Low skeletal muscle mass by computerized tomography is associated with increased mortality risk in end-stage kidney disease patients on hemodialysis

Myosteatosis is associated with adiposity, metabolic derangements and mortality in patients with chronic kidney disease

BACKGROUND/OBJECTIVES

Myosteatosis has been associated with sarcopenia, and increased mortality risk in patients on hemodialysis. We aimed to explore the associations between myosteatosis, as assessed by computed tomography (CT), with demographic parameters, body composition metrics, muscle strength, metabolic parameters and mortality in patients with chronic kidney disease (CKD).

SUBJECTS/METHODS

We enrolled 216 patients (age 60.3 ± 10.6 years, 63% men) with CKD stages 3-5. Abdominal CT scans at the third lumbar vertebra (L3) were used to assess body composition. Abdominal obesity was determined by abdominal adipose tissue (AT), sarcopenia by low skeletal muscle area (SMA) and low handgrip strength. Myosteatosis was evaluated by two parameters using CT scans at L3: mean muscle attenuation and percentage of intermuscular adipose tissue (%IMAT) within SMA. We evaluated the correlation between parameters of myosteatosis with demographic, clinical and metabolic variables. To determine independent predictors of myosteatosis, a multiple linear regression model was fitted. Mortality risk was evaluated with Cox-regression analysis.

RESULTS

Both parameters of myosteatosis were independently associated with age, metabolic syndrome, abdominal AT and SMA in the multiple linear regression analysis (adjusted R2 for multiple linear regression: muscle attenuation model 0.535, P < 0.001; %IMAT model 0.462, P < 0.001). Moreover, higher %IMAT and lower attenuation were associated with a higher mortality risk.

CONCLUSION

In patients with CKD, increased myosteatosis, as assessed by abdominal CT, was associated with old age, adiposity, metabolic dysfunction, and higher mortality risk.

Association of Muscle Radiodensity and Muscle Mass With Thoracic Aortic Calcification Progression in Dialysis Patients

BACKGROUND

Recent findings have spotlighted sarcopenia as a critical factor exacerbating cardiovascular risk in dialysis patients. However, no studies have investigated the relationship of muscle characteristics with thoracic aortic calcification (TAC). We explored whether skeletal muscle radiodensity (SMD) and skeletal muscle index (SMI) are associated with TAC in dialysis patients.

METHODS

In this study, 2517 dialysis patients (between January 2020 and June 2023) from four centres with chest computed tomography (CT) scans were analysed cross-sectionally. A cohort of 544 initial-dialysis patients (between January 2014 and December 2020) was followed for TAC progression. Chest CT images were used to assess SMD and SMI at the L1 level, as well as to measure the scores of TAC, including ascending TAC (ATAC), aortic arch calcification (AoAC) and descending TAC (DTAC). Multivariable linear regression models were employed to assess the effects of SMD and SMI on TAC and its progression. Restricted cubic spline was used to assess the potential non-linear relationships of SMD and SMI with TAC progression.

RESULTS

The mean (SD) age for the cross-sectional study was 54.8 (14.0) years, with males accounting for 58.2%. Over a mean (SD) follow-up duration of 3.45 (1.82) years, 85.7% showed TAC progression. Comparing the highest quartile of SMD to the lowest quartile, a significant inverse association was observed with TAC (β, -1.08 [-1.42 to -0.75]; p < 0.001); similar trends were noted for SMI (β, -0.42 [-0.74 to -0.10]; p = 0.011). SMD and SMI as continuous variables were also both significantly negatively correlated with TAC. In the longitudinal study, multivariable linear regression models revealed that an increase of 1 SD in SMD resulted in a decrease of 0.10 SD (95% CI, -0.17 to -0.02; p = 0.011) in TAC progression, and an increase of 1 SD in SMI resulted in a decrease of 0.12 SD (95% CI, -0.20 to -0.04; p = 0.003) in TAC progression. Restricted cubic spline models excluded non-linear trends for the relationships of SMD and SMI with TAC progression. The associations of SMD and SMI with DTAC were consistent with those observed for TAC, but neither showed a significant association with ATAC.

CONCLUSIONS

Higher SMD and higher SMI were significantly associated with lower TAC and its progression in dialysis patients. Improving SMD and SMI could be a new approach for reducing TAC.

Low appendicular skeletal muscle mass is associated with the risk of mortality among adults in the United States

Low skeletal muscle mass has been shown to be a predictor of mortality, but very few studies have focused on the association between appendicular skeletal muscle mass and mortality risk in a large sample. This study aimed to determine the associations of low appendicular skeletal muscle mass with all-cause and cause-specific mortality in an adult population in the United States. Data were retrieved from 21,938 participants aged 20-85 years from the National Health and Nutrition Examination Survey (NHANES) (1999-2006 and 2011-2018) and merged with the Public-use Linked Mortality File of 2018. The appendicular skeletal muscle mass index (kg/m2) was determined by the skeletal muscle mass in the arms and legs (in kg) and divided by the square of the height (in meters) 2 (kg/m2). Sex-specific quintiles were then used to categorize the appendicular skeletal muscle mass index. The major outcome in this study was mortality from all causes, and the secondary outcome was mortality from heart disease or cancer. Cox proportional hazards models were used to calculate hazard ratios, and 95% confidence intervals for all-cause and competing risk regression analyses were performed to analyze heart disease mortality and cancer mortality. During a 10.9-year median follow-up, 1632 males and 1253 females died. Compared with those of the 5th quintile of the skeletal muscle index, the fully adjusted HRs (95% CIs) of all-cause mortality were 0.81 (0.72-0.92), 0.63 (0.52-0.76), 0.52 (0.43-0.63), and 0.65 (0.52-0.81) for the 1st, 2nd, 3rd, and 4th quintiles of the skeletal muscle index, respectively. A 20-percentile increase in the appendicular skeletal muscle index was associated with a lower risk of all-cause mortality (HR, 0.86; 95% CI, 0.81-0.91) (P < 0.001 for trend) and a lower risk of cancer mortality (HR, 0.87; 95% CI, 0.78-0.96) (P = 0.009 for trend). High appendicular skeletal muscle mass was associated with decreased all-cause mortality and cancer mortality in adults, and interventions aimed at maintaining appropriate appendicular skeletal muscle mass may help prevent premature death.

Effects of Dulaglutide on Ectopic Fat Deposition in Chronic Kidney Disease (CKD): A Pilot and Feasibility Study (GLIMP)

Introduction

Patients with chronic kidney disease (CKD) often exhibit ectopic fat accumulation, including intermuscular adipose tissue (IMAT), which is associated with metabolic and muscular dysfunctions. This study aimed to evaluate the effects of dulaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), on reducing IMAT and improving metabolic and physical functions in patients with CKD stage 3-4.

Methods

Seven patients were recruited between April 2022 and November 2023. A 12-week dulaglutide (1.5 mg/wk) intervention was conducted with pre-and post-treatment assessments, including magnetic resonance imaging (MRI) for the IMAT evaluation and systemic physical performance battery test (SPPB) for physical performance evaluation. Their body mass indexes (BMI) were calculated and blood samples were analyzed for inflammatory and metabolic markers, including high sensitive C-reactive protein (Hs-CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), glucose, insulin resistance (IR), total cholesterol, triglyceride, adiponectin, leptin, and leptin-adiponectin ratio (LAR) before and after treatment. Paired t-tests and Mann-Whitney U tests were used for statistical analysis, with significance set at p < 0.05.

Results

Out of 58 assessed patients with CKD stage 3-4, 7 were enrolled, with 5 completing the full 12-week dulaglutide treatment. The total 7 people had a mean age of 59 years, mean BMI of 31.4 kg/m2, and baseline eGFR of 31.7 mL/min/1.73m2. IMAT decreased in 4 patients and increased in 3 patients, with no statistically significant changes overall (p = 0.69). The quadriceps muscle cross-sectional area (CSA) also showed no significant difference (p = 0.73). BMI and serum leptin levels significantly decreased after treatment (p < 0.05), while other inflammatory and metabolic markers, and physical performance scores showed no significant changes. No serious adverse events were reported.

Conclusions

This study examined the effects of a 12-week dulaglutide treatment on IMAT accumulation in patients with CKD stage 3-4. While BMI significantly decreased, changes in IMAT were modest and not statistically significant, with potential but unproven clinical and metabolic benefits. Many metabolic and inflammatory markers improved, though not statistically significantly, and physical performance remained unchanged. Muscle CSA and function were maintained, which may alleviate concerns about potential GLP-1RA-induced muscle loss. Dulaglutide was well-tolerated, with minimal side effects. The small sample size and short duration highlight the need for further research.

Evaluation of muscle mass and intramuscular fatty infiltration in dogs with hypercortisolism and their association with prognosis

BACKGROUND

Muscle atrophy and intramuscular fatty infiltration, as well as their association with prognosis, have not been quantified in dogs with spontaneous hypercortisolism (HC).

OBJECTIVE

To quantitatively evaluate muscle atrophy and IM fatty infiltration in dogs with HC and determine their prognostic impact.

ANIMALS

Fifty-three dogs with HC and 66 control dogs without HC.

METHODS

Retrospective cohort study. Medical records and computed tomography images obtained between 2014 and 2021 were evaluated. Kaplan-Meier curves and log-rank tests were used to analyze the effect of muscle atrophy and IM fatty infiltration on the prognosis of dogs with HC.

RESULTS

Dogs with HC showed lower visually measured cross-sectional area (VCSA) and cross-sectional area based on attenuation (HCSA) than control dogs (median [interquartile range {IQR}]: 50.3 mm2/mm [36.2-67.8] vs 66.7 mm2/mm [48.0-85.9]; P < .001; 30.4 mm2/mm [13.7-57.2] vs 54.8 mm2/mm [39.7-71.5]; P < .001, respectively). Dogs with HC had lower epaxial muscle attenuation (L3HU) than control dogs (median [IQR]: 21.2 Hounsfield [HU] [12.4-28.2] vs 33.2 HU [22.6-43.6]; P < .001). Dogs with HC with lower HCSA or L3HU had shorter survival (median [IQR]: 670 days [222-673] vs 949 days [788-1074], P < .01; 523 days [132-670] vs 949 days [756-1074], P < .01, respectively) but not lower VCSA (median [IQR]: 673 days [132-788] vs 949 days [523 to not applicable]; P = .30).

CONCLUSION AND CLINICAL IMPORTANCE

Hypercortisolism in dogs causes muscle atrophy and IM fatty infiltration and is associated with poor prognosis.

Myosteatosis and aortic calcium score on abdominal CT as prognostic markers in non-dialysis chronic kidney disease patients

We aimed to examine the relationship between abdominal computed tomography (CT)-based body composition data and both renal function decline and all-cause mortality in patients with non-dialysis chronic kidney disease (CKD). This retrospective study comprised non-dialysis CKD patients who underwent consecutive unenhanced abdominal CT between January 2010 and December 2011. CT-based body composition was measured using semiautomated method that included visceral fat, subcutaneous fat, skeletal muscle area and density, and abdominal aortic calcium score (AAS). Sarcopenia and myosteatosis were defined by decreased skeletal muscle index (SMI) and decreased skeletal muscle density, respectively, each with specific cutoffs. Risk factors for CKD progression and survival were identified using logistic regression and Cox proportional hazard regression models. Survival between groups based on myosteatosis and AAS was compared using the Kaplan-Meier curve. 149 patients (median age: 70 years) were included; 79 (53.0%) patients had sarcopenia and 112 (75.2%) had myosteatosis. The median AAS was 560.9 (interquartile range: 55.7-1478.3)/m2. The prognostic factors for CKD progression were myosteatosis [odds ratio (OR) = 4.31, p = 0.013] and high AAS (OR = 1.03, p = 0.001). Skeletal muscle density [hazard ratio (HR) = 0.93, p = 0.004] or myosteatosis (HR = 4.87, p = 0.032) and high AAS (HR = 1.02, p = 0.001) were independent factors for poor survival outcomes. The presence of myosteatosis and the high burden of aortic calcium were significant factors for CKD progression and survival in patients with non-dialysis CKD.

Making the invisible visible: imaging techniques for assessing muscle mass and muscle quality in chronic kidney disease

Muscle wasting and low muscle mass are prominent features of protein energy wasting (PEW), sarcopenia and sarcopenic obesity in patients with chronic kidney disease (CKD). In addition, muscle wasting is associated with low muscle strength, impaired muscle function and adverse clinical outcomes such as low quality of life, hospitalizations and increased mortality. While assessment of muscle mass is well justified, the assessment of skeletal muscle should go beyond quantity. Imaging techniques provide the means for non-invasive, comprehensive, in-depth assessment of the quality of the muscle such as the infiltration of ectopic fat. These techniques include computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Dual energy X-ray absorptiometry is also an imaging technique, but one that only provides quantitative and not qualitative data on muscle. The main advantage of imaging techniques compared with other methods such as bioelectrical impedance analysis and anthropometry is that they offer higher precision and accuracy. On the other hand, the higher cost for acquiring and maintaining the imaging equipment, especially CT and MRI, makes these less-used options and available mostly for research purposes. In the field of CKD and end-stage kidney disease (ESKD), imaging techniques are gaining attention for evaluating muscle quantity and more recently muscle fat infiltration. This review describes the potential of these techniques in CKD and ESKD settings for muscle assessment beyond that of muscle quantity.

Computed tomography-based body composition parameters can predict short-term prognosis in ulcerative colitis patients

OBJECTIVES

Emerging evidence suggests a potential relationship between body composition and short-term prognosis of ulcerative colitis (UC). Early and accurate assessment of rapid remission based on conventional therapy via abdominal computed tomography (CT) images has rarely been investigated. This study aimed to build a prediction model using CT-based body composition parameters for UC risk stratification.

METHODS

In total, 138 patients with abdominal CT images were enrolled. Eleven quantitative parameters related to body composition involving skeletal muscle mass, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were measured and calculated using a semi-automated segmentation method. A prediction model was established with significant parameters using a multivariable logistic regression. The receiver operating characteristic (ROC) curve was plotted to evaluate prediction performance. Subgroup analyses were implemented to evaluate the diagnostic efficiency of the prediction model between different disease locations, centers, and CT scanners. The Delong test was used for statistical comparison of ROC curves.

RESULTS

VAT density, SAT density, gender, and visceral obesity were significantly statistically different between remission and invalidation groups (all p < 0.05). The accuracy, sensitivity, specificity, and area under the ROC curve (AUC) of the prediction model were 82.61%, 95.45%, 69.89%, and 0.855 (0.792-0.917), respectively. The positive predictive value and negative predictive value were 70.79% and 93.88%, respectively. No significant differences in the AUC of the prediction model were found in different subgroups (all p > 0.05).

CONCLUSIONS

The predicting model constructed with CT-based body composition parameters is a potential non-invasive approach for short-term prognosis identification and risk stratification. Additionally, VAT density was an independent predictor for escalating therapeutic regimens in UC cohorts.

CRITICAL RELEVANCE STATEMENT

The CT images were used for evaluating body composition and risk stratification of ulcerative colitis patients, and a potential non-invasive prediction model was constructed to identify non-responders with conventional therapy for making therapeutic regimens timely and accurately.

KEY POINTS

• CT-based prediction models help divide patients into invalidation and remission groups in UC. • Results of the subgroup analysis confirmed the stability of the prediction model with a high AUC (all > 0.820). • The visceral adipose tissue density was an independent predictor of bad short-term prognosis in UC.

Intramuscular and abdominal fat measured by computed tomography and mortality of hemodialysis patients

BACKGROUND

In hemodialysis patients, high body mass index is associated with low mortality while abdominal obesity relates to increased mortality. We aimed to investigate the association between muscle mass, intramuscular fat and abdominal fat measured by abdominal computed tomography (CT), and mortality in this patients population.

METHODS

This two-center retrospective cohort study included hemodialysis patients who underwent abdominal CT between January 2013 and December 2018. Skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and visceral fat to subcutaneous fat ratio (VSR) were calculated using CT images at the third lumbar vertebral level. Multivariate Cox proportional hazards model was used to determine the independent predictors of all-cause, cardiovascular and non-cardiovascular mortalities.

RESULTS

The study included 344 patients (median age 71.0 years; female 33.7%), among whom 145 died during a median follow-up of 4.9 years-46 and 99 from cardiovascular and non-cardiovascular causes, respectively. Lower MRA [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.87, P = .001] and higher VSR (HR 1.17, 95% CI 1.01-1.37, P = .04) were independently associated with higher all-cause mortality but not with lower SMI (HR 0.87, 95% CI 0.68-1.11, P = .26). Lower MRA (HR 0.51, 95% CI 0.35-0.73, P < .001) and higher VSR (HR 1.29, 95% CI 1.09-1.54, P = .003) were also associated with cardiovascular and non-cardiovascular mortality, respectively.

CONCLUSIONS

Intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.

Computed tomography-determined skeletal muscle density predicts 3-year mortality in initial-dialysis patients in China

BACKGROUND

Skeletal muscle mass and quality assessed by computed tomography (CT) images of the third lumbar vertebra (L3) level have been established as risk factors for poor clinical outcomes in several illnesses, but the relevance for dialysis patients is unclear. A few studies have suggested a correlation between CT-determined skeletal muscle mass and quality at the first lumbar vertebra (L1) level and adverse outcomes. Generally, chest CT does not reach beyond L1. We aimed to determine whether opportunistic CT scan (chest CT)-determined skeletal muscle mass and quality at L1 are associated with mortality in initial-dialysis patients.

METHODS

This 3-year multicentric retrospective study included initial-dialysis patients from four centres between 2014 and 2017 in China. Unenhanced CT images of the L1 and L3 levels were obtained to assess skeletal muscle mass [by skeletal muscle index, (SMI), cm2 /m2 ] and quality [by skeletal muscle density (SMD), HU]. Skeletal muscle measures at L1 were compared with those at L3. The sex-specific optimal cutoff values of L1 SMI and L1 SMD were determined in relation to all-cause mortality. The outcomes were all-cause death and cardiac death. Cox regression models were applied to investigate the risk factors for death.

RESULTS

A total of 485 patients were enrolled, of whom 257 had both L1 and L3 images. Pearson's correlation coefficient between L1 and L3 SMI was 0.84 (P < 0.001), and that between L1 and L3 SMD was 0.90 (P < 0.001). No significant association between L1 SMI and mortality was observed (P > 0.05). Low L1 SMD (n = 280, 57.73%) was diagnosed based on the optimal cutoff value (<39.56 HU for males and <33.06 HU for females). Multivariate regression analysis revealed that the low L1 SMD group had higher risks of all-cause death (hazard ratio 1.80; 95% confidence interval 1.05-3.11, P = 0.034) and cardiac death (hazard ratio 3.74; 95% confidence interval 1.43-9.79, P = 0.007).

CONCLUSIONS

In initial-dialysis patients, there is high agreement between the L1 and L3 measures for SMI and SMD. Low SMD measured at L1, but not low SMI, is an independent predictor of both all-cause death and cardiac death.

Adherence to Caloric and Protein Recommendations in Older Hemodialysis Patients: A Multicenter Study

Hemodialysis (HD) patients are characterized by malnutrition, which adversely affects their survival. The development of malnutrition is influenced, among other factors, by improper diet and the advanced age of patients. The study aimed to assess the nutritional status and adherence to dietary recommendations among older patients. The multicenter study included 179 stable HD patients. The nutritional status was assessed by a 7-point Subjective Global Assessment (SGA). Anthropometry and body composition was analyzed. The diet was assessed based on the 3-day food diary and the Food Frequency Questionnaire with 6 answers (FFQ-6). Blood laboratory tests were performed. Based on the 7-point SGA, malnutrition was diagnosed in 38.5% of HD patients. The decreased content of the muscle tissue (LTI < 14 kg/m2) was observed in 70.4% of the examined patients and the decreased concentration of s-albumin was observed in 44.1% of patients. Older patients had significantly lower LTI. 26% of patients consumed less than 25 kcal/kg body weight and less than 0.8 g protein/kg body weight. Older patients’ diets contained significantly fewer calories. There were significant differences between nutrient intake on a weekday with dialysis, a weekday without dialysis, and a weekend day without dialysis. The lowest intake of nutrients was observed on the day of dialysis. Nutritional education and the determination of whether food is permitted during hemodialysis are necessary to improve patients’ nutrition.