Cognitive Impairment and HF
Is there an association between heart failure (HF) and cognitive impairment (including mild cognitive impairment, multidomain cognitive impairment, and varying severities of dementia), and what is the incidence within patients enrolled in research studies?
This is a systemic review of the literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included concepts around HF and cognitive impairment/cognitive testing using validated search strings and supplemented with Medical Subject Headings terms and other controlled vocabulary. Multidisciplinary databases from inception until May 31, 2015, were searched, including “explode” functions. Full text was reviewed based on significance of the title.
In this review, 350 abstracts, 87 full manuscripts, and 37 papers were reviewed (n = 8,411). After extensive analysis, 40% of patients with HF enrolled in research studies had some level of cognitive dysfunction. Considering that the incidence of dementia in the general UK population is 7%, the incidence of cognitive dysfunction in patients with HF is significantly higher. Subgroup analysis of patients with and without HF enrolled in case-controlled studies (n = 1,414), showed a significantly higher incidence of cognitive impairment and dementia in the HF group (odds ratio 2.64; 95% confidence interval, 1.83-3.80). Patients over the age of 69 had a higher incidence of cognitive dysfunction. There were insufficient studies to conduct a subgroup analysis of HF with preserved ejection fraction versus HF with reduced ejection fraction. Patients with poor cognitive functioning are not usually enrolled in research studies because they need to sign informed consent forms to participate; patients who are enrolled in research studies are perceived to have intact cognitive functioning.
The incidence of cognitive dysfunction in patients with HF who are enrolled in research is significantly higher than the general population. The clinician and researcher need to be aware that cognitive function maybe impaired when discussing complex medication regimens and advanced therapies. Routine screening for cognitive dysfunction was not recommended by the authors due to inconsistent cognitive function screening tools that were used in research.
Declining cognitive function can impact patient outcomes. Including families and care givers when instructions are being given on medication regimens is imperative. Additional time should be allowed for teaching at time of discharge and follow-up visits. Further research is needed to determine which cognitive assessment tool is superior.
Keywords: Heart Failure, Cognition Disorders, Mild Cognitive Impairment, Cognition, Dementia, Case-Control Studies
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