Assessing the impact of physical exercise on cognitive function in older medical patients during acute hospitalization: Secondary analysis of a randomized trial

Abstract

Background: Acute illness requiring hospitalization frequently is a sentinel event leading to long-term disability in older people. Prolonged bed rest increases the risk of developing cognitive impairment and dementia in acutely hospitalized older adults. Exercise protocols applied during acute hospitalization can prevent functional decline in older patients, but exercise benefits on specific cognitive domains have not been previously investigated. We aimed to assess the effects of a multicomponent exercise intervention for cognitive function in older adults during acute hospitalization.

Methods and findings: We performed a secondary analysis of a single-blind randomized clinical trial (RCT) conducted from February 1, 2015, to August 30, 2017 in an Acute Care of the Elderly (ACE) unit in a tertiary public hospital in Navarre (Spain). 370 hospitalized patients (aged ≥75 years) were randomly allocated to an exercise intervention (n = 185) or a control (n = 185) group (usual care). The intervention consisted of a multicomponent exercise training program performed during 5-7 consecutive days (2 sessions/day). The usual care group received habitual hospital care, which included physical rehabilitation when needed. The main outcomes were change in executive function from baseline to discharge, assessed with the dual-task (i.e., verbal and arithmetic) Gait Velocity Test (GVT) and the Trail Making Test Part A (TMT-A). Changes in the Mini Mental State Examination (MMSE) test and verbal fluency ability were also measured after the intervention period. The physical exercise program provided significant benefits over usual care. At discharge, the exercise group showed a mean increase of 0.1 m/s (95% confidence interval [CI], 0.07, 0.13; p < 0.001) in the verbal GVT and 0.1 m/s (95% CI, 0.08, 0.13; p < 0.001) in the arithmetic GVT over usual care group. There was an apparent improvement in the intervention group also in the TMT-A score (-31.1 seconds; 95% CI, -49.5, -12.7 versus -3.13 seconds; 95% CI, -16.3, 10.2 in the control group; p < 0.001) and the MMSE score (2.10 points; 95% CI, 1.75, 2.46 versus 0.27 points; 95% CI, -0.08, 0.63; p < 0.001). Significant benefits were also observed in the exercise group for the verbal fluency test (mean 2.16 words; 95% CI, 1.56, 2.74; p < 0.001) over the usual care group. The main limitations of the study were patients' difficulty in completing all the tasks at both hospital admission and discharge (e.g., 25% of older patients were unable to complete the arithmetic GVT, and 47% could not complete the TMT-A), and only old patients with relatively good functional capacity at preadmission (i.e., Barthel Index score ≥60 points) were included in the study.

Conclusions: An individualized, multicomponent exercise training program may be an effective therapy for improving cognitive function (i.e., executive function and verbal fluency domains) in very old patients during acute hospitalization. These findings support the need for a shift from the traditional (bedrest-based) hospitalization to one that recognizes the important role of maintaining functional capacity and cognitive function in older adults, key components of intrinsic capacity.

Trial registration: ClinicalTrials.gov Identifier: NCT02300896.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. Study flow diagram.

ACE, Acute Care of the Elderly; GDS, Yesavage Geriatric Depression Scale.

Fig 2. Changes from baseline to discharge (A and B) and within-group punctuation change distribution (C and D).

Dual-task GVT changes: “better” indicates an improvement of more than 0.1 m/s, “slightly better” indicates an improvement between 0.001 and 0.1 m/s, “unchanged” indicates no difference, “slightly worse” indicates a decline between 0.001 and 0.1 m/s, and “worse” indicates a decline of more than 0.1 m/s. The proportion of patients showing overall improvement and worsening in the dual-task GVTs was significantly higher and lower, respectively, in the intervention than in the control group (all p < 0.001 with χ2 test). In the violin plots, the horizontal dotted lines indicate Q1 and Q3, and the horizontal dashed line within the violin, the median. GVT, Gait Velocity Test; Q1, First Quartile; Q3, Third Quartile.

Fig 3. Changes in within-group punctuation in the MMSE test, TMT-A, and verbal fluency test.

In the violin plots, the horizontal dotted lines indicate Q1 and Q3, and the horizontal dashed line within the violin, median. MMSE, Mini Mental State Examination; Q1, First Quartile; Q3, Third Quartile; TMT-A, Trail Making Test Part A.