The study, based on a pool of 272 participants, is the first to examine the rate of depression among these patients using the Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM IV), which is considered the gold-standard in evaluating depression.
"Because patients in the early stages of chronic kidney disease are at increased risk for clinical depression, we as nephrologists should consider screening our patients for depression in clinic," said Dr. Susan Hedayati, assistant professor of internal medicine at UT Southwestern and a staff nephrologist at the Dallas Veterans Affairs Medical Center. She is the lead author of the study, available online and in the current issue of the American Journal of Kidney Diseases.
Previous research has shown that depression rates in the general community are 2 percent to 4 percent; among diabetes patients, 11 percent; among congestive heart failure patients, 14 percent; and among coronary artery disease after heart attack patients, 16 percent.
"Chronic kidney disease patient depression numbers may be higher due to the presence of the same simultaneously occurring conditions that resulted in progressive kidney disease, such as diabetes and atherosclerotic vascular disease," Dr. Hedayati said. "Alternatively, patients such as diabetics, who are depressed, may develop progressive kidney disease because of non-adherence to medications and physicians' advice."
Earlier estimates of depression among chronic kidney disease patients were based on self-report depression scales that can emphasise symptoms such as lack of appetite, weight loss and fatigue. Such symptoms can overlap with other medical conditions, so
UT Southwestern researchers took a novel approach.
From May 2005 to November 2006, researchers invited patients at the Dallas VA Medical Center who were visiting the clinic for chronic kidney disease appointments to join the study. Patients who agreed to participate then underwent a structured clinical interview to determine if they had a current major depressive episode, based on the DSM IV definition of major depressive disorder.
Fifty-seven patients, or 21 percent, were found to be depressed. The mean age of depressed patients was about 65; two were women; and nearly 56 percent were white. All patients were veterans.
The researchers also found that diabetic patients were twice as likely to be depressed as those without diabetes; 63 percent of patients had at least three other medical conditions; and 41 percent had at least four other diseases.
Twenty-six million people in America have chronic kidney disease and millions more are at increased risk, according to the National Kidney Foundation. If treatment does not begin early, the condition progresses to end-stage renal disease. At that point, a patient's kidneys have failed to the point where dialysis - a filtering of toxic chemicals in the blood and removing fluid to help control blood pressure - or a kidney transplant is needed.
According to the U.S. Renal Data System Annual Report, expenditures for end-stage renal disease patients totalled $15.5 billion, which is approximately 6 percent of the entire Medicare budget, and are projected to consume $28 billion by 2010.
Dr. Hedayati is now conducting the Chronic Kidney Disease Antidepressant Sertraline Trial (CAST) to determine whether antidepressant medication would be tolerated in kidney-disease patients and whether such treatment can improve depression.
Other UT Southwestern researchers involved in this study were Dr. Abu Minhajuddin, assistant professor of clinical sciences; Dr. Robert Toto, professor of internal medicine and clinical sciences; and Dr. David Morris, assistant professor of psychiatry. Also involved in the study was Dr. A. John Rush, a former professor of clinical sciences and psychiatry at
UT Southwestern, now vice dean of Duke-NUS Graduate Medical School Singapore.
The study was funded by the Veterans Integrated Service Network 17, Veterans Affairs North Texas Health Care System Research Corporation, the National Institutes of Health and the UT Southwestern O'Brien Kidney Research Core Center.
Visit www.utsouthwestern.org/kidneys to learn more about clinical services at
UT Southwestern for kidney diseases. Visit www.utsouthwestern.org/mentalhealth to learn more about UT Southwestern's clinical services in psychiatry.