In a 10-year study of more than a thousand kidney
failure patients, sudden cardiac death
emerged as the No. 1 cause of death for patients on
dialysis, according to a Johns Hopkins researcher.
The study, already published online and appearing in
the Nov. 2 issue of Kidney International,
identified systemic inflammatory response and malnutrition
as key risk factors for the fatal heart
"This is believed to be the first time anyone has
taken a rigorous prospective look at why so
many patients on dialysis die from sudden cardiac death,
and the results could help doctors identify
those at highest risk and potentially save lives," said
Rulan S. Parekh, associate professor in the
Department of Nephrology at the Johns Hopkins
University School of Medicine.
Parekh and her team gathered their data from a cohort
of 1,041 end-stage renal disease
patients on dialysis who were part of Choices for Healthy
Outcomes in Caring for ESRD, known as
CHOICE. In a 9.5-year period, 658 of this group died. The
largest number of these deaths, 146, was
the result of sudden cardiac death, or SDC — in this
case, unexpected deaths that occurred outside
the hospital setting.
The researchers then looked at previously recorded
blood test results from 122 of these 146
sudden cardiac death patients to search for a possible
relationship between the deaths and levels of
high-sensitivity C-reactive (hsCRP), interleukin-6 (IL-6)
and albumin. The proteins IL-6 and hsCRP are
both markers for widespread blood vessel and organ
inflammation, while low albumin levels are
associated with malnutrition.
Results showed that patients with high levels of
either hsCRP or IL-6 were twice as likely to die
from sudden cardiac death as those with low levels of these
proteins. Low albumin levels were
associated with a 1.35 times increase in the risk of dying
of sudden cardiac death when compared with
high levels, according to Parekh. In addition, those with
low levels of albumin and high levels of hsCRP
were four times more likely to die of sudden cardiac death
than those with high levels of albumin and
low levels of hsCRP.
"These results tell us that ESRD patients with low
albumin and/or high levels of IL-6 and hsCRP
are at a significantly higher risk of SCD," Parekh said.
The half-million people in the United States with ESRD
are 10 to 100 times more likely than the
general public to die from cardiovascular disease,
depending on age, according to Parekh. They have an
annual mortality rate of more than 20 percent, and
one-fifth of these deaths are attributed to
sudden cardiac death.
Systemic inflammatory response is common with ESRD
patients and occurs when the body
responds to an infectious or noninfectious attack. Parekh
said that because those with kidney failure
are quite ill, the chance of infection and chronic
inflammation is higher. Also common with ESRD
patients is malnutrition from the stress of kidney failure,
loss of appetite and a highly restricted diet;
compounding the issue, she said, is that Medicare does not
cover oral nutritional supplements.
"When people think of heart attacks, they think of
cholesterol and obesity," Parekh said, "but
these are risk factors for hardening of the arteries and
are not directly linked to sudden heart death
among patients on dialysis."
Other researchers from Johns Hopkins who contributed
to this study are Neil R. Powe, Josef
Coresh, Lucy A. Meoni, Bernard G. Jaar and Nancy E. Fink,
all of the School of Medicine; and Michael
J. Klag, W.H. Linda Kao and Laura C. Plantinga, all of the
Bloomberg School of Public Health.