The study used date from Alzheimer Disease Centers from September 2005 through December 2011 to look at how often cardiac implantable electronic devices are placed among older adults with and without cognitive impairment.
Of the 16,245 participants who had at least one baseline visit and at least 1 follow-up visit in the study period, 45.8% had no cognitive impairment, 21.3% had Mild Cognitive Impairment (MCI), and 33% had dementia. Rates of new pacemaker placement in these folks were as follows:
- 4 per 1000 person-years for participants without cognitive impairment
- 4.7 per 1000 person-years for participants with MCI
- 6.5 per 1000 person-years for participants with dementia
When adjusting for baseline demographics such as age, sex, race, intensity of pacemaker use in the the patients hospital referral region, cardiac comorbidity burden, functional status, and type of dementia, the authors found that:
- Patients were 1.6 times more likely to receive a pacemaker if they had dementia than if they didn't have any cognitive impairment
- Patients were 2.9 more likely to receive a pacemaker if they had severe dementia than if they didn't have any cognitive impairment.
So I guess that was a long answer to a simple question. Now we know a pacemaker is more likely to be placed in someone with dementia (and even more so in someone with severe dementia), our next post will address the issue of what happens when people consider turning them off.
by: Eric Widera (@ewidera)
NOTE: I'll also be reviewing Katy Butler's book "Knocking on Heaven's Door: The Path to a Better Way of Death" this week. Comment on any of the pacemaker posts this week or talk about it on twitter and you'll be entered into a drawing to win one of the paperback versions (for twitter, just make sure you include @geripalblog in the tweet)
9 comments:
I would be curious to know how this data correlates with use of an acetylcholinesterase inhibitor. I see that there is an expected difference in use of these medications between the cohorts of subjects, but more information about the implications would perhaps help clinicians further identify the risk/benefit ration of dementia "treaments." I look forward to seeing more about this in further publications.
Who were making the decision? Patient? DPOA? I guess it makes sense when considering severe dementia and that DPOA is probably making the decision. From my own family experience, I think my father and his sisters would have a hard time making that decision for my grandmother. Personally, I think she would not want one, but my father and aunts, as her children, have a much harder time separating what they want and what she would want.
Jessica, you make a great point about the use of acetylcholinesterase inhibitors. Several studies have shown an association not just with bradycardia in those taking these medications, but also an increased risk of pacemaker insertion.
I would like to hear some theories, knowing they are only that, about why this might be true.
I would be wondering about the profit motive; there is money in procedures. Repeat the study in the NHS and that would remove profit as a confounding factor
By the way, here are some studies looking at the association of cholinesterase inhibitors and increased rates of syncope, bradycardia, pacemaker insertion. The key point, discontinue aricept before even thinking about a pacemaker.
1. Syncope and its consequences in patients with dementia receiving cholinesterase inhibitors: a population-based cohort study. Arch Intern Med. 2009 May 11;169(9):867-73. doi: 10.1001/archinternmed.2009.43.
http://www.ncbi.nlm.nih.gov/pubmed/19433698
2. Cholinesterase inhibitors and incidence of bradycardia in patients with dementia in the veterans affairs new England healthcare system.
J Am Geriatr Soc. 2009;57(11):1997.
http://www.ncbi.nlm.nih.gov/pubmed/19793162
3. Cholinesterase inhibitors and hospitalization for bradycardia: a population-based study. PLoS Med. 2009 Sep;6(9):e1000157. doi: 10.1371/journal.pmed.1000157. Epub 2009 Sep 29.
http://www.ncbi.nlm.nih.gov/pubmed/19787032
Sort of like "Shark Week," only with pacemakers?
Really interesting phenomenon - but some theory to guide the process of interpreting the results and planning next steps would be very helpful.
One alternative that you suggest is that it is a consequence of the disease and its treatment - therapeutic cascade.
Alternatively, other comments suggest a "vulnerable patient" combined with mercenary health system interpretation.
I could also imagine that the perceived limitations in self-care for people with dementia would lead to preference for treatments like a pacemaker that at least seem to require less patient participation.
A research letter isn't the place for this kind of differentiation, but I do find myself wishing that medical research like this was more sensitive to the very different interpretations and did more to try to figure out why such phenomena might occur.
Thanks for posting On this topic Eric. This data is so amazingly counterintuitive. I wonder if one of the reasons for more pacemaker placement in people with severe dementia is because dementia is not thought of as a life limiting illness, the way stage iv cancer is considered a life limiting illness in many cases.
Another theory is that pacemakers are not thought about in the same category of interventions as CPR and intubation are, and so there are no discussions around pacemakers similar to discussions about code status.
Both cholinesterase inhibitors and memantine have a risk for bradycardia and/or heart block.
I think that you should strongly consider stopping either of these meds before placing a permanent pacemaker.
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