A simple blood test may be able to predict the likelihood that a patient with congestive heart failure will be readmitted to the hospital or die within a year of a hospital discharge, says a study published in the online issue of the American Journal of Cardiology. The inexpensive blood test, performed at admission and again at discharge, can help doctors make important decisions about care, and reduce the risk of costly readmissions.
Researchers examined heart failure patients on admission and discharge to determine levels of a certain protein (NT-proBNP) that's a marker for heart stress. They found that if a patient's levels decreased by less than 50% during their hospital stay, they were 57% more likely to be readmitted or to die within a year than those who experienced a larger drop.
The study group consisted of 241 patients admitted to Johns Hopkins Hospital in Baltimore for congestive heart failure between June 2006 and April 2007. They underwent the NT-proBNP test at admission, and the patients' doctors then treated their symptoms throughout the hospital stay. Researchers re-tested the protein level at discharge, and patients' treating physicians were not made aware of the level change. Researchers then followed up with hospital records, patient family interviews, and death records over the next 12 months.
Hospitals typically test CHF patients for this protein when they are admitted, but not when they are discharged. Instead, other clinical factors are relied upon to determine whether a patient is healthy enough for discharge. Physicians typically consider a patient's function, heart and lung sounds, and weight loss, among other factors.
Dr. Henry Michtalik, M.D., M.P.H. a clinical fellow in internal medicine and a hospitalist at Johns Hopkins Hospital, and lead researcher on the study, explained that physicians don't typically test NT-proBNP levels at discharge since the number alone may not be significant. A number that could be suspicious for one patient might be insignificant in another.
However, because the research looked at the percent change between the two numbers, doctors would be comparing how a patient is doing from the time of admission to the time of discharge.
"This test is a way to stratify who is at the highest risk of readmission or death," Dr. Michtalik said. "You could see a certain percent change and know that you need to be more aggressive at the outpatient setting, plugging the patient into resources sooner, or titrating the medication in a certain way."
Dr. Michalik was somewhat surprised by the study results. "It seemed like a simple concept to test the same marker at discharge. I can understand why there is hesitance since you don't want to treat to achieve a certain number, but it is a way to stratify," he said. He added that the blood test costs about $50, depending on the institution.
About 5 million people in the United States have congestive heart failure. CHF causes about 300,000 deaths in the United States each year. According to an article published last year in the Archives of Internal Medicine, the cost of treating CHF varies widely from hospital to hospital. Researchers found that the cost of treating a patient for CHF ranges from about $1,500 to about $18,000.
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