JOHNS HOPKINS (US) — A simple, 10-minute bedside exam can predict which kidney transplant patients are most likely to do well with a new organ.
A report in the journal Archives of Surgery suggests that a recently developed “frailty” test—typically used with elderly patients—is actually a useful tool for evaluating kidney transplant candidates of all ages.
“Few current measures are accurate in predicting kidney transplant success, but we think we have identified one that works incredibly well,” says study leader Dorry L. Segev, associate professor of surgery at the Johns Hopkins University School of Medicine.
“A few years ago, we showed that a frailty score is a simple, yet powerful, bedside tool to predict surgical outcomes in elderly patients, and now it seems it can do that same for younger patients with chronic diseases like kidney failure.”
Knowing which transplant patients are frail enables a surgeon to consider steps to compensate for the condition, Segev says.
Frailty, the surgeon says, is best defined medically as a low level of physiologic reserve and reduced ability to withstand stress to the body. It is measured using a five-point scale developed at Johns Hopkins.
Patients are classified as frail if they meet three or more of the following criteria: shrinking, or unintentional weight loss; weakness, as measured by grip strength; exhaustion; reduced physical activity; and slowed walking speed.
Segev and his team assessed 183 patients prior to kidney transplant between December 2008 and April 2010. Twenty-five percent met the criteria for frailty, three times the level of frailty found in elderly adults who live at home.
Frail kidney transplant patients were nearly twice as likely to have early problems with their new organs, a sign that their new kidneys would be more likely to fail in the future. This increased risk of a poor outcome, Segev says, occurred regardless of the age of the transplant recipient.
The team used delayed graft function (DGF)—meaning a non-functioning organ within the first week after transplant—as its marker for risk of longer-term concerns. Although a DGF kidney may recover and work eventually, Segev says, it is unlikely to work for as long as a kidney that begins working more quickly in its new body. Researchers found delayed graft function in 30 percent of the patients deemed frail and in just 15 percent of those who were not.
“This information tells us how long the kidney will likely last and how to best treat the patient,” he says. “Our ability to predict delayed function of a new kidney should help overcome one of the biggest barriers to improving outcomes in transplant right now.”
Segev says accurate predictions can help guide clinical decisions, such as ensuring that frail patients receive organs at least risk of delayed graft function. For example, risk of DGF increases when a kidney is outside a body longer on its way from donor to recipient.
Segev says a kidney coming from across the country might not be the best kidney for a frail patient, since it would less likely to function quickly and thereby more likely to have problems down the road.
The link between frailty and chronic kidney disease may lie in certain markers typically associated with inflammation, Segev says. As some people age, such genes and proteins are expressed at higher levels.
Frailty, typically found in at least some measure in the elderly, appears to occur in younger kidney patients undergoing dialysis as well. Those who are classified as more frail, young or old, seem to also have a risk of developing inflammation in the new transplanted kidney, which can lead to poor outcomes.
“We have found similarities between what makes people age and what makes dialysis patients sick,” Segev says. “But what makes people frail in the first place and what part of frailty affects the kidneys are the questions we have yet to answer.”
The Doris Duke Charitable Foundation funded the study.
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