Beta-hydroxy-beta-methylbutyrate supplementation and functional outcomes in multitrauma patients: A pilot randomized controlled trial

ICU nutrition research: did the evidence get better? Remaining sources of bias

PURPOSE OF REVIEW

To assess the quality of recently published (18 months from date of article request) randomized trials/systematic reviews of such trials that addressed the use of nutritional support in critically ill patients.

RECENT FINDINGS

Eligible papers were published between October 1, 2022 and April 7, 2024, only enrolled adults, described a comparison of a nutritional intervention to something else, and reported a clinically relevant outcome. Thirteen randomized trials and four systematic reviews of randomized trials were identified. Quality was assessed by determining the risks of bias of each trial. Two of these trials were at low risk of bias, six were rated as having some concern(s) about bias, and five were at high risk of bias. The four systematic reviews included 55 randomized trials; four were at low risk, 31 had some concerns, and 20 were at high risk. No randomized trial comparing nutritional support to a true control (no nutritional support) was identified in this search; seven older trials, all small and containing risks of bias, failed to demonstrate any consistent differences in clinical outcomes.

SUMMARY

The quality of the trials underlying the use of nutritional support in the intensive care unit is not very high.

Concurrent nutrition and physical rehabilitation interventions for patients with critical illness

PURPOSE OF REVIEW

The effects of either physical rehabilitation or nutrition on outcomes in patients with critical illness are variable and remain unclear. The potential for the combination of exercise and nutritional delivered concurrently to provide benefit is provocative, but data are only emerging. Herein, we provide a summary of evidence from 2023 and 2024 on combined physical rehabilitation and nutrition during and following critical illness.

RECENT FINDINGS

While latest trials on physical rehabilitation alone reported conflicting findings, recent nutrition trials found no difference between higher and lower protein delivery and even suggested harm in patients with acute kidney injury. In 2023 and 2024, we identified four studies (one randomized controlled trial) combining physical rehabilitation and nutrition (mainly protein supplementation) within the ICU setting. Overall, these suggested benefits, including reduction of muscle size loss, ICU acquired weakness, delirium, and improved mobility levels, although these benefits did not extend to mortality and hospital length of stay. No recent trials combining physical rehabilitation and nutrition for patients after ICU were identified.

SUMMARY

Current insights on combined physical rehabilitation and nutrition suggest improved clinically relevant outcomes, but further investigations across the continuum of care of patients with critical illness are warranted.

Beta-hydroxy-beta-methyl butyrate supplementation in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

Background

Beta-hydroxy-beta-methylbutyrate (HMB) is beneficial for restoring muscle mass. However, the evidence supporting its use in critically ill patients remains unclear. We conducted a systematic review and meta-analysis of HMB in this population to ascertain its effects.

Methods

We searched PubMed, Embase, China National Knowledge Infrastructure, Wanfang, and the Cochrane database for articles focusing on adult patients receiving HMB compared to controls. The primary outcome was mortality. To explore potential heterogeneity, we assessed study quality and performed subgroup analysis, sensitivity analysis, and quality of evidence.

Results

Nine randomized controlled trials were included. There were some differences in the study design, HMB protocols, and muscle measurements among these trials. Overall, there were no significant differences in mortality between the HMB and the control groups (risk ratio = 0.96; 95% CI, 0.44-2.08; P = 0.92). This finding was confirmed by the subgroup and sensitivity analyzes. Patients in the HMB group had similar durations of MV [mean difference (MD), -0.40; 95% CI, -0.91 to 0.12; P = 0.13], ICU stay (MD, -0.61 days; 95% CI, -3.59 to 2.38; P = 0.69), and hospital stay (MD, 1.52 days; 95% CI, -1.18 to 4.22; P = 0.27). In addition, HMB did not affect changes in body weight (P = 0.53), body mass index (P = 0.56), or quadriceps thickness (P = 0.74). The outcomes of changes in skeletal muscle area (P = 0.95) and muscle loss (P = 0.16) were similar between the two groups.

Conclusion

Beta-hydroxy-beta-methylbutyrate (HMB) did not improve the mortality or other clinical outcomes in critically ill patients. This may be because of the different HMB strategies used in the included trials. Our findings provide insights into future research designs that explore the clinical efficacy of HMB in this patient population.

Nutritional Support in the ICU

Critical illness is a complex condition that can have a devastating impact on health and quality of life. Nutritional support is a crucial component of critical care that aims to maintain or restore nutritional status and muscle function. A one-size-fits-all approach to the components of nutritional support has not proven beneficial. Recent randomized controlled trials challenge the conventional strategy and support the safety and potential benefits of below-usual calorie and protein intakes at the early, acute phase of critical illness. Further research is needed to define optimal nutritional support throughout the intensive care unit stay. Individualized nutritional strategies relying on risk assessment tools or biomarkers deserve further investigation in rigorously designed, large, multicenter, randomized, controlled trials. Importantly, although nutritional support is crucial, it might not be sufficient to enhance the recovery of critically ill patients. Thus, achieving the greatest efficacy may require individualized nutritional support combined with early, prolonged physical rehabilitation within a multimodal, holistic care program throughout the patient's recovery journey.

Dietary protein in the ICU in relation to health outcomes

PURPOSE OF REVIEW

Critical care nutrition guidelines recommend provision of higher protein doses than recommended in health. These recommendations have been predominately based on lower quality evidence and physiological rationale that greater protein doses may attenuate the significant muscle loss observed in critically ill patients. This review discusses the mechanistic action of protein in the critically ill, details results from recent trials on health outcomes, discusses considerations for interpretation of trial results, and provides an overview of future directions.

RECENT FINDINGS

Two recent large clinical trials have investigated different protein doses and the effect on clinical outcome. Important findings revealed potential harm in certain sub-groups of patients. This harm must be balanced with the potential for beneficial effects on muscle mass and physical function given that two recent systematic reviews with meta-analyses demonstrated attenuation of muscle loss with higher protein doses. Utilizing biological markers such as urea: creatinine ratio or urea levels may prove useful in monitoring harm from higher protein doses.

SUMMARY

Future research should focus on prospectively investigating biological signatures of harm as well as taking into the consideration elements that will likely enhance the effectiveness of protein dose.

Six-month outcomes after traumatic brain injury in the Augmented versus Routine Approach to Giving Energy multicentre, double-blind, randomised controlled Trial (TARGET)

BACKGROUND

Critically ill patients with a traumatic brain injury (TBI) may require prolonged intensive care unit (ICU) admission and hence receive greater exposure to hospital enteral nutrition. It is unknown if augmented energy delivery with enteral nutrition during ICU admission impacts quality of life in survivors or gastrointestinal tolerance during nutrition delivery in the ICU.

OBJECTIVES

The objective of this study was to compare health-related quality of life, using the EuroQol five-dimensions five-level visual analogue scale at 6 months, in survivors who presented with a TBI and received augmented energy (1.5 kcal/ml) to those who received routine energy (1.0 kcal/ml). Secondary objectives were to explore differences in total energy and protein delivery, gastrointestinal tolerance, and mortality between groups.

METHODS

Secondary analysis of participants admitted with a TBI in the Augmented versus Routine Approach to Giving Energy Trial (TARGET) randomised controlled trial. Data are represented as n (%) or median (interquartile range).

RESULTS

Of the 3957 patients in TARGET, 231 (5.8%) were admitted after a TBI (augmented = 124; routine = 107). Patients within TARGET who were admitted with a TBI were relatively young (42 [27, 61] years) and received TARGET enteral nutrition for an extended period (9 [5, 15] days). At 6 months, EuroQol five-dimensions five-level quality-of-life scores were available for 166 TBI survivors (72% of TBI cohort randomised, augmented = 97, routine = 69). There was no evidence of a difference in quality of life (augmented = 70 [52, 90]; routine = 70 [55, 85]; median difference augmented vs routine = 0 [95% confidence interval: -5, 10]). TBI participants assigned to augmented energy received more energy with a similar protein than the routine group. Gastrointestinal tolerance was similar between groups.

CONCLUSION

While patients admitted after a TBI received enteral nutrition for an extended period, an increased exposure to augmented energy did not affect survivors' quality-of-life scores.

Plasma beta-hydroxy-beta-methylbutyrate availability after enteral administration during critical illness after trauma: An exploratory study

BACKGROUND

During critical illness skeletal muscle wasting occurs rapidly. Although beta-hydroxy-beta-methylbutyrate (HMB) is a potential treatment to attenuate this process, the plasma appearance and muscle concentration is uncertain.

METHODS

This was an exploratory study nested within a blinded, parallel group, randomized clinical trial in which critically ill patients after trauma received enteral HMB (3 g daily) or placebo. Plasma samples were collected at 0, 60, and 180 min after study supplement administration on day 1. Needle biopsies of the vastus lateralis muscle were collected (baseline and day 7 of the HMB treatment intervention period). An external standard curve was used to calculate HMB concentrations in plasma and muscle.

RESULTS

Data were available for 16 participants (male n = 12 (75%), median [interquartile range] age 50 [29-58] years) who received placebo and 18 participants (male n = 14 (78%), age 49 [34-55] years) who received HMB. Plasma HMB concentrations were similar at baseline but increased after HMB (T = 60 min: placebo 0.60 [0.44-1.31]  µM; intervention 51.65 [22.76-64.72]  µM). Paired muscle biopsies were collected from 11 participants (placebo n = 7, HMB n = 4). Muscle HMB concentrations were similar at baseline between groups (2.35 [2.17-2.95]; 2.07 [1.78-2.31] µM). For participants in the intervention group who had the repeat biopsy within 4 h of HMB administration, concentrations were greater (7.2 and 12.3 µM) than those who had the repeat biopsy >4 h after HMB (2.7 and 2.1 µM).

CONCLUSION

In this exploratory study, enteral HMB administration increased plasma HMB availability. The small sample size limits interpretation of the muscle HMB findings.