(Reuters Health) - Frailty and brain health should be taken into account when determining whether patients should have a defibrillator implanted in their chest, suggests a new study.

More than 20 percent of patients with frailty or dementia died within a year of getting defibrillators, which means they likely didn't benefit from the devices, researchers found.

"If someone has a 20 percent risk of dying in one year, we’re not sure if they’ll benefit from a defibrillator," said lead author Dr. Ariel Green, of Johns Hopkins University in Baltimore.

Implantable cardioverter-defibrillators, or ICDs, are placed under the skin and attached to the heart. The devices use shocks to restore normal heartbeats in people known to have life-threatening irregular rhythms that could result in sudden death.

ICDs are not the same as pacemakers, which can't deliver the same kind of high-energy shocks to the heart. Shocks from an ICD, by contrast, can feel like a kick in the chest.

Over 140,000 ICDs are implanted in the U.S. each year, and about 40 percent are given to people at least 70 years old, the researchers write in Circulation: Cardiovascular Quality and Outcomes. Yet there is limited information on how older patients with other medical problems fare with ICDs.

For the new study, the researchers used data from nearly 84,000 people who received an ICD and were enrolled in Medicare, the U.S. government health insurance for older and disabled adults.

About one in 10 of the ICD recipients had dementia or frailty, which is generally a marker of overall health.

About 12 percent of patients who received an ICD died within one year, but that rate was much higher for people with frailty or dementia.

In fact, Green said, frailty and dementia seemed to predict risk of death better than other health problems.

In patients with frailty, 22 percent died within one year of getting an ICD. Of those with dementia, 27 percent died within a year. Almost a third of patients with both conditions died within a year of getting ICDs.

Similar rates of death were seen among the 8 percent of patients with other complex health conditions, like frailty and chronic obstructive pulmonary disease, and frailty with diabetes.

The increased risk of death is likely not due to the ICDs, said Green. Instead, it's likely due to the patients' overall health.

The findings, she said, suggest that people need to be very careful in their decision-making about ICDs, and they need to take frailty into account.

Dr. Oussama Wazni, who wasn't involved in the new study, said he thinks doctors already consider these factors when recommending treatment for their patients.

"Patients and their family members should have realistic expectations - especially in this group of patients that have frailty and dementia," said Wazni, director of the Outpatient Electrophysiology Department and co-director of the Ventricular Arrhythmia Center at the Cleveland Clinic.

"We want to make sure the family members and the patient understand we only recommend a procedure when the benefit is more than the risk in all instances," he said.

One of the next steps is to identify which patients would likely fall into the 20 percent who will die within a year, Wazni told Reuters Health.

Green also told Reuters Health that databases that track people with ICDs should include frailty and dementia to assist future research.

SOURCE: http://bit.ly/1QYpZEi Circulation: Cardiovascular Quality and Outcomes, online December 29, 2015.