People with dementia are more likely to get implanted pacemakers for heart rhythm irregularities, such as atrial fibrillation, than people who don't have cognitive difficulties, according to researchers at the University of Pittsburgh School of Medicine. In a research letter published online in JAMA Internal Medicine, the researchers noted the finding runs counter to expectations that less aggressive interventions are the norm for patients with the incurable and disabling illness.

To look at the relationships between cognitive status and implantation of a pacemaker, lead investigator Nicole Fowler, Ph.D., a health services researcher formerly at the Pitt School of Medicine, and her team examined data from 33 Alzheimer's disease centers (ADCs) entered between September 2005 and December 2011 into the National Alzheimer's Coordinating Center (NACC) Uniform Data Set.

Data from more than 16,000 people who had a baseline and at least one follow-up visit at an ADC were reviewed. At baseline, 48.5 percent of participants had no cognitive impairment, 21.3 percent had a mild cognitive impairment (MCI), and 32.9 percent had dementia.

The researchers found that participants with cognitive impairment were significantly older, more likely to be male, have ischemic heart disease and a history of stroke. Rates of atrial fibrillation and congestive heart failure were similar among the groups.

The likelihood of getting a pacemaker was lowest for those who had no cognitive difficulties and highest for dementia patients.

"Participants who had dementia before assessment for a new pacemaker were 1.6 times more likely to receive a pacemaker compared to participants without cognitive impairment, even after clinical factors were taken into account," said Dr. Fowler, now at Indiana University. "This was a bit surprising because aggressive interventions might not be appropriate for this population, whose lives are limited by a severely disabling disease. Future research should explore how doctors, patients and families come to make the decision to get a pacemaker."

There was no difference among the groups in the rates of implantation of cardioverter defibrillators.

Co-authors of the paper include Jie Li, M.S., Charity G. Moore, Ph.D., Samir Saba, M.D., Oscar L. Lopez, M.D., and Amber E. Barnato, M.D., M.P.H., M.S., all of the University of Pittsburgh, and Kim G. Johnson, M.D., of Duke University Medical Center.

The project was funded by the Agency for Healthcare Research and Quality and National Institutes of Health, National Institute on Aging grant AG05133. The NACC database is funded by National Institutes of Health, National Institute on Aging grant AG016976.