Serum cytokines and creatinine/cystatin C ratio as prognostic biomarkers in advanced cancer patients treated with anti-PD-1/PD-L1 therapy

OBJECTIVE

Immune checkpoint inhibitors (ICIs), specifically targeting the programmed cell death protein-1 or its ligand (PD-1/PD-L1), have been extensively used in the treatment of a spectrum of malignancies, although the predictive biomarkers remain to be elucidated. This study aims to investigate the association between baseline circulating levels of cytokines and the creatinine/cystatin C ratio (CCR) with the treatment outcomes of ICIs in patients with advanced cancer.

METHODS

The pre-treatment circulating levels of 10 cytokines (PD-L1, CTLA4, CXCL10, LAG3, HGF, CCL2, MIG, GRANB, IL-18, and IL-6) were measured via automated capillary-based immunoassay platform in the serum of 65 advanced cancer patients treated with anti-PD-1/PD-L1-based systemic therapy and 10 healthy volunteers. The levels of cytokines and CCR were quantified and categorized into high and low groups based on the median value. The associations of serum cytokines and CCR with response to treatment, survival, and immune-related adverse events were assessed.

RESULTS

Elevated circulating levels of 6 cytokines (PD-L1, CXCL10, HGF, CCL2, MIG, and IL-6) were observed in cancer patients compared with that in healthy volunteers. The correlation coefficients between cytokines, CCR and nutritional risk index were also calculated. In the cancer cohort (N = 65), low circulating HGF (P = 0.023, P = 0.029), low IL-6 (P = 0.002, P < 0.001), and high CCR (P = 0.031, P = 0.008) were associated with significantly improved progression-free survival (PFS) and overall survival (OS). Multi-variable COX analyses adjusted for clinicopathological factors revealed that low HGF, low IL-6, and high CCR were independent favorable prognostic factors for PFS (P = 0.028, P = 0.010, and P = 0.015, respectively) and OS (P = 0.043, P = 0.003, and P = 0.026, respectively). Grade 2 irAEs occurred more frequently in patients with low levels of circulating CCL2 and LAG3.

CONCLUSIONS

Pre-treatment circulating levels of serum IL-6, HGF, and CCR may serve as independent predictive and prognostic biomarkers in advanced cancer patients treated with ICIs-based systemic therapy. These findings might help to identify potential patients who would benefit from these therapies.

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.

Serum creatinine/cystatin C ratio is a predictor of all-cause mortality for older adults over 80 years

Objective

Sarcopenia is a prevalent condition in the senior population and has been related to adverse outcomes. This study aimed to investigate the performance of the serum creatinine/cystatin C ratio (Cr/CysC) in predicting all-cause mortality in elders over 80 years.

Methods

A total of 486 older patients over 80 were enrolled in this study. Calf circumference (CC) and handgrip strength (HGS) were carried out for each patient. All the participants accepted serum creatinine and cystatin C test. The primary clinical outcome was all-cause mortality during an over-4-year follow-up.

Results

During an over 4-year follow-up, 200 participants died. The non-survivors had a significantly lower baseline Cr/CysC level than the survivors (62.6 ± 13.1 vs. 71.4 ± 14.5 P < 0.001). The lowest Cr/CysC quartile group (Q1) had a significantly higher mortality rate than their counterparts (Q1 vs. Q2-4, 62.8% vs. 33.2%, P < 0.001). The Cr/CysC level was positively correlated with CC (R² = 0.17, P < 0.001) and HGS (R² = 0.19, P < 0.001). Moreover, survival curve was significantly worse in the lowest Cr/CysC quartile (Log-rank test χ² = 21.09, P < 0.001). After adjustment for potential confounders, age (HR, 1.10; 95% CI, 1.06-1.14, P < 0.001), coronary heart disease (HR, 1.49; 95% CI, 1.01-2.21, P = 0.045), and lowest Cr/CysC (HR, 1.59; 95% CI, 1.12-2.24, P = 0.009) were independent factors of all-cause mortality during the over-4-year follow-up.

Conclusion

Cr/CysC, also known as Sarcopenia Index, could be used as a predictor of all-cause mortality in older adults over 80 years.

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.

Sarcopenia index based on serum creatinine and cystatin C is associated with mortality in middle-aged and older adults in Chinese: A retrospective cohort study from the China Health and Retirement Longitudinal Study

Background

The sarcopenia index (SI, serum creatinine/serum cystatin C × 100) is recommended for predicting sarcopenia. There were several studies showing that lower SI is associated with poorer outcomes in the older adults. However, the cohorts studied in these researches were mainly patients hospitalized. The aim of this study was to evaluate the correlation between SI and all-cause mortality among middle-aged and older adults from the China Health and Retirement Longitudinal Study (CHARLS).

Materials and methods

A total of 8,328 participants meeting the criteria were enrolled in this study from CHARLS between 2011 and 2012. SI was calculated as [serum creatinine (mg/dL)/cystatin C (mg/L)] × 100. Mann-Whitney U-test and Fisher's exact test were used to assess balance in baseline characteristics. Kaplan-Meier, log-rang analysis, univariate and multivariate Cox hazard ratio regression models were used to compare the mortality between different SI levels. The dose relationship between sarcopenia index and all-cause mortality was further assessed by the cubic spline functions and smooth curve fitting.

Results

After adjustment for potential covariates, we found SI was significantly correlated with all-cause mortality [Hazard Ratio (HR) = 0.983, 95% confidence interval (CI) 0.977-0.988, P < 0.001]. Similarly, as SI was used as a categorical variable according to quartiles, higher SI was associated with lower mortality [Hazard Ratio (HR) = 0.44, 95% CI 0.34-0.57, P < 0.001] after adjustment for confounders.

Conclusions

Lower sarcopenia index was associated with higher mortality among middle-aged and older adults in China.

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.

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.

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.

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.

Serum Creatinine/Cystatin C Ratio Associated with Cross-Sectional Area of Erector Spinae Muscles and Pulmonary Function in Patients with Chronic Obstructive Pulmonary Disease

Purpose

Muscle atrophy is a major clinical feature of chronic obstructive pulmonary disease (COPD) and is considered a predictor of mortality in COPD patients. Recently, the cross-sectional area (CSA) of the erector spinae muscles measured by chest computed tomography (CT) scans (ESM_CSA) has been reported as a clinical parameter reflecting disease severity and future prognosis in patients with COPD. In addition, the serum creatinine (Cr)/cystatin C (CysC) ratio has been considered a quantitative marker of residual muscle mass, because serum Cr levels are affected by muscle mass, and correction by CysC counteracts the effect of renal function on serum Cr levels. The purpose of this study was to assess whether the serum Cr level corrected by serum CysC can be used as a predictive marker of pulmonary function and disease severity in patients with COPD.

Patients and Methods

A total of 99 patients without COPD and 201 patients with COPD, with a smoking history of more than 10 pack-years were enrolled in this study, and serum Cr and CysC levels were measured. On chest high-resolution CT images, %low attenuation area (LAA%) (≤960 Hounsfield units (HU)) and ESM_CSA at the Th₁₂ level were identified.

Results

There was a significant correlation between the ESM_CSA and the Cr/CysC ratio. The Cr/CysC ratio was significantly associated with forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) values, especially in former smokers.

Conclusion

The serum Cr/CysC ratio could be a convenient substitute for the measurement of muscle atrophy and pulmonary function testing in patients with COPD.

Serum creatinine to cystatin C ratio is associated with major adverse cardiovascular events in patients with obstructive coronary artery disease

BACKGROUND & AIMS

Sarcopenia is a clinical syndrome that features muscle atrophy and weakness, and has been associated with cardiovascular events and poor clinical outcomes. Recently, the sarcopenia index (SI) was developed as a simple screening tool based upon the serum creatinine to cystatin C (CysC) ratio. We investigated the association between SI and the prevalence of major adverse cardiovascular events (MACE) in patients with obstructive CAD.

METHODS & RESULTS

Between January 2010 and December 2018, patients with angina pectoris and obstructive CAD requiring coronary artery intervention were enrolled. Serum levels of CysC and other biomarkers were assessed. Patients were divided into two groups according to the SI ([Cr/CysC] x 100). Demographic characteristics and clinical outcomes of the two groups were evaluated. A total of 427 patients (79.6% men, mean age 69.55 ± 12.04 years) were enrolled. Patients with SI < 120 (n = 214, 28%) were older, more likely to be of the female gender, and to have more hypertension and congestive heart failure (all p < 0.05). The prevalence of major adverse cardiovascular events (MACE) composed of myocardial infarction, stroke, and all-cause mortality was higher in patients with lower SI (p = 0.026). After adjusting for potential confounding factors, multivariate Cox regression (hazard ratio 2.08, p = 0.045) and Kaplan-Meier analyses (log-rank p = 0.0371) revealed that lower SI was significantly associated with a higher prevalence of MACE.

CONCLUSIONS

Serum creatinine to cystatin C ratio (SI) may be a useful surrogate marker to predict the future prevalence of MACE in patients with obstructive CAD.

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.

Sarcopenia Index as a Predictor of Clinical Outcomes in Older Patients with Coronary Artery Disease

To demonstrate the association of the serum creatinine/serum cystatin C ratio (sarcopenia index, SI) with clinical outcomes including cardiovascular and bleeding risk in older patients who underwent percutaneous coronary intervention (PCI), we analyzed a multicenter nation-wide pooled registry. A total of 1086 older patients (65 years or older) who underwent PCI with second-generation drug-eluting stents (DES) were enrolled. The total population was divided into quartiles according to the SI, stratified by sex. The primary clinical outcomes were major adverse cardiovascular events (MACE, all-cause death, myocardial infarction and target lesion revascularization) and thrombolysis in myocardial infarction major and minor bleeding during a 3-year follow-up period. In the total population, MACE occurred within 3 years in 154 (14.2%) patients. The lowest SI quartile group (Q1) had a significantly higher 3-year MACE rate (Q1 vs. Q2-4; 23.1% vs. 11.2%, p < 0.001), while bleeding event rates were similar between the groups (Q1 vs. Q2-4; 2.6% vs. 2.2%, p = 0.656). The Cox proportional hazard model showed that lower SI is an independent predictor for MACE events (HR 2.23, 95% CI 1.62-3.07, p < 0.001). The SI, a surrogate for the degree of muscle mass, is associated with cardiovascular and non-cardiovascular death, but not with bleeding in older patients who underwent PCI.

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.

The association between cystatin C and COPD: a meta-analysis and systematic review

BACKGROUND

In recent years, many studies have discovered that cystatin C (Cys C) may play an important role in respiratory diseases, especially in chronic obstructive pulmonary disease (COPD). However, the findings of these studies were inconsistent. This systematic review and meta-analysis aimed to assess the relationship between serum Cys C and COPD.

METHODS

We conducted a systematic literature search in PubMed, Embase, Web of Science, Wanfang databases, and the China National Knowledge Infrastructure. The standardized mean difference (SMD), Fisher's Z-value and 95% confidence interval (CI) were calculated to investigate the effect sizes. Subgroup analyses were performed on disease status, ethnicity, assay method, and study design. Sensitivity was performed, and publication bias was assessed.

RESULTS

A total of 15 studies, including 4079 COPD patients and 5949 controls, were included in this meta-analysis. The results showed that serum Cys C levels in patients with COPD were significantly higher than those in controls (SMD = 0.99, 95% CI =0.62-1.37, P < 0.001), especially in AECOPD (SMD = 1.59, 95% CI =1.05-2.13, P < 0.001), and there were statistically different among AECOPD and SCOPD (SMD = 0.35, 95% CI =0.10-0.59, P = 0.005). The serum Cys C levels were negatively correlated with FEV1%pre (Z = - 0.45, 95%CI = -0.58--0.32, P = 0.011) and FEV1/FVC (Z = - 0.32, 95%CI = -0.50--0.14, P = 0.006). The serum Cys C levels were independent of ethnicity, assay method, and study design.

CONCLUSION

Serum Cys C levels were associated with COPD and COPD exacerbation, and they were inversely correlated with FEV1%pre and FEV1/FVC.

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.

Sarcopenia index based on serum creatinine and cystatin C is associated with 3-year mortality in hospitalized older patients

To investigate the association of the sarcopenia index (SI, serum creatinine value/cystatin C value × 100) with 3-year mortality and readmission among older inpatients, we reanalyzed a prospective study in the geriatric ward of a teaching hospital in western China. Older inpatients aged ≥ 60 years with normal kidney function were included. Survival status and readmission information were assessed annually during the 3-year follow-up. We applied Cox regression models to calculate the hazard ratio (HR) and 95% confidence intervals (CIs) of sarcopenia for predicting mortality and readmission. We included 248 participants (mean age: 81.2 ± 6.6 years). During the follow-up, 57 participants (23.9%) died, whereas 179 participants (75.2%) were readmitted at least one time. The SI was positively correlated with body mass index (BMI) (r = 0.214, p = 0.001), calf circumference (CC) (r = 0.253, p < 0.001), handgrip strength (r = 0.244, p < 0.001), and gait speed (r = 0.221, p < 0.001). A higher SI was independently associated with a lower risk of 3-year all-cause mortality after adjusting for potential confounders (HR per 1-SD = 0.80, 95% CI: 0.63–0.97). The SI was not significantly associated with readmission (HR per 1-SD = 0.97, 95% CI: 0.77–1.25). In conclusion, the SI is associated with 3-year all-cause mortality but not readmission in a study population of hospitalized older patients.

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.

A new diagnostic index for sarcopenia and its association with short-term postoperative complications in patients undergoing surgery for colorectal cancer

AIM

Sarcopenia is a robust prognostic indicator of outcomes after surgery for colorectal cancer (CRC). However, there are no serum markers routinely available for estimating skeletal muscle mass (SMM). The present study aimed to describe a new sarcopenia index (SI), serum creatinine (Scr) × cystatin C-based glomerular filtration rate, and investigate its association with short-term complications after curative resection of CRC.

METHOD

Consecutive patients who underwent curative resection of CRC from December 2011 to January 2017 were retrospectively identified. Skeletal muscle cross-sectional area was analysed on L3 computed tomographic images. Receiver operating characteristic curve analysis showed that the cutoff points of SI for sarcopenia were below 56.1 in men and below 43.7 in women. Patients were classified into low and high SI groups in accordance with these cutoff values. The association between SI and body composition and the impact of preoperative SI on postoperative outcomes were analysed.

RESULTS

Among 417 patients, SI showed a stronger correlation with skeletal muscle area (SMA) (r = 0.537, P < 0.001) than with the Scr/cystatin C ratio (r = 0.469, P < 0.001) and Scr (r = 0.447, P < 0.001). The low SI group had a lower SMA, lower preoperative haemoglobin, a higher prevalence of sarcopenia and experienced more postoperative complications compared with the high SI group (all P < 0.001). Multivariate logistic regression analysis showed that the independent risk factors for overall complications were low preoperative haemoglobin, low SI, sarcopenia and American Society of Anesthesiologists grade ≥ 3.

CONCLUSION

This new SI is a simple and useful surrogate marker for estimating SMM, and is associated with outcomes after CRC surgery.

Ratio between estimated glomerular filtration rates of creatinine and cystatin C predicts overall survival in patients with hepatocellular carcinoma

AIM

Hepatocellular carcinoma (HCC) patients with sarcopenia have a poor survival, but there are no predictive markers for survival relating to muscle mass and liver function. Therefore, we investigated whether the ratio between estimated glomerular filtration rates of serum creatinine (Scre) and serum cystatin C (Scys) (eGFRcre/eGFRcys) can be used as a predictive marker of survival in HCC patients.

METHODS

First, the correlation between Scre/Scys ratio and muscle mass was examined in 50 patients with chronic liver disease. Second, a change in Scre/Scys ratio relating to liver function was investigated in cirrhotic rats. Finally, the relationship between the eGFRcre/eGFRcys ratio and survival was assessed in 86 HCC patients.

RESULTS

The Scre/Scys ratio was correlated with skeletal muscle mass index (r = 0.331, P = 0.019) and psoas muscle area index (r = 0.397, P = 0.004) in chronic liver disease patients. In cirrhotic rats, Scre and Scre/Scys ratio were decreased corresponding with liver function. Thirty-five of 86 HCC patients died within the average follow-up period of 35 months. The patients with an eGFRcre/eGFRcys ratio <1.26 had significantly longer rates of survival compared to patients with an eGFRcre/eGFRcys ratio ≥1.26 (28.8 vs. 18.5 months, P = 0.001). Using multivariate Cox regression analyses, the patient-related eGFRcre/eGFRcys ratio (hazard ratio [HR], 4.178; P = 0.007), as well as the tumor-related factors α-fetoprotein (HR, 1.000; P < 0.001) and Barcelona Clinic Liver Cancer stage (HR, 2.589; P < 0.001), were independent predictors of survival.

CONCLUSION

The Scre/Scys ratio is associated with muscle mass and liver function. Furthermore, the eGFRcre/eGFRcys ratio could serve as a useful predictive marker for survival of HCC.

The value of serum cystatin C in early evaluation of renal insufficiency in patients undergoing chemotherapy: a systematic review and meta-analysis

PURPOSE

Several studies have shown that cystatin C levels can be used to detect decline in renal function in cancer patients receiving chemotherapy, and can serve as a supplement to creatinine level measurement for early detection of renal insufficiency. Nevertheless, use of the parameter remains controversial. This study aimed to assess the value of serum cystatin C levels in evaluation of early renal insufficiency due to chemotherapy.

METHODS

Studies were retrieved from PubMed, Ovid Embase, the Web of Science, the Cochrane Library, Ovid, and the CNKI databases up to May 15, 2018. Serum levels of cystatin C before and after chemotherapy were evaluated for its ability to assess renal function.

RESULTS

A total of 12 studies, including 1775 participants, met our inclusion and exclusion criteria. Pooled analysis revealed that the levels of serum cystatin C in cancer patients after chemotherapy were significantly higher than those of patients prior to treatment [standard mean difference (SMD) = 0.54, 95% CI 0.34-0.74, P = 0.0000]. Compared to creatinine, serum cystatin C increased significantly in the early phases of glomerular filtration rate (GFR) change before and after chemotherapy (GFR ≥ 90 ml/min/1.73 m², P < 0.05 vs. P > 0.05, 5.83%; 60 < GFR < 90 ml/min/1.73 m², P < 0.01 vs. P > 0.01, 38.83%) and increased more substantially in the later phases (GFR < 60 ml/min/1.73 m², P < 0.01 vs. P < 0.01, 70.87% vs. 23.09%). However, creatinine decreased even in the early phases and did not increase in an obvious manner until the later phases (GFR < 60 ml/min/1.73 m², P < 0.01, 23.09%). The GFR values were derived from measured methods.

CONCLUSIONS

Cystatin C may be superior to creatinine for the detection of minor changes in GFR in early stages of renal insufficiency secondary to chemotherapy. More studies are needed to further verify this result.

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 creatinine/cystatin C ratio provides effective evaluation of muscle mass in kidney transplant recipients

INTRODUCTION

Measuring muscle mass is an important step in detecting sarcopenia. The evaluation of sarcopenia is also important for kidney transplant recipients. Methods for estimating muscle mass have been established using computed tomography or magnetic resonance imaging, which are considered the gold standards. But these methods are invasive and costly, and there is a need for a more practical and simple method using blood samples from kidney transplant recipients.

METHODS

The study population was 62 patients who underwent kidney transplantation at Kansai Medical University Hospital, and were evaluated from August to October 2017. Muscle mass was measured using dual-energy X-ray absorptiometry. Serum creatinine and cystatin C levels were measured by immunoassay.

RESULTS

We analyzed 62 transplant recipients who met the inclusion criteria (20 females and 42 males, mean age of 45.6 ± 12.7 years). The creatinine/cystatin C ratio in the male group was > 1, whereas the creatinine/cystatin C ratio in the female group was < 1. Muscle mass was significantly larger in the male group than the female group. There was a significant positive correlation between the skeletal muscle index and creatinine/cystatin C ratio in the male (r = 0.553; p < 0.001) and female groups (r = 0.675; p < 0.001).

CONCLUSION

The creatinine/cystatin C ratio is appropriate for evaluating muscle mass in kidney transplant recipients.

A sarcopenia index based on serum creatinine and cystatin C cannot accurately detect either low muscle mass or sarcopenia in urban community-dwelling older people

The aim of this study was to evaluate the diagnostic value of the sarcopenia index (serum creatinine [mg/dl]/cystatin C [mg/dl] × 100) for estimating low muscle mass and sarcopenia in community-dwelling older adults. We included 371 older adults (≥60 years) with normal kidney function. Four common diagnostic criteria (the European Working Group on Sarcopenia in Older People (EWGSOP), Asia Working Group for Sarcopenia (AWGS), International Working Group on Sarcopenia (IWGS), and Foundation for the National Institutes of Health (FNIH) criteria) were separately applied as the "gold standard". The receiver operating characteristic (ROC) curves and the area under the ROC curves (AUC) were applied to evaluate the overall diagnostic accuracy. For identifying low muscle mass, the AUC ranged from 0.505 (95% confidence interval [CI] 0.453-0.557) to 0.558 (95% CI 0.506-0.609). For identifying sarcopenia, the AUC ranged from 0.555 (95% CI 0.503-0.606) to 0.618 (95% CI 0.566-0.668). Subgroup analyses according to gender showed similar results. In conclusion, the sarcopenia index based on serum creatinine and cystatin C may not serve as biomarkers of either low muscle mass or sarcopenia in urban community-dwelling older people with normal kidney function.

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.