Dialysis patients diagnosed with depression are nearly twice as likely to be hospitalized or die within a year than those who are not depressed, a UT Southwestern Medical Center researcher has found.
In the study, available online and in the Sept. 15 issue of Kidney International, researchers monitored 98 dialysis patients for up to 14 months. More than a quarter of dialysis patients received a psychiatric diagnosis of some form of depression based on a Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM IV).
This is the first reported link between adverse clinical outcomes in dialysis patients and depression made through a formal psychiatric interview based on the DSM-IV standards. More than 80 percent of the depressed patients died or were hospitalized, compared with 43 percent of non-depressed patients. Cardiovascular events, which previously have been linked to depression, led to 20 percent of the hospitalizations.
"Twenty percent of patients who start dialysis will die by the end of the first year," said Dr. Susan Hedayati, assistant professor of internal medicine and the study's lead author. "What we don't know yet is, if their depression is treated, could it extend dialysis patients' survival and improve their quality of life."
Dr. Hedayati, a staff nephrologist at the Dallas Veterans Affairs Medical Center, said depression-like symptoms – such as loss of energy, poor appetite and sleep disturbances – are often observed in patients with chronic disease, so it is important to get a scientifically valid diagnosis for clinical depression.
Twenty-six million people in America have chronic kidney disease and more than 20 million are at increased risk, according to the National Kidney Foundation. End-stage renal disease occurs when the patients' kidneys have failed to the point where dialysis or a kidney transplant is needed. Dialysis filters toxic chemicals in the blood and helps control blood pressure. With hemodialysis, the kind investigated in this latest study, a filter functions as an artificial kidney to remove waste, extra chemicals and fluid from the body.
Coronary artery disease, congestive heart failure and diabetes are known co-morbidities for patients with end-stage renal disease. In this paper, with the addition of each co-morbidity, a dialysis patient was about 30 percent more likely to be hospitalized or die. If the patient had depression, however, the relationship was even stronger, with about a 100 percent increase in these dire outcomes, Dr. Hedayati said.
"Nephrologists don't have as much data showing that treating anemia or increasing the dose of dialysis will improve survival, and yet during our routine rounds with dialysis patients we intervene on those issues," Dr. Hedayati said. "Nephrologists don't usually ask patients about depression. Since depression is so prevalent and can negatively affect dialysis patients, we need to ask about it."
Depression is a treatable disease, so Dr. Hedayati hopes hospitalizations and deaths can be reduced with further research. Other large trials involving dialysis patients, including some that evaluated treatment of high cholesterol, using ACE-inhibitors or increasing the dose of dialysis, haven't been shown to make a significant difference in life expectancy or hospitalization, Dr. Hedayati said.
"Now that we know depression in dialysis patients is associated with adverse outcomes such as death and hospitalization, we need to take another step forward and figure out if treating it will make a difference in patient outcomes," Dr. Hedayati said.
Researchers from Duke University Medical Center, Veterans Affairs Medical Center in Durham, N.C., and George Washington University also participated in the study.
The study was supported by the Agency for Health Care, Research and Quality; the John A. Hartford Foundation; the Claude D. Pepper Older Americans Independence Center; and the VA.
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