Care After Acute Kidney Injury Falls Short for Many

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Patients who survive an episode of acute kidney injury (AKI) and have persistently diminished kidney function are infrequently referred to a nephrologist, according to a recent study in the Journal of the American Society of Nephrology. The findings indicate that efforts are needed to identify and treat kidney injury patients who require subsequent care.

“This study is the first of its kind to demonstrate that patients who experience an acute decline in kidney function during hospitalization may not be receiving adequate attention paid to their future risk for developing kidney problems or its complications,” said Michael Matheny, MD, of the Vanderbilt University Medical Center and the Tennessee Valley Healthcare System Veterans Administration. “It also highlights an opportunity to improve communication between primary care providers and nephrologists to provide a more integrated approach in caring for the kidney health of these patients.”

The seriousness of AKI

AKI is increasingly common and often arises as a result of medical or surgical complications that deprive the kidneys of a normal blood flow for extended periods of time. This is why AKI is most common in people who are already hospitalized, particularly in critically ill patients who need intensive care.

The kidneys can often recover from AKI, and most patients can resume a normal life after treatment; however, they may remain at increased risk for various complications. Even mild injury, resulting in small changes in acute kidney function, can have significant short-term and long-term consequences.

For example, AKI is becoming increasingly recognized as an important determinant of incident chronic kidney disease, progression to ESRD, and long-term mortality. In fact, the current thinking regarding AKI is that it encompasses an entire spectrum of kidney disease, from its early onset as an injury, to its progressive loss of kidney function of increasing severity, to its development into kidney failure requiring renal replacement therapy.

Chronic kidney disease patients are especially susceptible to AKI, which in turn acts as a promoter of progression of the underlying disease. AKI is also possibly associated with an increased risk of nonkidney complications such as bleeding and sepsis as well as inflammatory effects on other organs.

As the interactions between AKI and these complications become better characterized, improving care for its survivors will depend on identifying high-risk individuals and implementing steps to prevent the progression of disease and its effects. One quality-of-care indicator for a patient with persistently diminished kidney function after an episode of AKI is the rate of nephrology referrals. When such a patient is not referred to a nephrologist, there is a missed opportunity to improve care for the patient.

Matheny, along with Edward Siew, MD, also of the Vanderbilt University Medical Center, and others examined the follow-up care received by patients who experienced AKI during hospitalization and whose information was available through a U.S. Department of Veterans Affairs database (which includes data from five Veterans Affairs medical centers in Tennessee, Kentucky, and West Virginia).

“The overarching goal of our research is to improve the care of patients with acute kidney injury. An important part of this goal is identifying what happens to these patients after leaving the hospital,” Matheny said. “As almost all will be discharged to the immediate care of their primary care physician, we wanted to see if there was a potential opportunity for nephrology-based care to make a positive impact.”

Post-AKI care

For their study, the researchers identified 3929 survivors of AKI who were hospitalized between January 2003 and December 2008 and who continued to have poor kidney function a month after their injury.

Over a 1-year surveillance period, 22 percent of patients died. Of the 1254 survivors with an initial baseline estimated GFR (eGFR) of at least 60 mL/min per 1.73 m2, 50.2 percent recovered to an eGFR of at least 60 mL/min per 1.73 m2 by the end of the 12-month surveillance period. The remainder demonstrated persistent kidney dysfunction. Among 1824 survivors with an initial baseline eGFR of less than 60 mL/min per 1.73 m2, 50.3 percent had a last eGFR of at least 45 mL/min per 1.73 m2, whereas the rest had lower kidney function.

“This research is an important contribution to the literature, as it highlights the course of patients who survived an episode of AKI by providing a detailed glimpse at clinical outcomes in the year following the initial event,” said Ron Wald, MD, an investigator at St. Michael’s Hospital in Toronto, who was not involved with the study but focuses much of his own research on AKI.

Only 8.5 percent of patients in the study were referred to a nephrologist before dying, starting dialysis, or experiencing an improvement in kidney function. Patients’ severity of AKI did not affect whether or not they were referred. Also, there were no statistically significant differences in race, sex, or rates of coronary artery disease, hypertension, or peripheral vascular disease among referred and nonreferred patients.

“The relatively small number of patients who were referred for nephrology consultation, even when post-AKI kidney function was impaired, may represent an important gap in the care of these patients,” Wald said.

Increasing awareness of the health risks that AKI patients face may lead to earlier and improved management of kidney-related complications.

Traditionally, physicians have not had a unified approach to categorize and treat AKI, but new guidelines being developed by Kidney Disease Improving Global Outcomes (KDIGO), an international program of the National Kidney Foundation, will soon be available and are meant to increase awareness about the prevention, recognition, and management of AKI (http://www.kdigo.org/clinical_practice_guidelines_3.php). The guidelines cover a range of topics: defining and diagnosing AKI, recognizing and modifying risk factors, and implementing treatment and follow-up. Such clinical guidelines should lead to improved outcomes and identify research questions to better understand, prevent, and manage AKI.

Study co-authors include Josh Peterson, MD, Adriana Hung, Theodore Speroff, PhD (Tennessee Valley Healthcare System Veterans Administration and Vanderbilt University Medical Center); Svetlana Eden, and T. Alp Ikizler, MD (Vanderbilt University Medical Center).