Background
Multi-modal prehabilitation programs, incorporating nutritional supplementation and resistance training, have been developed to combat sarcopenia in surgical patients with the goal of enhancing postoperative outcomes. However, the optimal prehabilitation regime and type of nutrition still remains unknown. The use of branched-chain amino acids and their metabolites, such as ?-hydroxy ?-methylbutyrate (HMB), has beneficial effects on muscle mass and strength. However, its effect on muscle quality in the preoperative setting has yet to be established. This study aims to explore the impact of using a high-protein, high-calorie oral nutritional supplementation (ONS) with HMB on muscle quality.
Methods
Sarcopenic adult patients undergoing major elective gastrointestinal surgeries were recruited for this pilot interventional cohort study. The participants were enrolled in an established 2-4-week multimodal prehabilitation program. Three units of ONS+HMB were provided per day pre-operatively and 2 units per day for 2 months post-operatively. Compliance was evaluated through a self-administered compliance diary and a review of leftover stock by the dietician. The primary outcome was changes in intramuscular adipose tissue (IMAT) as a proxy of muscle quality, assessed using artificial intelligence-aided ultrasonography. Secondary outcomes include changes in anthropometric measurements, functional characteristics, and surgical outcomes. Outcomes were measured before and after prehabilitation and 1 month post-operatively.
Results
30 patients, with median age 72.5 years (range: 55-90), were included in the interim analysis. Mean compliance to ONS was 82%. There was a significant increase in IMAT index (5.0 to 6.4 %/cm2, p = 0.03) after 2 weeks of prehabilitation with HMB, which is sustained at 1-month post-surgery (5.0 to 6.2 %/cm2, p = 0.02). Among functional parameters, significant improvement was observed in gait speed (0.94 to 1.0 m/s, p = 0.05) after 2 weeks. There was no significant change in hand grip strength or mid-arm circumference. Median length of stay was 7 days (range: 2-75), and 2 (6.7%) patients experienced a Clavien-Dindo (CD) grade 3B or higher complication.
Discussion
The increase in IMAT index in a sarcopenic cohort undergoing prehabilitation correlates with improved gait speed and may be due to the preferential storing of energy in intramuscular fat in elderly sarcopenic patients. A prehabilitation regime incorporating high-protein ONS with HMB is feasible and associated with increased physical performance, with acceptable patient compliance. There is promise in the use of HMB in prehabilitation, with future research further elucidating the impact of ONS+HMB on muscle regeneration. Longer-term outcomes will be evaluated at the conclusion of the study after the follow-up period is complete.
