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Dementia patients get more implantable cardioverter-defibrillators (ICDs) than expected, and even cognitively normal individuals don't understand their options about ICD replacement, studies suggested.

People with stable dementia were 80% more likely to get a pacemaker than with those without cognitive impairment (P<0.01), , of the University of Pittsburgh, and colleagues found.

than those with a score of 0, indicating no cognitive impairment (P=0.02), they reported in a research letter online in JAMA Internal Medicine.

"This runs counter to the normative expectation that patients with a serious life-limiting and cognitively disabling illness might be treated less aggressively," they wrote.

"While it is possible that unmeasured confounding by indication explains this observation, future research should explore the patient, caregiver, and clinician influences on decision making regarding cardiac devices in this population."

The retrospective population-based study included 16,245 people across the range of cognitive function in the National Alzheimer Coordinating Center Uniform Data Set with prospectively-collected data at 33 Alzheimer's disease centers from September 2005 through December 2011.

One-third had dementia, while 21% were controls who had minor deficits on cognitive testing not meeting criteria for mild cognitive impairment or dementia, and 46% had no impairment whatsoever.

Pacemaker implantation rates were four per 1,000 person-years for those without cognitive impairment, 4.7 per 1,000 person-years with mild cognitive impairment, and 6.5 per 1,000 person-years with dementia (P=0.001).

ICD Options Not Made Clear

But even patients with presumably normal cognition might not fully understand their options about ICD replacement, an accompanying research letter showed.

Nearly , , of the University of Ottawa Heart Institute in Ontario, and colleagues reported.

Among such patients, 27% said they would have considered nonreplacement if they had understood that it was a possibility.

"The proportion of patients who thought that ICD replacement was mandatory raises important questions regarding patients' awareness of the legalities of treatment refusal and their right to autonomous decision making," the group wrote, recommending "a thoughtful review of the way ICD replacement is approached."

Their study included 106 consecutive, responding patients who underwent ICD generator replacement at a single institution between 2009 and 2012 and were not pacemaker dependent or using cardiac resynchronization therapy.

Responses also showed most patients either overestimated the benefits of ICD therapy compared with the published literature, underestimated the risks of ICD generator change, or did not know.

From the American Heart Association:

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