The effect of dose, frequency, and timing of protein supplementation on muscle mass in older adults: A systematic review and meta-analysis.

Protein supplementation has shown to improve muscle mass in older adults. However, its effect may be influenced by supplementation dose, frequency and timing. This systematic review aimed to assess the effect of dose, frequency and timing of protein supplementation on muscle mass in older adults. Five databases were systematically searched from inception to 14 March 2023, for randomised controlled trials investigating the effect of protein supplementation on muscle mass in adults aged ≥65 years. Random effects meta-analyses were performed, stratified by population. Subgroups were created for dose (≥30 g, <30 g/day), frequency (once, twice, three times/day) and timing of supplementation (at breakfast, breakfast and lunch, breakfast and dinner, all meals, between meals). Heterogeneity within and between subgroups was assessed using I2 and Cochran Q statistics respectively. Thirty-eight articles were included describing community-dwelling (28 articles, n=3204, 74.6±3.4 years, 62.8 % female), hospitalised (8 articles, n=590, 77.0±3.7 years, 50.3 % female) and institutionalised populations (2 articles, n=156, 85.7±1.2 years, 71.2 % female). Protein supplementation showed a positive effect on muscle mass in community-dwelling older adults (standardised mean difference 0.116; 95 % confidence interval 0.032-0.200 kg, p=0.007, I2=15.3 %) but the effect did not differ between subgroups of dose, frequency and timing (Q=0.056, 0.569 and 3.084 respectively, p>0.05). Data including hospitalised and institutionalised populations were limited. Protein supplementation improves muscle mass in community-dwelling older adults, but its dose, frequency or timing does not significantly influence the effect.

Body Weight and Composition Changes in Geriatric Rehabilitation Are Dependent on Sarcopenia and Malnutrition: RESORT.

OBJECTIVES: Body weight and muscle mass loss following an acute hospitalization in older patients may be influenced by malnutrition and sarcopenia among other factors. This study aimed to assess the changes in body weight and composition from admission to discharge and the geriatric variables associated with the changes in geriatric rehabilitation inpatients. DESIGN: RESORT is an observational, longitudinal cohort. SETTING AND PARTICIPANTS: Geriatric rehabilitation inpatients admitted to geriatric rehabilitation wards at the Royal Melbourne Hospital, Melbourne, Australia (N = 1006). METHODS: Changes in body weight and body composition [fat mass (FM), appendicular lean mass (ALM)] from admission to discharge were analyzed using linear mixed models. Body mass index (BMI) categories, (risk of) malnutrition (Global Leadership Initiative on Malnutrition), sarcopenia (European Working Group on Sarcopenia in Older People), dependence in activities of daily living (ADL), multimorbidity, and cognitive impairment were tested as geriatric variables by which the changes in body weight and composition may differ. RESULTS: A total of 1006 patients [median age: 83.2 (77.7-88.8) years, 58.5% female] were included. Body weight, FM (kg), and FM% decreased (0.30 kg, 0.43 kg, and 0.46%, respectively) and ALM (kg) and ALM% increased (0.17 kg and 0.33%, respectively) during geriatric rehabilitation. Body weight increased in patients with underweight; decreased in patients with normal/overweight, obesity, ADL dependence and in those without malnutrition and sarcopenia. ALM% and FM% decreased in patients with normal/overweight. ALM increased in patients without multimorbidity and in those with malnutrition and sarcopenia; ALM% increased in patients without multimorbidity and with sarcopenia. CONCLUSIONS AND IMPLICATIONS: In geriatric rehabilitation, body weight increased in patients with underweight but decreased in patients with normal/overweight and obesity. ALM increased in patients with malnutrition and sarcopenia but not in patients without. This suggests the need for improved standard of care independent of patients' nutritional risk.

Malnutrition Screening Tools Are Not Sensitive Enough to Identify Older Hospital Patients with Malnutrition.

This study evaluates the concurrent validity of five malnutrition screening tools to identify older hospitalized patients against the Global Leadership Initiative on Malnutrition (GLIM) diagnostic criteria as limited evidence is available. The screening tools Short Nutritional Assessment Questionnaire (SNAQ), Malnutrition Universal Screening Tool (MUST), Malnutrition Screening Tool (MST), Mini Nutritional Assessment-Short Form (MNA-SF), and the Patient-Generated Subjective Global Assessment-Short Form (PG-SGA-SF) with cut-offs for both malnutrition (conservative) and moderate malnutrition or risk of malnutrition (liberal) were used. The concurrent validity was determined by the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the level of agreement by Cohen's kappa. In total, 356 patients were included in the analyses (median age 70 y (IQR 63-77); 54% male). The prevalence of malnutrition according to the GLIM criteria without prior screening was 42%. The conservative cut-offs showed a low-to-moderate sensitivity (32-68%) and moderate-to-high specificity (61-98%). The PPV and NPV ranged from 59 to 94% and 67-86%, respectively. The Cohen's kappa showed poor agreement (k = 0.21-0.59). The liberal cut-offs displayed a moderate-to-high sensitivity (66-89%) and a low-to-high specificity (46-95%). The agreement was fair to good (k = 0.33-0.75). The currently used screening tools vary in their capacity to identify hospitalized older patients with malnutrition. The screening process in the GLIM framework requires further consideration.