Table 2.

Studies examining cognitive changes over time in the heart failure population

Study	Sample	Population	Median age in years (SD)	Study methodology	Inclusion criteria	Exclusion criteria	CV measures	Cognitive assessment tool used	Follow-up period	Results
Karlsson 2005 [32]	146 CHF pts	Age >60 years and outpatients	76 (8)	Prospective	EF <45%	Co-morbid psychiatric, neurological or physical illness. Previous diagnosis of CI	LVEF	MMSE	6 months	12% of HF patients had MMSE scores <24 at baseline
					NYHA II-IV		NYHA			And 4% had MMSE scores <24 at 6 months
Tanne 2005 [33]	20 CHF underwent exercise programme 5 CHF pts as control pts	Outpatients	63 (13)	Prospective	EF ≤35%	Co-morbid psychiatric, neurological or physical illness	LVEF	Multidomain neuropsychiatric battery	18 weeks	Improvement in executive function post-exercise programme
					NYHA III		NYHA
					History of HF for ≥6 months		Mod-Bruce ETT			No change in cognition in control group with time
					Stable on medication ≥6 weeks		6 minute walk test
Stanek 2009 [19]	40 HF pts, 35 CAD controls	Age >53 and <84 years. Outpatients	70 (8)	Prospective	HF: English speaking	Co-morbid psychiatric or neurological illness. Previous diagnosis of CI	NYHA	DRS	12 months	HF patients improved at 12 months, particularly in attention
					NYHA II or III
					CO <4 L/minute		CO			Cardiac controls stable at 12 months
					CAD controls: CO ≥4 L/minute, history of MI/CAD
Almeida 2013 [34]	77 HF pts	Age >45 years and outpatients	HF: 68 (10)	Prospective	HF: EF <40%, English speaking	Co-morbid psychiatric or neurological illness. Previous diagnosis of CI	NYHA	Multidomain neuropsychiatric battery	2 years	CHF group showed cognitive decline compared with CAD and healthy controls
	73 CAD controls		CAD controls: 68 (10)		CAD controls: previous MI and EF >60%, English speaking		LVEF
	81 healthy controls		Healthy controls: 69 (11)		Healthy controls: no history of CAD, English speaking		6 minute walk test
Hjelm 2011 [35]	95 HF pts 607 non-CHF controls	Age >80 years and outpatients	84 (3)	Prospective	Not specified	Not specified	HF diagnosis based on documentation in medical records	Multidomain neuropsychiatric battery	10 years	HF patients showed significant decline in episodic memory and spatial performance compared with controls
Riegel 2012 [36]	279 consecutive HF pts (HF-REF and HF-PEF)	Age <80 years and outpatients	62 (12)	Prospective	Stage C HF and English speaking	Co-morbid psychiatric or physical illness. Previous diagnosis of CI	NYHA I-IV	Multidomain neuropsychiatric battery	6 months	No significant change in cognition over 6 months (HF-REF and HF-PEF)
							LVEF			Minimal improvement in DSST in both groups (likely due to learned effect)
										Higher LVEF associated with lower DSST score
Huijts 2013 [30]	491 HF-REF 120 HF-PEF	Age >60 years and outpatients	77 (8)	Prospective	HF-REF: hospitalization within past year	Co-morbid physical illness	HF-REF: LVEF <45%, NYHA II-IV, NT-proBNP >400 pg/ml	AMT	18 months	HF-REF: 23% of HF pts showed decline of ≥1 point in AMT over 18 months
					HF-PEF: NT-proBNP ≥400 pg/ml if pt <75 years or ≥800 pg/ml if pt ≥75 years		120 HF-PEF: LVEF ≥45%			HF-PEF: 24% of HF pts showed improvement of ≥1 point in AMT over 18 months

AMT, Abbreviated Mental Test; CAD, coronary artery disease; CHF, congestive heart failure; CI, cognitive impairment; CO, cardiac output; CV, cardiovascular; DRS, Disability Rating Scale; DSST, digit symbol substitution test; EF, ejection fraction; ETT, exercise tolerance test; HF, heart failure; HF-REF, heart failure-reduced ejection fraction; HF-PEF, heart failure-preserved ejection fraction; LVEF, left ventricular ejection fraction; MI, myocardial infarction; MMSE, Mini-Mental State Examination; NT-pro BNP, N-terminal prohormone brain natriuretic peptide; NYHA, New York Heart Association; pts, patients; SD, standard deviation.