Predictive value of phase angle in sarcopenia in patients on maintenance hemodialysis

Comparing Device-Generated and Calculated Bioimpedance Variables in Community-Dwelling Older Adults

Despite BIA emerging as a clinical tool for assessing older adults, it remains unclear how to calculate whole-body impedance (Z), reactance (Xc), resistance (R), and phase angle (PhA) from segmental values using modern BIA devices that place electrodes on both sides of the body. This investigation aimed to compare both the whole-body and segmental device-generated phase angle (PhADG) with the phase angle calculated using summed Z, Xc, and R from the left, right, and combined sides of the body (PhACalc) and to compare bioelectric variables between sides of the body. A sample of 103 community-dwelling older adults was assessed using a 50 kHz direct segmental multifrequency BIA device. Whole-body PhACalc values were assessed for agreement with PhADG using 2.5th and 97.5th quantile nonparametric limits of agreement and Spearman's rho. Bioelectrical values between sides of the body were compared using Wilcoxon rank and Spearman's rho. A smaller mean difference was observed between PhADG and right PhACalc (-0.004°, p = 0.26) than between PhACalc on the left (0.107°, p = 0.01) and on the combined sides (0.107°, p < 0.001). The sum of Z, R, and PhACalc was significantly different (p < 0.01) between the left (559.66 ± 99.55 Ω, 556.80 ± 99.52 Ω, 5.51 ± 1.5°, respectively) and the right sides (554.60 ± 94.52 Ω, 552.02 ± 94.23 Ω, 5.41 ± 0.8°, respectively). Bilateral BIA values do not appear to be interchangeable when determining whole-body measurements. Present data suggest that using right-sided segmental values would be the most appropriate choice for calculating whole-body bioelectrical variables.

Association of phase angle with sarcopenia in patients undergoing maintenance hemodialysis: A case-control study

Background

Sarcopenia, characterized by reduced muscle strength and mass, is commonly observed in patients with kidney disease. This study aimed to investigate the factors that influence sarcopenia in patients undergoing maintenance hemodialysis (HD patients).

Materials and Methods

A case-control study was conducted from 2022 to 2023, involving a total of 137 HD patients receiving regular dialysis. Relevant data were collected, and based on diagnostic criteria, patients were classified into sarcopenia and nonsarcopenia groups. All patients received polysulfone membrane HD at a flow rate of 500 mL/min. Bioelectrical impedance analysis was used to evaluate phase angle (PhA), muscle volume, and body composition.

Results

The prevalence of sarcopenia among maintenance HD patients was found to be 40.14%. There was a higher proportion of women (76.36%) with sarcopenia compared to men (P < 0.001). Furthermore, a significant difference was observed in PhA (P < 0.006) between patients undergoing maintenance HD with and without sarcopenia. PhA was positively associated with body mass index, body cell mass, basal metabolic rate, fat-free mass, soft lean mass, and minerals, whereas age and skeletal muscle index showed an inverse significant correlation.

Conclusion

Sarcopenia, a condition associated with increased mortality risk, affects a considerable proportion of dialysis patients. It is imperative to urgently identify and develop preventive and therapeutic strategies to counteract the detrimental effects of sarcopenia on the health outcomes of kidney patients.

Phase Angle and Impedance Ratio as Indicators of Physical Function and Fear of Falling in Older Adult Women: Cross-Sectional Analysis

Background

Older adults experience a significant decline in muscle integrity and function with aging. Early detection of decreased muscle quality can pave the way for interventions to mitigate the progression of age-related physical declines. Phase angle (PhA) and impedance ratio (IR) are measures of muscle integrity, which can be assessed quickly via bioelectrical impedance analysis (BIA) and may be indicative of physical function.

Objective

This study aimed to characterize the relationships among handgrip strength (HGS), sit-to-stand (STS), BTrackS balance scores, fear of falling (evaluated using the Short Falls Efficacy Scale-International [Short FES-I]), and IR among community-dwelling older adult women classified as having a low or high PhA.

Methods

A cross-sectional analysis was conducted with 85 older women (mean age 75.0, SD 7.2 years; mean weight 71.0, SD 15.0 kg; mean height 162.6, SD 6.1 cm). To examine the influence of PhA on performance measures, participants were divided into 2 PhA groups: high (>4.1°; n=56) and low (≤4.1°; n=29). Data were nonnormative; hence, the Mann-Whitney U test was used to evaluate between-group differences, and Kendall τ coefficients were used to determine the partial correlations.

Results

The low PhA group had a significantly higher IR (mean 0.85, SD 0.03) than the high PhA group (mean 0.81, SD 0.03; r=.92; P<.001). The high PhA group had superior HGS (mean 21.4, SD 6.2 kg; P=.007; r=0.36), BTrackS balance scores (mean 26.6, SD 9.5 cm; P=.03; r=0.30), and STS scores (mean 16.0, SD 5.5; P<.001; r=0.49) than the low PhA group (mean HGS 17.6, SD 4.7 kg; mean BTrackS balance score 37.1, SD 21.1 cm; mean STS score 10.7, SD 6.2). Both PhA and IR were significantly correlated with HGS and BTrackS balance, STS, and Short FES-I scores (P<.05). However, on adjusting for the whole sample's age, only PhA was strongly correlated with HGS (τb=0.75; P=.003) and STS scores (τb=0.76; P=.002). Short FES-I scores were moderately correlated with IR (τb=0.46; P=.07) after controlling for age. No significant between-group differences were observed for height, weight, or BMI.

Conclusions

PhA and IR are associated with physical function and the fear of falling in older women. However, only PhA was significantly associated with physical function (HGS and STS) independent of age. Conversely, only IR was significantly associated with the fear of falling. Diminished physical function and increased IR appear to be characteristics of older women with a PhA of ≤4.1°. These findings suggest that PhA and IR measured through BIA together may serve as a valuable tool for early identification of older women at the risk of functional decline and a heightened fear of falling.

Association of phase angle with sarcopenia and muscle function in patients with COPD: a case-control study

BACKGROUND AND AIMS

The predictive value of phase angle for sarcopenia diagnosis has been discussed for years. The present investigation was conducted to determine the association between phase angle and sarcopenia in patients with COPD.

METHODS

In this case-control study, 222 smoker men were divided into healthy and COPD groups. COPD was diagnosed by a pulmonologist through spirometry. Anthropometric indices, phase angle, muscle function, sarcopenia, and dietary intake were assessed.

RESULTS

A significant inverse association was observed between phase angle and sarcopenia after adjustment for age and energy intake (OR: 0.31, 95% CI 0.18-0.52) and after adjustment for BMI (OR: 0.31, 95% CI 0.18-0.52). A significant decrease was detected in anthropometric indices and indicators of sarcopenia and muscle function in COPD cases compared to the healthy controls.

CONCLUSIONS

Although further studies are suggested, phase angle might be considered an indicator of sarcopenia and muscle function in COPD patients.

Is Phase Angle Useful in Screening for Sarcopenia in Patients with Hematologic Malignancies?

The purposes of this study were to investigate the relationship between sarcopenia and phase angle (PhA), and to examine whether PhA cutoff values can be used to identify sarcopenia in patients with hematologic malignancies. The study population comprised 108 patients with hematologic malignancies who were admitted for chemotherapy, and were undergoing rehabilitation for exercise therapy. The diagnostic criteria for sarcopenia were determined according to the Asian Working Group for Sarcopenia 2019. Muscle strength, endurance, and body composition (including PhA), were assessed. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to investigate associations between sarcopenia and PhA, and to determine cutoff values. Sarcopenia was found in 17.6% of the participants. PhA was significantly associated with sarcopenia (p < 0.01). The areas under the curve were 0.84 for the males and 0.87 for the females, and the cutoff values were 4.75° for the males (sensitivity 69%, specificity 83%) and 3.95° for the females (sensitivity 78%, specificity 85%). Our results suggest that PhA, which can be measured noninvasively, objectively, and rapidly, can be used as a screening tool for sarcopenia in patients with hematologic malignancies.

Low Phase Angle Values Are Associated with Malnutrition according to the Global Leadership Initiative on Malnutrition Criteria in Kidney Transplant Candidates: Preliminary Assessment of Diagnostic Accuracy in the FRAILMar Study

Malnutrition has a negative impact on patients with chronic diseases and its early identification is a priority. The primary objective of this diagnostic accuracy study was to assess the performance of the phase angle (PhA), a bioimpedance analysis (BIA)-derived parameter, for malnutrition screening using the Global Leadership Initiative for Malnutrition (GLIM) criteria as the reference standard in patients with advanced chronic kidney disease (CKD) waiting for kidney transplantation (KT); criteria associated with low PhA in this population were also analyzed. Sensitivity, specificity, accuracy, positive and negative likelihood ratios, predictive values, and area under the receiver operating characteristic curve were calculated for PhA (index test) and compared with GLIM criteria (reference standard). Of 63 patients (62.9 years old; 76.2% men), 22 (34.9%) had malnutrition. The PhA threshold with the highest accuracy was ≤4.85° (sensitivity 72.7%, specificity 65.9%, and positive and negative likelihood ratios 2.13 and 0.41, respectively). A PhA ≤ 4.85° was associated with a 3.5-fold higher malnutrition risk (OR = 3.53 (CI95% 1.0-12.1)). Considering the GLIM criteria as the reference standard, a PhA ≤ 4.85° showed only fair validity for detecting malnutrition, and thus cannot be recommended as a stand-alone screening tool in this population.

Bioelectrical impedance analysis-derived phase angle predicts sarcopenia in patients on maintenance hemodialysis

BACKGROUND

This study aimed to investigate the association between phase angle (PhA) and sarcopenia and evaluate its performance as a sarcopenia predictor in patients receveing maintenance hemodialysis (MHD).

METHODS

All enrolled patients underwent handgrip strength (HGS) and the 6-m walk test, and muscle mass was measured using bioelectrical impedance analysis. Sarcopenia was diagnosed according to the diagnostic criteria of the Asian Sarcopenia Working Group. Logistic regression analysis was used to evaluate the PhA as an independent predictor of sarcopenia after adjusting for confounding factors. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of PhA in sarcopenia.

RESULTS

Two hundred forty-one patients receiving hemodialysis were enrolled in this study, and the prevalence of sarcopenia was 28.2%. Patients with sarcopenia presented a lower PhA value (4.7° vs 5.5°; P < 0.001), lower muscle mass index (6.0 vs 7.2 [kg/m² ]; P < 0.001), lower HGS (19.7 vs 26.0 [kg]; P < 0.001), and lower walk speed (0.83 ± 0.27 vs 0.92 ± 0.23 [m/s]; P = 0.007) than patients without sarcopenia. The odds of patients receiving MHD presenting with sarcopenia increased as PhA decreased, even after adjustment (odds ratio = 0.39; 95% CI, 0.18-0.85; P = 0.019). ROC analysis revealed that the best cutoff value of PhA for sarcopenia was 4.95° in patients receiving MHD.

CONCLUSION

PhA may be a useful and simple predictor for predicting patients undergoing hemodialysis who are at risk of sarcopenia. To further facilitate the application of PhA in the diagnosis of sarcopenia, more research need to be conducted.

High prevalence of sarcopenia and myosteatosis in patients undergoing hemodialysis

BACKGROUND AND PURPOSE

Sarcopenia is highly prevalent (28.5-40.3%) in patients undergoing hemodialysis and leads to poor clinical outcomes. However, the association between muscle quality and sarcopenia in patients receiving hemodialysis remains unclear. Therefore, we aimed to explore the association between muscle cross-sectional area (CSA) and proton-density fat-fraction (PDFF) in patients with sarcopenia undergoing hemodialysis.

METHODS

Seventy-six patients undergoing hemodialysis for > 3 months were enrolled. Their handgrip strength (HGS), short physical performance battery (SPPB) performance, and appendicular skeletal muscle mass index (ASMI) were measured. Sarcopenia was defined using the Asian Working Group for Sarcopenia 2019 consensus update. All patients underwent quantitative magnetic resonance imaging. CSA and PDFF were measured for the thigh, trunk, and gluteus muscles.

RESULTS

The prevalence of probable, confirmed, and severe sarcopenia in this study was 73.7%, 51.3%, and 22.4%, respectively. Older age (OR: 1.061, P < 0.003); lower body mass index (BMI) (OR: 0.837, P = 0.008), albumin (OR: 0.765, P = 0.004), prealbumin (OR: 0.987, P = 0.001), predialysis blood urea nitrogen (BUN) (OR: 0.842, P < 0.001), predialysis creatinine (OR: 0.993, P < 0.001), phosphorus (OR: 0.396, P = 0.047); lower CSA of the thigh (OR: 0.58, P = 0.035), third lumbar (L3) trunk (OR: 0.37, P = 0.004), gluteus minimus and medius (OR: 0.28, P = 0.001), and gluteus maximus (OR: 0.28, P= 0.001); and higher PDFF of the thigh (OR: 1.89, P = 0.036) and L3 trunk (OR: 1.71, P = 0.040) were identified as sarcopenia risk factors. The gluteus minimus and medius CSA was lower in patients with sarcopenia than in those without after adjusting for age and BMI (OR: 0.37, P = 0.017). Higher thigh (P = 0.031) and L3 trunk (P = 0.006) muscle PDFF were significantly associated with lower HGS. Furthermore, higher thigh (P = 0.011) and L3 trunk (P = 0.010) muscle PDFF were also inversely correlated with lower ASMI.

CONCLUSION

Our findings demonstrate the high prevalence of sarcopenia and myosteatosis in patients undergoing hemodialysis and might trigger a paradigm shift in intervention strategies for patients receiving hemodialysis.

Phase angle derived from bioelectrical impedance analysis as a marker for predicting sarcopenia

Sarcopenia is commonly defined as the age-related loss of muscle mass and function and may be caused by several factors, such as genetics, environmental conditions, lifestyle, drug use, and, in particular, comorbidities. People with pre-existing conditions are more likely to develop sarcopenia and subsequently have a less favorable prognosis. Recently, phase angle (PhA), which is derived from bioelectrical impedance analysis (BIA), has received a great deal of attention, and numerous studies have been carried out to examine the relationship between PhA and sarcopenia in different conditions. Based on these studies, we expect that PhA could be used as a potential marker for sarcopenia in the future.

Phase angle is a useful bioelectrical marker for skeletal muscle quantity and quality in hospitalized elderly patients

To analyze whether phase angle (PhA) can be a useful bioelectrical marker for skeletal muscle quantity and quality in hospitalized elderly patients. Two hundred hospitalized elderly patients were included in this retrospective observational study. PhA was obtained by Bioelectrical Impedance Analysis, skeletal muscle area index (SMI) and skeletal muscle density (SMD) were measured at the third lumbar vertebra level in computed tomography images using SliceOmatic software. PhA was positively associated with SMD and SMI, with correlation coefficients of 0.629 and 0.674, respectively. Multiple logistic regression analysis showed that 1° reduction of PhA was significantly associated with low SMI [odds ratio (OR) = 4.331 (1.681-11.161)] and low SMD [OR = 6.418 (2.963-13.899)]. Receiver operating characteristic curve analysis showed that the area under the curve (AUC) for PhA to identify patients with low SMI was 0.772 for male and 0.784 for female; the AUC for PhA to identify low SMD patients was 0.829 for male and 0.812 for female; the AUC for PhA to identify low SMD combined with low SMD patients was 0.801 for male and 0.773 for female. The results of this study showed that PhA was highly related to SMI, which can indicate the quantity of skeletal muscle in the entire body, and was highly related to SMD, which can be used to assess skeletal muscle quality. Therefore, PhA may be a useful bioelectrical marker for skeletal muscle quantity and quality.

Prevalence of Sarcopenia and Its Impact on Cardiovascular Events and Mortality among Dialysis Patients: A Systematic Review and Meta-Analysis

Sarcopenia in end-stage kidney disease patients requiring dialysis is a frequent complication but remains an under-recognized problem. This meta-analysis was conducted to determine the prevalence of sarcopenia and explored its impacts on clinical outcomes, especially cardiovascular events, and mortality in dialysis patients. The eligible studies were searched from PubMed, Scopus, and Cochrane Central Register of Controlled trials up to 31 March 2022. We included studies that reported the interested outcomes, and the random-effects model was used for analysis. Forty-one studies with 7576 patients were included. The pooled prevalence of sarcopenia in dialysis patients was 25.6% (95% CI 22.1 to 29.4%). Sarcopenia was significantly associated with higher mortality risk (adjusted OR 1.83 (95% CI 1.40 to 2.39)) and cardiovascular events (adjusted OR 3.80 (95% CI 1.79 to 8.09)). Additionally, both low muscle mass and low muscle strength were independently related to increased mortality risk in dialysis patients (OR 1.71; 95% CI (1.20 to 2.44), OR 2.15 (95% CI 1.51 to 3.07)), respectively. This meta-analysis revealed that sarcopenia was highly prevalent among dialysis patients and shown to be an important predictor of cardiovascular events and mortality. Future intervention research to alleviate this disease burden in dialysis patients is needed.