), compared with younger patients, and are more likely to die than to progress to kidney
failure, even at the lowest levels of estimated glomerular filtration rate (eGFR; flow rate of filtered fluid through a kidney),” they explain
in the article.
Previous studies have defined kidney failure as those receiving long-term dialysis, which reflects both disease
progression and a treatment decision.
“Because it is plausible that the likelihood of initiating long-term dialysis among individuals with kidney failure
varies by age, earlier studies may provide an incomplete picture of the burden of advanced kidney disease in older adults, based on the
incidence of long-term dialysis alone,” the researchers wrote.
The study to determine whether age is associated with the likelihood of treated kidney failure (renal replacement
therapy: receipt of long-term dialysis or kidney transplantation), untreated kidney failure, and all-cause mortality, was conducted by Brenda
R. Hemmelgarn, M.D., Ph.D., of the University of Calgary, Alberta, Canada, and colleagues.
The study included 1,816,824 adults in Alberta, Canada, who had outpatient eGFR measured between May 2002 and March 2008,
with a baseline eGFR of 15 mL/min/1.73 m2 or higher and who did not require renal replacement therapy at the beginning of the study.
The primary outcome measures for the study were adjusted rates of treated kidney failure, untreated kidney failure
(progression to eGFR <15 mL/min/1.73 m2 without renal replacement therapy), and death.
During a median (midpoint) follow-up of 4.4 years,
● 97,451 (5.4 percent) of study participants died,
● 3,295 (0.18 percent) developed treated kidney failure, and
● 3,116 (0.17 percent) developed untreated kidney failure.
The researchers found that within each eGFR stratum, adjusted rates of death increased with increasing age.
Also, within each eGFR stratum, rates of treated kidney failure were consistently higher among the youngest age group.
“For example, in the lowest eGFR stratum (15-29 mL/min/1.73 m2), adjusted rates of treated kidney failure were more than 10-fold higher among
the youngest (18-44 years) compared with the oldest (85 years or older) groups,” the authors write.
The opposite results were evident for untreated kidney failure. The risk of untreated kidney failure increased with lower
vs. higher eGFR categories, and this association was stronger with increasing age.
“For the lowest eGFR stratum (15-29 mL/min/1.73 m2), adjusted rates of untreated kidney failure were more than 5-fold
higher among the oldest age stratum (85 years or older) compared with the youngest age stratum (18-44 years).”
Rates of kidney failure overall (treated and untreated combined) demonstrated less variation across age groups.
The researchers write that their results suggest that the incidence of advanced kidney disease in the elderly may be
substantially underestimated by rates of treated kidney failure alone.
“These findings have important implications for clinical practice and decision making; coupled with the finding that many
older adults with advanced chronic kidney disease [CKD] are not adequately prepared for dialysis, these results suggest a need to prioritize
the assessment and recognition of CKD progression among older adults.
“Our findings also imply that clinicians should offer dialysis to older adults who are likely to benefit from it - and
should offer a positive alternative to dialysis in the form of conservative management (including end-of-life care when appropriate) for
patients who are unlikely to benefit from (or prefer not to receive) long-term dialysis.
“Given the large number of older adults with severe CKD, these results also highlight the need for more proactive
identification of older adults with CKD, assessment of their symptom burden, and development of appropriate management strategies.
“Finally, our study demonstrates the need to better understand the clinical significance of untreated kidney failure, the
factors that influence dialysis initiation decisions in older adults, and the importance of a shared decision making process for older adults
with advanced CKD.”
Editorial: This debate can no longer be avoided
This important scientific and ethical debate can no longer be avoided, for both individual and societal good,” write
Manjula Kurella Tamura, M.D., M.P.H., and Wolfgang C. Winkelmayer, M.D., M.P.H., Sc.D., of the Stanford University School of Medicine in an
editorial. Dr. Winkelmayer is also Contributing Editor of JAMA
They note that the study “highlights a potentially sizeable unmeasured burden of untreated kidney failure among older
And, they add, “It is of paramount importance to refine the current understanding of what constitutes appropriate
treatment for kidney failure, which factors influence the decision-making process, and which methods are optimal for aligning treatment plans
with patient goals and prognosis. Finding the right balance between overtreatment and undertreatment is challenging but necessary.”
What Your Kidneys Do
have two kidneys. They are bean-shaped, and
about the size of a fist. They are located in
the middle of your back, on the left and right
sides of your spine, just below your rib cage.
Their main job is to filter extra water and
wastes out of your blood and make urine. They
also help control blood pressure and make
hormones that your body needs to stay healthy.
disease - called kidney disease here for short - is a condition
in which the small blood vessels in the kidneys are damaged,
making the kidneys unable to do their job. Waste then builds
up in the blood, harming the body.
disease is most often caused by diabetes or high blood
Diabetes and high blood pressure damage the blood vessels in
the kidneys, so the kidneys are not able to filter the blood
as well as they used to. Usually this damage happens slowly,
over many years. As more and more blood vessels are damaged,
the kidneys eventually stop working.
factors for kidney disease are cardiovascular (heart)
disease and a family history of kidney failure. If you have
any of these risk factors, you should get tested for kidney
kidney disease has no symptoms
That means you can’t feel that you have it. In fact, you
might feel just fine until your kidneys have almost stopped
working. Don’t wait for symptoms. Blood and urine tests are
the only way to know if you have kidney disease. A blood
test measures your GFR and a urine test checks for protein.
Learn more about tests for kidney disease.
disease can be treated if detected early.
The right treatment can help prevent further kidney damage
and slow down kidney disease. The earlier kidney disease is
found, the sooner you can take medications, called ACE
inhibitors or ARBs, and other steps that can keep your
kidneys healthy longer.
Learn more about how to keep your kidneys healthy.
disease is progressive.
Kidney disease does not go away. Instead, it usually gets
worse over time. Kidney disease can turn into kidney
failure, at which point dialysis or a kidney transplant is
needed. Kidney disease can also lead to heart disease.
Learn more about what happens if your kidneys fail.
the first step
If you are at risk, get your blood and urine checked for
is an initiative of the National Institute of Diabetes and
Digestive and Kidney Diseases (NIDDK), National Institutes
of Health (NIH), U.S. Department of Health & Human Services
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