Mediterranean Diet, In-Hospital Exercise, and the Incidence of Hospital-Acquired Disability in Old Patients

Hospital-acquired disability (HAD) refers to the loss of capacity to perform one or more activities of daily living following hospitalization (1, 2). This condition is highly insidious and results from the combined effects of the acute illness and hospitalization (e.g., prolonged bedrest, adverse effects of medications, nosocomial infections) (1). Old patients who developed HAD can rarely take care of themselves at discharge (1, 3) and most of them experience persistent disability (4). Indeed, old patients with HAD show a three-fold greater risk of nursing-home admission than those with no in-hospital deterioration of functional status (3). This scenario is concerning, given that the prevalence of HAD in advanced age is approximately 30% (2).

The implementation of strategies to mitigate the incidence of HAD is mandatory to improve patient recovery, avoid adverse outcomes, and reduce healthcare and societal costs. The Acute Care for Elders (ACE) model is an evidence-based approach involving a multidisciplinary team that provides a patient-centered geriatric assessment, specific management and care plans, and comprehensive care transition planning at hospital admission to prevent incident geriatric syndromes, including HAD (5, 6). This intervention reduces the risk of functional decline during hospitalization and increases the likelihood to be discharged home (7).

Exercise training has been proposed as an additional strategy to prevent HAD. Results of a randomized clinical trial indicate that a multicomponent exercise program performed twice a day improved physical function at discharge in acutely hospitalized old patients (8). These findings are in line with a meta-analysis that examined more than 2000 old patients ranging in age from 65 to 102 years and found that exercise training improved functionality in acute care settings, which was accompanied by enhancements in mobility, muscle strength and power (9). However, a systematic review of randomized or quasi-randomized controlled trials evaluating in-hospital exercise interventions found that exercise did not substantially affect functional status at discharge in patients 65 years or older (10). A possible explanation for the variability in the response to exercise among acutely hospitalized older adults has been proposed from Valenzuela et al. (11). The authors noted that the response to exercise training in patients hospitalized in acute geriatric care settings was influenced by the length of hospital stay, the presence of comorbidities, functional status at admission, and nutritional status (11).

In this edition of The Journal of Nutrition, Health & Aging, Tor-Roca et al. (12) provide further insights on strategies to reduce the incidence of HAD in old patients. The authors examined the moderation of adherence to a Mediterranean (MED) diet, estimated according to the MEDAS scale and urinary total polyphenols, on the effects of a multicomponent training program or a health education intervention on functional status of 109 old patients admitted to an acute geriatric unit. The authors found that exercise improved functional status in participants with a low MED diet adherence, regardless of the method used to estimate adherence. The moderation effect of MED diet was independent of several confounders.

How should we interpret these findings? Should we recommend a low MED diet adherence to improve functionality in old patients during their hospital stay? The answer is probably no! Indeed, a low adherence to MED diet is frequently accompanied by unhealthy lifestyle habits, including a sedentary behavior, poor social engagement, inadequate hydration, insufficient sleep time and quality, and inadequate food preparation methods (13, 14). Altogether, they contribute to endanger the functional status of older adults and their overall health.

Hence, in the studies by Tor-Roca et al. (12), participants with a low adherence to MED diet might have pre-existing deficits in health domains that were not accounted for in the analysis (e.g., social engagement, sleep quality, physical activity levels). The modified Haskell model proposed by Brahms et al. (15) offers an additional explanation for the findings of Tor-Roca et al. (12). Following this approach, the authors discuss why individuals with low mobility status, assessed through accurate and adequate instruments, can experience benefits from nonspecific interventions (15). An example of this scenario is the SPRINTT randomized clinical trial, in which greater improvements in physical performance in response to a multicomponent exercise program plus nutritional counseling were observed among older adults with low physical function at baseline (16). On the other hand, nonspecific interventions may fail at conveying substantial functional benefits to older adults with high mobility status at the beginning of the intervention (15). Future studies are warranted to evaluate whether training protocols tailored to pre-admission functional status are effective at reducing the incidence of HAD in older adults. Studies are also needed to determine whether the effects of in-hospital exercise are influenced by specific dietary patterns.

Conflict of interest statement

The authors have no conflict of interest to disclose.