Studies raise questions about decisions to implant, replace ICDs

Two new research letters raise questions about the decision-making process for implanting new implantable cardioverter-defibrillators (ICDs), as well as replacing existing ICDs.

The first letter describes a retrospective cohort study of data from 33 Alzheimer disease centers (ADC) from September 2005 through September 2011. Researchers evaluated information on 16,245 patients who had had a baseline ADC visit and at least 1 follow-up visit during the study period. At baseline, 32.9% of patients had dementia, 21.3% had mild cognitive impairment (MCI), and 45.8% patients had no cognitive impairment. Over the study period, rates of incident (new) cardiac device implantation were 6.5 per 1,000 person-years for those with dementia, 4.7 per 1,000 for those with MCI, and 4.0 per 1,000 for those without cognitive impairment (P=0.001).

An adjusted model showed that patients who had dementia on the visit before an assessment for a new pacemaker were 1.6 times more likely to receive a pacemaker compared to those without cognitive impairment (P=0.02); the same trend held true in a model for consecutive visits (P<0.01). A separate model found patients whose Clinical Dementia Rating Scale score was 3 (severe dementia) were 2.9 times more likely to receive a pacemaker than those with a Clinical Dementia Rating Scale score of 0 (no cognitive impairment) (P=0.02). The findings run counter to conventional wisdom that patients who are cognitively disabled generally are treated less aggressively, the researchers wrote. More research needs to examine the decision-making process for cardiac devices in the cognitively disabled population, they added.

The second letter describes a study in which researchers surveyed consecutive patients who underwent ICD replacement at a single institution between 2009 and 2012 about their decisions to undergo replacement. Of the 106 responses, 51.9% of patients said they were unaware that ICD generator replacement was not mandatory. Twenty-seven percent of those patients said that, if given the option, they would have considered not replacing the ICD. There were no demographic or clinical differences between those who might have considered non-replacement and those who would not. Eighty-three percent of all 106 patients said it was “important” or “very important” to them to talk about the risks and benefits of ICDs before making a decision to continue with the therapy.

Many patients overestimated the life-saving benefits of ICD generator change and underestimated the risks; in particular, patients weren't aware of the risk of pocket infection, the researchers noted. “A thoughtful review of the way ICD replacement is approached is warranted,” the researchers concluded, in order to elicit true preferences from informed patients and incorporate them into decision making.

Both research letters were published online July 28 by JAMA Internal Medicine.