Heart failure associated with cognitive impairment, more rapid decline
Individuals with prevalent heart failure were 60% more likely to have dementia and 36% more likely to have mild cognitive impairment than those without heart failure.
Heart failure is associated with neurocognitive dysfunction and decline independent of other comorbidities, a study found.
To examine whether persons with heart failure have a higher prevalence of cognitive impairment and more rapid cognitive decline, researchers analyzed data from the Atherosclerosis Risk in Communities (ARIC) study, an observational cohort study of U.S. adults.
Participants who had cognitive scores and no prevalent heart failure were compared at study visit 4 in 1996 to 1998 and study visit 5 in 2011 to 2013. Cross-sectional analysis examined the association between prevalent heart failure and cognition, and change-over-time analysis looked at the association between incident heart failure and change in cognition over 15 years.
The study's primary outcome was cognitive status, classified as normal, mild cognitive impairment, and dementia on the basis of standardized cognitive tests (delayed word recall, word fluency, and digit symbol substitution). Control variables included sociodemographic characteristics and vascular and smoking/drinking measures. Results were published July 20 by the Journal of General Internal Medicine.
A total of 953 individuals had prevalent heart failure at visit 5, and of these, 38% were classified as having dementia or mild cognitive impairment (compared to 24% of those without heart failure). The sample included only 105 cases of heart failure with reduced ejection fraction (defined as an ejection fraction <50% at visit 5), 11% of those with heart failure, while 184 (19%) individuals with heart failure were missing ejection fraction data. Among those with heart failure with reduced ejection fraction, the average ejection fraction was 40% and only 33 had an ejection fraction of 35% or less.
After adjustment for comorbid conditions, individuals with prevalent heart failure were more likely to have dementia (relative risk ratio, 1.60; 95% CI, 1.13 to 2.25) and mild cognitive impairment (relative risk ratio, 1.36; 95% CI, 1.12 to 1.64) than those without heart failure. A similar effect size was seen when groups were compared by ejection fraction, but the ability to detect a statistically significant difference in cognition was limited, potentially due to small sample size.
Cognitive decline was significantly greater among persons who developed heart failure over the 15-year period (mean standardized z score of −0.50 at visit 4 to −1.02 at visit 5) versus those who did not develop heart failure (mean score of 0.24 at visit 4 to −0.20 at visit 5), with an adjusted difference of −0.07 (95% CI, −0.13 to −0.01). This difference is interpreted as a 15-year change in SD units for patients with heart failure versus those without, the authors noted. This change represents an estimated additional 1.5 years of cognitive decline when compared to normal aging, they said.
Further study is needed to determine the underlying pathophysiology of these results, the authors concluded.
“These findings can aid clinicians when caring for [heart failure] patients and ensure they are attuned to the risk of cognitive decline associated with this disease,” the authors wrote. “It also provides potential areas for further analysis and therefore intervention to prevent cognitive decline, whether by improved [heart failure] treatment, increasing cardiac output, or adjusting medications.”