The Impact of Nutritional Therapy on Resting Energy Expenditure in Malnourished Older Hospitalized Patients

Research Article

Austin J Nutr Metab. 2020; 7(5): 1095.

The Impact of Nutritional Therapy on Resting Energy Expenditure in Malnourished Older Hospitalized Patients

Pourhassan M*, Daubert D and Wirth R

Department of Geriatric Medicine, Marien Hospital Herne, Ruhr-Universität Bochum, Germany

*Corresponding author: Pourhassan M, Department of Geriatric Medicine, Marien Hospital Herne, Ruhr-Universität Bochum, Germany, Hölkeskampring 40, D-44625 Herne, Germany

Received: June 30, 2020; Accepted: July 30, 2020; Published: August 06, 2020

Abstract

Background and Aims: Little is known about the effect of nutritional therapy on Resting Energy Expenditure (REE) in malnourished older hospitalized patients. We sought to evaluate longitudinal changes in REE during nutritional therapy and to examine the different factors associated with changes in REE among these patients.

Methods: Twenty-three malnourished older patients (age range 67-93, 65% women) participated in this prospective longitudinal observational study. Malnutrition was defined as Mini Nutritional Assessment Short Form (MNA-SF) <8. REE was measured by using indirect calorimetry on hospital admission and at discharge. Body composition (i.e. Fat Free Mass (FFM)) was assessed by bioelectrical impedance analysis. The Parker mobility score was performed to evaluate the patient’s mobility. Nutritional support (i.e. high protein and/or high calorie oral nutritional supplements) was provided to all malnourished patients during hospitalization.

Results: All patients were malnourished with a median MNA-SF score of 6. The median time between two REE measurements was 13 days (interquartile range: 11-15). On admission, REE was significantly lower in patients with lower FFM (P=0.043) and decreased along with the degree of malnutrition (P=0.008). REE (+212.6 kcal, P=0.010) and REE/FFM (+5.6 kcal/kg, P=0.021) increased significantly during hospitalization. In a multiple regression analysis, age, gender and BMI followed by MNA-SF score and mobility were the major independent risk factors of changes in REE.

Conclusion: Low REE in malnourished older patients increased to normal after 2 weeks of nutritional treatment.

Keywords: Malnutrition; Resting Energy Expenditure; Fat Free Mass; Nutritional Therapy; Older Persons

Abbreviations

REE: Resting Energy Expenditure; MNA-SF: Mini Nutritional Assessment Short Form; BIA: Bioelectrical Impedance Analysis; FFM: Fat Free Mass; FM: Fat Mass; SMM: Skeletal Muscle Mass; BW: Body Weight; CRP: C-Reactive Protein; TSH: Thyroid-Stimulating Hormone; IQR: Interquartile Range; SE: Standard Error

Introduction

Malnutrition is a frequent finding in older patients and has commonly a multifactorial etiology. Malnutrition is associated with high risk of complications such as infections, falls, low quality of life, prolonged rehabilitation and hospitalization and higher mortality and morbidity [1]. Although, the prevalence of malnutrition is as high as 50% in hospital admitted older persons [2,3], it remains widely unrecognized and the pathophysiological role and relevance of potential causes are still not well understood [1,4].

It is clear that low energy intake and increased energy requirements are the main mechanisms causing malnutrition [5]. However, malnutrition is often reversible and can be treated with an increase in energy and nutrients provision [6]. For determining the exact energy needs and preventing a negative energy balance, it is of great importance to assess Resting Energy Expenditure (REE). REE is responsible for more than two thirds of Total Energy Expenditure (TEE) and represents the energy needs of an individual to maintain vital organs during rest [7]. REE can be measured by Indirect Calorimetry (IC) which is considered as gold standard.

It is well known that REE declines with age mainly due to decrease in Fat Free Mass (FFM). However, previous studies demonstrated that even after adjustment for FFM and Fat Mass (FM), older individuals have significantly lower REE than younger adults [8,9]. REE may be influenced by other factors such as immobility, inflammation, thyroid hormones and malnutrition. Currently, it remains unclear to what extent this lower REE is a consequence of malnutrition.

A decreased REE in malnourished patients may be a consequence of metabolic adaptation to low energy intake. If this is true, measured REE would be decreased due to malnutrition and may not represent patient’s true energy requirements. It is known that energy deficit and weight loss lead to metabolic adaptation which results in reducing energy expenditure and enhancing metabolic efficiency [10-12]. However, such adaptation may be reversed by nutritional therapy which could lead to an increase in REE and promote body weight regain. Findings of a 6-week subsequent overfeeding-caloric restriction-refeeding study among 32 healthy young men indicated that REE significantly decreased during 3-week caloric restriction due to metabolic adaptation and normalized within 2-week of refeeding [10].

Assessing REE is useful for optimizing and managing nutritional support in malnourished hospitalized patients. However, there is a lack of data on energy needs of malnourished older patients and limited data is available with accurate assessment of total and resting energy expenditure. To the best of our knowledge, there is no study in malnourished older hospitalized patients investigating the effect of nutritional therapy on REE. We hypothesize that the low REE in these patients can be normalized by nutritional treatment. Therefore, the aim of the present study was to evaluate longitudinal changes in REE during nutritional therapy and to examine the different factors associated with changes in REE among malnourished older hospitalized patients.

Materials and Methods

This prospective longitudinal observational study was undertaken between September 2019 - January 2020 at a geriatric acute care unit, at the university hospital, Marien Hospital Herne in Germany. The study participants comprise 23 consecutive malnourished older hospitalized patients with mean age 81.8 ± 8.1 years. Malnutrition was defined as Mini Nutritional Assessment Short Form (MNASF) <8 (13) or weight loss >10% of initial body weight in 6 months or shorter. Other eligibility criteria were age > 65 years, a probable hospital stay of at least 14 days, ability to understand and cooperate and written informed consent. Participants with severe dementia, severe depression, dysphagia, edema, artificial nutrition, i.e. tube feeding and significantly reduced cognitive abilities (Montreal Cognitive Assessment (MoCA) <10) were excluded from the study.

Body weight, REE, activity of daily living and patient’s mobility were conducted during the first days of hospital admission (baseline) and at the time of discharge (follow-up). In addition, body composition analysis and geriatric assessment were performed at hospital admission. Serum concentrations of Thyroid-Stimulating Hormone (TSH) and C-Reactive Protein (CRP) were measured on admission according to standard clinical procedures. CRP level ≥ 2 (mg/dl) was defined as moderate inflammation.

The degree of weight loss was obtained by interview or derived from the patients’ medical records. Furthermore, all malnourished patients received individualized nutritional therapy i.e. high protein and/or high calorie oral nutritional Supplements (ONS) during hospitalization, although, the composition was different based On patient’s Nutritional needs and preferences. The study protocol had been approved by the ethical committee of Ruhr-University Bochum (17-6217, approved on 14.11.2017). Written informed consent was obtained from all patients.

Geriatric assessment

Activities of daily living were determined using Barthel-Index [14]. The point’s range of the German version of the BI is 0-100 pts., with 100 pts. Indicating independency in all activities of daily living. FRAIL scale [15], scoring from 0 (no frail) to 5 (frail), was used to identify persons at risk of frailty. The risk of sarcopenia was screened using SARC-F questionnaire [16], which ranges from 0 to 10, with higher scores representing probable sarcopenia. MoCA [17] was used to evaluate cognitive function with a total score of 30 whereas a score of 26 and higher was considered as normal. Depressive symptoms were diagnosed using Depression in Old Age Scale (DIA-S) [18] with scores 0-2 as having no depression, 3 suspected depression and 4-10 probable depression. The Parker mobility score [19] was performed to evaluate the patient’s mobility indoors, outdoors and during shopping with the total score ranges from 0 to 9. The highest overall score of 9 demonstrates the best possible mobility.

REE

REE was measured by using indirect calorimetry (Q-NRG, Cosmed, Rome, Italy). The device was warmed up before each measurement and flowmeter was calibrated using 3L calibration syringe weekly. In addition, the device was calibrated with a gas mixture of 16% O2, 5% CO2 and balance nitrogen monthly. Clear plastic canopy hood was used for collection of continuous gas exchange measurements for a minimum of ten minutes. The first three minutes of every test were discarded. The measurement of REE was carried in the morning after an overnight fast > 8 h. REE was calculated from whole-body O2 consumption and whole-body CO2 production according to Weir equation [20]. Measured REE was also expressed as a function of FFM (kcal/kg of FFM/day) and body weight (kcal/kg of body weight/day).

Body composition

Measurement of FFM, Fat Mass and (FM), Skeletal Muscle Mass (SMM) of the participants was performed using the phase-sensitive, multi-frequency 8 electrode SECA medical Body Composition Analyser 525 device (BIA, seca mBCA 525, Hamburg, Germany). Measurement was taken in the supine position while 4 pairs of surface electrodes attached 2 to each hand and foot, as described by the manufacturer.

Statistical analysis

All statistical analysis was performed using SPSS statistical software (SPSS Statistics for Windows, IBM Corp, Version 26.0, Armonk, NY, USA). Means and Standard Deviations (SDs) were used for continuous data with normal distribution whereas median values are expressed with Interquartile Ranges (IQR) for non-normally distributed data. Categorical variables are reported as absolute numbers and percentages (n, %). Differences between variables and between baseline and follow-up were analyzed by using paired samples t test for normally distributed values.

Differences in variables at baseline between men and women were analyzed by using an unpaired t test in normally distributed variables and the Mann-Whitney U test for continuous variables with non-normal distribution. Categorical variables were compared by the Chi square test. Pearson’s correlation coefficient was calculated for relations between variables. In addition, multiple regression analysis was performed to investigate the independent effects of age, gender, mobility, BMI, changes in body weight during hospitalization, FFM, inflammation (CRP) and total MNA-SF (as independent variables) on changes in REE as dependent variable. A P-value of <0.05 was considered as the limit of significance.

Results

Baseline characteristics of study participants stratified by gender are summarized in Table 1. Of 23 patients, 65% of subjects were women. All patients were malnourished with a median MNA-SF score of 6. The age range was between 67 and 93 years. The majority of the subjects were frail (91%) and demonstrated an impaired cognitive function (94%) and 48% of the participants exhibited severe depressive symptom.