The Disappearing Subject: Exclusion of People with Cognitive Impairment and Dementia from Geriatrics Research

Abstract

Persons with cognitive impairment are frequently excluded from research, often without rationale or mention of exclusion as a limitation or any discussion of its potential effect on the evidence base in geriatrics. When necessary, exclusion should be done thoughtfully and with awareness that this may reduce the clinical utility of study findings.

Participant exclusion criteria in treatment research on neurological disorders: Are unrepresentative study samples problematic?

“…Excluding patients with cognitive impairments is common but, as noted earlier, a strong rationale is rarely provided. In the Taylor study described earlier [22], only 6% of reviewed studies provided any justification for using exclusion criteria. In patients with neurological disorders this is particularly problematic since conditions such as dementia are defined by cognitive capacity, and conditions such as TBI are often accompanied by some level of cognitive impairment.…”

Effects of alternative interventions among hospitalized, cognitively impaired older adults

“…This growing patient population is at high risk for cognitive decline, increased use of costly healthcare resources and other poor outcome [51,52]. Unfortunately, research efforts designed to enhance care management have traditionally excluded older adults with cognitive deficits [53].…”

A call for comparative effectiveness research to learn whether routine clinical care decisions can protect from dementia and cognitive decline

“…[32]). Even in geriatrics, cognitively impaired patients are rarely recruited for clinical research on other conditions [33] and those that develop impairment during the trial are likely to drop out before their outcome can be assessed [14]. Most of the clinical research that has been done on other health conditions cannot therefore accurately inform how those treatments affect cognitive decline and dementia risk even if those outcomes were recorded.…”