Clin Nutr. 2015 Oct;34(5):1033-4.

Combined intervention of protein supplementation and resistance training in medical patients.

Maeda K, Wakabayashi H, Shamoto H.

Tamana Regional Health Medical Center, Japan.

Yokohama City University Medical Center, Japan.

Minamisoma Municipal General Hospital, Japan.

In a recent issue of Clinical Nutrition (March 2015), Buhl and coworkers [1] reported the results of their randomized control study in which a combination of protein supplement and resistance training failed to maintain muscle mass and physical function in geriatric patients after systemic inflammatory syndrome, in contrast to what was expected. We agree with the study concept; however, we have several concerns about the interpretation, design, and statistical methods employed.

First, the results can be interpreted as that medical patients without malnutrition may not predict poorer outcomes if they were on diet restriction, owing to the fact that many subjects at risk of malnutrition due to their clinical courses might not be considered as having malnutrition and sarcopenia according to their body mass index and lean mass. The skeletal muscle mass indices (SMIs), which were estimated using the mean appendicular lean mass, body mass index, and body weight, were 6.20 and 7.20 kg/m2 for the intervention and control groups, respectively, indicating that, considering the gender distribution, most subjects were not sarcopenic, as the cut-off values of SMI to diagnose sarcopenia are 7.26 and 5.50 kg/m2 in men and women, respectively [2]. Regarding the protein intake, we recognize that the intervention and control groups consumed normal (1.02 g/kg/day) and restricted amounts (0.82 g/kg/day), respectively.

Second, the study design is not applicable in clinical situations. Seventy-three percent of subjects, who were significantly older than the analyzed ones, were excluded, mainly for presenting an estimated glomerular filtration rate (eGFR) < 60 ml/min (61%). The application of eGFR <60 ml/min, which is estimated using age, infers a generalization of the study. We suggest that eGFR <30 ml/min is a more suitable exclusion criterion, since protein restriction is not always necessary for patients with eGFR >30 ml/min [3]. Further, aging impacts both eGFR and sarcopenia, and the effects of protein supplementation and resistance training on muscle mass and function have been mostly studied in sarcopenic elderly people [4].

Third, the intervention methodology required compliance to the resistance training. Since protein intake immediately after resistance training is known to be the best way to increase muscle mass and improve muscle function [5], poor compliance to the resistance training might not allow the true effects of the resistance training and protein supplementation combination to be proven.

Finally, we suggest assessing 1) the SMI at baseline and throughout the intervention, as SMI is widely used to assess decline of muscle mass [2]; and 2) the effect size (such as eta, phi, etc.) for the baseline comparison, because the p-value alone cannot describe statistical differences in such a small study population. Considering that the negative results obtained warrant further investigations, the study by Buhl et al. is worth discussing in detail.

References  

1. Buhl SF, Andersen AL, Andersen JR, et al. The effect of protein intake and resistance training on muscle mass in acutely ill old medical patients e a randomized controlled trial. Clin Nutr. 2015. DOI: 10.1016/j.clnu.2015.02.015

2. Cruz-Jentoft AJ, Baeyens JP, Bauer JM, et al. Sarcopenia: European consensus on definition and diagnosis: report of the European Working Group on Sarcopenia in Older People. Age Ageing. 2010;39:412e23. DOI: 10.1093/ageing/afq034

3. Deutz NE, Bauer JM, Barazzoni R, et al. Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert Group. Clin Nutr. 2014;33:929e36. DOI: 10.1016/j.clnu.2014.04.007

4. Malafarina V, Uriz-Otano F, Iniesta R, et al. Effectiveness of nutritional supplementation on muscle mass in treatment of sarcopenia in old age: a systematic review. J Am Med Dir Assoc. 2013;14:10e7. DOI: 10.1016/j.jamda.2012.08.001

5. Esmarck B, Andersen JL, Olsen S, et al. Timing of postexercise protein intake is important for muscle hypertrophy with resistance training in elderly humans. J Physiol. 2001;535:301e11. DOI: 10.1111/j.1469-7793.2001.00301.x

KEYWORDS: Protein supplementation; Resistance training; Sarcopenia

PMID: 26051495

DOI: 10.1016/j.clnu.2015.05.008

Clin Nutr. 2015 Mar 5. [Epub ahead of print]

The effect of protein intake and resistance training on muscle mass in acutely ill old medical patients - A randomized controlled trial.

Buhl SF, Andersen AL, Andersen JR, Andersen O, Jensen JE, Rasmussen AM, Pedersen MM, Damkjaer L, Gilkes H, Petersen J.

Clinical Research Centre (056), Amager Hvidovre Hospital, University of Copenhagen, DK-2650 Hvidovre, Denmark.

University of Copenhagen, DK-1958 Frederiksberg C, Denmark.

Nutrition Unit 5711, Rigshospitalet, DK-2100 Copenhagen Oe, Denmark.

Amager Hvidovre Hospital, DK-2650 Hvidovre, Denmark.

Municipality of Copenhagen, DK-2200 Copenhagen N, Denmark.

BACKGROUND & AIM: Stress metabolism is associated with accelerated loss of muscle that has large consequences for the old medical patient. The aim of this study was to investigate if an intervention combining protein and resistance training was more effective in counteracting loss of muscle than standard care. Secondary outcomes were changes in muscle strength, functional ability and body weight.

METHODS: 29 acutely admitted old (>65 years) patients were randomly assigned to the intervention (n = 14) or to standard care (n = 15). The Intervention Group received 1.7 g protein/kg/day during admission and a daily protein supplement (18.8 g protein) and resistance training 3 times per week the 12 weeks following discharge. Muscle mass was assessed by Dual-energy X-ray Absorptiometry. Muscle strength was assessed by Hand Grip Strength and Chair Stand Test. Functional ability was assessed by the de Morton Mobility Index, the Functional Recovery Score and the New Mobility Score. Changes in outcomes from time of admission to three-months after discharge were analysed by linear regression analysis.

RESULTS: The intention-to-treat analysis showed no significant effect of the intervention on lean mass (unadjusted: β-coefficient = -1.28 P = 0.32, adjusted for gender: β-coefficient = -0.02 P = 0.99, adjusted for baseline lean mass: β-coefficient = -0.31 P = 0.80). The de Morton Mobility Index significantly increased in the Control Group (β-coefficient = -11.43 CI: 0.72-22.13, P = 0.04). No other differences were found.

CONCLUSION: No significant effect on muscle mass was observed in this group of acutely ill old medical patients. High compliance was achieved with the dietary intervention, but resistance training was challenging. Clinical trials identifier NCT02077491.

KEYWORDS: Geriatric; Muscle mass; Nutrition; Oral Nutritional Supplement; Resistance training; Systemic Inflammatory Response Syndrome

PMID: 25796103

PII: S0261-5614(15)00073-4

DOI: 10.1016/j.clnu.2015.02.015