Creatinine/cystatin C ratio as a surrogate marker of residual muscle mass in amyotrophic lateral sclerosis

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.

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.

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.

Sarcopenia Index Predicts Short-Term Prognosis of Head and Neck Squamous Cell Carcinoma

The sarcopenia index (SI), calculated as [(serum creatinine/serum cystatin C) × 100], maybe a simpler alternative for measuring muscle mass than computed tomography (CT) and bioelectrical impedance analysis (BIA). We enrolled 112 patients with head and neck cancers (HNC). The correlation of the SI with muscle surface area measured by CT (CTMSA, n = 82) and muscle mass by BIA (BIA-MM, n = 41) was tested. Cutoff values were set for SI, CTMSA, and BIA-MM. Overall survival (OS) was compared between the high- and low-SI/CTMSA/BIA-MM groups. The SI was correlated with CTMSA (r = 0.43) and BIA-MM (r = 0.52). The optimal cutoff values of SI, CTMSA, and BIA-MM were 76.1 (area under the curve [AUC] = 0.67), 129.2 (AUC = 0.59), and 46.1 (AUC = 0.62), respectively. OS was significantly lower in the low-SI group (78% at 1 year and 69% at 2 years) than in the high-SI group (94% at 1 year and 86% at 2 years; p = 0.006). There was no significant difference in OS between the low-and high-CTMSA and -BIA-MM groups. The SI, which only requires a blood sample, is a useful marker of muscle mass that correlates with short-term prognosis in patients with HNC.

Serum creatinine-to-cystatin C ratio as an indicator of sarcopenia in hemodialysis patients

BACKGROUND AND AIMS

In hemodialysis patients, sarcopenia is common and related to morbidity and mortality. In non-dialysis patients, the serum creatinine-to-cystatin C (Cre/Cys-C) ratio is a marker of sarcopenia. Its clinical utility in hemodialysis populations, however, is still unknown. Our study aimed to determine whether sarcopenia could be detected using the Cre/Cys-C ratio in hemodialysis patients.

METHODS

This retrospective cross-sectional study included 85 hemodialysis patients whose handgrip strength (HGS) and bioimpedance analysis-estimated skeletal muscle index (SMI) were assessed. Sarcopenia was diagnosed as a combination of reduced muscle strength (women: HGS <18 kg; men: HGS <28 kg) and decreased muscle mass volume (women: SMI <5.7 kg/m²; men: SMI <7.0 kg/m²).

RESULTS

Sarcopenia was observed in 33 (38.8%) patients. Patients with sarcopenia had a significantly lower Cre/Cys-C ratio than those without (1.3 ± 0.2 vs 1.7 ± 0.3, respectively; p < 0.0001). The Cre/Cys-C ratio was independently associated with HGS (β = 0.303, p = 0.011) and SMI (β = 0.376, p = 0.0007). After adjustment for sex and age, the C-statistic of the Cre/Cys-C ratio that predicted sarcopenia was 0.898 (95% CI [0.827, 0.969], p < 0.0001). Moreover, as Cre/Cys-C ratios increased, the risk of sarcopenia significantly decreased (adjusted OR: 0.665 for each 0.1 increase in the Cre/Cys-C ratio) (95% CI [0.501, 0.857], p = 0.0002).

CONCLUSION

The Cre/Cys-C ratio may be a helpful prediction tool for sarcopenia in patients receiving hemodialysis.

Clinical significance of serum cystatin C-to-creatinine ratio as a surrogate marker for incident osteoporotic fracture predictions

Background

Detection of appropriate indicators is valuable for preventing incidental osteoporotic fractures. We statistically evaluated the significance of serum cystatin C-to-creatinine ratio (CysC/Cr) as a surrogate marker for incident major osteoporotic fractures (MOF) prediction.

Methods

Eligible patients with simultaneous measurement of CysC/Cr and bone mineral density in the lumbar spine and proximal femur were selected, and their fracture histories until 5 years after baseline were observed in the retrospective area cohort data. Patients who were followed up until termination or the first osteoporotic fracture were included, and loss of follow-up or death was excluded. Candidate risk factors for osteoporotic fractures were tested for risk ratios using a cox regression analysis. Receiver operating characteristic tests were performed on factors with significantly higher risk ratios and evaluated with Kaplan-Meier survival analysis to determine the hazard ratios of the factors.

Results

A total of 175 patients of whom 28 had incident MOF, 38 men, and 137 women, were enrolled. The mean age was 70.2 years. A significantly higher risk ratio was shown in the presence of prevalent MOF, hyper fall-ability, lifestyle-related diseases, chronic kidney diseases ≥ Grade3a, and higher CysC/Cr. All parameters had cutoff indices and showed significantly higher hazard ratios.

Conclusions

These results suggested that CysC/Cr may be a predictive marker of incident osteoporotic fractures. It might work as a screening tool for MOF risk.

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.

Serum Creatinine-to-Cystatin-C Ratio as a Potential Muscle Mass Surrogate and Racial Differences in Mortality

OBJECTIVES

Serum creatinine-based estimated glomerular filtration rate equations and muscle mass are powerful markers of health and mortality risk. However, the serum creatinine-to-cystatin-C ratio may be a better indicator of health status. The objective of this study was to describe the relationship between creatinine-to-cystatin-C ratio and all-cause mortality when stratifying patients as per race and as per chronic kidney disease status.

METHODS

This was a retrospective cohort study examining black and nonblack US veterans between October 2004 and September 2019, with baseline cystatin C and creatinine data from those not on dialysis during the study period. Veterans were divided into four creatinine-to-cystatin-C ratio groups: <0.75, 0.75-<1.00, 1.0-<1.25, and ≥1.25. The primary outcome of interest was all-cause mortality subsequent to the cystatin C laboratory measure.

RESULTS

Among 22,316 US veterans, the mean (± standard deviation) age of the cohort was 67 ± 14 years, 5% were female, 82% were nonblack, and 18% were black. The proportion of black veterans increased across creatinine-to-cystatin-C ratio groups. In the fully adjusted model, compared with the reference (creatinine-to-cystatin-C ratio: 1.00-<1.25), a creatinine-to-cystatin-C ratio <0.75 had the highest mortality risk among both black and nonblack veterans (nonblack: hazard ratio [HR] [95% confidence interval {CI}]: 3.01 [2.78-3.26] and black: 4.17 [3.31-5.24]). A creatinine-to-cystatin-ratio ≥1.25 was associated with lower death risk than the referent in both groups (nonblack: HR [95% CI]: 0.89 [0.80-0.99] and black: HR [95% CI]: 0.55 [0.45-0.69]). However, there was a significant difference in the effect by race (Wald's P-value: <0.01).

CONCLUSIONS

Higher creatinine-to-cystatin-C ratios indicate better health status and are strongly associated with lower mortality risk regardless of the kidney function level, and the relation was similar for both black and nonblack veterans, but with different strengths of effect across racial groups. Thereby, use of a fixed race coefficient in estimating kidney function may be biased.

The Relationship Between Vitamin D and Activity of Daily Living in the Elderly

Objective

To analyze the association between vitamin D and the performance of activity of daily living in the elderly.

Methods

A total of 94 patients over the age of 65 were eligible to participate if they had undergone a bone mineral density test and if they were in a stable health condition. Subjects were further divided into two groups according to activity of daily living (ADL): the score over 40 of the patients as the high ADL group and the below as the low ADL group.

Results

According to univariate analysis, the mean of total hip T score, serum creatinine/cystatin C ratio (CCR), and vitamin D were significantly different between the two groups (P=0.024, 0.008, 0.010). Multivariate ORs showed that the CCR (OR: 0.948; 95%CI: 0.910–0.989; P=0.013) and vitamin D (OR: 865; 95%CI: 0.752–0.994; P=0.047) were inversely associated with having low ADL. Furthermore, on multiple linear regression analysis, the Barthel ADL index was related to geriatric nutritional risk index (GNRI), CCR and vitamin D but independent of patients’ age with the slope of 0.732, 0.539, and 0.689 separately, reflected the stronger relative within the variables.

Conclusion

We demonstrated that there is a negative correlation of CCR and vitamin D with having low ADL in elderly population. Monitoring the trend of serum vitamin D and CCR, may have a role in the early detection of low ADL with loss of muscle mass and strength in the population of the elderly.

Creatinine-cystatin C ratio and mortality in cancer patients: a retrospective cohort study

BACKGROUND

Muscle wasting is prevalent in cancer patients, and early recognition of this phenomenon is important for risk stratification. Recent studies have suggested that the creatinine-cystatin C ratio may correlate with muscle mass in several patient populations. The association between creatinine-cystatin C ratio and survival was assessed in cancer patients.

METHODS

A total of 3060 patients who were evaluated for serum creatinine and cystatin C levels at the time of cancer diagnosis were included. The primary outcome was 6-month mortality. The 1-year mortality, and length of intensive care unit (ICU) and hospital stay were also evaluated.

RESULTS

The mean age was 61.6 ± 13.5 years, and 1409 patients (46.0%) were female. The median creatinine and cystatin C levels were 0.9 (interquartile range [IQR], 0.6-1.3) mg/dL and 1.0 (IQR, 0.8-1.5) mg/L, respectively, with a creatinine-cystatin C ratio range of 0.12-12.54. In the Cox proportional hazards analysis, an increase in the creatinine-cystatin C ratio was associated with a significant decrease in the 6-month mortality (per 1 creatinine-cystatin C ratio, hazard ratio [HR] 0.35; 95% confidence interval [CI], 0.28-0.44). When stratified into quartiles, the risk of 6-month mortality was significantly lower in the highest quartile (HR 0.30; 95% CI, 0.24-0.37) than in the lowest quartile. Analysis of 1-year mortality outcomes revealed similar findings. These associations were independent of confounding factors. The highest quartile was also associated with shorter lengths of ICU and hospital stay (both P < 0.001).

CONCLUSIONS

The creatinine-cystatin C ratio at the time of cancer diagnosis significantly associates with survival and hospitalization in cancer patients.

Temporal muscle thickness and survival in patients with amyotrophic lateral sclerosis

Temporal muscle thickness (TMT) is a new potential MRI biomarker, which has shown prognostic relevance in neuro-oncology. We aim at investigating the potential prognostic value of TMT in patients with Amyotrophic Lateral Sclerosis (ALS). We retrospectively evaluated 30 ALS patients, whose clinical, Magnetic Resonance Imaging (MRI) and Electrodiagnostic testing (EDX) data were available, in comparison to age-matched 30 healthy subjects. TMT calculated on T1-weighted MR images was significantly lower in ALS patients than in healthy subjects (p < 0.001), correlating with the ALS Functional Rating Scale (FRS) (p:0.018) and compound motor action potential (CMAP) (p:0.012) in the patients group. Multivariate analysis of overall survival (OS) showed that the only parameters that remained significant were TMT (p:0.002, OR 0.45, 95%vCI: 0.28-0.75) and ALS FRS-R (p:0.023, OR: 0.80, 95%CI: 0.67-0.92). TMT seems to be a promising surrogate biomarker of survival and functional status in ALS. Our data deserve further investigations in multicenter and prospective trials.

Serum creatinine/cystatin C ratio as a screening tool for sarcopenia and prognostic indicator for patients with esophageal cancer

Background & aims

Sarcopenia is associated with poor clinical outcomes of patients who underwent esophagectomy. The current diagnostic criteria for sarcopenia are complex and laborious. We aimed to employ the simple and economic indicator sarcopenia index (SI = creatinine/cystatin C ×100) to screen for sarcopenia and to evaluate its prognostic value in patients with esophageal cancer (EC).

Methods

Older participants in the National health and nutrition examination survey (NHANES) database (1999–2002) were divided into three groups according to tertiles of the SI value to explore the feasibility of SI in the diagnosis of sarcopenia. Restricted cubic spline (RCS) was utilized to show the non-linear relationship between all-cause mortality and SI. Patients with EC admitted to Jinling Hospital were enrolled to validate the efficacy and prognostic value of SI. Cut-off values of SI were determined using receiver operating characteristic curves. Multivariable logistic analyses and Cox analyses were used to identify the independent factors of postoperative complications and long-term survival, respectively.

Results

A total of 989 participants were identified from the NHANES database. SI showed the diagnostic value of sarcopenia (tertile 1 vs. tertile 3: odds ratio [OR]=3.67, 95% confidence interval [CI]: 1.52–8.87, p=0.004; tertile 2 vs. tertile 3: OR=1.79, 95% CI: 0.75–4.28, p=0.191) adjusted for race, gender, and body mass index (BMI). Individuals with SI ≤ 68 had a poorer overall survival (OS) (hazard ratio [HR]=2.14, 95% CI: 1.71–2.68, p<0.001), and the RCS plot showed that the all-cause mortality risk gradually decreased with the increase in SI. Then, 203 patients with EC were enrolled, of which 76 patients were diagnosed with sarcopenia. There was a linear correlation between SI and skeletal muscle index and prealbumin, indicating that SI was reliable for diagnosing sarcopenia. Patients in the high sarcopenia risk group (Male: SI < 62; Female: SI < 55) showed a higher incidence of complications (OR=3.50, 95% CI: 1.85–6.61, p<0.001) and poorer long-term survival (HR=2.62, 95% CI: 1.02–6.77, p=0.046).

Conclusion

SI could be used to identify sarcopenia in patients with EC, and it is a useful prognostic factor of postoperative complications and long-term survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02925-8.

Serum creatinine/cystatin C ratio as a surrogate marker for sarcopenia in patients with gastric cancer

Background

Sarcopenia is an age-related syndrome that may have negative impact on surgical outcomes and long-term survival of patients with gastric cancer. Serum creatinine/cystatin C (Cr/CysC) ratio has attracted attention as a surrogate marker for sarcopenia but has not been adequately studied in patients with gastric cancer. The purpose of this study was to investigate the validity of serum Cr/CysC ratio as a predictor of sarcopenia, evaluate a statistical cut-off value, and assess the relationship between Cr/CysC ratio and prognosis of patients with gastric cancer.

Methods

We retrospectively studied 327 patients who underwent surgery for gastric cancer from June 2009 to October 2021. The skeletal muscle mass index was calculated using computed tomography (CT). We determined the relevance of serum Cr/CysC ratio as a surrogate maker for sarcopenia by comparing it with various biomarkers. The Concordance index (C-index) was calculted to measure whether the Cr/CysC ratio can prognosis of patients with gastric cancer.

Results

Serum Cr/CysC was significantly correlated with with Skeletal Muscle Index (SMI) (r = 0.221, p < 0.001) and Skeletal Muscle Area (SMA) (r = 0.258, p < 0.001). The area under the curve for sarcopenia was significantly larger for serum Cr/CysC ratio than for other biomarkers (Cr/CysC: 0.644, CysC: 0.535, Cr: 0.556). Patients in the high-Cr/CysC group have longer survival time than that in low-Cr/CysC group, defined by the cutoff value 0.67. The C-index of both Cr/CysC ratio and SMI with OS was 0.63.

Conclusions

Serum Cr/CysC ratio can be used accurately, inexpensively, and easily to evaluate sarcopenia in male patients with gastric cancer. Our study shows that patients with Cr/CysC below 0.67 had possibility of sarcopenia and would be poor prognosis.

Nutritional and Non-Nutritional Predictors of Low Spot Urinary Creatinine Concentration in Patients with Heart Failure

Low spot urinary creatinine concentration (SUCR) is a marker of muscle wasting and clinical outcome. The risk factors for low SUCR in heart failure (HF) remain poorly understood. We explored the risk factors for low SUCR related to poor outcomes. In 721 HF patients (age: 52.3 ± 11 years, female: 14%, NYHA: 2.7 ± 0.7) SUCR and Dexa body composition scans were performed. BMI prior HF-onset, weight loss, and appendicular muscle mass were obtained. Each patient was classified as malnutrition or normal by GLIM criteria and three other biochemical indices (CONUT, PNI, and GRNI). Sarcopenia index (SI) as creatinine to cystatin C ratio was also calculated. Within 1 year, 80 (11.1%) patients died. In ROC curve we identified a SUCR value of 0.628 g/L as optimally discriminating surviving from dead. In low SUCR group more advanced HF, higher weight loss and catabolic components of weight trajectory (CCWT), more frequent under-nutrition by GLIM, and lower SI were observed. In multivariate analysis the independent predictors of low SUCR were SI, CCWT, and GNRI score. In conclusion: the risk of low SUCR was associated with a worse outcome. Low SUCR was associated with greater catabolism and sarcopenia but not with biochemical indices of malnutrition.

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.

Sarcopenia index based on serum creatinine and cystatin C predicts the risk of postoperative complications following hip fracture surgery in older adults

OBJECTIVE

To assess the utility of the preoperative Sarcopenia index (SI) as a predictive marker of the risk of postoperative complications following hip fracture surgery in older adults.

STUDY DESIGN

This observational study enrolled older adults with hip fracture who were hospitalized in the Department of Orthopedics of West China Hospital, Sichuan University, from December 7, 2010 - June 14, 2017, and who underwent hip fracture surgery.

PRIMARY OUTCOME AND MEASURES

Clinical data were collected from medical records and serum creatinine and cystatin C were measured before surgery. Outcomes included postoperative complications such as pneumonia, urinary tract infection, respiratory failure, heart failure, and non-grade A healing. Binary logistic regression analyses were used to analyze association between SI and postoperative complications.

RESULTS

A total of 897 patients aged 60 years and over were enrolled in this study (age range: 60 - 100 years), of whom 306(34.1%)were male, and 591(65.9%)were female. Postoperative complications included pneumonia (12%), urinary tract infections (1.8%), respiratory failure (1.5%), heart failure (1.6%), and non-A- grade healing (3.6%). In the patient group that received joint replacements, the incidence of pneumonia was negatively associated with SI values. After adjusting for potential confounding factors, binary logistic regression analyses showed that a higher SI was independently associated with a lower risk of pneumonia after joint replacement surgery (OR:0.39, 95% CI:0.18-0.89, P<0.05). However, we did not find statistically significant association between SI and the risk of postoperative complications other than pneumonia among patients with two types of hip fracture surgery.

CONCLUSION

The SI based on serum creatinine and cystatin C can predict pneumonia rather than other postoperative complications among older patients with hip fracture after joint replacement surgery.

Serum indices based on creatinine and cystatin C predict mortality in patients with non-dialysis chronic kidney disease

Serum indices based on creatinine and cystatin C, including creatinine/cystatin C ratio (Cr/CysC), ratio and difference of estimated glomerular filtration rate (eGFR) based on cystatin C and creatinine (eGFRcys/eGFRcre and eGFR_Diff), and serum creatinine × eGFRcys, are recently identified serum markers for sarcopenia. We aimed to evaluate the association between these serum indices and mortality in patients with chronic kidney disease (CKD). A single-center retrospective cohort study included 1141 adult patients with stage 1–5 CKD between 2016 and 2018. Basic characteristics, comorbidities, laboratory parameters, and serum creatinine and cystatin C values were obtained. Patients were followed up until death, dialysis, transfer to another hospital, or end of the study. The median age (interquartile range) of our participants was 71 (62–81) years. During a median follow-up of 39 months, 116 (10.2%) patients died. Compared to the survivor group, Cr/CysC, eGFRcys/eGFRcre, eGFR_Diff, and Cr × eGFRcys were all lower in the non-survivors (p < 0.001 for all). The receiver operating characteristic curves of serum indices for predicting mortality showed that all four indices had significant discriminative power. Based on the Cox proportional hazard models, lower values of four serum indices, both as continuous and categorical variables, independently predicted mortality. Our findings suggest that low serum indices of Cr/CysC, eGFRcys/eGFRcre, eGFRDiff, and Cr × eGFRcys are independent indicators of mortality in patients with non-dialysis CKD.

Sarcopenia index as a predictor of clinical outcomes in older patients undergoing transcatheter aortic valve replacement

BACKGROUND

Sarcopenia is a prevalent condition in elderly patients and has been associated with adverse outcomes following transcatheter aortic valve replacement (TAVR). The present study aimed to determine the predictive value of serum creatinine-cystatin C ratio, that is, "Sarcopenia Index" (SI) as a surrogate marker of sarcopenia, and investigate its association with clinical outcomes after TAVR.

METHODS

We conducted a retrospective observational study of patients undergoing TAVR between January, 2016 and December, 2018 at Hospital Italiano de Buenos Aires, Argentina. Patients were excluded if <65-years old, presented previous surgical aortic valve replacement, severe chronic kidney disease, or hemodialysis requirement. The SI was obtained at baseline before TAVR. All-cause mortality and/or readmissions for congestive heart failure (CHF) were defined as the primary endpoint.

RESULTS

In total 100 patients met inclusion criteria for the purpose of the study. Sarcopenia Index was significantly correlated with Timed Up and Go (r = -0.272, p = .010) and Gait Speed (r = -0.278, p = .005). During follow-up, 5/100 patients died within 30 days and a total of 10/100 patients died at 1-year follow-up. Moreover, survival curves were significantly worse (Log-rank test = p = .02) and CHF readmissions were more prevalent in the lowest SI tertile (Log-rank test = p = .01). In multivariate Cox regression analysis, we identified low SI (cutoff ≤66) as an independent predictor of long-term adverse outcomes (HR = 4.01, 95% CI = 1.31-12.27, p = .015) at 1-year follow-up.

CONCLUSION

Sarcopenia Index, surrogate for the degree of skeletal muscle mass (SMM), could be used as a predictor of adverse outcomes in patients undergoing TAVR.

Serum Creatinine-to-Cystatin C Ratio in the Progression Monitoring of Non-alcoholic Fatty Liver Disease

Background

The simultaneous assessment of visceral adiposity and muscle mass might be useful to monitor the risk of non-alcoholic fatty liver disease (NAFLD) progression in large population. We aimed to investigate the value of serum creatinine-to-cystatin C ratio (CCR) in evaluating these two parameters and predicting liver steatosis and fibrosis.

Methods

154 overweight/obese inpatients (49 males, 105 females) scheduled for bariatric surgery and 49 non-overweight/obese volunteers (18 males, 31 females) responded to the hospital advertisement were involved in the cross-sectional study. Liver steatosis and fibrosis were diagnosed with transient elastography (TE). The psoas muscle area (PMA) and visceral fat area (VFA) were measured using magnetic resonance imaging.

Results

The body mass index, insulin resistance, and lipid profiles showed significant differences between the CCR tertiles. Multiple regression analyses revealed that the CCR was significantly associated with the controlled attenuation parameter (β = −0.30, P = 0.006 in males; β = −0.19, P = 0.017 in females) and liver stiffness measurements in males (β = −0.246, P = 0.044). A low CCR was associated with moderate-to-severe steatosis (P < 0.001), significant liver fibrosis (P < 0.01), and excellent predictive power for these two conditions (P < 0.01). The CCR had a negative correlation with the VFA/PMA ratio (r = −0.584, P < 0.001 in males; r = −0.569, P < 0.001 in females).

Conclusions

The CCR is a serum marker for muscle-adjusted visceral fat mass, and a low CCR is associated with an increased risk of progressive NAFLD.

The Role of Baseline Sarcopenia Index in Predicting Chemotherapy-Induced Undesirable Effects and Mortality in Older People with Stage III or IV Non-Small Cell Lung Cancer

OBJECTIVES

To assess the predictability value of Sarcopenia index( (SI, serum creatinine value/cystatin C value×100) in determining potential chemotherapy-induced undesirable reactions and eventual death of older patients diagnosed with stage III or IV of non-small cell lung cancer (NSCLC).

METHODS

General information was retrieved from health records and mortality data was obtained by phone interview. Serum Cr and CysC levels were measured before chemotherapy. The endpoints recorded were chemotherapy-induced undesirable reactions and mortality from any causes. Logit regression analysis was employed for the analysis of correlation between the SI and short-term adverse reactions to chemotherapy. Cox regression analysis was employed to analyze correlation between the SI and mortality.

RESULTS

In this study, 664 NSCLC patients were enrolled. Among them, 83.13% were diagnosed with adenocarcinoma lung cancer and 16.87% with squamous cell carcinoma lung cancer. As of March 1, 2019, 486 patients died, including 361(74.28%) males and 125 (25.72%) females. After the first course of chemotherapy, the proportion of short-term adverse reactions, including bone marrow suppression, digestive reactions, all infection, liver function impairment, and other adverse reactions (non-infectious fever or rashes) was 16%, 4.7%, 7.4, %, 6.6%, and 2.11%, respectively. After adjusting for confounding factors, there was no association between the SI and adverse reactions. We found that high SI was independently associated with a lower risk of mortality after adjusting for confounding factors in females (HR=0.593,95% CI: 0.382-0.92; p=0.02). There was no marked association existed between the SI and mortality in males.

CONCLUSION

Among patients with stage III or IV non-small cell lung cancer, the SI is associated with mortality in females, but not in males.

Association Between Low Muscle Mass and Prognosis of Patients With Coronary Artery Disease Undergoing Percutaneous Coronary Intervention

Background

Low muscle mass has been associated with poor prognosis in certain chronic diseases, but its clinical significance in patients with coronary artery disease is unclear. We assessed the clinical significance of 2 easily measured surrogate markers of low muscle mass: the ratio of serum creatinine to serum cystatin C (Scr/Scys), and the ratio of estimated glomerular filtration rate by Scys to Scr (eGFRcys/eGFRcr).

Methods and Results

Patients with coronary artery disease undergoing percutaneous coronary intervention were prospectively enrolled from a single tertiary center, and Scr and Scys levels were simultaneously measured at admission. Best cut‐off values for Scr/Scys and eGFRcys/eGFRcr to discriminate 3‐year mortality were determined; 1.0 for men and 0.8 for women in Scr/Scys, and 1.1 for men and 1.0 for women in eGFRcys/eGFRcr. The prognostic values on 3‐year mortality and the additive values of 2 markers on the predictive model were compared. In 1928 patients enrolled (mean age 65.2±9.9 years, 70.8% men), the risk of 3‐year mortality increased proportionally according to the decrease of the surrogate markers. Both Scr/Scys‐ and eGFRcys/eGFRcr‐based low muscle mass groups showed significantly higher risk of death, after adjusting for possible confounders. They also increased predictive power of the mortality prediction model. Low Scr/Scys values were associated with high mortality rate in patients who were ≥65 years, nonobese, male, had renal dysfunction at baseline, and presented with acute myocardial infarction.

Conclusions

Serum surrogate markers of muscle mass, Scr/Scys, and eGFRcys/eGFRcr may have clinical significance for detecting patients with coronary artery disease at high risk for long‐term mortality.

Creatinine-Cystatin C Ratio and Mortality in Patients Receiving Intensive Care and Continuous Kidney Replacement Therapy: A Retrospective Cohort Study

RATIONALE & OBJECTIVE

Studies have suggested associations between lower ratios of serum creatinine to cystatin C with both lower muscle mass and adverse clinical outcomes in multiple disease conditions. Identifying risk factors for mortality among patients with acute kidney injury (AKI) undergoing continuous kidney replacement therapy (CKRT) may improve assessment of prognosis. We sought to evaluate the association of creatinine-cystatin C ratio with outcomes in patients with AKI undergoing CKRT.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

1,588 patients treated with intensive care and CKRT for AKI at a tertiary Korean medical center.

PREDICTOR

Baseline serum creatinine-cystatin C ratio at the time of CKRT initiation.

OUTCOMES

Age- and sex-adjusted 90-day mortality after CKRT initiation.

ANALYTICAL APPROACH

Cox proportional hazard models to estimate the association between creatinine-cystatin C ratio and outcome.

RESULTS

Mean age was 64.7 ± 14.5 years and 635 patients (40.0%) were women. The range of creatinine-cystatin C ratios was 0.08 to 10.48. The 30- and 90-day mortality rates were significantly lower for the higher creatinine-cystatin C ratio groups. Multivariable Cox proportional hazards regression analyses revealed that mortality risk became successively lower across quartiles of greater creatinine-cystatin C ratio. When creatinine-cystatin C ratio was evaluated using cubic spline analyses, risks for both 30- and 90-day mortality were lower with higher creatinine-cystatin C ratios. These associations remained significant even after adjustment for confounding variables.

LIMITATIONS

Retrospective analysis, serum creatinine and cystatin C may not be in steady state in the setting of AKI.

CONCLUSIONS

Higher serum creatinine-cystatin C ratios were associated with better survival in patients receiving intensive care and CKRT.

Assessment of muscle mass in critically ill patients: role of the sarcopenia index and images studies

PURPOSE OF REVIEW

Sarcopenia is a progressive generalized decline in skeletal muscle mass, strength, and function. This condition is highly prevalent in critically ill patients and is associated with poor outcomes in the ICU. In this review, we describe the use, evidence, and limitations of the most common validated imaging studies used to assess muscle mass in ICU, and we provide an overview of the benefits of using the sarcopenia index [(serum creatinine/serum cystatin C) × 100]) in the ICU.

RECENT FINDINGS

Currently, the determination of muscle mass using anthropometric measurements and serum biomarkers is unreliable. Several new techniques, including a dual-energy X-ray absorptiometry, computed tomography scan, ultrasonography, and bioimpedance analysis, have been studied and validated for the diagnosis and prognosis of sarcopenia in the ICU. However, these techniques are often not accessible for the majority of critically ill patients. The sarcopenia index constitutes an accurate method to diagnose sarcopenia, predict ICU outcomes, and nutritional status in critically ill patients.

SUMMARY

Diagnosis of sarcopenia has substantial implications in ICU patients. Choosing the correct test to identify patients who may need preventive or therapeutic support for this condition will favorably impact ICU outcomes.

Screening osteoporotic femoral neck without measuring bone mineral density with the use of tartrate resistant acid phosphatase-5b and serum-creatinine-to-cystatin C ratio in Japanese postmenopausal women

BACKGROUND

Screening osteoporosis in Japanese postmenopausal women is an important subject for preventing bone fragility fracture (BFF). Measuring bone mineral density (BMD) is included in the criteria for osteoporosis diagnosis. However, it has not gained popularity.

METHODS

BMD of lumbar spine (LS) and femoral neck (FN) were measured, the serum creatinine-to-cystatin C ratio (Cr/CysC), tartrate-resistant acid phosphatase-5b (TRACP-5b), body mass index (BMI) were also simultaneously measured. These subjects had no potential secondary osteoporosis factors or concomitant drug administration for osteoporosis (pSubjects; primary subjects). Best subsets regression analysis (BeStR) was evaluated for determining the statistically significant factors, and multivariate regression analysis (MLR) was used to assess the correlation of these factors with BMD at each part. Relationship between osteoporotic criteria whether T score≤-2.5 and each factor was also evaluated at each part with binary logistic regression analysis (BLR). Cut-off index (COI) at each part was determined, and sensitivity and specificity were evaluated in pSubjects and in subjects with whom potential secondary osteoporosis factors were included (sSubjects).

RESULTS

BMI and Cr/CysC had a significant influence on BMD at the LS with BeStR, whereas only BMI demonstrated significant correlation with BMD both with MLR and BLR, with 22.7 of COI and sensitivity and specificity of 48.7% and 94.7%, respectively, in pSubjects with 60 and 49.1% and 87.5%, respectively, in sSubjects with 83. At the FN, Cr/CysC, BMI, and TRACP-5b significantly influenced BMD, whereas all these factors demonstrated significant correlation with BMD. Cr/CysC and TRACP-5b demonstrated significant correlation with T score≤-2.5 in BLR. With COI that was made in combination with these factors and subjects' age, sensitivity and specificity were 67.7% and 82.4%, respectively, in pSubjects and 55.8% and 82.8%, respectively, in sSubjects.

CONCLUSIONS

These results suggested that BMI, TRACP-5b, and Cr/CysC may be realistic surrogate markers for screening osteoporosis in Japanese postmenopausal women.

Serum creatinine levels in patients with amyotrophic lateral sclerosis: a systematic review and meta-analysis

BACKGROUND

Serum creatinine (Cr) is a biosynthetic product of creatine phosphate metabolism in muscles and is closely related to total muscle mass, but it is not easily affected by diet. Several studies have tried to explore the role of serum Cr levels in amyotrophic lateral sclerosis (ALS), but the results were inconsistent. Therefore, our study aims to explore the differences of serum Cr levels between ALS patients and controls and whether serum Cr at baseline is an independent predictor of survival. Methods: We searched all the related studies that probed into the association between Serum Cr levels and ALS based on PubMed, EMBASE and Cochrane library from October 1952 to February 2019. The quality of the included studies was evaluated by using Newcastle-Ottawa Scale (NOS), and all the statistical analysis of this meta-analysis was performed by Stata version 12.0. Results: Eight studies with a total of 11377 ALS patients and 937 controls were included. Among them, five studies indicated that ALS patients had lower serum Cr levels (SMD = -0.78, 95%CI [-0.97, -0.60]) compared to controls, and three studies showed that higher serum Cr levels in ALS patients were related to lower overall mortality (HR 0.89, 95%CI [0.80, 0.99]). Conclusion: The levels of serum Cr in ALS patients are significantly lower than those in controls, and they are inversely related to overall mortality in ALS patients. Therefore, the serum Cr, an easily accessible serological factor, may serve as a prognostic biomarker.

Creatinine-to-cystatin C ratio and bioelectrical impedance analysis for the assessement of low lean body mass in cancer patients: Comparison to L3-computed tomography scan

OBJECTIVES

Lean body mass (LBM) is an important prognostic factor in patients with cancer. Although the L3-computed tomography (CT) scan is considered a reference method for assessment, a convenient and easily available method for longitudinal follow-up is required. Although bioelectrical impedance analysis (BIA) is widely used, its accuracy is questioned; plasma creatinine-to-cystatin C (CC) ratio could be an attractive alternative. The aim of this study was to evaluate the ability of the CC ratio and BIA to detect myopenia in patients with cancer compared with the use of the CT scan as a standard.

METHODS

Patients with any kind of cancer had body composition evaluation by CT scan, BIA, and CC. Statistical analysis included correlation test, Bland-Altman, and receiver operating characteristic curve analysis.

RESULTS

Forty-four patients (14 women) were included. Of the participants, 59% had myopenia on CT scan. Both BIA LBM and CC ratio were well correlated with CT scan LBM (r = 0.763 and 0.648, respectively) but concordance analysis revealed a 3-kg constant bias toward BIA compared with CT scan. In terms of ability to detect myopenia, areas under the curve (AUC) for BIA were 0.675 and 0.388 for men and women, respectively. For CC ratio, AUCs were 0.813 and 0.673.

CONCLUSION

This study demonstrated that LBM assessed by the CC ratio or BIA is well correlated with that determined by L3-CT scan. The ability of the CC ratio to detect myopenia was better than that of BIA. Findings from the present study demonstrated that CC ratio can be conveniently used in patients with cancer as a reliable biomarker of muscularity.

Cystatin C: A Primer for Pharmacists

Pharmacists are at the forefront of dosing and monitoring medications eliminated by or toxic to the kidney. To evaluate the effectiveness and safety of these medications, accurate measurement of kidney function is paramount. The mainstay of kidney assessment for drug dosing and monitoring is serum creatinine (SCr)-based estimation equations. Yet, SCr has known limitations including its insensitivity to underlying changes in kidney function and the numerous non-kidney factors that are incompletely accounted for in equations to estimate glomerular filtration rate (eGFR). Serum cystatin C (cysC) is a biomarker that can serve as an adjunct or alternative to SCr to evaluate kidney function for drug dosing. Pharmacists must be educated about the strengths and limitations of cysC prior to applying it to medication management. Not all patient populations have been studied and some evaluations demonstrated large variations in the relationship between cysC and GFR. Use of eGFR equations incorporating cysC should be reserved for drug management in scenarios with demonstrated outcomes, including to improve pharmacodynamic target attainment for antibiotics or reduce drug toxicity. This article provides an overview of cysC, discusses evidence around its use in medication dosing and in special populations, and describes practical considerations for application and implementation.

Predictive value of serum creatinine/cystatin C in neurocritically ill patients

OBJECTIVE

To explore the predictive value of serum creatinine (Cr) to cystatin C (CysC) ratio in neurocritically ill patients.

METHODS

We conducted a retrospectively observational study of adult patients admitted to a neurocritical care unit (NCU) between Jan 2013 and Jan 2017. Patients were excluded if <18 years old, required neurocritical care <72 hr, did operation during hospitalization, had premorbid disability or acute kidney injury (AKI) at admission. The Cr/CysC ratio was obtained at NCU admission. Primary end points were short-term (30-day) mortality and long-term (6-month) poor outcome, with the latter defined as modified Rankin Scale (mRS) of 4-6.

RESULTS

Of 538 eligible patients, the etiology included acute ischemic stroke (N = 193, 35.9%), intracranial hemorrhage (N = 116, 21.6%), encephalitis and/or meningitis (N = 85, 15.8%), and others (N = 144, 26.7%). Serum Cr/CysC ratio was significantly correlated with body mass index (BMI) (r = .161, p < .001), the length of NCU stay (r = -.161, p < .001), duration of mechanical ventilation (r = -.138, p = .001), and risk of tracheotomy (r = -.095, p = .028). During follow-up, 88 (16.4%), patients died within 30 days and 307 (57.1%) patients achieved good outcome at 6 months. In multivariate logistic regression analysis, we identified serum Cr/CysC ratio as an independent predictor of long-term functional outcome (OR: 0.989, 95% CI: 0.980-0.998, p = .015) but not 30-day mortality (p = .513).

CONCLUSIONS

Serum Cr/CysC ratio at admission could be used as a predictor of long-term poor prognosis in neurocritically ill patients.

Serum creatinine to cystatin C ratio predicts skeletal muscle mass and strength in patients with non-dialysis chronic kidney disease

BACKGROUND & AIMS

Muscle wasting is highly prevalent in patients with chronic kidney disease (CKD). However, the assessment of skeletal muscle mass and strength in clinical settings is not commonly available. We aimed to evaluate the feasibility of serum creatinine/cystatin C (Cr/CysC) ratio in the assessment of muscle wasting.

METHODS

In 272 patients with CKD aged 66.5 ± 15.1 years, skeletal muscle mass and handgrip strength (HGS) were assessed. Skeletal muscle index (SMI) was calculated as skeletal muscle mass/height². Low muscle mass was defined as SMI below the sex-specific 10th percentile of study population and low handgrip strength as less than 26 Kg for men and 18 Kg for women.

RESULTS

The Cr/CysC ratio was significantly lower in both the low SMI and low HGS groups. Moreover, the Cr/CysC ratio correlated with SMI (r = .306, p < .001) and HGS (r = .341, p < .001). After adjusting for confounding factors, age, sex, waist circumference, body fat mass, and Cr/CysC ratio were independently associated with SMI, whereas age, sex, diabetes, hemoglobin, estimated glomerular filtration rate, urine protein/creatinine ratio, SMI, and Cr/CysC ratio were independently associated with HGS.

CONCLUSIONS

Cr/CysC ratio appears to be a promising surrogate marker for detecting muscle wasting in patients with CKD. Further studies are needed to extend our findings.

Age- and sex-specific reference intervals for the serum cystatin C/creatinine ratio in healthy children (0-18 years old)

Objective

This study aimed to investigate serum levels of the cystatin C (CysC)/creatinine (Cr) ratio and renal serum markers (CysC, Cr, urea, and uric acid [UA]) for different ages and by sex. We also aimed to establish pediatric reference intervals for the serum CysC/Cr ratio.

Methods

Serum samples were collected from 4765 healthy children (0–18 years old). Serum markers of renal function were measured, and the CysC/Cr ratio of each participant was calculated and statistically analyzed.

Results

The renal marker CysC did not substantially change after 1 year old. Cr, urea, and UA levels generally increased with age. However, the serum CysC/Cr ratio steadily decreased with age. The CysC/Cr ratio showed significant differences in age among all age groups and varied with sex, except for in the 1 to 6-year-old groups. The overall serum CysC/Cr ratio in girls was higher than that in boys.

Conclusion

Reference intervals of the serum CysC/Cr ratio in the pediatric population were established. These intervals need to be partitioned by age and sex.

Plasma creatinine and amyotrophic lateral sclerosis prognosis: a systematic review and meta-analysis

Background: Plasma creatinine has been described as a prognostic biomarker for Amyotrophic Lateral Sclerosis (ALS), but with conflicting results in the literature. We performed a systematic review followed by a meta-analysis to address this question. Methods: We performed a systematic review of Pubmed, Embase and Cochrane databases and retrieved 14 distinct cohorts (19 studies) reporting results regarding the relationship between plasma creatinine and a clinical marker for ALS progression, notably ALSFRS (ALS Functional Rating Scale) and survival. Results: For baseline plasma creatinine, mortality risk was 28% lower when creatinine was higher than 88.4 µmol/L (hazard ratio (HR): 0.72; 95% confidence interval (CI): 0.58 to 0.88; p = 0.0003) and was 25% lower if creatinine was above versus below the median (HR: 0.75; 95% CI: 0.63 to 0.89; p = 0.0008). We found a significant positive correlation between plasma creatinine at baseline and functional score, and between creatinine decline and functional score decline (p < 0.0001 for both); but a negative correlation between plasma creatinine and functional score decline (p = 0.033). The overall quality of the studies was low mainly due to potential attrition bias, and several studies did not report analyzable results raising concern regarding a potential reporting bias. Conclusions: Plasma creatinine seems to be a promising prognostic biomarker for ALS. However, new studies with sound methodology and standardized criteria for the evaluation of ALS progression should be conducted to validate plasma creatinine as a clinical biomarker for ALS prognosis.

Body composition and sarcopenia: The next-generation of personalized oncology and pharmacology?

Body composition has gained increasing attention in oncology in recent years due to fact that sarcopenia has been revealed to be a strong prognostic indicator for survival across multiple stages and cancer types and a predictive factor for toxicity and surgery complications. Accumulating evidence over the last decade has unraveled the "pharmacology" of sarcopenia. Lean body mass may be more relevant to define drug dosing than the "classical" body surface area or flat-fixed dosing in patients with cancer. Since sarcopenia has a major impact on patient survival and quality of life, therapeutic interventions aiming at reducing muscle loss have been developed and are being prospectively evaluated in randomized controlled trials. It is now acknowledged that this supportive care dimension of oncological management is essential to ensure the success of any anticancer treatment. The field of sarcopenia and body composition in cancer is developing quickly, with (i) the newly identified concept of sarcopenic obesity defined as a specific pathophysiological entity, (ii) unsolved issues regarding the best evaluation modalities and cut-off for definition of sarcopenia on imaging, (iii) first results from clinical trials evaluating physical activity, and (iv) emerging body-composition-tailored drug administration schemes. In this context, we propose a comprehensive review providing a panoramic approach of the clinical, pharmacological and therapeutic implications of sarcopenia and body composition in oncology.

The serum creatinine to cystatin C ratio predicts bone fracture in patients with type 2 diabetes: The Fukuoka Diabetes Registry

AIMS

Sarcopenia is involved in the pathogenesis of increased fracture risk associated with diabetes. The serum creatinine to cystatin C (Cr/CysC) ratio has been reported as a surrogate marker for muscle mass. We aimed to prospectively investigate the relationship between the Cr/CysC ratio and fracture risk.

METHODS

We followed 1911 postmenopausal women and 2689 men with type 2 diabetes (mean age, 66 years) for a median of 5.3 years, and divided into Cr/CysC ratio quartiles by sex. The primary outcome was fragility fractures and the secondary outcome was any fracture.

RESULTS

Fragility fractures occurred in 192 participants, and any fracture occurred in 645 participants. Multivariate-adjusted hazard ratios (95% CI) for fragility fractures were 2.15 (1.19-3.88) (Q1), 1.63 (0.89-2.98) (Q2), 1.34 (0.72-2.51) (Q3) and 1.0 (ref.) (Q4) in postmenopausal women, and 1.75 (0.64-4.50) (Q1), 2.09 (0.83-5.26) (Q2), 1.56 (0.58-4.18) (Q3) and 1.0 (ref.) (Q4) in men. Those for any fracture were 1.46 (1.07-1.98) (Q1), 1.33 (0.98-1.81) (Q2), 1.40 (1.03-1.88) (Q3) and 1.0 (ref.) (Q4) in postmenopausal women, and 2.33 (1.54-3.54) (Q1), 2.02 (1.54-3.04) (Q2), 1.13 (0.71-1.78) (Q3) and 1.0 (ref.) (Q4) in men.

CONCLUSIONS

A lower Cr/CysC ratio is a significant risk factor for fractures in patients with type 2 diabetes.

The Ratio Serum Creatinine/Serum Cystatin C (a Surrogate Marker of Muscle Mass) as a Predictor of Hospitalization in Chronic Obstructive Pulmonary Disease Outpatients

BACKGROUND

In chronic obstructive pulmonary disease (COPD), low muscle mass has been associated with several clinical outcomes such as low exercise capacity, hospital admission, and mortality. The Sarcopenia Index (SI) is a novel way to estimate muscle mass based on the ratio of serum creatinine (produced exclusively by muscle)/cystatin C (produced by all nucleated body cells).

OBJECTIVES

This study aims to assess the SI in stable COPD outpatients, as compared with a healthy control group, to quantify its relationship with several important clinical features in COPD, and to study its potential usefulness to predict COPD exacerbations and hospital admissions.

METHODS

The SI was calculated in 18 healthy control subjects and 65 stable COPD outpatients were included in the study. Patients were prospectively followed for 1 year after being enrolled in the study.

RESULTS

COPD patients had a lower SI than controls, that is lower muscle mass. Furthermore, patients with a modified Medical Research Council dyspnea score ≥2, patients with a COPD Assessment Test score ≥10, and patients with a high risk of exacerbation had lower levels of SI compared with patients without these characteristics. SI correlated with FEV1 (r = 0.491, p < 0.001), the 6-min walking test (r = 0.560, p = 0.001), and the Fat-Free Mass Index (r = 0.431, p = 0.017). Univariate and multivariate Cox proportional risk analysis showed that a low SI is an independent predictor of hospital admission in COPD outpatients followed for 1 year (HR 5.16, p = 0.025).

CONCLUSIONS

The ratio serum creatinine/serum cystatin C correlates with several COPD characteristics, and it can be used to predict COPD hospitalization.

Biomarkers in Neurodegenerative Diseases

The past decade has seen tremendous efforts in biomarker discovery and validation for neurodegenerative diseases. The source and type of biomarkers has continued to grow for central nervous system diseases, from biofluid-based biomarkers (blood or cerebrospinal fluid (CSF)), to nucleic acids, tissue, and imaging. While DNA remains a predominant biomarker used to identify familial forms of neurodegenerative diseases, various types of RNA have more recently been linked to familial and sporadic forms of neurodegenerative diseases during the past few years. Imaging approaches continue to evolve and are making major contributions to target engagement and early diagnostic biomarkers. Incorporation of biomarkers into drug development and clinical trials for neurodegenerative diseases promises to aid in the development and demonstration of target engagement and drug efficacy for neurologic disorders. This review will focus on recent advancements in developing biomarkers for clinical utility in Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).

Decreased the creatinine to cystatin C ratio is a surrogate marker of sarcopenia in patients with type 2 diabetes

AIMS

Sarcopenia has recently been shown to affect quality of life and mortality in patients with diabetes. However, early detection requires an expensive equipment. We hypothesized that the ratio of the creatinine/cystatin (Cre/CysC) could be used as a marker for sarcopenia.

METHODS

We investigated the association between the Cre/CysC ratio and sarcopenia in a cross-sectional study of patients with type 2 diabetes. Skeletal muscle mass (SMM) was estimated by bioelectrical impedance. The skeletal muscle index (SMI) was defined as the appendicular SMM divided by the square of the height. Sarcopenia was defined with SMI and a grip strength.

RESULTS

We identified 285 patients with type 2 diabetes, of whom 25 (8.8%) had sarcopenia. The Cre/CysC ratio was associated with an increased risk of sarcopenia [odds ratio per 0.01 increment, 1.05; 95% confidence interval (CI), 1.01-1.09] after adjusting for covariates. Receiver operating characteristic curve analysis indicated that the optimal the Cre/CysC ratio cut-off point for identifying sarcopenia was 0.9, with an area under the curve, sensitivity, and specificity of 0.683 (95% CI, 0.573-0.793), 0.80, and 0.48, respectively.

CONCLUSIONS

We recommend the Cre/CysC ratio as a practical screening marker for sarcopenia in patients with type 2 diabetes.

Relationship between sarcopenia and the serum creatinine/cystatin C ratio in Japanese rural community-dwelling older adults

Background:Sarcopenia, the age-related decline in skeletal muscle volume and function, is associated with negative clinical and socioeconomic outcomes in elderly people. Clinical biomarkers to diagnose sarcopenia that can be quantified in a reliable, and cost- effective manner, are needed. We investigated whether the creatinine (Cr) /cystatin C (CysC) ratio is correlated with muscle volume and physical function in Japanese community-dwelling elderly subjects. Methods: The present study included 213 men aged 73.2±6.2 years and 464 women aged 72.4±5.5 years from a rural area in the Hyogo prefecture of Japan. To evaluate whether the Cr/CysC ratio is correlated with sarcopenia criteria in elderly individuals with preserved kidney function, we excluded subjects with estimate glomerular filtration rate (eGFR) <45. Results:The prevalence of sarcopenia diagnosed according to the AWGS criteria was 2.8% in men and 3.4% in women. The Cr/CysC ratio correlated with skeletal mass index (r = 0.49, p <0.0001), skeletal muscle mass (r = 0.53, p <0.0001), grip power (r = 0.59, p <0.0001), knee extension muscle strength (r = 0.49, p <0.0001), normal gait speed (r = 0.18, p <0.0001), and maximal gait speed (r = 0.32, p <0.0001). A negative correlation between the Cr/CysC ratio and, body fat mass (r = -0.20, p <0.0001) and percentage of body fat mass (r = -0.39, p <0.0001) was observed. In a multiple regression analysis, Cr/CysC was also found to be significantly positively correlated with each component of the sarcopenia criteria. Conclusions:Even in elderly individuals with preserved kidney function, the Cr/CysC ratio was positively correlated with muscle volume and physical function and negatively correlated with body fat mass. Therefore, the Cr/CysC ratio might be a useful biomarker to predict sarcopenia. 

Evaluating Muscle Mass by Using Markers of Kidney Function: Development of the Sarcopenia Index

OBJECTIVES

Sarcopenia is associated with a poor prognosis in the ICU. The purpose of this study was to describe a simple sarcopenia index using routinely available renal biomarkers and evaluate its association with muscle mass and patient outcomes.

DESIGN

A retrospective cohort study.

SETTING

A tertiary-care medical center.

PATIENTS

High-risk adult ICU patients from October 2008 to December 2010.

INTERVENTIONS

The gold standard for muscle mass was quantified with the paraspinal muscle surface area at the L4 vertebrae in the subset of individuals with an abdominal CT scan. Using Pearson's correlation coefficient, serum creatinine-to-serum cystatin C ratio was found to be the best performer in the estimation of muscle mass. The relationship between sarcopenia index and hospital and 90-day mortality, and the length of mechanical ventilation was evaluated.

MEASUREMENTS AND MAIN RESULTS

Out of 226 enrolled patients, 123 (54%) were female, and 198 (87%) were white. Median (interquartile range) age, body mass index, and body surface area were 68 (57-77) years, 28 (24-34) kg/m, and 1.9 (1.7-2.2) m, respectively. The mean (± SD) Acute Physiology and Chronic Health Evaluation III was 70 (± 22). ICU, hospital, and 90-day mortality rates were 5%, 12%, and 20%, respectively. The correlation (r) between sarcopenia index and muscle mass was 0.62 and coefficient of determination (r) was 0.27 (p < 0.0001). After adjustment for Acute Physiology and Chronic Health Evaluation III, body surface area, and age, sarcopenia index was independently predictive of both hospital (p = 0.001) and 90-day mortality (p < 0.0001). Among the 131 patients on mechanical ventilator, the duration of mechanical ventilation was significantly lower on those with higher sarcopenia index (-1 d for each 10 unit of sarcopenia index [95% CI, -1.4 to -0.2; p = 0.006]).

CONCLUSIONS

The sarcopenia index is a fair measure for muscle mass estimation among ICU patients and can modestly predict hospital and 90-day mortality among patients who do not have acute kidney injury at the time of measurement.

Impaired muscle uptake of creatine in spinal and bulbar muscular atrophy

Objective

The aim of this study was to explore the pathomechanism underlying the reduction of serum creatinine (Cr) concentrations in spinal and bulbar muscular atrophy (SBMA).

Methods

We evaluated blood chemistries, motor function, and muscle mass measured by dual‐energy X‐ray absorptiometry in male subjects with SBMA (n = 65), amyotrophic lateral sclerosis (ALS; n = 27), and healthy controls (n = 25). We also examined the intramuscular concentrations of creatine, a precursor of Cr, as well as the protein and mRNA expression levels of the creatine transporter (SLC6A8) in autopsy specimens derived from subjects who had SBMA and ALS and disease controls. Furthermore, we measured the mRNA expression levels of SLC6A8 in cultured muscle cells (C2C12) transfected with the polyglutamine‐expanded androgen receptor (AR‐97Q).

Results

Serum Cr concentrations were significantly lower in subjects with SBMA than in those with ALS (P < 0.001), despite similar muscle mass values. Intramuscular creatine concentrations were also lower in with the autopsied specimen of SBMA subjects than in those with ALS subjects (P = 0.018). Moreover, the protein and mRNA expression levels of muscle SLC6A8 were suppressed in subjects with SBMA. The mRNA levels of SLC6A8 were also suppressed in C2C12 cells bearing AR‐97Q.

Interpretation

These results suggest that low serum Cr concentration in subjects with SBMA is caused by impaired muscle uptake of creatine in addition to being caused by neurogenic atrophy. Given that creatine serves as an energy source in skeletal muscle, increasing muscle creatine uptake is a possible therapeutic approach for treating SBMA.

Prediction of prognosis of ALS: Importance of active denervation findings of the cervical-upper limb area and trunk area

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease characterized by serious muscle atrophy and weakness. The purpose of this study was to find prognostic factors in patients with mild ALS using application forms for the Specified Disease Treatment Research Program in Japan. We classified ALS as mild, moderate and severe. The subjects consisted of 363 patients with mild ALS who underwent needle electromyography at registration and were followed for more than one year. Time to progression to severe ALS and time to deterioration of activities of daily living such as speech dysfunction, upper limb dysfunction, and walking disability were used as outcomes. Cox proportional hazards model analysis was performed to identify prognostic factors. Of the patients with initially mild ALS, 38.3% (139/363) had progressed severe ALS at the last follow-up. In multivariate analysis of time to progression to severe ALS, bulbar onset (hazard ratio [95% confidence interval]: 1.68 [1.13-2.49], p = 0.010), tongue atrophy (1.69 [1.14-2.51], p = 0.009), dyspnea (1.57 [1.02-2.41], p = 0.042) and active denervation findings (ADFs) of the cervical-upper limb area (1.81 [1.25-2.63], p = 0.002) emerged as prognostic factors. Furthermore ADFs in the trunk area were prognostic factors for upper limb dysfunction and walking disability (1.72 [1.05-2.81], p = 0.031, and 1.97 [1.09-3.59], p = 0.026). In conclusion ADFs of the cervical-upper limb area and trunk area were prognostic factors in ALS patients.

Utility of creatinine/cystatin C ratio as a predictive marker for adverse effects of chemotherapy in lung cancer: A retrospective study

Objective

To determine whether the creatinine/cystatin C (Cr/CysC) ratio, which is influenced by muscle mass, can be used as a predictive marker of the adverse effects of chemotherapy.

Methods

This single-centre, retrospective, observational study assessed patients with lung cancer. Serum Cr and CysC levels were measured once within 1 month prior the commencement of chemotherapy.

Results

A total of 25 patients with lung cancer were enrolled in the study: 22 received first-line therapy; three received second-line therapy. A significant difference was noted regarding the Cr/CysC ratios between patients with nonsmall-cell lung cancer (NSCLC) and those with small-cell lung cancer (0.78 versus 0.92, respectively). A significant difference was also noted in the Cr/CysC ratios of patients with NSCLC with toxicity grades <3 and ≥3 (0.84 versus 0.70, respectively). Similar findings were observed in patients with NSCLC who received platinum-based combination therapy (toxicity grade < 3, 0.85; toxicity grade ≥3, 0.69).

Conclusion

The Cr/CysC ratio could serve as a useful predictive marker for chemotherapy-related adverse effects in patients with NSCLC.

Use of biomarkers in ALS drug development and clinical trials

The past decade has seen a dramatic increase in the discovery of candidate biomarkers for ALS. These biomarkers typically can either differentiate ALS from control subjects or predict disease course (slow versus fast progression). At the same time, late-stage clinical trials for ALS have failed to generate improved drug treatments for ALS patients. Incorporation of biomarkers into the ALS drug development pipeline and the use of biologic and/or imaging biomarkers in early- and late-stage ALS clinical trials have been absent and only recently pursued in early-phase clinical trials. Further clinical research studies are needed to validate biomarkers for disease progression and develop biomarkers that can help determine that a drug has reached its target within the central nervous system. In this review we summarize recent progress in biomarkers across ALS model systems and patient population, and highlight continued research directions for biomarkers that stratify the patient population to enrich for patients that may best respond to a drug candidate, monitor disease progression and track drug responses in clinical trials. It is crucial that we further develop and validate ALS biomarkers and incorporate these biomarkers into the ALS drug development process. This article is part of a Special Issue entitled ALS complex pathogenesis.