Cognitive dysfunction mediates the effects of poor physical fitness on decreased functional independence in heart failure

Abstract

Aim Heart failure (HF) patients require assistance with activities of daily living (ADL). Poor physical fitness has recently been identified as a contributor to the high rates of disability in HF, though the mechanisms for such effects are unclear. Although not previously examined, decreased fitness may adversely impact ADLs in HF through its known association with cognitive impairment, a key correlate of self-care abilities in this population. We sought to test this possibility using a model-based approach. Methods 197 patients with HF completed a physical fitness test and a neuropsychological test battery. A total ADL composite was derived from the Lawton Brody scale. Structural equation modeling tested whether cognitive function mediated the association between physical fitness and total ADLs. Results Fitness was reduced and cognitive dysfunction and impaired ADLs were prevalent. The initially significant association between fitness and total ADLs was attenuated when cognitive function was introduced as a mediator. This model demonstrated good fit (CFI = .91: RMSEA = .077) with a significant indirect pathway between physical fitness and total ADLs through cognitive function: Decreased physical fitness was associated with cognitive dysfunction (β = 0.35), which predicted greater assistance with ADLs (β = 0.22). Conclusions Poor physical fitness may lead to decreased functional independence in HF through its negative effects on cognitive function. Prospective studies are needed to confirm our findings, identify other mechanisms by which poor fitness impacts ADLs, and examine whether exercise interventions can improve cognition and help preserve ADL independence in HF.

Reduced Physical Fitness in Patients With Heart Failure as a Possible Risk Factor for Impaired Driving Performance

“…Poorer physical fitness in our sample was associated with worse simulated driving performance, including more collisions and stop signs missed. Reduced physical fitness is a primary symptom of HF because of exercise intolerance (Piña et al, 2003), and past work in HF linked poor physical fitness with decreased functional capacity, including worse self-reported independence in driving (Alosco et al, 2014). The mechanism for the negative effects of decreased physical fitness on driving performance may in part involve cognitive dysfunction.…”

“…In particular, poor physical fitness is a primary symptom of HF (Wegrzynowska-Teodorczyk et al, 2010) that is believed in part to underlie cognitive dysfunction and impaired IADLs in HF (Alosco, Spitznagel, Cleveland, & Gunstad 2013;Alosco et al, 2014). There is reason to believe that reduced physical fitness may contribute to unsafe driving in people with HF.…”

“…There is reason to believe that reduced physical fitness may contribute to unsafe driving in people with HF. For example, decreased physical fitness has been associated with worse performance in driving-relevant cognitive domains (e.g., executive function; Alosco et al, 2012) and reduced selfreported independence in driving among people with HF (Alosco et al, 2014). Exercise, a promoter of physical fitness, has been shown to be an important modifier of on-road driving performance in healthy older adults (Marmeleira, Godinho, & Fernandes, 2009;Marottoli et al, 2007).…”

Management of Noncardiac Comorbidities in Chronic Heart Failure

“…Reduced physical activity is a strong predictor of cognitive dysfunction and functional dependence in patients with CHF [156][157][158]. Exercise intervention, such as cardiac rehabilitation, has been shown to improve physical fitness and cognition in patients with CHF [159][160][161].…”

Reversible Motor Paralysis and Early Cardiac Rehabilitation in Patients With Advanced Heart Failure Receiving Left Ventricular Assist Device Therapy

“…[1][2][3][4][5] Improvement of such brain impairment is strongly expected after left ventricular assist device (LVAD) implantation because resocialization is encouraged in such LVAD patients. 6) However, little is known about the perioperative therapeutic strategy for brain impairment, particularly from the viewpoint of cardiac rehabilitation.…”