heart failure ( hf ) is a chronic form of cardiovascular disease ( cvd ) . the prevalence of hf continues to increase , with approximately 825000 new cases diagnosed each year in the united states.1 ) in korea , cvd ranks third in terms of the length of hospitalization and is among the leading diagnoses at discharge.2 ) the increasing proportion of aged population in korea may spur the prevalence of hf associated with fundamental changes in cardiovascular structure and function , which could increase susceptibility to cvd in the senior population.3 ) in hf management , patients with more effective self - care skills exhibit lower mortality and readmission rates than those with poor self - care.4 ) self - care is an important strategy in maintaining optimal health for individuals with hf . given its importance in preventing potentially fatal clinical crises , patient education about self - care behaviors is a key component of hf management in the chronic progression of hf disease.5 ) cognitive decline may affect a person 's decision - making capacity in terms of self - care and interfere with their ability to comply with treatment requirements , and to recognize and manage symptom exacerbation.5)6)7 ) cognitive decline in hf often presents deficits in one or more domains of cognition that include attention , memory , executive function , and psychomotor speed.7)8)9 ) cognitive decline or frailty is a particular concern in elderly outpatients with reduced or preserved hf and concomitant comorbidities that complicate early hf diagnosis and management.10)11 ) despite the substantial deficits in one or more areas , few studies have investigated cognitive function in these multiple domains using a comprehensive test battery in korea . one of the most commonly used neuropsychological tests for cognitive evaluation is the seoul neuropsychological screening battery.12 ) the validity and reliability of this comprehensive neuropsychological test battery have been documented from patients with stroke , parkinson disease , and dementia.12)13 ) empirical evaluation of cognitive function in hf involving global cognition , memory , or executive function , using such a comprehensive neuropsychological test battery is lacking . cognitive decline adversely affects adherence to therapeutic regimens for hf management and major adverse cardiac events ( mace ) in western countries.5)8)14)15)16 ) however , little is known about the relationship between cognitive decline and self - care among hf patients in korea . the present study had four purposes : to estimate the levels of cognitive function in domains of global , memory , and executive function ; examine differences in each domain of cognitive function between patients with asymptomatic and symptomatic hf ; examine the association of cognitive function with self - care adherence in korean hf patients ; and examine the influence of cognitive impact on mace . the study involved korean hf patients with preserved and reduced left ventricular ejection fraction ( lvef ) . this study adopted a prospective study design in which associations of cognitive function with self - care adherence and mace at 24 months after the enrollment were examined in hf patients . study participants were recruited and enrolled from a national university - affiliated outpatient clinic in 2012 . eligible criteria included adult patients who were over 30 years of age , hf diagnosed at least 6 months previously , ability to communicate verbally , and voluntary informed consent to participate . patients with a documented history of disorders potentially associated with cognitive deficits , such as stroke , dementia or alzheimer 's disease , were excluded . written informed consent statement was obtained from each participant before a face - to - face interview for neuropsychological tests to evaluate cognition , self - care , and functional classification . cognitive function was measured with the seoul neuropsychological screening battery12 ) which was established to assess comprehensive neuropsychological aspects involving global cognition ( korean - mini mental state examination , k - mmse ) , memory ( seoul verbal learning test ) , and executive function ( controlled oral word association ) . the mini mental state examination ( mmse ) is a measure of global cognition originally developed by folstein et al.17 ) the k - mmse is a standardized and modified form of the mmse for elderly korean people . the k - mmse is a 30 item - instrument with possible scores ranging from 0 to 30 , with higher scores indicating greater general cognition.18 ) memory function contains both immediate and delayed recall memory . it was measured with the seoul verbal learning test that involves oral presentation using a list of 12 words to the patients during three trials . patients were asked to recall and repeat the words in any order after each trial ( total list learning , immediate recall , range 0 - 36 ) . twenty minutes later , when the third trial was complete , patients were asked to recall as many of the 12 words they could ( delayed recall , range 0 - 12).12 ) executive function is an umbrella term for the regulation or control of cognitive processes including working memory , reasoning , and problem solving as well as planning and execution.19 ) it was measured using the controlled oral word association test by presenting three letters to the patients . the patients were asked to generate as many words beginning with each letter as they could over a 60-s period . the number of words generated for the three letters indicated an individual score of executive function , with higher scores indicating greater function.12 ) self - care is defined as a naturalistic decision - making process involving the choice of behaviors that maintain physiologic stability ( maintenance ) and the response to symptoms when they occur ( management ) , and the confidence in self - care for hf management.20 ) self - care was measured with the self - care of heart failure index21 ) which included three subscale scores associated with self - care maintenance ( 10 items ; behavioral adherence to some of the major treatment recommendations such as checking weight and ankle swelling , exercise , taking medication , keeping physician 's appointment , and low - sodium diet ) , self - care management ( 6 items ; when dyspnea or leg edema occur , ability to recognize symptom changes , implement remedies , and evaluate their effectiveness ) , and self - care confidence ( 6 items ; confidence to engage in each phase of the self - care process ) . self - care management was assessed only for patients who indicated having experienced dyspnea or a leg edema . scores of maintenance and management reflect the degrees of self - care ability , and confidence scores explain how some patients master self - care and others do not.21 ) responses from each of the three self - care subscales were transformed to 100 points ; higher scores reflected superior self - care . self - care adequacy for each subscale area was determined using a cut - off point 70.7)20 ) new york heart association ( nyha ) functional classification was used in this study , as it is the most widely - used system to categorize patients according to the degrees of functional limitation imposed by hf symptom severity.22 ) patient data on cognitive function , self - care , and functional classes were collected by a trained research nurse from february to september 2012 through a 60-minute , one - on - one interview . follow - up clinical data including mace were obtained 24 months after the enrollment by the research nurse . data are presented as meanstandard deviation , with ranges for continuous variables and percentages for categorical variables . neuropsychological test variables were scored following author guidelines,12 ) with raw scores for general cognition , memory , and executive function . student 's t - tests were performed to examine differences in cognitive function and self - care between patients with asymptomatic and symptomatic hf . a series of multiple logistic regression analyses were also performed to determine factors that predicted self - care and mace in hf patients . for logistic regression analyses , the subscales of self - care maintenance and confidence were dichotomized for determination of self - care adequacy using a cut - off point of 70 . this study adopted a prospective study design in which associations of cognitive function with self - care adherence and mace at 24 months after the enrollment were examined in hf patients . study participants were recruited and enrolled from a national university - affiliated outpatient clinic in 2012 . eligible criteria included adult patients who were over 30 years of age , hf diagnosed at least 6 months previously , ability to communicate verbally , and voluntary informed consent to participate . patients with a documented history of disorders potentially associated with cognitive deficits , such as stroke , dementia or alzheimer 's disease , were excluded . written informed consent statement was obtained from each participant before a face - to - face interview for neuropsychological tests to evaluate cognition , self - care , and functional classification . cognitive function was measured with the seoul neuropsychological screening battery12 ) which was established to assess comprehensive neuropsychological aspects involving global cognition ( korean - mini mental state examination , k - mmse ) , memory ( seoul verbal learning test ) , and executive function ( controlled oral word association ) . the mini mental state examination ( mmse ) is a measure of global cognition originally developed by folstein et al.17 ) the k - mmse is a standardized and modified form of the mmse for elderly korean people . the k - mmse is a 30 item - instrument with possible scores ranging from 0 to 30 , with higher scores indicating greater general cognition.18 ) memory function contains both immediate and delayed recall memory . it was measured with the seoul verbal learning test that involves oral presentation using a list of 12 words to the patients during three trials . patients were asked to recall and repeat the words in any order after each trial ( total list learning , immediate recall , range 0 - 36 ) . twenty minutes later , when the third trial was complete , patients were asked to recall as many of the 12 words they could ( delayed recall , range 0 - 12).12 ) executive function is an umbrella term for the regulation or control of cognitive processes including working memory , reasoning , and problem solving as well as planning and execution.19 ) it was measured using the controlled oral word association test by presenting three letters to the patients . the patients were asked to generate as many words beginning with each letter as they could over a 60-s period . the number of words generated for the three letters indicated an individual score of executive function , with higher scores indicating greater function.12 ) self - care is defined as a naturalistic decision - making process involving the choice of behaviors that maintain physiologic stability ( maintenance ) and the response to symptoms when they occur ( management ) , and the confidence in self - care for hf management.20 ) self - care was measured with the self - care of heart failure index21 ) which included three subscale scores associated with self - care maintenance ( 10 items ; behavioral adherence to some of the major treatment recommendations such as checking weight and ankle swelling , exercise , taking medication , keeping physician 's appointment , and low - sodium diet ) , self - care management ( 6 items ; when dyspnea or leg edema occur , ability to recognize symptom changes , implement remedies , and evaluate their effectiveness ) , and self - care confidence ( 6 items ; confidence to engage in each phase of the self - care process ) . self - care management was assessed only for patients who indicated having experienced dyspnea or a leg edema . scores of maintenance and management reflect the degrees of self - care ability , and confidence scores explain how some patients master self - care and others do not.21 ) responses from each of the three self - care subscales were transformed to 100 points ; higher scores reflected superior self - care . self - care adequacy for each subscale area was determined using a cut - off point 70.7)20 ) new york heart association ( nyha ) functional classification was used in this study , as it is the most widely - used system to categorize patients according to the degrees of functional limitation imposed by hf symptom severity.22 ) patient data on cognitive function , self - care , and functional classes were collected by a trained research nurse from february to september 2012 through a 60-minute , one - on - one interview . follow - up clinical data including mace were obtained 24 months after the enrollment by the research nurse . data are presented as meanstandard deviation , with ranges for continuous variables and percentages for categorical variables . neuropsychological test variables were scored following author guidelines,12 ) with raw scores for general cognition , memory , and executive function . student 's t - tests were performed to examine differences in cognitive function and self - care between patients with asymptomatic and symptomatic hf . a series of multiple logistic regression analyses were also performed to determine factors that predicted self - care and mace in hf patients . for logistic regression analyses , the subscales of self - care maintenance and confidence were dichotomized for determination of self - care adequacy using a cut - off point of 70 . cognitive function was measured with the seoul neuropsychological screening battery12 ) which was established to assess comprehensive neuropsychological aspects involving global cognition ( korean - mini mental state examination , k - mmse ) , memory ( seoul verbal learning test ) , and executive function ( controlled oral word association ) . the mini mental state examination ( mmse ) is a measure of global cognition originally developed by folstein et al.17 ) the k - mmse is a standardized and modified form of the mmse for elderly korean people . the k - mmse is a 30 item - instrument with possible scores ranging from 0 to 30 , with higher scores indicating greater general cognition.18 ) it was measured with the seoul verbal learning test that involves oral presentation using a list of 12 words to the patients during three trials . patients were asked to recall and repeat the words in any order after each trial ( total list learning , immediate recall , range 0 - 36 ) . twenty minutes later , when the third trial was complete , patients were asked to recall as many of the 12 words they could ( delayed recall , range 0 - 12).12 ) executive function is an umbrella term for the regulation or control of cognitive processes including working memory , reasoning , and problem solving as well as planning and execution.19 ) it was measured using the controlled oral word association test by presenting three letters to the patients . the patients were asked to generate as many words beginning with each letter as they could over a 60-s period . the number of words generated for the three letters indicated an individual score of executive function , with higher scores indicating greater function.12 ) self - care is defined as a naturalistic decision - making process involving the choice of behaviors that maintain physiologic stability ( maintenance ) and the response to symptoms when they occur ( management ) , and the confidence in self - care for hf management.20 ) self - care was measured with the self - care of heart failure index21 ) which included three subscale scores associated with self - care maintenance ( 10 items ; behavioral adherence to some of the major treatment recommendations such as checking weight and ankle swelling , exercise , taking medication , keeping physician 's appointment , and low - sodium diet ) , self - care management ( 6 items ; when dyspnea or leg edema occur , ability to recognize symptom changes , implement remedies , and evaluate their effectiveness ) , and self - care confidence ( 6 items ; confidence to engage in each phase of the self - care process ) . self - care management was assessed only for patients who indicated having experienced dyspnea or a leg edema . scores of maintenance and management reflect the degrees of self - care ability , and confidence scores explain how some patients master self - care and others do not.21 ) responses from each of the three self - care subscales were transformed to 100 points ; higher scores reflected superior self - care . self - care adequacy for each subscale area was determined using a cut - off point 70.7)20 ) new york heart association ( nyha ) functional classification was used in this study , as it is the most widely - used system to categorize patients according to the degrees of functional limitation imposed by hf symptom severity.22 ) patient data on cognitive function , self - care , and functional classes were collected by a trained research nurse from february to september 2012 through a 60-minute , one - on - one interview . follow - up clinical data including mace were obtained 24 months after the enrollment by the research nurse . data were analyzed using spss version 18.0 ( spss inc . , chicago , il , usa ) . data are presented as meanstandard deviation , with ranges for continuous variables and percentages for categorical variables . neuropsychological test variables were scored following author guidelines,12 ) with raw scores for general cognition , memory , and executive function . student 's t - tests were performed to examine differences in cognitive function and self - care between patients with asymptomatic and symptomatic hf . a series of multiple logistic regression analyses were also performed to determine factors that predicted self - care and mace in hf patients . for logistic regression analyses , the subscales of self - care maintenance and confidence were dichotomized for determination of self - care adequacy using a cut - off point of 70 . the mean age of the patients was 58.3212.87 years and 67.4% ( n=58 ) were men . more than half of the patients ( 55% ) had been diagnosed with hf for 24 months or longer before enrollment . approximately , one in five patients ( n=19 , 22% ) had reduced lvef < 45% . during the 24-month follow - up there were 67 event - free survivors ; 19 mace 's including two deaths occurred . hf patients were on optimal medication including angiotensin converting enzyme inhibitors , angiotensin receptor blockers , beta - blockers , and diuretics . cognitive function and self - care level data are presented in tables 2 and 3 . using the korean norm values for comparisons , 33.0% , 65.1% , and 65.1% , and 60.5% of hf patients had a cognitive deficit in global cognition , immediate and delayed memory , and executive function , respectively . using a score of 70 as the cut - off to determine self - care adequacy for each subscale , 84.9% and 86.0% patients showed inadequate self - care maintenance and confidence , respectively . all patients who had dyspnea or leg edema ( n=35 ) had inadequate self - care management with scores below the norm . all subscale scores of self - care were significantly lower in symptomatic hf patients ( nyha class ii ) than in asymptomatic hf patients ( nyha class i ; p<0.05 ) . compared with asymptomatic hf patients , symptomatic hf patients also had poorer cognitive function in domains of general , executive function , and memory ( p<0.05 ) ( table 4 ) . however , no significant differences were found in cognitive function and self - care between hf patients with preserved and reduced lvef ( p>0.05 ) . multivariate logistic regression analyses indicated that delayed recall memory { odds ratio ( or ) 1.41 , 95% confidence interval ( ci ) 1.03 - 1.92 , p=0.033 } was an independent predicting factor of self - care confidence adequacy after controlling for age and gender . there was no significant relationship between cognitive function and self - care maintenance in the multiple logistic regression analysis ( table 5 ) . in comparisons of cognitive function between event - free survivors and those with mace , event - free survival was associated significantly with higher global cognitive function ( k - mmse ; 23.9 vs. 27.1 ; t=2.30 p=0.024 ) . other areas of cognitive function did not significantly differ between the two groups : immediate recall ( 14.5 vs. 15.6 , t=0.74 p=0.462 ) , delayed recall memory ( 4.7 vs. 4.9 , t=0.33 p=0.773 ) , and executive function ( 16.9 vs. 21.0 , t=1.17 p=0.085 ) . however , multiple logistic regression analysis showed that , for testing cognitive impacts on the likelihood of mace , none of the cognitive domains were significant predictors of maces after adjusting for age , gender , and lvef . this is the only study to our knowledge that has investigated cognitive function in hf using a neuropsychological test battery.12 ) a major finding was that substantial extent of poor cognitive function in korean hf patients , with the deficits poorer among patients who had more functional limitation indicated by nyha class ii and higher than those with nyha class i. such cognitive deficits adversely affected self - care in korean hf patients . in particular , delayed recall memory was predictive for poor self - care confidence adequacy . poor cognitive function was evident in all domains of global , immediate , and delayed recall memory , and executive function , with the prevalence of cognitive deficit ranging from 33.0% to 63.8% , compared with the korean norm values of neuropsychological test scores.12 ) post hoc analysis was performed to examine whether cognitive dysfunction differed by preserved and reduced lvef . compared with hf patients with preserved lvef , there were no differences in all domains of cognitive function among hf patients with low lvef . poor cognitive function is well - documented in hf ; chronic cerebral hypoperfusion and , subsequently , ischemic structural change and functional alteration are mostly responsible for the impairment.9)16)23 ) particularly , adults with hf showed an evidence of cerebral grey matter loss , and had worse immediate and long - term memory and psychomotor speed than controls without ischemic heart disease.24 ) further research is needed to determine the differences of cognitive function by preserved and reduced lvef in a larger sample . our findings are consistent with a study that investigated cognitive function among 121 hf patients in korea.25 ) using a single screening measure of the k - mmse to examine cognitive function and a score < 20 as a cut - off , 29 patients ( 24% ) had a cognitive deficit.25 ) pressler et al.23 ) also found that global cognitive function ( mmse , p=0.004 ) , working memory ( digit span backward , p=0.018 ) , and memory ( hopkins verbal learning test delayed recall , p=0.047 ) were poorer among 166 hf patients with left ventricular dysfunction , compared with those having chronic illness other than hf or healthy people . a systematic literature review also indicated that patients with severe hf can have mild cognitive deficit , with the prevalence of cognitive deficit being 53 - 58% of patients.16 ) when comparing cognitive function by functional limitation imposed by hf symptoms , patients with symptomatic hf ( nyha class ii ) had substantially poorer cognitive function in all domains than patients with asymptomatic hf ( nyha class i ; p<0.05 ) . this finding validates a previous report that pilot - tested cognitive function among seven hf patients.22 ) in this pilot test , poor global cognition , memory , and executive function were found in more than half of patients , with 57% , 50% , and 83% having poor global cognition , memory , and executive function , respectively . in another study , nyha class i or ii had greater cognitive function than those in nyha class iii and higher.26 ) most patients with hf in this study demonstrated poor self - care adequacy in maintenance ( 84.9% ) , management ( 100% ) , and confidence ( 86.0% ) , using the cut - off score of 70 . especially , all 35 patients who acknowledged dyspnea or leg edema did not response properly to symptoms when they occurred . self - care management is an active , deliberate process that recognizes a change in health , evaluating the change , deciding to take action , and implementing a treatment strategy.20 ) symptom monitoring is an essential segue into self - care management , which refers to decision - making in response to symptoms.20 ) an educational strategy is valuable to help patients monitor their symptoms regularly and recognize early worsening symptom(s ) on a daily basis . those who were symptomatic and had more functional limitation , as indicated by nyha class ii or higher , also had poorer self - care confidence compared with those who were asymptomatic ( nyha class i ) . in a previous pilot study , poor self - care maintenance and management were observed ; cognitive function was substantially poorer in korean hf patients who showed inadequate self - care adherence.26 ) our findings were consistent with this pilot report , further validating poor self - care in a larger sample of korean hf patients . more important and consistent with results from previous studies , delayed recall memory was a significant factor that may have affected self - care confidence in hf patients in this study . however , cognitive function between event - free survivors and those with mace was not significantly different , except for global function , with event - free survival having a higher global function . multiple logistic regression analyses showed that no cognitive domain predicted mace among hf patients with both preserved and reduced lvef . on the contrary , data from a larger sample of hf patients with low lvef ( n=166 , 27.010.1 ) support that cognitive deficit is associated with adverse health outcomes.23 ) poor cognitive function in the domains of global cognition , working memory , psychomotor speed , and executive function were reported to be significant predictors of 12-month all - cause mortality in a series of logistic regression analyses with lvef , with each cognitive function variable as a predictor.23 ) although memory loss explained only 1% of the variance , hf severity , age , depressive symptoms , and immediate recall memory were significant predictors of health - related quality of life in hf patients ( n=249).27 ) given that damaged areas associated with cerebral hypoxia may prevent hf patients from engaging in self - care activities for hf management,23 ) our results add empirical evidence in korean hf research , with outcome measures expanding to daily functional ability , self - care , and mace on cognitive deficits in hf involving those with preserved or reduced lvef ; and cognitive function as a critical modifiable factor with regard to improving such health outcomes . first , the findings should be validated in comparison with other patient groups and healthy individuals using a larger sample . second , patients who participated in this study were recruited from a single university - affiliated hospital , limiting the generalization of the results . korean hf patients showed poor cognitive function and inadequate levels of self - care maintenance , management , and confidence . those with more functional limitation demonstrated poorer cognitive function and worse self - care confidence than their counterparts . future research is warranted to determine how cognitive deficits impede self - care decision - making processes separately in preserved and reduced hf patients over a longer time frame . further , intervention studies are needed to learn how to delay or prevent poor cognitive function in hf patients . first , the findings should be validated in comparison with other patient groups and healthy individuals using a larger sample . second , patients who participated in this study were recruited from a single university - affiliated hospital , limiting the generalization of the results . korean hf patients showed poor cognitive function and inadequate levels of self - care maintenance , management , and confidence . those with more functional limitation demonstrated poorer cognitive function and worse self - care confidence than their counterparts . future research is warranted to determine how cognitive deficits impede self - care decision - making processes separately in preserved and reduced hf patients over a longer time frame . further , intervention studies are needed to learn how to delay or prevent poor cognitive function in hf patients .
background and objectivesthis study examined the association of cognitive function with self - care and major adverse cardiac events ( mace ) among heart failure ( hf ) patients.subjects and methodsin this prospective study , 86 outpatients with hf completed face - to - face interviews including neuropsychological testing to evaluate cognitive function and the use of the self - care of heart failure index to measure self - care . 
 functional status was assessed with the new york heart association ( nyha ) classification . 
 follow - up data on mace were obtained at 24 months after enrollment.resultscompared with the korean norm values , more than half of the hf patients had cognitive deficits in global function ( 33.0% ) , immediate recall ( 65.1% ) , delayed recall memory ( 65.1% ) , and executive function ( 60.5% ) . 
 patients with symptomatic hf ( nyha class ii ) had the higher risk for substantially poor cognitive function in all areas of cognitive function than asymptomatic hf patients ( nyha class i , p<0.05 ) . 
 most patients demonstrated poor self - care adequacy in maintenance ( 84.9% ) , management of symptoms ( 100% ) , and confidence ( 86.0% ) . 
 after adjustment for age and gender , memory function was significantly associated with self - care confidence ( odds ratio 1.41 , 95% confidence interval 1.03 - 1.92 , p=0.033 ) . no relationship was found between cognition and self - care maintenance . 
 there were 19 mace 's during the 24-month follow - up . 
 patients without mace had a significantly higher global cognitive function ( p=0.024 ) , while no cognitive domains were significant predictors of mace when adjusted for age and gender.conclusionhf patients with memory loss have poorer self - care confidence . 
 studies are warranted to examine the functional implication of cognitive deficits and adverse outcomes in a larger sample .