Serum creatinine/cystatin C ratio as a surrogate marker for sarcopenia in patients with chronic obstructive pulmonary disease

Creatinine-to-cystatin C ratio and frailty in older adults: a longitudinal cohort study

BACKGROUND

Creatinine-to-cystatin C ratio (CCR) has been associated with multiple adverse outcomes. However, little is known about its relationship with frailty. We aimed to explore the association between CCR and frailty among older adults.

METHODS

A total of 2599 participants aged ≥ 60 years (mean age 67.9 ± 6.0 years, 50.4% males) were included from the China Health and Retirement Longitudinal Study (2011-2015). Baseline CCR was calculated as plasma creatinine (mg/dL) / cystatin C (mg/L) × 10 and was grouped by quartiles. Frailty was evaluated by the validated physical frailty phenotype (PFP) scale and was defined as PFP score ≥ 3. The generalized estimating equations model was used to explore the relationship between CCR and frailty.

RESULTS

The frailty risk decreased gradually with increasing CCR in the quartiles (P for trend = 0.002), and the fourth CCR quartile was associated with a significantly lower risk of frailty compared with the lowest quartile (odds ratio [OR] 0.37, 95% confidence interval [CI] 0.19-0.70). When modeling as a continuous variable, per 1-unit increase in CCR was related to 17% decreased odds of frailty (OR 0.83, 95% CI 0.74-0.93). The association was consistent in male and female participants (P for interaction = 0.41). Poisson models revealed that frailty score was negatively associated with CCR (β= -0.11, 95% CI= -0.19 to -0.04), and sex did not significantly moderate the associations (P for interaction = 0.22). The results were not affected by further adjusting for high-sensitivity C-reactive protein. Similar results were observed by analyses with multiple imputation technique and analyses excluding participants with baseline frailty.

CONCLUSIONS

Higher CCR was associated with a lower frailty risk. CCR may be a simple marker for predicting frailty in older adults.

Serum creatinine and serum cystatin C as an index of muscle mass in adults

PURPOSE OF REVIEW

Serum creatinine reflects both muscle mass and kidney function. Serum cystatin C has recently been recommended as an additional marker for estimating kidney function, and use of both markers together may provide an index of muscle mass. This review aims to describe the biological basis for and recent research examining the relationship of these markers to muscle mass in a range of adult populations and settings.

RECENT FINDINGS

This review identified 67 studies, 50 of which had direct measures of muscle mass, and almost all found relationships between serum creatinine and cystatin C and muscle mass and related outcomes. Most studies have been performed in older adults, but similar associations were found in general populations as well as in subgroups with cancer, chronic kidney disease (CKD), and other morbid conditions. Creatinine to cystatin C ratio was the measure examined the most often, but other measures showed similar associations across studies.

SUMMARY

Measures of serum creatinine and cystatin C together can be an index of muscle mass. They are simple and reliable measures that can be used in clinical practice and research. Further study is needed to determine actionable threshold values for each measure and clinical utility of testing and intervention.

Relationship between creatinine-cystatin C ratio and all-cause mortality in hospitalized patients with COVID-19: A prospective study in China

Background

This study was conducted to investigate whether baseline creatinine-cystatin C ratio is associated with all-cause mortality in adult Chinese patients hospitalized with coronavirus disease 2019.

Methods

This study included 933 patients with coronavirus disease 2019 who were admitted to The Affiliated Hospital of Guangdong Medical University between December 2022 and March 2023. All-cause mortality was determined by telephone follow-up after 28 days. Multivariate Cox proportional risk models were used to investigate the relationship between baseline creatinine-cystatin C ratio and all-cause mortality. Restricted cubic spline and two-piecewise Cox proportional hazards risk models were used to identify non-linear correlations.

Results

Of the 933 patients, 128 died during the 28 days follow-up. The restricted cubic spline analysis of hospitalized patients with coronavirus disease 2019 revealed an L-shaped association between baseline creatinine-cystatin C ratio and all-cause mortality, with a threshold creatinine-cystatin C ratio of ≤0.93 predicting all-cause mortality. Specifically, a baseline creatinine-cystatin C ratio below this threshold value was negatively correlated with mortality (hazard ratio 0.12, 95 % confidence interval 0.03-0.48), but a creatinine-cystatin C ratio >0.93 was not correlated with mortality (hazard ratio 1.29, 95 % confidence interval 0.65-2.55).

Conclusions

In Chinese adult patients hospitalized with coronavirus disease 2019, an L-shaped relationship was observed between the baseline creatinine-cystatin C ratio and all-cause mortality.

Clinical significance and normal reference value of serum creatinine to cystatin C ratio in children

BACKGROUND & AIMS

Sarcopenia is a serious problem in adults and children. However, limited modalities are available for diagnosing pediatric sarcopenia. The serum creatinine to cystatin C ratio (Cre/CysC ratio) is a promising method for muscle quantification, although its clinical significance in the pediatric population is unknown. This study aimed to evaluate the relationship between the Cre/CysC ratio and physical performance.

METHODS

This was a single-center retrospective study. Patients aged <15 years who had visited the University of Tokyo Hospital for measurements of serum creatinine and cystatin C levels, body height, and body weight were included. The patients were assigned according to their age (<2 or ≥2 years), and the relationship between the Cre/CysC ratio and physical performance at the time of measurement was analyzed.

RESULTS

We included 266 patients, revealing a significant relationship between Cre/CysC ratio and physical performance in children aged ≥2 years (p < 0.001) but not in children aged <2 years (p = 0.42). The repeater-operator curve analysis of Cre/CysC to predict bedridden status showed good performance (the area under the curve was 0.82 (95% CI, 0.75-0.89)) and the cut-off value 0.44 had good accuracy (sensitivity 0.87, specificity 0.61).

CONCLUSIONS

The Cre/CysC ratio was a significant marker of impaired physical performance, and a Cre/CysC ratio <0.44 accurately predicted bedridden status in children aged >2 years.

Impact of the serum creatinine and cystatin C ratio for prediction of sarcopenia and prognosis in biliary tract cancer

BACKGROUND

Sarcopenia is a poor prognostic factor in cancer patients. In recent years, there have been reports that serum creatinine and cystatin C (Cr/CysC) ratio is associated with sarcopenia. However, the prognostic value of the Cr/CysC ratio in biliary tract cancer is unclear. We evaluated the impact of the Cr/CysC ratio on sarcopenia and prognosis in biliary tract cancer.

METHODS

We retrospectively reviewed the records of 190 patients with biliary tract cancer who had undergone surgical resection from January 2017 to March 2023. Frozen serum samples collected at the time of surgery were used to measure CysC. We calculated the Cr/CysC ratio and investigated the relationship with sarcopenia and the prognostic significance.

RESULTS

We calculated the cutoff value of the Cr/CysC ratio for low skeletal muscle index (SMI) (< 42 cm2/m2 for males and < 38 cm2/m2 for females). The optimal cutoff value of the Cr/CysC ratio was 0.848. The low Cr/CysC ratio group was significantly associated with higher preoperative CRP and lower albumin, lower SMI, lower handgrip strength, and higher intramuscular adipose tissue content. In multivariate analysis, patients with a low Cr/CysC ratio showed poorer overall survival (hazard ratio 2.60, 95% confidence interval 1.07-6.29, p = 0.033), which was significantly worse than in those with a high Cr/CysC ratio.

CONCLUSIONS

In patients with biliary tract cancer, the Cr/CysC ratio showed weak correlation with sarcopenic indicators. However, the Cr/CysC ratio could be strong prognostic factor in biliary tract cancer.

Association of the sarcopenia index with cognitive impairment in a middle-aged to older patients with acute ischemic stroke or transient ischemic attack: A multicenter cohort study

OBJECTIVES

The sarcopenia (SI) index, defined as the serum creatinine to cystatin C ratio, is considered a predictor of poor muscle health and malnutrition, which is related to major adverse cardiovascular events. However, the effect of the SI index on cognitive function in stroke patients remains unknown. In this study, we aimed to examine the association between the SI and longitudinal cognitive impairment in patients with acute ischemic stroke or transient ischemic attack.

RESEARCH DESIGN AND METHODS

Participants who met the inclusion criteria in this national, multicenter, prospective cohort study were enrolled from the Impairment of Cognition and Sleep (ICONS) study of the China National Stroke Registry-3 (CNSR-3). They were categorized into four groups according to the quartile of the SI index. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) scale. Multivariable-adjusted logistic regression models were performed to evaluate the association between the SI index and post-stroke cognitive impairment (PSCI) at the 3-month follow-up. Moreover, discrimination tests were used to evaluate the incremental predictive value of the SI index beyond the potential risk factors. Furthermore, we performed subgroup analyses to test interactions.

RESULTS

Among the enrolled participants, the lower the SI index was, the worse the cognitive performance. At the 3-month follow-up, participants in the lowest SI quartile group exhibited a 42% increase in the risk of cognitive impairment relative to the highest quartile group [OR 0.58 (95% CI 0.37-0.90)]. Moreover, after applying the discrimination test, adding the SI index into the potential risk factors resulted in a slight improvement in predicting the risk of cognitive impairment [NRI 14% (P = 0.01)].

CONCLUSION

This study demonstrated that a lower sarcopenia index was positively associated with a higher prevalence of PSCI. Monitoring the SI index in stroke patients and early identification and treatment of individuals with low SI level may be helpful to reduce the risk of cognitive impairment.

Diagnostic accuracy of a 'sarcopenia index' based on serum biomarkers creatinine and cystatin C in 458,702 UK Biobank participants

BACKGROUND & AIMS

There is an emerging and urgent need to identify biomarkers of sarcopenia. A novel sarcopenia index (SI), based on serum creatinine and cystatin C, has emerged as a potential biomarker for use. The SI can predict clinical outcomes and discriminate between the presence of sarcopenia in a range of chronic and acute conditions. However, the SI has not yet been tested in a large real-world general population dataset. This study aimed to investigate the accuracy of the SI in the identification of sarcopenia in a large prospective general population cohort.

METHODS

Data were taken from UK Biobank, a large prospective epidemiological study in the United Kingdom (UK). Serum creatinine and cystatin C values were used to calculate the SI [creatinine (mg/dl)/cystatin C (mg/dl) × 100]. Probable sarcopenia was defined by maximum handgrip strength (HGS). Muscle mass was assessed using bioelectrical impedance analysis. Low muscle mass was defined as an appendicular lean mass (ALM) index below prespecified thresholds. Confirmed sarcopenia was defined as both low HGS and low muscle mass. Pearson correlation coefficients and logistic regression were used to explore the association between various sarcopenia traits (probable sarcopenia, low ALM index, and confirmed sarcopenia) and the SI. The diagnostic value of the SI was investigated using the area under the receiver operating characteristic curve (area under the curve, AUC).

RESULTS

458,702 participants were included in the analysis (46.4% males, mean age, males: 68.7 (±8.2) years; females: 68.2 (±8.0) years)). Probable sarcopenia was observed in 4.5% of males and 6.1% of females; low ALM index in 2.8% of males and 0.7% of females; confirmed sarcopenia in 0.3% of males and 0.1% of females. SI was significantly lower in individuals with confirmed sarcopenia (males: 86.3 ± 16.6 vs. 99.5 ± 15.3, p < .01; females: 73.6 ± 13.7 vs. 84.6 ± 14.0, p < .01). For every 1-unit increase in the SI, the odds of confirmed sarcopenia were reduced by 5% in males (odds ratio (OR): 0.95, p < 0.001) and 7% in females (OR: 0.923, p < 0.001). The AUC showed acceptable discriminative ability of confirmed sarcopenia (males: AUC = 0.731; females: AUC = 0.711).

CONCLUSIONS

Using a large real-world dataset of almost half a million people, our study indicated the SI has acceptable diagnostic accuracy when identifying those with sarcopenia and may be a useful biomarker to aid the stratification of those at risk and in need of intervention.

Usefulness of the serum creatinine/cystatin C ratio as a blood biomarker for sarcopenia components among age groups in community-dwelling older people: The SONIC study

AIM

The serum creatinine/cystatin C ratio (CCR) or sarcopenia index is considered a useful marker of muscle mass. However, its usefulness in late-stage older adults remains unclear. We aimed to determine the usefulness of CCR as an indicator of sarcopenia in community-dwelling Japanese adults aged >75 years.

METHODS

Our study recruited participants aged 70, 80, and 90 ± 1 years during the baseline years, and included a 3-year follow-up in the Septuagenarians, Octogenarians, Nonagenarians, Investigation with Centenarians study. From 2015 to 2018, 955 participants were eligible: 367 in their 70s, 304 in their 80s, and 284 in their 90s. The diagnostic components of sarcopenia, including "low muscle mass, plus low muscle strength, and/or low physical performance," were evaluated using the bioelectrical impedance analysis-measured skeletal muscle mass index (SMI), handgrip strength, and short physical performance battery (SPPB) score, respectively, in accordance with the Asia Working Group for Sarcopenia 2019 criteria. Separate analyses were performed between each component and CCR, adjusting for sex, body mass index, and other blood biomarkers in each group.

RESULTS

The relationship between CCR and sarcopenia components was significant for handgrip strength (β = 0.21, 0.13, 0.19, and P < 0.0001, =0.0088, <0.0001, for the 70s, 80s, and 90s age groups, respectively); however, it was limited for SMI (β = 0.14; P = 0.0022, only for the 90s) and not significant for the SPPB score.

CONCLUSION

CCR is a limited indicator of sarcopenia in late-stage older adults. Although its association with muscle strength was significant, its relationship with muscle mass and physical performance was less pronounced. Geriatr Gerontol Int 2024; 24: 529-536.

Association between macro- and microvascular damage and sarcopenia index in individuals with type 2 diabetes mellitus

Sarcopenia was recently reported to be relevant to an increased macro-and microvascular disease risk. Sarcopenia index (SI) has been identified as a surrogate marker for sarcopenia. The aim of the present study was to investigate the association between macro- and microvascular disease and SI in patients with type 2 diabetes mellitus (T2DM). A total of 783 patients with T2DM were enrolled in this cross-sectional study. The SI was calculated by (serum creatinine [mg/dL]/cystatin C [mg/L]) × 100. The subjects were divided into three groups according to SI tertiles: T1 (41.27-81.37), T2 (81.38- 99.55), and T3 (99.56-192.31). Parameters of macro- and microvascular complications, including diabetic retinopathy (DR), micro- and macroalbuminuria (MAU), diabetic peripheral neuropathy (DPN), and lower extremity peripheral artery disease (LEAD) were evaluated. Multivariate logistic regression analysis revealed that when taking the top tertile of SI as a reference, an increasing trend of the prevalence of DR, MAU, DPN, and LEAD were presented (all P for trend  < 0.05), where the OR (95% CI) for DR prevalence was 1.967 (1.252-3.090) in T2, 2.195 (1.278-3.769) in T1, for MAU was 1.805 (1.149-2.837) in T2, 2.537 (1.490-4.320) in T1, for DPN was 2.244 (1.485-3.391) in T2, 3.172 (1.884-5.341) in T1, and for LEAD was 2.017 (1.002-4.057) in T2, 2.405 (1.107-5.225) in T1 (all P < 0.05). Patients with lower SI were more inclined to have an increased risk of macro- and microvascular damage in T2DM population, which may be related to sarcopenia.

Muscle-origin creatinine-cystatin C ratio is an osteoporosis marker in individuals with normal renal function: evidence from observational and Mendelian randomization analysis

Background

Creatinine-cystatin C ratio (CCR) has been demonstrated as an objective marker of sarcopenia in clinical conditions but has not been evaluated as an osteoporosis marker in individuals with normal renal function.

Methods

We selected 271,831 participants with normal renal function from UK Biobank cohort. Multivariable linear/logistic regression and Cox proportional hazards model were used to investigate the phenotypic relationship between CCR and osteoporosis in total subjects and gender-stratified subjects. Based on the genome-wide association study (GWAS) data, linkage disequilibrium regression (LDSC) and Mendelian randomization (MR) analysis were performed to reveal the shared genetic correlations and infer the causal effects, respectively.

Results

Amongst total subjects and gender-stratified subjects, serum CCR was positively associated with eBMD after adjusting for potential risk factors (all P<0.05). The multivariable logistic regression model showed that the decrease in CCR was associated with a higher risk of osteoporosis/fracture in all models (all P<0.05). In the multivariable Cox regression analysis with adjustment for potential confounders, reduced CCR is associated with the incidence of osteoporosis and fracture in both total subjects and gender-stratified subjects (all P<0.05). A significant non-linear dose-response was observed between CCR and osteoporosis/fracture risk (P non-linearity < 0.05). LDSC found no significant shared genetic effects by them, but PLACO identified 42 pleiotropic SNPs shared by CCR and fracture (P<5×10-8). MR analyses indicated the causal effect from CCR to osteoporosis/fracture.

Conclusions

Reduced CCR predicted increased risks of osteoporosis/fracture, and significant causal effects support their associations. These findings indicated that the muscle-origin serum CCR was a potential biomarker to assess the risks of osteoporosis and fracture.

Association of serum creatinine to cystatin C to waist circumference ratios and hypertension: evidence from China health and retirement longitudinal study

Background

The objective of this study was to explore the association between the ratio of serum creatinine to cystatin C to waist circumference (CCR/WC) and hypertension.

Methods

The study utilized data extracted from the China Health and Retirement Longitudinal Study. In the cross-sectional analysis, logistic regression analyses were employed to examine the association between the CCR/WC ratio and hypertension. By utilizing restricted cubic splines, potential non-linear associations between the CCR/WC ratio and hypertension were explored. In the longitudinal analysis, the association between CCR/WC quartiles (Q1-Q4) and the risk of new-onset hypertension was evaluated by Cox proportional-hazards models.

Results

In total, 7,253 participants were enrolled. The study unveiled an inverse association with hypertension, demonstrating an odds ratio (OR) of 0.29 (95% confidence interval [CI]: 0.23-0.37, P < 0.001). Among males, an OR of 0.38 (95% CI: 0.25-0.58, P < 0.001) was observed, while among females, an OR of 0.41 (95% CI: 0.28-0.60, P < 0.001) was noted. There was an absence of a nonlinear association between the CCR/WC ratio and hypertension. Cox regression analysis unveiled a reduced risk of hypertension in Q3 (Hazard ratios [HR]: 0.69, 95% CI: 0.58-0.82, P < 0.001) and Q4: (HR: 0.70, 95% CI: 0.59-0.83, P < 0.001) in compared to the Q1 of the CCR/WC ratio, and sex-specific analysis yielded consistent results.

Conclusion

This study emphasizes the potential association between an elevated CCR/WC ratio and a reduced risk of hypertension.

The diagnostic performance of Cr/CysC for sarcopenia and its predictive value on clinical outcomes in hospitalized older patients: a prospective cohort study

PURPOSE

The utilization of the creatinine-to-cystatin C ratio (Cr/CysC) represents an innovative method for predicting sarcopenia. Our objectives encompassed the evaluation of sarcopenia diagnostic accuracy for Cr/CysC, SARC-F, SARC-CalF, the combination of Cr/CysC and SARC-CalF, and the Ishii score, as well as an exploration of the predictive value of Cr/CysC concerning clinical outcomes within hospitalized older individuals.

METHODS

We employed receiver operating characteristic (ROC) curves and calculated areas under the curves (AUCs) to assess the diagnostic accuracy. Furthermore, we applied univariate and multivariate Cox proportional-hazard models to calculate the hazard ratio (HR) and 95% confidence interval (CI) of risk factors affecting prognosis.

RESULTS

Our study included 312 participants, comprising 167 men and 145 women, with an average age of 71 years. Among males, the AUCs for Cr/CysC, SARC-F, SARC-CalF, the combination of Cr/CysC and SARC-CalF, and the Ishii score were 0.717 [95% CI 0.642-0.784], 0.669 (95% CI 0.592-0.739), 0.845 (95% CI 0.781-0.896), 0.882 (95% CI 0.823-0.926), and 0.938 (95% CI 0.890-0.969), respectively. In females, the AUCs for Cr/CysC, SARC-F, SARC-CalF, the combination of Cr/CysC and SARC-CalF, and the Ishii score were 0.706 (95% CI 0.625-0.779), 0.631 (95% CI 0.547-0.710), 0.763 (95% CI 0.686-0.830), 0.789 (95% CI 0.714-0.853), and 0.898 (95% CI 0.837-0.942), respectively. After adjusting for age, sex, physical exercise, smoking, drinking, hypertension, coronary heart disease (CHD), chronic obstructive pulmonary disease (COPD), chronic kidney disease (CKD), and cancer, sarcopenia identified by Cr/CysC (adjusted HR = 2.176, 95% CI 1.062-4.460, P = 0.034) was independently associated with poor overall survival in hospitalized older patients.

CONCLUSIONS

Cr/CysC has satisfactory diagnostic accuracy for sarcopenia diagnosis and predictive value for poor outcomes in hospitalized older patients. The combination of Cr/CysC and SARC-CalF may provide a more accurate screening for sarcopenia and the Ishii score may be the most accurate clinical method for detecting sarcopenia.

Diabetes Mellitus Should Be Considered While Analysing Sarcopenia-Related Biomarkers

Sarcopenia is a chronic, progressive skeletal muscle disease characterised by low muscle strength and quantity or quality, leading to low physical performance. Patients with type 2 diabetes mellitus (T2DM) are more at risk of sarcopenia than euglycemic individuals. Because of several shared pathways between the two diseases, sarcopenia is also a risk factor for developing T2DM in older patients. Various biomarkers are under investigation as potentially valuable for sarcopenia diagnosis and treatment monitoring. Biomarkers related to sarcopenia can be divided into markers evaluating musculoskeletal status (biomarkers specific to muscle mass, markers of the neuromuscular junction, or myokines) and markers assuming causal factors (adipokines, hormones, and inflammatory markers). This paper reviews the current knowledge about how diabetes and T2DM complications affect potential sarcopenia biomarker concentrations. This review includes markers recently proposed by the expert group of the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) as those that may currently be useful in phase II and III clinical trials of sarcopenia: myostatin (MSTN); follistatin (FST); irisin; brain-derived neurotrophic factor (BDNF); procollagen type III N-terminal peptide (PIIINP; P3NP); sarcopenia index (serum creatinine to serum cystatin C ratio); adiponectin; leptin; insulin-like growth factor-1 (IGF-1); dehydroepiandrosterone sulphate (DHEAS); C-reactive protein (CRP); interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). A better understanding of factors influencing these biomarkers' levels, including diabetes and diabetic complications, may lead to designing future studies and implementing results in clinical practice.

The relationship between serum creatinine/cystatin C ratio and mortality in hypertensive patients

BACKGROUND AND AIMS

Sarcopenia is a disease characterized by loss of skeletal muscle mass and function that is closely associated with cardiovascular disease. The serum creatinine/cystatin C (Cr/CysC) ratio has been shown to be a simplified indicator for identifying low muscle mass (LMM) or sarcopenia. The aim of this study was to investigate whether the Cr/CysC ratio helps to predict prognostic information in hypertensive patients.

METHODS AND RESULTS

This cohort study included 2509 patients with hypertension from the National Health and Nutrition Survey 1999-2002. To evaluate the association between Cr/CysC ratio and mortality, we used Kaplan Meier estimates to calculate cumulative survival probabilities for all-cause mortality and cardiovascular mortality, Cox regression analyses, and hazard ratio (HR) and 95% confidence interval (CI) were calculated. Over a median follow-up of 11.76 years, lower Cr/CysC ratio was associated with lower risk of all-cause mortality (per 0.1 increase, HR:0.81, 95% CI: 0.77-0.85, P < 0.001) and cardiovascular mortality (per 0.1 increase, HR:0.80, 95% CI: 0.72-0.89, P < 0.001). Compared with patients with normal muscle mass, all-cause mortality, and cardiovascular mortality HR for patients with LMM diagnosed by Cr/CysC ratio were 1.57 (95% CI: 1.36-1.82, P < 0.001) and 1.64 (95% CI: 1.12-2.42, P = 0.012), respectively.

CONCLUSION

We found that low muscle mass shown by lower Cr/CysC ratio was an independent risk factor for poor prognosis in hypertensive patients. We recommend routine screening of Cr/CysC ratio in hypertensive patients and early intervention for low muscle mass or sarcopenia.

Lower creatinine to cystatin C ratio is associated with an increased risk of MASLD: A cross-sectional and prospective study of 368,634 UK Biobank participants

OBJECTIVE

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects many populations, and screening out the high-risk populations at an early stage is a challenge. As a sarcopenia index, the relationship between creatinine to cystatin C ratio (CCR) and MASLD remains unclear. This cross-sectional, prospective study aimed to explore the relationship between CCR and MASLD. Design Firstly, explored the correlation between CCR and MASLD in cross-sectional analyses. Then excluded the population with baseeline diagnosis of MASLD and analyzed the association with baseline CCR levels and the onset of MASLD in the population with available follow-up data. Univariate and multivariate logistic regression analyses were used to calculate odds ratios (ORs) to evaluate the association between CCR levels and MASLD.

PATIENTS AND MEASUREMENTS

This study included 368,634 participants from the UK Biobank for cross-sectional and prospective analyses. The demographic characteristics and laboratory measurements of all participants were obtained from the UK Biobank. MASLD was diagnosed according to the multi-society consensus nomenclature. Hepatic steatosis was defined as FLI  ≥60.

RESULTS

We grouped the study participants according to CCR tertiles. In cross-sectional analyses, participants in CCR tertile 1 had the highest MASLD risk (OR: 1.070, 95% CI: 1.053-1.088, p < .001). And the similar association was observed in the prospective analyses (CCR tertile 1 OR: 1.340, 95% CI: 1.077-1.660, p = .009; CCR tertile 2 OR: 1.217, 95% CI: 1.021-1.450, p = .029, respectively). After stratification by gender, the significant association between CCR and the onset of MASLD was only observed in males (CCR tertile 1 OR: 1.639, 95% CI: 1.160-2.317, p = .005; CCR tertile 2 OR: 1.322, 95% CI: 1.073-1.628, p = .005, respectively).

CONCLUSION

Our results indicated that lower CCR was significantly associated with higher risk of MASLD, based on which predictive models can be developed to screen populations at high risk of developing MASLD.

Diagnostic test accuracy of serum creatinine and cystatin C-based index for sarcopenia: a systematic review and meta-analysis

BACKGROUND

Sarcopenia is an important prognostic factor, but its optimal screening methods remain challenging. Several new indices developed based on serum creatinine (Cr) and cystatin C (CysC) have been proposed to be diagnostic biomarkers for sarcopenia screening.

OBJECTIVE

This review aimed to evaluate the diagnostic accuracy of serum Cr- and CysC-based indices for sarcopenia diagnosis.

METHODS

We systematically searched MEDLINE, EMBASE, SCIE and SCOPUS from inception to 2 April 2023. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. A bivariate random-effects model was used to synthesise the pooled sensitivity, specificity and area under the curves of the summary receiver operating characteristic (SROC-AUC).

RESULTS

We retrieved 936 publications and included 16 studies with 5,566 participants (mean age ranged: 51.0-78.4 years, 50.2% men). The prevalence of sarcopenia ranged from 7.8 to 69.5%. All included studies presented a moderate to high risk of bias. The serum Cr- and CysC-based indices showed moderate diagnostic accuracy for sarcopenia (pooled sensitivity: 0.67, 95% CI 0.57-0.75; pooled specificity: 076, 95% CI 0.67-0.83; pooled SROC-AUC: 0.78, 95% CI 0.74-0.81). The Cr/CysC ratio is the most widely studied index, followed by the Cr × eGFRcys index. Overall, both indicators had satisfactory and comparable performance in screening sarcopenia.

CONCLUSION

Serum Cr- and CysC-based indices showed moderate diagnostic accuracy for sarcopenia. The most studied indices-the Cr/CysC ratio and Cr × eGFRcys index-had comparable diagnostic accuracy for evaluating sarcopenia and may serve as surrogate markers for sarcopenia. However, further validation is required to verify these findings.

Blood biomarkers for sarcopenia: A systematic review and meta-analysis of diagnostic test accuracy studies

Biomarkers are emerging as a potential tool for screening or diagnosing sarcopenia. We aimed to summarize the current evidence on the diagnostic test accuracy of biomarkers for sarcopenia. We comprehensively searched Ovid MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials up to January 2023 and only included diagnostic test accuracy studies. We identified 32 studies with 23,840 participants (women, 58.26%) that assessed a total of 30 biomarkers. The serum creatinine to cystatin C ratio (Cr/CysC) demonstrated a pooled sensitivity ranging from 51% (95% confidence interval [CI] 44-59%) to 86% (95% CI 70-95%) and a pooled specificity ranged from 55% (95% CI 38-70%) to 76% (95% CI 63-86%) for diagnosing sarcopenia defined by five different diagnostic criteria (11 studies, 7240 participants). The aspartate aminotransferase to alanine aminotransferase ratio demonstrated a pooled sensitivity of 62% (95% CI 56-67%) and a pooled specificity of 66% (95% CI 60-72%) (3 studies, 11,146 participants). The other 28 blood biomarkers exhibited low-to-moderate diagnostic accuracy for sarcopenia regardless of the reference standards. In conclusion, none of these biomarkers are optimal for screening or diagnosing sarcopenia. Well-designed studies are needed to explore and validate novel biomarkers for sarcopenia.

Prognostic value of the serum creatinine/cystatin C ratio in patients with chronic obstructive pulmonary disease

BACKGROUND

Sarcopenia, characterized by skeletal muscle atrophy and physical inactivity, is a manifestation of chronic obstructive pulmonary disease (COPD) and is associated with a poor prognosis. The serum creatinine (Cr)/cystatin C (CysC) ratio has been proposed as a marker of sarcopenia, given its correlation with total skeletal muscle mass, and as a prognostic indicator in COPD. This study aimed to evaluate the usefulness of the serum Cr/CysC ratio as a prognostic determinant in these patients.

METHODS

A total of 124 outpatients with COPD were enrolled in this study. Their serum Cr and CysC levels were measured. Survival time analyses were conducted to compare mortality rates between the low and high serum Cr/CysC ratio groups. Multivariate analysis was performed to investigate the association between various factors.

RESULTS

Using a serum Cr/CysC cut-off value of 0.885, the mortality rate (per 1000 person-years) for overall mortality was significantly higher in the low serum Cr/CysC ratio group (69.2 versus 28.6; hazard ratio, 2.47; 95% confidence interval, 1.06-5.79; p < 0.05). Similarly, the mortality rate due to respiratory disease was also higher (37.8 versus 8.2; hazard ratio, 4.68; 95% confidence interval, 1.05-20.9; p < 0.05). Multivariate Cox proportional hazards analysis revealed that serum Cr/CysC was an independent risk factor for respiratory disease mortality, regardless of age and airflow limitations.

CONCLUSIONS

The serum Cr/CysC ratio could be a valuable clinical parameter for identifying sarcopenia and severe airflow obstruction. The study findings highlight the utility of this ratio as a prognostic predictor in patients with COPD.

Serum-Creatinine-to-Cystatin C-to-Waist-Circumference Ratios as an Indicator of Severe Airflow Limitation in Older Adults

BACKGROUND

This study aimed to investigate the association between the serum-creatinine-to-cystatin C-to-waist-circumference (CCR/WC) ratio with lung function and severe airflow limitation (SAL).

METHODS

The data were derived from the China Health and Retirement Longitudinal Study. Peak expiratory flow (PEF) was used as a measure of lung function parameter. Logistic and linear regression were utilized separately to evaluate the relationship between the CCR/WC ratio with PEF and SAL in baseline. Restricted cubic spline was used to explore potential non-linear associations between the CCR/WC ratio and SAL. Cox proportional-hazards models were used to assess the association between CCR/WC quartiles and the risk of new-onset SAL.

RESULTS

A total of 6105 participants were included. This study revealed a positive association between the CCR/WC ratio and lung function (PEF: β [partial coefficient]: 25.95, 95%CI: 12.72 to 39.18, p < 0.001; PEF/PEF prediction: β = 0.08, 95%CI: 0.05 to 0.12, p < 0.001) and an inverse association relationship with SAL (OR [odds ratio]: 0.64, 95% confidence interval [CI]: 0.47 to 0.85, p = 0.003). Subgroup analysis showed a significant association between the CCR/WC ratio and SAL in males (OR: 0.58, 95% CI: 0.37 to 0.90, p = 0.017) but not in females (p = 0.059). Cox regression analysis revealed a decreased risk of SAL in the quartiles (Q2-4) compared to the first quartile of the CCR/WC ratio (hazard ratios [HRs]: 0.49 to 0.73, all p < 0.05).

CONCLUSIONS

This study highlights a positive association between the CCR/WC ratio and lung function, with a potential protective effect against SAL.

Low Skeletal Muscle Mass and Clinical Outcomes in Chronic Obstructive Pulmonary Disease

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD), decreased muscle mass is a frequently encountered comorbidity in clinical practice. However, the evaluation of muscle mass in patients with COPD in real-world practice is rare.

METHODS

We retrospectively reviewed the electronic medical records of all patients with COPD who underwent bioelectrical impedance analysis at least once between January 2011 and December 2021 in three hospitals. Then, we analyzed the performance rate of muscle mass measurement in the patients and the correlation between muscle mass, clinical parameters, and COPD prognosis.

RESULTS

Among the 24,502 patients with COPD, only 270 (1.1%) underwent muscle mass measurements. The total skeletal muscle mass index was significantly correlated with albumin, alanine transaminase, and creatinine to cystatin C ratio in patients with COPD (r=0.1614, p=0.011; r=0.2112, p=0.001; and r=0.3671, p=0.001, respectively). Acute exacerbation of COPD (AE COPD) was significantly correlated with muscle mass, especially the truncal skeletal muscle mass index (TSMI) in males (r=-0.196, p=0.007). In the multivariate analysis, TSMI and cystatin C were significant risk factors for AE COPD (hazard ratio, 0.200 [95% confidence interval, CI, 0.048 to 0.838] and 4.990 [95% CI, 1.070 to 23.278], respectively).

CONCLUSION

Low muscle mass negatively affects the clinical outcomes in patients with COPD. Despite its clinical significance, muscle mass measurement is performed in a small proportion of patients with COPD. Therefore, protocols and guidelines for the screening of sarcopenia in patients with COPD should be established.

Diagnostic Value of Serum Creatinine and Cystatin-C-Based Indices and Ishii Score in Cancer-Related Sarcopenia

BACKGROUND

Sarcopenia is a key factor affecting the prognosis of cancer patients; however, identifying patients at risk remains challenging. The serum creatinine/cystatin C ratio (CCR) and the sarcopenia index (SI) are new biomarkers for sarcopenia screening. The Ishii test score is an equation based on age, grip strength, and calf circumference for sarcopenia screening. However, their performances in advanced cancer patients have not been thoroughly studied. We aimed to evaluate and compare the accuracy of three screening tools in diagnosing cancer-related sarcopenia.

METHODS

A total of 215 cancer patients with a median age of 60.5 y were enrolled in this cross-sectional study. The Asian Working Group for Sarcopenia 2019 (AWGS2019) criteria were used as a standard. The diagnostic accuracies of the CCR, SI, and Ishii screening test were analyzed in terms of sensitivity, specificity, negative and positive predictive values, the Youden index, and the receiver operating characteristic (ROC) curve.

RESULTS

According to the AWGS2019 criteria, the prevalence of sarcopenia and severe sarcopenia was 47.9% and 18.6%, respectively. The CCR, SI (positively), and Ishii scores (negatively) were correlated with muscle mass. Accordingly, sarcopenia was negatively correlated with CCR and SI, while it was significantly positively correlated with the Ishii score. In males, the AUCs of the CCR, SI, and Ishii scores were 0.743 (95%CI 0.65-0.836), 0.758 (95%CI 0.665-0.852), and 0.833 (95%CI 0.751-0.909), respectively. In females, the AUCs of the CCR, SI, and Ishii scores were 0.714 (95%CI 0.61-0.818), 0.737 (95%CI 0.635-0.839), and 0.849 (95%CI 0.775-0.932), respectively. The AUC of the Ishii score was significantly higher than that of the other screening tools (p < 0.001). The cut-off value of the optimal Ishii score was 102.3 (sensitivity: 93.2%, specificity: 59.1%) for males and 98.3 (sensitivity: 93.3%, specificity: 64.7%) for females.

CONCLUSIONS

The CCR and SI based on serum CysC and creatinine had a remarkably similar overall diagnostic accuracy for sarcopenia in advanced cancer. Among the above three sarcopenia screening tools, the Ishii score chart seemed to have better predictive values of sarcopenia in cancer patients.

The serum creatinine to cystatin C ratio predicts the risk of acute exacerbation of chronic obstructive pulmonary disease

The purpose of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) treatment is to minimize the negative impact of the current exacerbation and to prevent the development of subsequent events. Therefore, it is important to identify readily available serological indicators during hospital admission to assess the prognosis of patients with AECOPD. All patients hospitalized in a Department of Respiratory and Critical Care Medicine of tertiary care hospital between January 2021 and December 2021 for AECOPD were analyzed using univariate correlations and binary logistic regression analysis with 2 models for associations between demographic, clinical, and laboratory features and AECOPD risk. The ratio of creatinine to cystatin C (Cre/Cys C) ratio was significantly associated with age (r = -0.206, P = .000), weight (R = 0.331, P = .000), body mass index (BMI) (R = 0.133, P = .007), and forced vital capacity (FVC)% predicted (R = 0.130, P = .009). Multiple regression was performed to predict the Cre/Cys C ratio from age, weight, BMI, forced expiratory volume during 1 second/FVC ratio, and FVC% predicted FABP-4, with F (5, 405) = 24.571, P = .000, R2 = 0.233. The results showed that the most significant predictors of the Cre/Cys C ratio were age (P = .007), weight (P = .000), BMI (P = .000), and predicted forced expiratory volume during 1 second (P = .000). Multivariate analysis was performed to determine whether the Cre/Cys C ratio was a predictor of AECOPD risk. Model 1 showed that a low Cre/Cys C ratio was associated with an increased hospital length of stay (odds ratio: -0.114, 95% confidence interval: -0.061 to -0.005) and admission to the intensive care unit (odds ratio: 0.951, 95% confidence interval: 0.907-0.996). After adjustment for potential confounding factors, model 2 showed that a low Cre/Cys C ratio was not independently associated with AECOPD risk. The present study indicated that the Cre/Cys C ratio is an easy, cheap, repeatable, and promising tool that allows us to evaluate the risk of AECOPD using serum markers. A low Cre/Cys C ratio was associated with a prolonged hospital length of stay and admission to the intensive care unit in AECOPD patients. However, the associations were not independent.

The Systemic Immune Inflammation Index (SII) Combined with the Creatinine-to-Cystatin C Ratio (Cre/CysC) Predicts Sarcopenia in Patients with Liver Cirrhosis Complicated with Primary Hepatocellular Carcinoma

BACKGROUND

Sarcopenia is a risk factor for poor cancer prognosis. Early identification and timely intervention of sarcopenia can improve patient prognosis.

METHODS

A total of 91 patients with liver cirrhosis complicated with primary hepatocellular carcinoma were retrospectively analyzed. Based on the results of multivariable logistic regression analysis, a nomogram was developed. Moreover, 50 patients were enrolled for external validation. The predictive efficacy of the nomogram was evaluated using the receiver operating characteristic curve (ROC).

RESULTS

According to the logistic regression analysis results, age, body mass index (BMI), creatinine-to-cystatin C ratio (Cre/CysC), and systemic immune inflammation index (SII) were independent risk factors of sarcopenia in patients with cirrhosis complicated with primary hepatocellular carcinoma (HCC) (all p < 0.05). The ABCS nomogram model was established, and the area under the ROC curve (AUC) was 0.896 (84.7% sensitivity, 81.2% specificity). The calibration curve of the nomogram was close to the ideal diagonal line. The predictive efficacy of the nomogram was verified through the external validation.

CONCLUSION

The ABCS model based on SII and Cre/CysC can be used to identify high-risk sarcopenia in patients with cirrhosis complicated with HCC in the early stage.

Sarcopenia index as a predictor of clinical outcomes among older adult patients with acute exacerbation of chronic obstructive pulmonary disease: a cross-sectional study

BACKGROUND

Sarcopenia is a geriatric syndrome with progressive loss of skeletal muscle mass and function and has a negative impact on clinical outcomes associated with chronic obstructive pulmonary disease (COPD). Recently, the sarcopenia index (SI) was developed as a surrogate marker of sarcopenia based upon the serum creatinine to cystatin C ratio. We aimed to assess the value of SI for predicting clinically important outcomes among elderly patients with acute exacerbation of COPD (AECOPD).

METHODS

This cross-sectional study included elderly patients with AECOPD in China from 2017 to 2021. Clinical data were collected from medical records, and serum creatinine and cystatin C were measured. Outcomes included respiratory failure, heart failure, severe pneumonia, invasive mechanical ventilation, and mortality. Binary logistic regression was used to analyze the association between SI and clinical outcomes.

RESULTS

A total of 306 patients (260 men, 46 women, age range 60-88 years) were enrolled in this study. Among the total patients, the incidence of respiratory failure and severe pneumonia was negatively associated with SI values. After adjusting for potential confounding factors, binary logistic regression analyses showed that a higher SI was still independently associated with a lower risk of respiratory failure (odds ratio [OR]: 0.27, 95% confidence interval [CI]: 0.13-0.56, P < 0.05). In subgroup analysis, the incidence of respiratory failure was negatively associated with SI values in groups with both frequent exacerbation and non-frequent exacerbation. After adjustment for potential confounders, binary logistic regression analyses showed that a higher SI was also independently associated with a lower risk of respiratory failure in both groups (OR: 0.19, 95% CI: 0.06-0.64 and OR: 0.31, 95% CI: 0.11-0.85). However, there were no significant differences in the correlations between SI and the risk of heart failure, invasive mechanical ventilation, and mortality in all groups.

CONCLUSION

The SI based on serum creatinine and cystatin C can predict respiratory failure in patients with AECOPD and either frequent or infrequent exacerbations. This indicator provides a convenient tool for clinicians when managing patients with AECOPD in daily clinical practice.

Association between oral frailty and cystatin C-related indices-A questionnaire (OFI-8) study in general internal medicine practice

BACKGROUND

Cystatin C-related indices such as the ratio of creatinine to cystatin C (Cr/CysC) and the ratio of estimated glomerular filtration rate by cystatin C (eGFRcys) to creatinine eGFRcre (eGFRcys/eGFRcre) levels have been shown to be associated with muscle mass and strength and can be markers of sarcopenia. Oral frailty is defined as an age-related gradual loss of oral functions, accompanied by a decline in cognitive and physical functions. It results in adverse health-related outcomes in older age, including mortality, physical frailty, functional disability, poor quality of life, and increased hospitalization and falls. Therefore, poor oral health among the elderly is an important health concern due to its association with the pathogenesis of systemic frailty, suggesting it to be a multidimensional geriatric syndrome. The Oral Frailty Index-8 (OFI-8) is a questionnaire that can be used for easy screening of oral frailty. This study aimed to investigate whether cystatin C- related indices are different between patients with low to moderate risk of oral frailty and those at high risk of oral frailty, using the OFI-8 in attending a general internal medicine outpatient clinic.

MATERIALS AND METHODS

This is a cross-sectional study that included 251 patients with a mean age of 77.7±6.6 years and a median age of 77 years (128 men: mean age, 77.1±7.3 years; median age, 77 years and 123 women: mean age, 78.4±5.7 years; median age, 78 years) attending general internal medicine outpatient clinics. OFI-8 scores were tabulated by gender to determine whether there were differences between patients at low to moderate risk of oral frailty (OFI-8 score ≤3 points) and those at high risk (OFI-8 score ≥4 points) in Cr/CysC, eGFRcys/eGFRcre levels, height, weight, grip strength, etc. were examined.

RESULTS

The OFI-8 score was higher in women than in men, suggesting that oral frailty is more common in women. Cr/CysC, eGFRcys/eGFRcre and grip strength were significantly lower in both men and women in the high-risk group for oral frailty (OFI-8 score ≥ 4). Height, hemoglobin level, red blood cell count, and serum albumin levels were significantly lower in men with an OFI-8 score ≥4. Receiver operating characteristic curve (ROC) analysis also showed that Cr/CysC and eGFRcys/eGFRcre were significantly associated with an OFI-8 score≥4 in both men and women.

CONCLUSION

Cr/CysC and eGFRcys/eGFRcre were significantly lower in the high-risk group for oral frailty on the OFI-8in both men and women. A relationship exists among cystatin C-related indices, which can effectively screen systemic frailty. Similarly, the OFI-8 score can be used to effectively screen oral frailty. Thus, a collaboration that incorporates both systemic and oral frailty from medical and dental perspectives is required.

Prevalence of sarcopenia in patients with COPD through different musculature measurements: An updated meta-analysis and meta-regression

Aim

Chronic obstructive pulmonary disease (COPD) patients vary widely in terms of the prevalence of sarcopenia, which is partially attributed to differences in diagnostic criteria and disease severity. There are several different musculature measurements that are used to quantify sarcopenia. This study included published literature for meta-analysis to assess the sarcopenia prevalence in COPD patients and correlate the disease with the clinical characteristics of such patients.

Methods

A comprehensive review of the English and Chinese literature on sarcopenia prevalence in COPD patients was conducted using electronic databases such as China National Knowledge Infrastructure (CNKI), Web of Science, Cochrane Library, EMBASE, PubMed, and Wanfang. Two researchers analyzed the studies for Newcastle-Ottawa Scale. The software Stata 11.0 was employed for the analysis of the acquired data. The standard mean differences method was utilized for the estimation and quantification of the effect size. Furthermore, a fixed- or random-effects model was employed for conducting a combined analysis.

Results

In total, 56 studies were included as per the specific inclusion criteria. The resulting data of the assessed COPD patients in this research indicated a 27% prevalence of sarcopenia. Further analysis of subgroups was executed per disease severity, ethnicity, diagnostic criteria, gender, and age. Per these findings, increased disease severity elevated the prevalence of sarcopenia. The Latin American and Caucasian populations indicated an increased prevalence of sarcopenia. In addition, the prevalence of sarcopenia was related to diagnostic criteria and definition. Male COPD patients had a higher prevalence of sarcopenia than female COPD patients. COPD patients with an average age greater than 65 had a slightly higher prevalence of sarcopenia. COPD patients with comorbid sarcopenia had poorer pulmonary function, activity tolerance, and clinical symptoms than patients with COPD alone.

Conclusion

Sarcopenia prevalence is high (27%) in COPD patients. In addition, these patients had worse pulmonary function and activity tolerance compared to patients without sarcopenia.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=367422, identifier CRD42022367422.

Sex differences in the relationship of serum creatinine to cystatin C ratio and depressive symptoms among middle-aged and older adults in China

BACKGROUND

Sarcopenia is reported to be associated with depression. Recently, serum creatinine to cystatin C ratio (CCR) has been recommended as a promising biomarker for detecting sarcopenia. The purpose of this study was to explore the relationship between CCR and depressive symptoms among middle-aged and older adults using the baseline data of the China Health and Retirement Longitudinal Study (CHARLS).

METHODS

This study included 7083 participants aged 45 and older. A score of 10-item Center for Epidemiological Studies Depression Scale (CESD-10) ≥ 12 was used as the cut-off of having depressive symptoms. CCR was calculated by serum creatinine (mg/dL)/cystatin C (mg/L). The t-test and Chi-squared test were applied to compare the differences between the depressive symptoms group and no depressive symptoms group in both sexes. Unadjusted and adjust logistic regression models were used to further investigate the relationship between CCR and depressive symptoms.

RESULTS

In the fully adjusted logistic regression models, higher CCR was significantly correlated with a lower incidence of depressive symptoms in males (OR = 0.486, P = 0.001, 95 % CI = 0.314-0.752), but not in females (OR = 0.775 P = 0.184, 95 % CI = 0.532-1.129).

LIMITATIONS

1. Self-reported method was used to define depressive symptoms by CESD-10; 2. History of chronic diseases were all self-reported; 3. Residual bias was still possible after controlling for many confounding factors.

CONCLUSIONS

Lower CCR was significantly correlated with increased depressive symptoms in males, but not in females. More studies are needed to further confirm this conclusion.

Prognostic value of creatinine-to-cystatin c ratio in patients with type 2 diabetes mellitus: a cohort study

BACKGROUND

The serum creatinine-to-cystatin C ratio (Scr/Scys) has been suggested as a surrogate marker of muscle mass and a predictor of adverse outcomes in many diseases. However, the prognostic value of Scr/Scys in patients with type 2 diabetes mellitus (T2DM) is unknown. The aim of this study is to assess the prognostic value of Scr/Scys in patients with T2DM.

METHODS

In this retrospective observational study, we enrolled 3668 T2DM patients undergoing coronary angiography (CAG). Serum creatinine (Scr) and serum cystatin C (Scys) levels were measured at admission. The study population was separated into low muscle mass (low-MM) and normal muscle mass (normal-MM) groups by Scr/Scys cut-off point. The association between muscle mass and long-term all-cause mortality was examined using Cox regression analysis.

RESULTS

During a median follow-up of 4.9 (3.0-7.1) years, a total of 352 (9.6%) patients died. The mortality was higher in patients with low-MM as compared with patients with normal-MM (11.1% vs. 7.3%; p < 0.001). Low muscle mass was associated with increased risk for long-term all-cause mortality, regardless of whether Scr/Scys were used as a continuous variable (adjusted hazard ratio: 1.08 [95% confidence interval (CI) 1.03 to 1.13]; p = 0.009) or a categorial variable (adjusted hazard ratio: 1.36 [95% CI 1.03 to 1.75]; p = 0.021).

CONCLUSION

Low muscle mass assessed by Scr/Scys was associated with increased risk of long-term all-cause mortality in diabetic patients.

High blood urea nitrogen to creatinine ratio is associated with increased risk of sarcopenia in patients with chronic obstructive pulmonary disease

BACKGROUND AND AIMS

Sarcopenia has been reported to be a prognostic factor for chronic obstructive pulmonary disease (COPD). However, the relationship between the ratio of blood urea nitrogen to creatinine (BUN/Cr) and sarcopenia in patients with COPD remain unclear. Therefore, the purpose of this study is to explore whether the ratio can be used as a predictor of sarcopenia in hospitalized COPD patients.

METHODS

The skeletal muscle area index (SMI) at the level of the 12th thoracic vertebra (T12) was used to assess the risk of sarcopenia in patients. This single center cross-sectional study was conducted by analyzing the clinical parameters and identifying the T12 skeletal muscle area (SMA) and density (SMD) on chest CT images of COPD hospitalized patients admitted to the respiratory department of our hospital from March 2018 to August 2021. The study enrolled 265 hospitalized patients. Based on the different statistical properties of the above variables, differences between groups were measured by independent sample Student t-tests, Mann-Whitney U tests, or Chi-Square tests. Multivariable linear regression analysis was used to evaluate the relationship between the value of BUN/Cr and the risk of sarcopenia.

RESULTS

The serum BUN/Cr ratio was negatively correlated with SMI (r = -0.201, p = 0.001) in COPD patients, and multivariate linear regression analysis showed that this ratio was associated with the risk of sarcopenia (β = -0.109, p = 0.041). The optimal cut-off value of BUN/Cr ratio for identifying COPD patients with sarcopenia was 97.893. There was also a significant negative correlation between serum BUN/Cr ratio and forced vital capacity (FVC; r = -0.235, p < 0.001) and forced expiratory volume in the first second (FEV1; r = -0.219, p < 0.001).

CONCLUSION

The BUN/Cr ratio can be used to predict sarcopenia and evaluate pulmonary function in hospitalized COPD patients.

Serum creatinine to cystatin C ratio and clinical outcomes in adults with non-dialysis chronic kidney disease

Background

Studies have suggested that the serum creatinine/cystatin C (Cr/CysC) ratio is a surrogate marker for muscle wasting is associated with adverse outcomes in several disease conditions. To clarify the utility of the Cr/CysC ratio as a prognostic marker in chronic kidney disease (CKD) we evaluated the association between the Cr/CysC ratio clinical outcomes in patients with non-dialysis CKD.

Methods

This prospective observational cohort study included 1,966 participants of the KoreaN cohort study Outcomes in patients With CKD (KNOW-CKD). We evaluated associated factors with the serum Cr/CysC ratio and association between the serum Cr/CysC ratio and composite outcomes of all-cause death and cardiovascular events (CVEs).

Results

The mean age was 54 ± 12 (SD) years and 61% were men. The mean serum Cr/CysC ratio was 10.97 ± 1.94 in men and 9.10 ± 1.77 in women. The Cr/CysC ratio correlated positively with urinary creatinine excretion, a marker of muscle mass. In the fully adjusted Cox proportional hazard model, the Cr/CysC ratio was associated with the occurrence of adverse outcomes through a median follow-up of 5.9 years [hazard ratio (HR) = 0.92, 95% confidence interval (CI) = 0.85–0.99 for the composite outcomes, HR = 0.87, 95% CI, 0.78 − 0.97 for all-cause death, and HR = 0.93; 95% CI, 0.84–1.04 for CVEs]. In subgroup analyses, there were interactions of the Cr/CysC ratio with age and sex for risk of the clinical outcomes, but not eGFR group.

Conclusion

A higher Cr/CysC ratio is associated with a lower risk of the composite outcomes, especially all-cause mortality, even after adjusting for eGFR. These suggest that the Cr/CysC ratio is a useful prognostic marker in CKD.

Serum Creatinine/Cystatin C Ratio as a Predictor of In-hospital Mortality in Patients Hospitalized with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Purpose

Low serum creatinine/cystatin C ratio (CCR) is associated with unfavorable characteristics in patients with chronic obstructive pulmonary disease (COPD); however, the relationship between CCR and in-hospital mortality of patients with acute exacerbation of COPD (AECOPD) is unexplored. Our objective was to assess the value of CCR for predicting in-hospital mortality of patients hospitalized with AECOPD.

Methods

Patients with AECOPD (n = 597) were retrospectively enrolled. Patient’s clinical characteristics and laboratory tests, including serum cystatin C and creatinine, were reviewed. The prediction value of CCR was evaluated using area under the receiver operating characteristic curve (AUC) values. Factors potentially impacting in-hospital mortality were investigated using univariate and multivariate logistic regression analyses.

Results

Mortality rate during hospitalization was 10.05%. CCR was lower in non-surviving vs. survived patients (41.67 vs. 61.52, P < 0.001). AUC value for CCR for in-hospital mortality prediction was 0.79 [95% confidence interval (CI) 0.73–0.85]. On multivariate logistic regression analysis, in-hospital mortality was strongly associated with CCR < 52.27 [odds ratio (OR) 6.23, 95% CI (3.00–12.92), P < 0.001], age ≥ 81 years [OR 2.97, 95% CI (1.20–7.37), P = 0.019], oxygenation index < 300 [OR 3.28, 95% CI (1.27–8.44), P = 0.014], CRP > 8 mg/L [OR 1.84, 95% CI (1.15–2.95), P = 0.012], and D-dimer > 500 ng/L [OR 5.19, 95% CI (1.51–17.79), P = 0.009].

Conclusions

CCR was significantly lower, and is a potential prognostic indicator, in patients with AECOPD who died during hospitalization.

Serum creatinine/cystatin C ratio is a systemic marker of sarcopenia in patients with gastrointestinal stromal tumours

Background

It is well known that sarcopenia is a common risk factor in patients with gastrointestinal tumours, which may negatively affect the clinical outcome and prognosis. Recent studies suggest that serum creatinine-cystatin C (Cr/CysC) ratio may be associated with sarcopenia, but this association lacks sufficient evidence in patients with gastrointestinal stromal tumours (GIST). Therefore, this study aimed to investigate whether the Cr/CysC ratio was associated with sarcopenia and recurrence-free survival (RFS) in patients with GIST.

Materials and methods

The study retrospectively analysed 413 patients with GIST who underwent surgical resection from January 2016 to January 2020. The serum Cr/CysC ratio was determined as a proxy for sarcopenia by comparing it with various biomarkers and Cox multifactorial analysis was used to determine the relationship between Cr/CysC ratio and prognosis.

Results

Serum Cr/CysC was positively correlated with skeletal muscle area (SMA) (r = 0.256, p &lt; 0.001), skeletal muscle index (SMI) (r = 0.300, p &lt; 0.001), and hand grip strength (HGS) (r = 0.251, p &lt; 0.001). The area under the receiver operator characteristic curve for sarcopenic subjects with serum Cr/CysC ratio was significantly greater than other biomarkers (Cr/CysC: 0.840, CysC: 0.732, Cr: 0.518). The optimal cut-off value for Cr/CysC was 0.65, and patients in the high Cr/CysC group had a higher 3-year recurrence-free survival (RFS) than those in the low Cr/CysC group (92.72 vs. 72.46%, p &lt; 0.001). Cox multifactorial analysis found that the Cr/CysC ratio was an independent risk factor for RFS in GIST patients (HR = 2.143, 95% CI: 1.431–5.459, p = 0.011).

Conclusion

Serum Cr/CysC ratio has satisfactory and comparable diagnostic accuracy, and prognostic value for sarcopenia in patients with GIST. Therefore, it can be a simple and practical clinical tool to screen sarcopenia in GIST patients. However, further studies are required to validate these findings.

Serum Derivatives of Reactive Oxygen Metabolites are Associated with Severity of Chronic Obstructive Pulmonary Disease and Affected by a p53 Gene Polymorphism

Purpose

Oxidative stress is known to activate tumor suppressor p53, which inhibits cell cycle progression and induces apoptosis. Levels of p53 in lung tissues from patients with chronic obstructive pulmonary disease (COPD) are increased compared with levels in nonsmokers or smokers without emphysema. A polymorphism in p53 codon 72 (rs1042522) is associated with emphysematous changes in patients with COPD. However, whether oxidative stress in the serum is associated with the p53 polymorphism and disease severity in COPD patients is unclear.

Patients and Methods

A total of 251 patients with a history of smoking more than 10 pack-years were enrolled in this study, and serum levels of derivatives of reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), and d-ROMs/BAP ratio (oxidative stress index; OSI) were measured. The percent low-attenuation area (LAA%) and cross-sectional area of the erector spinae muscles (ESM_CSA) at the Th₁₂ level were calculated from chest high-resolution computed tomography images. p53 codon 72 C/G genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism analysis.

Results

In patients carrying the p53 GG genotype, LAA% was significantly higher than in those carrying the CC genotype. d-ROM levels and OSI were associated with COPD severity and correlated with airflow limitation and markers of muscle atrophy (ESM_CSA and creatinine/cystatin C ratio). Associations between markers of oxidative stress and COPD severity were observed primarily in patients carrying the p53 codon 72 GG genotype.

Conclusion

Susceptibility to pulmonary emphysema and responses to oxidative stress may be affected by the p53 gene polymorphism.

Creatinine-to-cystatin C ratio as a marker of sarcopenia for identifying osteoporosis in male patients with type 2 diabetes mellitus

Background

Type 2 diabetes mellitus (T2DM) is associated with the increased incidence rate of sarcopenia and osteoporosis. Serum creatinine-to-cystatin C ratio (CCR) is a novel and simple tool which can be used as an index of sarcopenia. This study aims to investigate the association between CCR and osteoporosis as well as bone mineral density (BMD) in T2DM patients.

Methods

Four hundred eighteen T2DM patients were recruited, including 166 females and 252 males. General information, BMD data and laboratory data were collected. The correlation between CCR, BMD, bone metabolism markers and osteoporosis was explored by spearman correlation, receiver-operating characteristic (ROC) curve analysis and multiple regression analysis.

Results

Spearman correlation analysis showed that there was a positive correlation between CCR and BMD as well as serum calcium in male patients (r = 0.181–0.381, P < 0.01), but such correlation was not found in the female group. In multivariate regression analysis, it was found that there was a significant correlation between CCR and BMD of total lumbar spine, hip as well as femoral neck in male patients. ROC curve showed that the optimal cut-off value of CCR for predicting osteoporosis in male patients was 6.73 with the sensitivity of 88% and specificity of 63%.

Conclusion

In male T2DM patients, CCR was negatively correlated with osteoporosis and positively correlated with BMD.

Resistin as a Systemic Inflammation-Related Biomarker for Sarcopenia in Patients With Chronic Obstructive Pulmonary Disease

Background

Sarcopenia is common in patients with chronic obstructive pulmonary disease (COPD) and is mainly caused by systemic inflammation. Resistin acts as a proinflammatory cytokine and is involved in the activation of multiple inflammatory signaling pathways. The aim of this study was to determine the relationship between resistin levels and systemic inflammation and to assess the clinical value of circulating resistin for sarcopenia in patients with COPD.

Methods

In this prospective observational study, we enrolled 235 patients with COPD who were divided into development and validation sets. The definition of sarcopenia followed the guidelines from the Asian Working Group for Sarcopenia. Serum concentrations of resistin and TNF-α were measured using an enzyme-linked immunosorbent assay (ELISA).

Results

In this study, higher serum resistin levels were significantly associated with lower skeletal muscle mass and muscular strength. The serum resistin levels in patients with sarcopenia were significantly higher than those in patients without sarcopenia. The serum resistin level had positive correlations with the serum TNF-α level (r = 0.250, p = 0.007). The predictive efficacy of the serum resistin level (AUC: 0.828) for sarcopenia was superior to that of the serum TNF-α level (AUC: 0.621). The cutoff point (7.138 ng/ml) for the serum resistin level was validated in the validation set (AUC: 0.818).

Conclusions

Serum resistin levels were associated with systemic inflammation and can be used accurately and easily to predict sarcopenia in patients with COPD.

Sarcopenia HIBA score predicts sarcopenia and mortality in patients on the liver transplant waiting list

Sarcopenia is a prevalent condition that predicts prognosis in patients awaiting liver transplantation (LT). The gold standard for the diagnosis of sarcopenia is the assessment of the muscular area at L3 with computed tomography (CT) scan (skeletal muscle index [SMI]), but the routine use of CT scan is limited in clinical practice. Thus, we designed a single-center observational study aimed to evaluate the clinical factors associated with the presence of sarcopenia by SMI, and to build a score capable of predicting or excluding the presence of sarcopenia in patients on the LT waiting list (WL). Binary logistic regression analysis was performed to establish the factors independently associated with sarcopenia, and the Sarcopenia Hospital Italiano de Buenos Aires (HIBA) score was built from the resulting model after internal validation analysis by bootstrapping and correction for optimism. The predictive capability of mortality on the WL was evaluated with competing risk regression analysis. A total of 215 patients with cirrhosis on the LT WL were included. The independent factors associated with the presence of sarcopenia were male sex (odds ratio [OR]: 6.09, p < 0.001), body mass index (OR: 0.74, p < 0.001), Child Pugh (OR: 1.44, p < 0.001), and the ratio creatinine/Cystatin C (OR: 0.03, p = 0.007). The Sarcopenia HIBA score constructed with these variables showed an area under the curve of 0.862. During follow-up, 77 (36%) patients underwent LT, 46 (21%) died, and 92 (43%) remained alive. After adjusting for Model for End-Stage Liver Disease-Sodium, Sarcopenia HIBA score was an independent predictor of WL mortality (subhazard ratio: 1.19; 95% confidence interval 1.01-1.40; p = 0.042). Sarcopenia HIBA score is an easy-to-use, objective, and reliable diagnostic and predictive tool that can be useful to improve the prognostic evaluation and allow identifying a group of patients with a higher risk of death while awaiting LT.

Growth Differentiation Factor-15 as a Biomarker for Sarcopenia in Patients With Chronic Obstructive Pulmonary Disease

Purpose

Sarcopenia is an important factor contributing to comorbidities in patients with chronic obstructive pulmonary disease (COPD) and is an independent risk factor for increased mortality. The diagnostic process for sarcopenia requires specific equipment and specialized training and is difficult procedurally. A previous study found that GDF15 levels are associated with skeletal muscle mass and function in patients with COPD. However, whether circulating GDF15 levels can be used for the prediction of sarcopenia in patients with COPD is unknown.

Methods

This study included 235 patients with stable COPD who were divided into a development set (n = 117) and a validation set (n = 118), and we followed the definition of sarcopenia as defined by the guidelines from the Asian Working Group for Sarcopenia. Serum concentrations of GDF15 were measured using an enzyme-linked immunosorbent assay (ELISA), and construction of a nomogram and decision curve analysis were performed using the R package “rms.”

Results

In this study, serum GDF15 levels were negatively associated with skeletal muscle mass (r = –0.204, p = 0.031), handgrip strength (r = –0.274, p = 0.004), quadriceps strength (r = –0.269, p = 0.029), and the thickness (r = –0.338, p < 0.001) and area (r = –0.335, p < 0.001) of the rectus femoris muscle in patients with COPD. Furthermore, the serum levels of GDF15 in patients with sarcopenia were significantly higher than those in controls. Importantly, serum levels of GDF15 could effectively predict sarcopenia in patients with COPD based on the development set (AUC = 0.827) and validation set (AUC = 0.801). Finally, a nomogram model based on serum GDF15 levels and clinical features showed good predictive ability (AUC > 0.89) in the development and validation sets.

Conclusion

Serum GDF15 levels could be used to accurately and easily evaluate sarcopenia in patients with COPD.

Serum cystatin C to creatinine ratio is associated with sarcopenia in non-dialysis-dependent chronic kidney disease

Background

Methods

Results

Conclusion

Low serum creatinine to cystatin C ratio is independently associated with sarcopenia and high carotid plaque score in patients with type 2 diabetes

BACKGROUND AND AIMS

Low serum creatinine (Cr) to cystatin C (cysC) ratio has been suggested to be associated with low muscle mass and strength and poor prognosis in various chronic disease. We investigated the associations of CCR with sarcopenia and carotid plaque score (PS) in patients with type 2 diabetes mellitus.

METHODS AND RESULTS

A total of 1577 patients with type 2 diabetes were enrolled. High PS was defined as PS ≥ 3. Sarcopenia was assessed by the measurement of appendicular skeletal muscle mass (ASM) and grip strength (GS). Compared to the highest CCR group, the lowest tertile group was older; had higher C-reactive protein levels, CIMT, and PS, but lower cysC-based estimated glomerular filtration rate (cysC-eGFR), ASM/BMI, and GS. Positive correlations between CCR and ASM/BMI (r = 0.239 in men and 0.303 in women, p < 0.001) and GS (r = 0.282 in men and 0.270 in women, p < 0.001) were observed in both genders. Odds ratios and 95% confidence intervals for high PS after adjusting for age and sex were 1.22 (0.92-1.61, p = 0.18) in the middle and 1.74 (1.31-2.30, p < 0.001) in the lowest tertiles, respectively, with those of the lowest tertile remaining significant after further adjusting for multiple confounders.

CONCLUSIONS

Low CCR was independently associated with sarcopenia and high PS in patients with type 2 diabetes mellitus, especially after adjusting for ASM/BMI and GS.

Relationship between serum creatinine to cystatin C ratio and subclinical atherosclerosis in patients with type 2 diabetes

INTRODUCTION

Sarcopenia index (SI), calculated by (serum creatinine/cystatin C)×100, is reported to be associated with sarcopenia. Few studies reported the association between SI and subclinical atherosclerosis. We evaluated the association between SI and subclinical atherosclerosis, assessed by brachial-ankle pulse wave velocity (baPWV).

RESEARCH DESIGN AND METHODS

One hundred seventy-four patients with type 2 diabetes were included in this cross-sectional study. The relationship between SI and baPWV was assessed by Pearson's correlation coefficient. To calculate area under the receiver operator characteristic (ROC) curve (AUC) of SI for the presence of subclinical atherosclerosis, which was defined as baPWV >1800 cm/s, ROC analysis was performed. Logistic regression analyses were performed to assess the effect of SI on the prevalence of subclinical atherosclerosis adjusting for covariates.

RESULTS

Mean age, duration of diabetes, baPWV, and SI were 66.9 (10.1) years, 17.7 (11.6) years, 1802 (372) cm/s, and 77.6 (15.8), respectively. There was an association between SI and baPWV (men; r=-0.25, p=0.001, and women; r=-0.37, p=0.015). The optimal cut-off point of SI for the presence of subclinical atherosclerosis was 77.4 (sensitivity=0.72, specificity=0.58, p<0.001, AUC 0.66 (95% CI: 0.57 to 0.74)). In addition, SI was associated with the prevalence of subclinical atherosclerosis (adjusted OR 0.95, 95% CI: 0.91 to 0.99, p=0.015).

CONCLUSIONS

SI is associated with the prevalence of subclinical atherosclerosis in patients with type 2 diabetes.

Serum creatinine and cystatin C-based diagnostic indices for sarcopenia in advanced non-small cell lung cancer

BACKGROUND

Sarcopenia is an important prognostic factor of lung cancer. The serum creatinine/cystatin C ratio (CCR) and the sarcopenia index (SI, serum creatinine × cystatin C-based glomerular filtration rate) are novel screening tools for sarcopenia; however, the diagnostic accuracy of the CCR and SI for detecting sarcopenia remains unknown. We aimed to explore and validate the diagnostic values of the CCR and SI for determining sarcopenia in non-small cell lung cancer (NSCLC) and to explore their prognostic values for overall survival.

METHODS

We conducted a prospective cohort study of adult patients with stage IIIB or IV NSCLC. Levels of serum creatinine and cystatin C were measured to calculate the CCR and SI. Sarcopenia was defined separately using CCR, SI, and the Asian Working Group for Sarcopenia (AWGS) 2019 criteria. Participants were randomly sampled into derivation and validation sets (6:4 ratio). The cutoff values for diagnosing sarcopenia were determined based on the derivation set. Diagnostic accuracy was analysed in the validation set through receiver operating characteristic (ROC) curves. Cox regression models and survival curves were applied to evaluate the impact of different sarcopenia definitions on survival.

RESULTS

We included 579 participants (women, 35.4%; mean age, 58.4 ± 8.9 years); AWGS-defined sarcopenia was found in 19.5% of men and 10.7% of women. Both CCR and SI positively correlated with computed tomography-derived and bioimpedance-derived muscle mass and handgrip strength. The optimal cutoff values for CCR and SI were 0.623 and 54.335 in men and 0.600 and 51.742 in women, with areas under the ROC curves of 0.837 [95% confidence interval (CI): 0.770-0.904] and 0.833 (95% CI: 0.765-0.901) in men (P = 0.25), and 0.808 (95% CI: 0.682-0.935) and 0.796 (95% CI: 0.668-0.924) in women (P = 0.11), respectively. The CCR achieved sensitivities and specificities of 73.0% and 93.7% in men and 85.7% and 65.7% in women, respectively; the SI achieved sensitivities and specificities of 75.7% and 86.5% in men and 92.9% and 62.9% in women, respectively. CCR-defined, SI-defined, and AWGS-defined sarcopenia were independently associated with a high mortality risk [hazard ratio (HR) = 1.75, 95% CI: 1.25-2.44; HR = 1.55, 95% CI: 1.11-2.17; and HR = 1.76, 95% CI: 1.22-2.53, respectively].

CONCLUSIONS

CCR and SI have satisfactory and comparable diagnostic accuracy and prognostic values for sarcopenia in patients with advanced NSCLC. Both may serve as surrogate biomarkers for evaluating sarcopenia in these patients. However, further external validations are required.

Serum creatinine/cystatin C ratio is a surrogate marker for sarcopenia in patients with idiopathic pulmonary fibrosis

BACKGROUND

The serum creatinine/cystatin C (Cr/CysC) ratio has attracted attention as a marker for sarcopenia, but has not been studied in patients with idiopathic pulmonary fibrosis (IPF). This study aimed to confirm the utility of the serum Cr/CysC ratio in predicting sarcopenia and investigate its clinical relevance.

METHODS

This cross-sectional pilot study prospectively enrolled patients with stable IPF. IPF was diagnosed through multidisciplinary discussions according to the 2018 international guidelines, and sarcopenia was diagnosed according to the 2019 consensus report of the Asian Working Group for Sarcopenia. Patient-reported outcomes (PROs) were evaluated using the modified Medical Research Council (mMRC) dyspnea scale, chronic obstructive pulmonary disease assessment test (CAT), and King's Brief Interstitial Lung Disease (K-BILD) questionnaire. The associations between serum Cr/CysC ratio and the presence of sarcopenia and other clinical parameters, including PROs scores, were examined.

RESULTS

The study enrolled 49 Japanese patients with IPF with a mean age of 73.0 ± 7.7 years and a mean percentage of predicted forced vital capacity of 80.4 ± 15.5%. Sarcopenia was diagnosed in 18 patients (36.7%), and the serum Cr/CysC ratio was 0.86 [0.76-0.94] (median [interquartile range]). The receiver operating characteristic curve analyses for the detection of sarcopenia according to the serum Cr/CysC showed that the area under the curve, optimal cutoff value, specificity, and sensitivity were 0.85, 0.88, 0.65, and 0.94, respectively. Sarcopenia was identified in 13% of patients with a high serum Cr/CysC ratio (≥ 0.88) and 60% of patients with a low serum Cr/CysC ratio (< 0.88) (P < 0.001). Multiple linear regression analysis showed that the serum Cr/CysC ratio was an independent predictive marker of worse PROs evaluated using mMRC (P < 0.05), CAT (P < 0.05), and K-BILD (P < 0.05).

CONCLUSIONS

This study showed that the serum Cr/CysC ratio may be a surrogate marker of sarcopenia in patients with IPF. Furthermore, it is important to pay attention to the serum Cr/CysC ratio because a lower serum Cr/CysC ratio is associated with worse PROs. Further studies are required to validate these observations to determine whether the Cr/CysC ratio can be used to detect sarcopenia in patients with IPF.

Endothelin-1-mediated miR-let-7g-5p triggers interlukin-6 and TNF-α to cause myopathy and chronic adipose inflammation in elderly patients with diabetes mellitus

Background: Diabetes and sarcopenia are verified as mutual relationships, which seriously affect the quality of life of the elderly. Endothelin-1 is well investigated, is elevated in patients with diabetes, and is related to muscle cellular senescence and fibrosis. However, the mechanism of ET-1 between diabetes and myopathy is still unclear. The aim of this study was to evaluate the prevalence of sarcopenia in the elderly with diabetes and to clarify its relationship with ET-1 molecular biological mechanism, progress as well as changes in muscle and fat.

Methods: We recruited 157 type 2 diabetes patients over 55 years old and investigated the prevalence of sarcopenia in diabetes patients and examined the association of ET-1 alterations with HbA1c, creatinine, or AMS/ht2. Next, sought to determine how ET-1 regulates inflammation in muscle cells by western blot and qPCR assay. Using XF Seahorse Technology, we directly quantified mitochondrial bioenergetics in 3T3-L1 cells.

Results: ET-1 was positively correlated with HbA1c, creatinine levels, and duration of disease, and negatively correlated with AMS/ht2. We found that ET-1 dose-dependently induces tumor necrosis factor-α (TNF-α) and interleukin (IL)-6β expression through the PI3K/AKT, and NF-κB signaling pathways in C2C12 cells. Also identified that TNF-α, IL-6β, and visfatin releases were found in co-cultured with conditioned medium of ET-1/C2C12 in 3T3-L1 cells. ET-1 also reduces the energy metabolism of fat and induces micro-environment inflammation which causes myopathy. ET-1 also suppresses miR-let-7g-5p expression in myocytes and adipocytes.

Conclusion: We describe a new mechanism of ET-1 triggering chronic inflammation in patients with hyperglycemia.

Serum creatinine to cystatin C ratio reflects preoperative and early postoperative walking ability in older patients with hip fracture

BACKGROUND

The sarcopenia index (SI), calculated as the ratio of serum creatinine to cystatin C levels, reflects skeletal muscle mass and strength. Patients with hip fracture (HF) and sarcopenia have poor functional outcomes, and many require long-term care after surgery. We hypothesized that the SI can predict preoperative and early postoperative functional outcomes.

METHODS

Preoperative serum creatinine and cystatin C were measured to calculate the SI for patients with surgically treated HF (n = 130, mean age: 87.8 ± 6.9 years). Walking ability before and 2 weeks after surgery was assessed, and patients were dichotomized into independent and assistance groups. To assess the validity of the SI, we examined its correlation with the quality [computed tomography (CT) value] and quantity (cross-sectional area) of the muscles around the hip on the non-operated side, which were preoperatively measured using CT. Receiver operating characteristic (ROC) analysis was performed to evaluate the prognostic value of the SI.

RESULTS

The SI of the preoperative independent (n = 77) and assistance groups (n = 53) significantly differed (70.2 ± 12.4 and 60.1 ± 9.8, respectively, P < 0.000001). At 2 weeks after surgery, the SI was significantly higher in the independent group (n = 31, 73.0 ± 14.9) than in the assistance group (n = 99, 64.0 ± 10.7, P = 0.0003). In the preoperative independent group, 28 could walk independently after surgery (SI: 74.8 ± 14.0) while 49 required assistance (SI: 67.7 ± 10.6, P = 0.01). For patients with femoral neck fracture (FNF), the SIs were significantly higher in the postoperative independent group (78.6 ± 15.7) than in the postoperative assistance group (63.2 ± 10.9, P = 0.002). Logistic regression analysis showed that the odds ratio (95% confidence interval) of the SI for postoperative walking ability was 0.95 (0.91-0.99, P = 0.03). The correlations of SIs with CT values and cross-sectional areas were as follows: iliopsoas at the apex of the femoral head, r = 0.40, P < 0.001 and r = 0.49, P < 0.001, respectively; rectus femoris at the level of the lessor trochanter, r = 0.26, P = 0.007 and r = 0.37, P < 0.001, respectively. ROC analysis for predicting postoperative walking ability in preoperative independent patients with HF and FNF revealed areas under the curve (95% confidence interval) of 0.63 (0.50-0.76) and 0.80 (0.65-0.96), respectively.

CONCLUSIONS

In patients with HF, the SI correlated with preoperative walking ability and could predict postoperative walking ability. Among patients who could walk independently before surgery, those with high SIs could walk independently early in the postoperative period. The SI is beneficial for estimating walking ability in patients with HF.

Serum Creatinine to Cystatin C Ratio is an Effective Indicator for Muscle Strength Decline in Men with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Purpose

This study explored the value of the serum creatinine/cystatin C (Cr/CysC) ratio in diagnosing the reduction of muscle strength in men with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Patients and Methods

In this study, we enrolled 72 male patients with AECOPD and 32 male patients with stable chronic obstructive pulmonary disease (COPD). We compared clinical characteristics between the AECOPD and stable COPD groups. Then, we subdivided AECOPD patients into normal muscle strength and low muscle strength groups; we compared the clinical characteristics between these two groups. We analyzed the relationships of serum creatinine (Cr), cystatin C (CysC), and Cr/CysC ratio with clinical characteristics in male AECOPD patients. We also investigated whether the Cr/CysC ratio could aid in the diagnosis of muscle strength decline via receiver operating characteristic curve and binary logistic regression analysis.

Results

We found that handgrip strength, Cr/CysC ratio, serum Cr, FEV₁, FVC, and FEV₁%pred were lower in AECOPD patients than in stable COPD patients. Among AECOPD patients, BMI, weight, FEV₁, FVC, FEV₁%pred, and Cr/CysC ratio were lower in the low muscle strength group than in the normal muscle strength group; there were more patients with ≥2 acute exacerbations within the past year in the low muscle strength group. The Cr/CysC ratio was correlated with handgrip strength, FEV₁, FVC, FEV₁%pred, BMI and weight. The area under curve for low handgrip strength was greater for the Cr/CysC ratio than for Cr. Binary logistic regression analysis showed that a Cr/CysC ratio <0.99 was a risk factor for decreased muscle strength in male patients with AECOPD.

Conclusion

The Cr/CysC ratio is a useful predictor of muscle strength decline in male AECOPD patients, while a low Cr/CysC ratio is a risk factor for muscle strength decline in male patients with AECOPD.

Changes in Mortality According to Creatinine/Cystatin C Ratio in Chronic Kidney Disease and Non-chronic Kidney Disease Patients

Background

Serum creatinine and cystatin C are not only good indicators of renal function but have also been confirmed to be related to disease prognosis and mortality in various diseases via creatinine/cystatin C ratio (CCR). However, although they are biomarkers of renal function, there is no study regarding renal impairment as a confounding variable in the relationship between CCR and all-cause mortality.

Methods

Patients who had simultaneous measurements of serum creatinine and cystatin C between 2003 and 2020 were enrolled. The patients with chronic kidney disease (CKD) were defined as having an estimated glomerular filtration rate (eGFR) CKD-EPI Cr-Cystatin C < 60 ml/min/1.73 m². CCR was calculated by dividing the serum creatinine level by the cystatin C level measured on the same day. The main outcome assessed was all-cause mortality according to CCR in CKD or non-CKD groups.

Results

Among the 8,680 patients in whom creatinine and cystatin C levels were measured simultaneously, 4,301 were included in the CKD group, and 4,379 were included in the non-CKD group, respectively. CCR was 1.4 ± 0.6 in total participants. The non-CKD group showed higher mean CCR, (1.5 ± 0.7 vs. 1.3 ± 0.5) as well as a wider distribution of CCR (p < 0.001) when compared to the CKD group. In non-CKD group, 1^st, 4^th and 5^th quintiles of CCR significantly increased the all-cause mortality risk compared to 2^nd quintile of CCR, suggesting U-shaped mortality risk according to CCR in non-CKD. On the other hand, in CKD group, the risk of all-cause mortality linearly increased and 5^th quintile of CCR showed 1.82 times risk of mortality compared to 2^nd quintile of CCR. In the subgroup analysis of mortality by age and sex, the mortality difference according to CCR were diminished in old age and female sex subgroups.

Conclusion

We discovered a U-shaped relationship between mortality and CCR levels in normal renal function, and an increased risk of mortality in CKD with elevated CCR.

Correlation Between Bioelectrical Impedance Analysis and Chest CT-Measured Erector Spinae Muscle Area: A Cross-Sectional Study

BACKGROUND

Skeletal muscle mass (SMM) plays an important part in diverse health and disease states. Bioelectrical impedance analysis (BIA) and computed tomography (CT) are available for its assessment. However, muscle mass assessed by BIA may be influenced by multiple factors. The erector spinae muscle area (ESA) on chest CT is recently presumed to be representative of SMM. This study aimed to derive BIA from the ESA and evaluate the magnitude of association (between ESA measured from chest CT) and BIA.

METHODS

Subjects hospitalized for health checkups between December 2020 and December 2021, having undergone both BIA (50 kHz, 0.8 mA) and chest CT, were included. ESA was quantified at the level of the 12th thoracic vertebra (T12-ESA) by a standardized semi-automated segmentation algorithm. Low SMM was defined using the Asian Working Group for Sarcopenia criteria. The association between T12-ESA and BIA was then evaluated. Stratified analyses by sex and BMI were also performed.

RESULTS

Among 606 included subjects (59.7 ± 16.6 years, 63.5% male), 110 (18.2%) had low SMM. BMI in low and normal SMM groups was 20.1 and 24.7 kg/m², respectively. Current smoking, drinking, chronic obstructive pulmonary disease, and chronic renal dysfunction were more frequently seen in the low SMM group than in the normal SMM group. The final regression model included T12-ESA, weight, BMI, and age, and had an adjusted R² of 0.806 with BIA. In the validation group, the correlation between T12-ESA-derived BIA and BIA remained high (Pearson correlation = 0.899). Stratified analysis disclosed a stronger correlation between T12-ESA and BIA in male subjects than in female subjects (adjusted R² = 0.790 vs. adjusted R² = 0.711, p < 0.05), and a better correlation was observed in obese (BMI ≥ 30 kg/m²) compared with underweight (BMI < 18.5 kg/m²) subjects (adjusted R^{2 =} 0.852 vs. adjusted R² = 0.723, p < 0.05). Additional analysis revealed a significant correlation between T12-ESA and skeletal muscle cross-sectional area at the 3rd lumbar vertebra (L3-CSA) (adjusted R² = 0.935, p < 0.001).

CONCLUSIONS

CT-based assessment of ESA at the T12 level is feasible and correlated well with BIA, especially in male subjects and obese subjects.

Cognitive Function, Sarcopenia, and Inflammation Are Strongly Associated with Frailty: A Framingham Cohort Study

BACKGROUND

Frailty is an important contributor to morbidity and mortality in chronic liver disease. Understanding the contributors to frailty has the potential to identify individuals at risk for frailty and may potentially provide targets for frailty-modifying interventions. We evaluated the relationship among cognitive function, inflammation, and sarcopenia and frailty.

METHODS

Using cohorts from the Framingham Heart Study (2011-2014), we evaluated for factors associated with frailty. Exposures included cognitive tests (combined Trails A/B test, Animal Naming Test, and combined Digit Span Forward/Backward test), inflammation (interleukin-6 and tumor necrosis factor receptor II), and sarcopenia (creatinine-to-cystatin C ratio). We performed linear and logistic regression to identify the relationship between these exposures and the Liver Frailty Index (LFI).

RESULTS

The study population (N = 1208) had a median age of 70 years, was 56% female, and 48.5% had evidence of liver disease. The combined Trails A/B test (β 0.05, P < .001), creatinine-to-cystatin C (β -0.17, P = .006), and both inflammatory markers, interleukin-6 levels (β 0.16, P = .002) and tumor necrosis factor receptor II (β 0.21, P = .04), were independently associated with the LFI. Using an LFI cutoff of ≥4.5 to define frailty, Trails A/B (odds ratio [OR] 1.21, 95% confidence interval [CI] 1.07-1.37), Animal Naming Test (OR 0.64, 95% CI 0.42-0.97), sarcopenia (OR 0.10, 95% CI 0.01-0.73), and interleukin-6 (OR 4.99, 95% CI 1.03-15.53) were all associated with frailty. Although liver disease did not modify the relationship between the LFI and the Trails A/B test, interleukin-6 was significantly associated with the LFI only in the presence of liver disease.

CONCLUSIONS

Cognitive performance, inflammation, and sarcopenia, each highly prevalent in cirrhosis, are associated with the LFI in this population-based study of persons without cirrhosis. Further research is warranted for interventions aiming to prevent frailty by tailoring their approach to the patient's underlying risk factors.

Cre/CysC ratio may predict muscle composition and is associated with glucose disposal ability and macrovascular disease in patients with type 2 diabetes

INTRODUCTION

Since the ratio of creatinine to cystatin C (Cre/CysC) can reflect muscle volume, it has been proven to be a predictor of sarcopenia in patients with or without diabetes. Here, we investigated the predictive value of Cre/CysC for the skeletal muscle composition and its correlations with glucose disposal ability and diabetic complications in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The skeletal muscle index (SMI) and mean skeletal muscle attenuation (MMA) values of 193 patients with type 2 diabetes were obtained through analyses of CT images at the lumbar 3 level.

RESULTS

Serum Cre/CysC was significantly correlated with both the SMI (r=0.375, p<0.001) and MMA (r=0.378, p<0.001). Multiple stepwise linear regression analysis demonstrated that Cre/CysC was the only biochemical predictor of the SMI (β=0.48 (95% CI 0.02 to 0.94)) and MMA (β=0.57 (95% CI 0.14 to 1.01)). Furthermore, the fat mass index (FMI) was significantly associated with the MMA (r=-0.481, p<0.001) but not the SMI (r=0.101, p=0.164). In the diabetic complications analysis, Cre/CysC was significantly lower in patients with cardiovascular disease (95% CI (-1.47 to -0.22), p=0.008) and lower extremity arterial disease (95% CI (-1.44 to -0.29), p=0.004). Moreover, in the 100 g steamed bun test, Cre/CysC was significantly correlated with glucose levels at 60 min (r=-0.162, p=0.045), 120 min (r=-0.287, p<0.001) and 180 min (r=-0.313, p<0.001).

CONCLUSIONS

Cre/CysC may be a valuable predictor of skeletal muscle composition in type 2 diabetes. Patients with a higher Cre/CysC may have a better ability to dispose of postprandial glucose and are at a lower risk of macrovascular disease.

Estimation of Muscle Mass Using Creatinine/Cystatin C Ratio in Japanese Community-Dwelling Older People

OBJECTIVES

Sarcopenia is defined as a combination of low skeletal muscle mass index (SMI), weak muscle strength, and reduced physical function. Recently, many studies have reported that the creatinine/cystatin C ratio (Cr/CysC) is useful for evaluating muscle mass. We designed a cross-sectional study with separate model development and validation groups to develop a prediction equation to estimate bioimpedance analysis (BIA)-measured SMI with Cr/CysC.

DESIGN

The current study was a retrospective cross-sectional study.

SETTING AND PARTICIPANTS

The model development group included 908 subjects (288 men and 620 women) from the Frail Elderly in the Sasayama-Tamba Area (FESTA) study, and the validation group included 263 subjects (112 men and 151 women) from participants in the medical checkup program at the Anti-Aging Center in Ehime Prefecture.

MEASURES

Multivariate regression analysis indicated that age, hemoglobin (Hb), body weight (BW), and Cr/CysC were independently associated with SMI in both men and women. The SMI prediction equation was developed as follows: Men:4.17-0.012×Age+1.24×(Cr/CysC)-0.0513×Hb+0.0598×BW Women:3.55-0.00765×Age+0.852×(Cr/CysC)-0.0627×Hb+0.0614×BW RESULTS: The SMI prediction equation was applied to the validation group and strong correlations were observed between the BIA-measured and predicted SMI (pSMI) in men and women. According to the receiver operator characteristic (ROC) analysis, the areas under the curve were 0.93 (specificity 89.0%, sensitivity 87.2%) among men and 0.88 (specificity 83.6%, sensitivity 79.6%) among women for using pSMI to identify low SMI in the model development group. The pSMI also indicated high accuracy in ROC analysis for low SMI in the validation group. The Bland-Altman plot regression showed good agreement between BIA-measured and pSMI.

CONCLUSIONS AND IMPLICATIONS

Our new prediction equation to estimate SMI is easy to calculate in daily clinical practice and would be useful for diagnosing sarcopenia.