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.

The role of fat indices as factors leading to sarcopenia in older adults residing in underpopulated areas

Simplifying the diagnostic criteria for sarcopenia is key to establishing effective interventions. Herein, we aimed to clarify novel diagnostic factors. We calculated novel fat indices [total fat index (TFI) and limb fat index (LFI)] and clarified factors leading to pre-sarcopenia and sarcopenia in 594 enrolled older adults. Physical measurements [height, weight, body mass index (BMI), gait speed, grip strength, and skeletal muscle mass] were performed. Sarcopenia was determined using established diagnostic criteria (pre-sarcopenia, n = 102; sarcopenia, n = 42). Age was associated with sarcopenia status. BMI, TFI, and LFI were lower in patients with pre-sarcopenia and sarcopenia. Logistic regression analysis showed the following odds ratios (ORs) for pre-sarcopenia: BMI [OR: 0.787, 95% confidence interval (CI): 0.7-0.885], LFI (OR: 0.589, 95% CI: 0.402-0.863), and age (OR: 1.06, 95% CI: 1.02-1.1). ORs for sarcopenia (vs pre-sarcopenia) were as follows: LFI (OR: 50.6, 95% CI: 10.2-250.0), age (OR: 1.1, 95% CI: 1.0-1.2), and BMI (OR: 0.418, 95% CI: 0.28-0.608). Our findings contribute to informing medical guidelines.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Difference Between Cystatin C- and Creatinine-Based Estimated GFR in Heart Failure With Reduced Ejection Fraction: Insights From PARADIGM-HF

RATIONALE & OBJECTIVE

The clinical implications of the discrepancy between cystatin C (cysC)- and serum creatinine (Scr)-estimated glomerular filtration rate (eGFR) in patients with heart failure (HF) and reduced ejection fraction (HFrEF) are unknown.

STUDY DESIGN

Post-hoc analysis of randomized trial data.

SETTING & PARTICIPANTS

1,970 patients with HFrEF enrolled in PARADIGM-HF with available baseline cysC and Scr measurements.

EXPOSURE

Intraindividual differences between eGFR based on cysC (eGFRcysC) and Scr (eGFRScr; eGFRdiffcysC-Scr).

OUTCOMES

Clinical outcomes included the PARADIGM-HF primary end point (composite of cardiovascular [CV] mortality or HF hospitalization), CV mortality, all-cause mortality, and worsening kidney function. We also examined poor health-related quality of life (HRQoL), frailty, and worsening HF (WHF), defined as HF hospitalization, emergency department visit, or outpatient intensification of therapy between baseline and 8-month follow-up.

ANALYTICAL APPROACH

Fine-Gray subdistribution hazard models and Cox proportional hazards models were used to regress clinical outcomes on baseline eGFRdiffcysC-Scr. Logistic regression was used to investigate the association of baseline eGFRdiffcysC-Scr with poor HRQoL and frailty. Linear regression models were used to assess the association of WHF with eGFRcysC, eGFRScr, and eGFRdiffcysC-Scr at 8-month follow-up.

RESULTS

Baseline eGFRdiffcysC-Scr was higher than +10 and lower than-10mL/min/1.73m2 in 13.0% and 35.7% of patients, respectively. More negative values of eGFRdiffcysC-Scr were associated with worse outcomes ([sub]hazard ratio per standard deviation: PARADIGM-HF primary end point, 1.18; P=0.008; CV mortality, 1.34; P=0.001; all-cause mortality, 1.39; P<0.001; worsening kidney function, 1.31; P=0.05). For a 1-standard-deviation decrease in eGFRdiffcysC-Scr, the prevalences of poor HRQoL and frailty increased by 29% and 17%, respectively (P≤0.008). WHF was associated with a more pronounced decrease in eGFRcysC than in eGFRScr, resulting in a change in 8-month eGFRdiffcysC-Scr of-4.67mL/min/1.73m2 (P<0.001).

LIMITATIONS

Lack of gold-standard assessment of kidney function.

CONCLUSIONS

In patients with HFrEF, discrepancies between eGFRcysC and eGFRScr are common and are associated with clinical outcomes, HRQoL, and frailty. The decline in kidney function associated with WHF is more marked when assessed with eGFRcysC than with eGFRScr.

PLAIN-LANGUAGE SUMMARY

Kidney function assessment traditionally relies on serum creatinine (Scr) to establish an estimated glomerular filtration rate (eGFR). However, this has been challenged with the introduction of an alternative marker, cystatin C (cysC). Muscle mass and nutritional status have differential effects on eGFR based on cysC (eGFRcysC) and Scr (eGFRScr). Among ambulatory patients with heart failure enrolled in PARADIGM-HF, we investigated the clinical significance of the difference between eGFRcysC and eGFRScr. More negative values (ie, eGFRScr>eGFRcysC) were associated with worse clinical outcomes (including mortality), poor quality of life, and frailty. In patients with progressive heart failure, which is characterized by muscle loss and poor nutritional status, the decline in kidney function was more pronounced when eGFR was estimated using cysC rather than Scr.

On variance estimation of target population created by inverse probability weighting

Inverse probability weighting (IPW) is frequently used to reduce or minimize the observed confounding in observational studies. IPW creates a pseudo-sample by weighting each individual by the inverse of the conditional probability of receiving the treatment level that he/she has actually received. In the pseudo-sample there is no variation among the multiple individuals generated by weighting the same individual in the original sample. This would reduce the variability of the data and therefore bias the variance estimate in the target population. Conventional variance estimation methods for IPW estimators generally ignore this underestimation and tend to produce biased estimates of variance. We here propose a more reasonable method that incorporates this source of variability by using parametric bootstrapping based on intra-stratum variability estimates. This approach firstly uses propensity score stratification and intra-stratum standard deviation to approximate the variability among multiple individuals generated based on a single individual whose propensity score falls within the corresponding stratum. The parametric bootstrapping is then used to incorporate the target variability by re-generating outcomes after adding a random error term to the original data. The performance of the proposed method is compared with three existing methods including the naïve model-based variance estimator, the nonparametric bootstrap variance estimator, and the robust variance estimator in the simulation section. An example of patients with sarcopenia is used to illustrate the implementation of the proposed approach. According to the results, the proposed approach has desirable statistical properties and can be easily implemented using the provided R code.

Association Between Timed Up-and-Go Test and Future Changes in the Frailty Status in a Longitudinal Study of Japanese Community-Dwelling Older Adults

Purpose

This study aimed to evaluate the relationship between timed up-and-go (TUG) test time and changes in frailty status in a longitudinal cohort study of rural Japanese older adults.

Patients and Methods

This prospective cohort study included 545 community-dwelling older adults. Initial and 2-year follow-up surveys were conducted. We compared the number of the Japanese version of the Cardiovascular Health Study components during the follow-up period and classified the participants into three groups: the favorable change, unchanged as prefrail, and unfavorable change groups. Associations between changes in frailty status and TUG time in the first survey were examined. The predictive ability of the TUG test was determined using the receiver operating characteristic (ROC) curve.

Results

The favorable change group comprised 315 individuals (57.8%), the unchanged as prefrail group 105 (19.2%), and the unfavorable change group 125 (22.9%). TUG time was associated with the favorable and unfavorable changes after adjustment for covariates (OR 0.79, 95% CI 0.68-0.92, P=0.001 and OR 1.27, 95% CI 1.09-1.49, P=0.002). The ROC curve of TUG time as a predictor of unfavorable changes showed an area under the curve of 0.59. A cut-off point of TUG was calculated as 6.3 s with 49.6% sensitivity and 66.0% specificity.

Conclusion

TUG time in the first survey was significantly associated with changes in frailty status 2 years later. However, its predictive value as a stand-alone test is limited and has the potential to predict future changes in the frailty status in older adults in combination with other tests.

Cross-Sectional and Longitudinal Associations of Creatinine-to-Cystatin C Ratio with Sarcopenia Parameters in Older Adults

OBJECTIVES

Accumulating evidence from cross-sectional studies suggests that the serum creatinine-to-cystatin C ratio (CCR) may be a useful biomarker for sarcopenia. This study aimed to assess the cross-sectional and longitudinal associations of CCR with sarcopenia and its parameters in community-dwelling older adults.

DESIGN

Cross-sectional and longitudinal study.

SETTING AND PARTICIPANTS

This 6-year prospective cohort study included the repeated measurement data from 1,253 Japanese residents (662 males and 591 females) aged ≥65 years who underwent medical checkups in Kusatsu and Hatoyama, Japan. A total of 4,421 observations were collected.

MEASUREMENTS

The CCR was grouped into quartiles by sex (Q1-Q4) using Q4 as the reference category. Sarcopenia was defined according to the Asian Working Group for Sarcopenia 2019 algorithm. Skeletal muscle mass index (SMI) measured using segmental multifrequency bioelectrical impedance analysis, handgrip strength (HGS), usual gait speed (UGS), and maximal gait speed (MGS) were measured repeatedly as sarcopenia parameters. The association of the CCR with changes in sarcopenia, SMI, HGS, UGS, and MGS during the 6-year period were analyzed using a generalized linear mixed-effects model.

RESULTS

The prevalence of sarcopenia at baseline was 13.1% (11.9% in males and 14.5% in females). In a cross-sectional analysis, the CCR quartile was inversely associated with sarcopenia and was positively associated with SMI, HGS, and MGS (P for trend < 0.001). In a longitudinal analysis during the 6 years, a significant increase in sarcopenia in Q2 (B = 1.1% point/year; P = 0.026 for group-by-time interaction) and significant declines in SMI (B = -0.01 kg/m2/year; P = 0.044 for group-by-time interaction) and MGS (B = -0.008 m/sec/year; P = 0.041 for group-by-time interaction) in Q1 were observed compared with Q4. However, the dose-response relationship was significant only for MGS (P = 0.033 for trend). No significant group-by-time interaction was observed for HGS. CCR was not significantly associated with UGS either cross-sectionally or longitudinally.

CONCLUSIONS

CCR is a useful biomarker regarding the status of sarcopenia. It may be used for sarcopenia screening even in older adults whose physical function is difficult to assess. However, further longitudinal studies are needed to determine whether CCR can be a predictor of future sarcopenia.

The difference between cystatin C- and creatinine-based assessment of kidney function in acute heart failure

AIMS

Acute heart failure (HF) is associated with muscle mass loss, potentially leading to overestimation of kidney function using serum creatinine-based estimated glomerular filtration rate (eGFR_sCr ). Cystatin C-based eGFR (eGFR_CysC ) is less muscle mass dependent. Changes in the difference between eGFR_CysC and eGFR_sCr may reflect muscle mass loss. We investigated the difference between eGFR_CysC and eGFR_sCr and its association with clinical outcomes in acute HF patients.

METHODS AND RESULTS

A post hoc analysis was performed in 841 patients enrolled in three trials: Diuretic Optimization Strategy Evaluation (DOSE), Renal Optimization Strategies Evaluation (ROSE), and Cardiorenal Rescue Study in Acute Decompensated Heart Failure (CARRESS-HF). Intra-individual differences between eGFRs (eGFR_diff ) were calculated as eGFR_CysC -eGFR_sCr at serial time points during HF admission. We investigated associations of (i) change in eGFR_diff between baseline and day 3 or 4 with readmission-free survival up to day 60; (ii) index hospitalization length of stay (LOS) and readmission with eGFR_diff at day 60. eGFR_CysC reclassified 40% of samples to more advanced kidney dysfunction. Median eGFR_diff was -4 [-11 to 1.5] mL/min/1.73 m² at baseline, became more negative during admission and remained significantly different at day 60. The change in eGFR_diff between baseline and day 3 or 4 was associated with readmission-free survival (adjusted hazard ratio per standard deviation decrease in eGFR_diff : 1.14, P = 0.035). Longer index hospitalization LOS and readmission were associated with more negative eGFR_diff at day 60 (both P ≤ 0.026 in adjusted models).

CONCLUSIONS

In acute HF, a marked difference between eGFR_CysC and eGFR_sCr is present at baseline, becomes more pronounced during hospitalization, and is sustained at 60 day follow-up. The change in eGFR_diff during HF admission and eGFR_diff at day 60 are associated with clinical outcomes.

A Novel Application of Serum Creatinine and Cystatin C to Predict Sarcopenia in Advanced CKD

Sarcopenia is highly prevalent in patients with advanced chronic kidney disease (CKD), yet a reliable serum index has not been established. The product of serum creatinine and the estimated glomerular filtration rate based on cystatin C (Cr×eGFRcys) was recently proposed as a sarcopenia index (SI), approximately to 24-h filtered creatinine through the glomerulus. We aimed to evaluate the diagnostic validity of the novel SI in advanced CKD. In 297 patients with non-dialysis stage 3b-5 CKD, aged 68.8 ± 12.9 years, the total skeletal muscle mass (SMM), handgrip strength (HGS), and usual gait speed were assessed. Sarcopenia was defined based on the Asian Working Group for Sarcopenia 2019 consensus update. The prevalence of sarcopenia in this cohort was 20.2%. The SI correlated moderately with SMM (r = 0.503, P &lt; 0.001), HGS (r = 0.508, P &lt; 0.001), and gait speed (r = 0.381, P &lt; 0.001); the independency of the SI with three muscle metrics was confirmed after extensive adjustment. For sarcopenia prediction, the SI had acceptable discriminative powers in males [area under the receiver operating characteristic curve (AUC) 0.646, 95% confidence interval (CI) 0.569–0.718] and females (AUC 0.754, 95% CI 0.670–0.826). In males, the best cut-off was 53.9, which provided 71.1% sensitivity, 58.0% specificity, 32.9% positive predictive value (PPV), and 87.4% negative predictive value (NPV); in females, the best cut-off was 45.8, which provided 81.8% sensitivity, 62.3% specificity, 31.0% PPV, and 94.3% NPV. In conclusion, Cr×eGFRcys could be served as a surrogate marker for sarcopenia and may be helpful for sarcopenia screening in advanced CKD. Further studies are needed to expand our investigation.

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.

Low back pain is closely associated with frailty but not with sarcopenia: Cross-sectional study of rural Japanese community-dwelling older adults

AIM

We speculated that low back pain, which is the most common ailment in older adults, is associated with frailty and/or sarcopenia and contributes to the progression of either condition. Our objective was to evaluate the relationship between low back pain, sarcopenia and frailty in rural Japanese community-dwelling older adults.

METHODS

We recruited 730 participants aged ≥65 years who underwent a comprehensive health examination between November 2016 and December 2018. The Oswestry Disability Index (ODI) was used to assess low back pain quantitatively, and scores were compared for the frail groups determined by the Japanese version of Cardiovascular Health Study, and the sarcopenia groups as determined by the Asian Working Group for Sarcopenia 2019.

RESULTS

Among 730 participants, the prevalence of low back pain was 57.8%. There were significant differences in the ODI scores between the robust, prefrail and frail groups (P < 0.001). In contrast, there were no significant differences in the ODI scores among the robust, low appendicular skeletal muscle and sarcopenia groups. Logistic regression analysis showed that the prevalence of low back pain and the ODI scores were significantly associated with frailty after adjustment for age, sex and body mass index (odds ratio 3.41, 95% confidence interval 1.39-8.39, P = 0.008, and odds ratio 1.06, 95% confidence interval 1.04-1.09, P < 0.001, respectively).

CONCLUSIONS

To the best of our knowledge, this study is the first to show the close association between low back pain and frailty, and suggests that not only the decline in physical function but also neuropsychiatric factors, including chronic pain, constitute a vicious cycle of frailty in community-dwelling older adults. Geriatr Gerontol Int 2021; 21: 54-59.