Effects of muscle mass and muscle quality estimated by phase angle on functional outcomes in older patients undergoing rehabilitation: A prospective cohort study

Bioelectrical impedance analysis (BIA) phase angle in stroke patients: A systematic review

BACKGROUND AND AIMS

Phase angle (PhA), a raw variable of bioelectrical impedance analysis (BIA), is an index of muscle structure and quality and might have a potential role in the evaluation of nutritional status. The aim of this systematic review was to evaluate in stroke patients: baseline PhA and its changes during hospital stay; the association of PhA with clinical features of patients, comorbidities, nutritional status or sarcopenia, and clinical outcomes.

METHODS

Systematic research on electronic databases (PubMed, Scopus, and Web of Science) up to June 14th, 2024 was performed according to PRISMA checklist. Using PECOS strategy, "P" (patients) = stroke patients, "E" (exposure) = lowest PhA values, "C" (comparison) = versus greatest PhA values, "O" (outcome) = nutritional and clinical outcomes, and "S" (study design) = all study types. Methodological quality was assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies (NIH).

RESULTS

Eighteen papers met the inclusion criteria, with a low risk of bias. In stroke patients, evidence suggests that PhA was associated with malnutrition, sarcopenia and sarcopenic obesity, as well as with physical function. In addition, patients with low PhA had a longer hospital stay, higher inflammatory status and higher incidence of urinary tract infections and hospital-acquired pneumonia.

CONCLUSIONS

Selected papers, although not conclusive, show that in acute and subacute stroke patients PhA was inversely associated with malnutrition and poor physical function. PhA could be a marker of health status and disease progression. PhA may be useful in a more comprehensive evaluation of nutritional status to be used for diagnosis and implementing therapy.

Relationship among low baseline muscle mass, skeletal muscle quality, and mortality in critically ill children

BACKGROUND

Studies in adults have shown that low baseline muscle mass at intensive care unit (ICU) admission was associated with poor clinical outcomes. However, no information on the relationship between baseline muscle quality or mass and clinical outcomes in critically ill children was found.

METHODS

3775 children were admitted to the pediatric ICU (PICU), 262 were eligible for inclusion. Abdominal computed tomography was performed to assess baseline skeletal muscle mass and quality. Patients were categorized to normal or low group based on the cutoff value for predicting hospital mortality of the skeletal muscle index (SMI; 30.96 cm2/m2) and skeletal muscle density (SMD; 41.21 Hounsfield units).

RESULTS

Body mass index (BMI) (18.07 ± 4.44 vs 15.99 ± 4.51) and BMI-for-age z score (0.46 [-0.66 to 1.74] vs -0.87 [-1.69 to 0.05]) were greater in the normal-SMI group, the length of PICU stay was longer in the low-SMI group (16.00 days [8.50-32.50] vs 13.00 days [7.50-20.00]), and the in-PICU mortality rate in the normal-SMI group (10.00%) was lower than the low-SMI group (22.6%). Children with low SMD had a higher in-PICU mortality rate (25.6% vs 7.7%), were younger (36.00 months [12.00-120.00] vs 84.00 months [47.50-147.50]) and weighed less (16.40 kg [10.93-37.25] vs 23.00 kg [16.00-45.00]). Mortality was greater in patients with lower SMD and prolonged hospital stay (log-rank, P = 0.007). SMD was an independent predictor for length of PICU stay and in-PICU mortality.

CONCLUSIONS

Low baseline skeletal muscle quality in critically ill children is closely tied with a higher in-PICU mortality and longer PICU stay and is an independent risk factor for unfavorable clinical outcomes.

Relationship between phase angle and lower-extremity function in older adults: Itabashi Longitudinal Study on Aging

OBJECTIVE

Evaluating muscle quality instead of its mass has gained attention in diagnosing sarcopenia. The aim of this study was to examine whether phase angle (PhA) as a bioelectrical impedance analysis (BIA)-derived muscle quality indicator is associated with overall lower extremity function better than appendicular skeletal muscle mass index (ASMI) in community-dwelling older adults.

METHODS

This cross-sectional study used data from the Itabashi Longitudinal Study on Aging, a community-based cohort study. A sex-stratified multivariate logistic regression analysis was conducted using PhA and ASMI as exposures, and low physical function defined as short physical performance battery score <10 as the outcome, adjusted for age, being overweight, knee pain, and non-communicable diseases. Discrimination of low physical function was compared using the receiver operating characteristic curve.

RESULTS

This study included 1464 participants (age 76 [73-80] y; 757 women), with 58 men (8%) and 66 women (9%) exhibiting low physical function. The multivariate odds ratio (OR; 95% confidence interval [CI]) for low physical function among the highest quartile, compared with the lowest quartile were significant in PhA in multiple sites (e.g., OR, 0.09; 95% CI, 0.03-0.32] for men and 0.12; 95% CI, 0.04-0.33 for women in the left leg) but not in ASMI (OR, 0.51; 95% CI, 0.19-1.34 for men and 0.56; 95% CI, 0.21-1.47 for women). Legs and whole-body PhA outperformed the ASMI in discriminating low physical function (P < 0.001).

CONCLUSION

PhA reflected physical function better than ASMI; using PhA instead of ASMI in BIA-based morphometric evaluation may add information on low physical function and enhance the diagnostic value of sarcopenia.