Cognitive impairment in heart failure: towards a consensus on screening.

The evidence that patients with heart failure (HF) experience cognitive impairment is compelling.1 Cognitive impairment occurs in oneto three-quarters of HF patients2 and leads to poor health outcomes including reduced activities of daily living,3 inadequate engagement in HF self-care,2 clinical instability,4 and premature death.5 The escalating number of research papers investigating cognitive impairment in HF patients attests to the significance of this co-morbidity.1–5 Even so, inconsistencies in the operationalization of cognitive impairment are widespread, resulting in a variety of screening methods6 and conflicting estimates of its severity and prevalence in HF populations.7 This point is highlighted by four studies published in the past 2 years in this journal, whereby cognitive impairment has been assessed with: brief screening questionnaires of global cognitive functioning;8,9 a more comprehensive screening recognized to diagnose mild cognitive impairment and primary degenerative dementia;10 and a battery of neuropsychological tests, that included a global cognitive screening questionnaire.11 It is acknowledged that HF patients typically exhibit cognitive impairment in domains of memory (working and delayed recall), attention, processing speed, and executive function;12 yet, to date, studies have been limited by use of only screening questionnaires rather than a gold standard neuropsychological battery of tests. This is reflected in two studies published recently in this journal. In the TIME-CHF study,8 cognitive impairment was classified as severe if HF patients scored ≤7 on the Hodkinson Abbreviated Mental Test. This screening questionnaire has been used in general ageing populations to screen for dementia. From the 611 patients enrolled in the study, 56 (9%) were classified with severe cognitive impairment on the basis of the screening questionnaire, with no other neuropsychological assessment.8 Likewise, Davis and colleagues9 had used the classification of mild cognitive impairment as the study inclusion criterion for a cognitive training intervention aimed at improving self-care behaviours. The Montreal Cognitive Assessment had been applied, and only HF patients who had scored between 17 and 25 were invited to participate in the study. Once again, no other neuropsychological assessment had been used to characterize cognitive impairment among the 125 HF patients who participated in the study.9