Bone is Not Alone: the Effects of Skeletal Muscle Dysfunction in Chronic Kidney Disease

Associations between skeletal muscle strength and chronic kidney disease in patients with MASLD

BACKGROUND

A skeletal muscle strength (SMS) decline is associated with metabolic diseases, but whether SMS also declines with chronic kidney disease (CKD) in individuals with metabolic dysfunction-associated steatotic liver disease (MASLD) is uncertain. This study examined the associations between SMS and the risk of CKD in MASLD population.

METHOD

We performed a large-scale study with four cohorts: PERSONS and NHANES 2011-2014 cohorts for the cross-sectional investigation, and TCLSIH and UK Biobank cohorts for the longitudinal investigation. A handgrip dynamometer measured handgrip strength as a proxy for overall SMS. Participants were stratified according to CKD status [non-CKD vs. CKD (stages 1-5) groups].

RESULTS

In the PERSONS cohort, the CKD group has a lower handgrip strength than the non-CKD group (27.14 ± 9.19 vs. 33.59 ± 11.92 kg, P < 0.001). Higher handgrip strength is associated with lower odds of abnormal albuminuria or CKD (OR: 0.96, 95%CI:0.92-0.99 and OR:0.95, 95%CI: 0.91-0.99 respectively). The highest handgrip strength tertile is associated with the lowest risk of having abnormal albuminuria or CKD (compared with the lowest or middle tertile). Results are similar in NHANES cohort. Furthermore, the highest handgrip strength is independently associated with the lowest risk of incident CKD in MASLD (HR: 0.95, 95%CI: 0.92-0.99 and HR:0.99, 95%CI: 0.98-0.99 in TCLSIH and UK Biobank cohorts). In Kaplan-Meier curve analysis, the cumulative incidence of CKD is lowest in the highest handgrip strength tertile compared to the lowest or the middle tertile.

CONCLUSIONS

Higher handgrip/muscle strength is independently associated with a lower risk of CKD and abnormal albuminuria in MASLD population.

Nine-year survival after intertrochanteric fracture in elderly with chronic kidney disease

The outcome of this study was to identify 9-year survivors of intertrochanteric fracture at each stage of chronic kidney disease (CKD) and to investigate the risk factors associated with mortality following surgery with proximal femoral nail anti-rotation (PFNA). 443 elderly intertrochanteric fractures underwent PFNA fixation were recruited. Mortality rate was identified until 9 years. We compared the survival time of hip fracture in each stage of CKD. A regression analysis was used to determine the association between risk factors and one-year mortality. The overall median survival time was 7.1 years. The Kaplan-Meier curve was significantly different in each CKD stage especially in CKD5. In addition, the incidence rate of mortality was highest in CKD 5 (17.4%) and the median survival time in CKD 5 was 3.3 years. The multivariate analysis demonstrated that heart disease, operative time > 60 min, presence of pulmonary embolism, and poor to fair Harris hip score were significantly increased mortality. CKD stage 5 is associated with the highest mortality rate and the shortest median time of survival during the 9-year follow up. Patients who have high risk should focus on long-term care planning, including the counseling for their healthcare providers and families.

The role of osteopontin and osteocyte-derived factors in secondary hyperparathyroidism-induced myopathy

Muscle weakness is a common symptom in CKD patients, and the pathway by which secondary hyperparathyroidism (SHPT) affects muscle function is unknown. Osteopontin (OPN), a bone matrix protein stimulated by PTH and phosphate, has been associated with inflammatory muscle diseases. In this observational and prospective cohort study, we evaluated 30 patients with severe SHPT (39 ± 12 yr; 18 women), before and 6 mo after parathyroidectomy (PTx). We examined the relationships among CKD-mineral and bone disorder parameters; myokine and inflammatory cytokine levels; and changes in resting energy expenditure (REE), muscle function, BMD, and muscle-related proteins. At baseline, the patients showed low gene expression of muscle turnover markers and irisin, as well as high protein expression of OPN, transforming growth factor beta (TGF-β), and fibroblast growth factor 21. Six months after PTx, REE and muscle mass had not changed, but physical performance, muscle strength, and bone mass improved, more so in patients undergoing total PTx. Also, there were reductions in the protein expression of OPN (11 vs 3%, p=.01) and TGF-β (21 vs 7%, p=.002) in muscle, together with a significant increase in irisin muscular levels (30 vs 35 pg/mg, p=.02). The gain in bone mass and the increase in irisin levels correlated with a reduction in PTH. The levels of interleukin (IL)-1β, tumor necrosis factor alpha, and IL-17 (markers of myositis) were also lower after PTx. Our data suggest that SHPT plays a role in CKD-induced muscle dysfunction, indirectly, via release of bone-specific proteins, which is partially reverted with PTx.

Physical exercise as a modulator of the purinergic system in the control of sarcopenia in individuals with chronic kidney disease on hemodialysis

The word sarcopenia derives from the Greek terms "sarx" for meat and "penia" for loss, thus being used to define reductions in muscle mass, muscle strength, and lower physical performance that compromise, mainly, the elderly population. Its high negative impact on patients' quality of life encourages the production and publication of new studies that seek to find methods to prevent and reverse cases of loss of muscle mass and strength. Furthermore, the high prevalence of sarcopenia in patients with chronic kidney disease (CKD) is closely related to its pathophysiology, which consists of a state of increased protein catabolism and decreased muscle tissue synthesis. Also considering the inflammatory nature of CKD and sarcopenia, the purinergic system has been an important target of studies, which seek to relate it to the two previous conditions. This system achieves anti-inflammatory action by inhibiting, through adenosine, pro-inflammatory factors such as interleukin-12 (IL-12), tumor necrosis factor alpha (TNF-α), and nitric oxide (NO), as well as by releasing anti-inflammatory substances such as interleukin-10 (IL-10). Simultaneously, the purinergic system presents pro-inflammatory activity, signaled by adenosine triphosphate (ATP), which occurs through the activation of T cells and the release of pro-inflammatory factors such as those mentioned above. Therefore, the ability of this system to act on inflammatory processes can promote positive and negative changes in the clinical aspect of patients with CKD and/or sarcopenia. Furthermore, it appears that there is a correlation between the practice of repeated physical exercise with the clinical improvement and in the quality of life of these patients, presenting a decrease in the levels of C-reactive protein (CRP), NTPDase, and the pro-inflammatory cytokine IL-6, such as increases in IL-10 resulting from modulation of the purinergic system. In this way, the present article seeks to evaluate the effect of physical exercise as a modulator of the purinergic system in the control of sarcopenia in patients with CKD on hemodialysis, in order to trace a relationship that can bring benefits both for biological markers and for quality of life of these patients.

Definition and evolution of the concept of sarcopenia

Sarcopenia and dynapenia are two terms associated with ageing that respectively define the loss of muscle mass and strength. In 2018, the European Working Group on Sarcopenia in Older People (EWGSOP) introduced the EWGSOP2 diagnostic algorithm for sarcopenia, which integrates both concepts. It consists of 4 sequential steps: screening for sarcopenia, examination of muscle strength, assessment of muscle mass and physical performance; depending on these last 3 aspects sarcopenia is categorised as probable, confirmed, and severe respectively. In the absence of validation of the EWGSOP2 algorithm in various clinical contexts, its use in haemodialysis poses several limitations: (a) low sensitivity of the screening, (b) the techniques that assess muscle mass are not very accessible, reliable, or safe in routine clinical care, (c) the sequential use of the magnitudes that assess dynapenia and muscle mass do not seem to adequately reflect the muscular pathology of the elderly person on dialysis. We reflect on the definition of sarcopenia and the use of more precise terms such as "myopenia" (replacing the classic concept of sarcopenia to designate loss of muscle mass), dynapenia and kratopenia. Prospective evaluation of EWGSOP2 and its comparison with alternatives (i.e. assessment of kratopenia and dynapenia only; steps 2 and 4) is proposed in terms of its applicability in clinical routine, resource consumption, identification of at-risk individuals and impact on events.

Narrative Review: Clinical Implications and Assessment of Frailty in Patients With Advanced CKD

Frailty is a multidimensional clinical syndrome characterized by low physical activity, reduced strength, accumulation of multiorgan deficits, decreased physiological reserve, and vulnerability to stressors. Frailty has key social, psychological, and cognitive implications. Frailty is accelerated by uremia, leading to a high prevalence of frailty in patients with advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD) as well as contributing to adverse outcomes in this patient population. Frailty assessment is not routine in patients with CKD; however, a number of validated clinical assessment tools can assist in prognostication. Frailty assessment in nephrology populations supports shared decision-making and advanced communication and should inform key medical transitions. Frailty screening and interventions in CKD or ESKD are a developing research priority with a rapidly expanding literature base.

Impact of COVID-19 versus other pneumonia on in-hospital mortality and functional decline among Japanese dialysis patients: a retrospective cohort study

Coronavirus disease 2019 (COVID-19) affects both life and health. However, the differentiation from other types of pneumonia and effect of kidney disease remains uncertain. This retrospective observational study investigated the risk of in-hospital death and functional decline in ≥ 20% of Barthel Index scores after COVID-19 compared to other forms of pneumonia among Japanese adults, both with and without end-stage kidney disease (ESKD). The study enrolled 123,378 patients aged 18 years and older from a national inpatient administrative claims database in Japan that covers the first three waves of the COVID-19 pandemic in 2020. After a 1:1:1:1 propensity score matching into non-COVID-19/non-dialysis, COVID-19/non-dialysis, non-COVID-19/dialysis, and COVID-19/dialysis groups, 2136 adults were included in the analyses. The multivariable logistic regression analyses revealed greater odds ratios (ORs) of death [5.92 (95% CI 3.62-9.96)] and functional decline [1.93 (95% CI 1.26-2.99)] only in the COVID-19/dialysis group versus the non-COVID-19/non-dialysis group. The COVID-19/dialysis group had a higher risk of death directly due to pneumonia (OR 6.02, 95% CI 3.50-10.8) or death due to other diseases (OR 3.00, 95% CI 1.11-8.48; versus the non-COVID-19/non-dialysis group). COVID-19 displayed a greater impact on physical function than other types of pneumonia particularly in ESKD.

Musculoskeletal Health Worsened from Carnitine Supplementation and Not Impacted by a Novel Individualized Treadmill Training Protocol

INTRODUCTION

Chronic kidney disease (CKD) negatively affects musculoskeletal health, leading to reduced mobility, and quality of life. In healthy populations, carnitine supplementation and aerobic exercise have been reported to improve musculoskeletal health. However, there are inconclusive results regarding their effectiveness and safety in CKD. We hypothesized that carnitine supplementation and individualized treadmill exercise would improve musculoskeletal health in CKD.

METHODS

We used a spontaneously progressive CKD rat model (Cy/+ rat) (n = 11-12/gr): (1) Cy/+ (CKD-Ctrl), (2) CKD-carnitine (CKD-Carn), and (3) CKD-treadmill (CKD-TM). Carnitine (250 mg/kg) was injected daily for 10 weeks. Rats in the treadmill group ran 4 days/week on a 5° incline for 10 weeks progressing from 30 min/day for week one to 40 min/day for week two to 50 min/day for the remaining 8 weeks. At 32 weeks of age, we assessed overall cardiopulmonary fitness, muscle function, bone histology and architecture, and kidney function. Data were analyzed by one-way ANOVA with Tukey's multiple comparisons tests.

RESULTS

Moderate to severe CKD was confirmed by biochemistries for blood urea nitrogen (mean 43 ± 5 mg/dL CKD-Ctrl), phosphorus (mean 8 ± 1 mg/dL CKD-Ctrl), parathyroid hormone (PTH; mean 625 ± 185 pg/mL CKD-Ctrl), and serum creatinine (mean 1.1 ± 0.2 mg/mL CKD-Ctrl). Carnitine worsened phosphorous (mean 11 ± 3 mg/dL CKD-Carn; p < 0.0001), PTH (mean 1,738 ± 1,233 pg/mL CKD-Carn; p < 0.0001), creatinine (mean 1 ± 0.3 mg/dL CKD-Carn; p < 0.0001), cortical bone thickness (mean 0.5 ± 0.1 mm CKD-Ctrl, 0.4 ± 0.1 mm CKD-Carn; p < 0.05). Treadmill running significantly improves maximal aerobic capacity when compared to CKD-Ctrl (mean 14 ± 2 min CKD-TM, 10 ± 2 min CKD-Ctrl; p < 0.01).

CONCLUSION

Carnitine supplementation worsened CKD progression, mineral metabolism biochemistries, and cortical porosity and did not have an impact on physical function. Individualized treadmill running improved maximal aerobic capacity but did not have an impact on CKD progression or bone properties. Future studies should seek to better understand carnitine doses in conditions of compromised renal function to prevent toxicity which may result from elevated carnitine levels and to optimize exercise prescriptions for musculoskeletal health.

Skeletal muscle atrophy in clinical and preclinical models of chronic kidney disease: A systematic review and meta-analysis

Patients with chronic kidney disease (CKD) are often regarded as experiencing wasting of muscle mass and declining muscle strength and function, collectively termed sarcopenia. The extent of skeletal muscle wasting in clinical and preclinical CKD populations is unclear. We evaluated skeletal muscle atrophy in preclinical and clinical models of CKD, with multiple sub-analyses for muscle mass assessment methods, CKD severity, sex and across the different preclinical models of CKD. We performed a systematic literature review of clinical and preclinical studies that measured muscle mass/size using the following databases: Ovid Medline, Embase and Scopus. A random effects meta-analysis was utilized to determine standard mean difference (SMD; Hedges' g) between healthy and CKD. Heterogeneity was evaluated using the I2 statistic. Preclinical study quality was assessed via the Systematic Review Centre for Laboratory Animal Experimentation and clinical studies quality was assessed via the Newcastle-Ottawa Scale. This study was registered in PROSPERO (CRD42020180737) prior to initiation of the search. A total of 111 studies were included in this analysis using the following subgroups: 106 studies in the primary CKD analysis, 18 studies that accounted for diabetes and 7 kidney transplant studies. Significant atrophy was demonstrated in 78% of the preclinical studies and 49% of the clinical studies. The random effects model demonstrated a medium overall SMD (SMD = 0.58, 95% CI = 0.52-0.64) when combining clinical and preclinical studies, a medium SMD for the clinical population (SMD = 0.48, 95% CI = 0.42-0.55; all stages) and a large SMD for preclinical CKD (SMD = 0.95, 95% CI = 0.76-1.14). Further sub-analyses were performed based upon assessment methods, disease status and animal model. Muscle atrophy was reported in 49% of the clinical studies, paired with small mean differences. Preclinical studies reported significant atrophy in 78% of studies, with large mean differences. Across multiple clinical sub-analyses such as severity of CKD, dialysis modality and diabetes, a medium mean difference was found. Sub-analyses in both clinical and preclinical studies found a large mean difference for males and medium for females suggesting sex-specific implications. Muscle atrophy differences varied based upon assessment method for clinical and preclinical studies. Limitations in study design prevented conclusions to be made about the extent of muscle loss with disease progression, or the impact of dialysis. Future work would benefit from the use of standardized measurement methods and consistent clinical staging to improve our understanding of atrophy changes in CKD progression, and analysis of biological sex differences.

Calf circumference predicts sarcopenia in maintenance hemodialysis

BACKGROUND

Early recognition of sarcopenia in hemodialysis (HD) patients will be of great importance in preventing adverse outcomes and improving the quality of life in these patients. The main goal of this study was to evaluate the diagnostic accuracy of calf circumference (CC) measurement in detecting sarcopenia among CKD patients undergoing maintenance HD.

METHODS

This cross-sectional study included 52 patients (53 ± 17 years) who were currently in a maintenance HD. Muscle strength was evaluated using handgrip strength, and smooth muscle mass index (SMI) was assessed through bioelectrical impedance analysis, and CC was measured at the widest part of the calf with the foot pressed against a hard surface.

RESULTS

Out of the total patient population, sarcopenia was identified in 32.7% (n = 17). The two groups were comparable in terms of age, weight, and height, but the median body mass index of sarcopenic group was statistically lower than nonsarcopenic group (21.6 kg/m2 [18.9-24.6] vs 24.7 kg/m2 [21.4-27.3]. The sarcopenic group had a substantially smaller CC than the nonsarcopenic group (30.0 cm [26.5-32.0] vs 31.5 cm [30.3-34.8], P = 0.013; respectively). In the regression analysis, CC was found to be independently associated with post-HD SMI (P < 0.001; odds ratio, 1.938; and 95% CI, 1.020-2.856). CC was positively but weakly correlated with handgrip strength, however strong and significant correlation was found between CC and SMI (r = 0.277, P = 0.047 and r = 0.733, P < 0.001; respectively). A CC of 31 cm or less predicted confirmed sarcopenia in HD patients (area under the curve = 0.709, P = 0.006, specificity = 0.556, sensitivity = 0.765).

CONCLUSIONS

Low muscle mass and potentially low muscle strength in HD patients can be accurately identified through the use of CC measurements. Specifically, a CC measurement below 31 cm has found to be a useful indicator to identify individuals on maintenance HD.

Identification of molecular mediators of renal sarcopenia risk: a mendelian randomization analysis

BACKGROUND

Observational studies have shown an association between reduced renal function and the risk of sarcopenia. However, the causal relationship and the underlying biological mechanisms remain uncertain. Using a Mendelian randomization (MR) framework, we investigated the causal role of 27 hypothetical risk mediators, including metabolites, hormones, inflammation, and stress traits, on the risk of sarcopenia.

METHODS

Instrumental variables (IVs) to proxy renal function were identified by selecting single nucleotide polymorphisms (SNPs) reliably associated with creatinine and cystatin C-based glomerular filtration rate (GFR) in CKDGen summary data. IVs for putative risk traits and sarcopenia traits were constructed from relevant genome-wide association studies (GWAS). MR estimated effects were obtained using an inverse-variance weighted effects model, and various sensitivity analyses were performed. The mediating role of hypothetical risk factors in the relationship between GFR and sarcopenia was assessed through multivariate MR.

RESULTS

Genetically predicted reduced GFRcrea was associated with higher odds of appendicular lean mass (ALM) (odds ratio (OR): 0.64, 95% confidence interval (CI) 0.37 to 0.68) and grip strength (OR: 0.67; 95% CI 0.58 to 0.78). Likewise, GFRcys highlighted a causal relationship with ALM (OR: 0.52; 95% CI 0.42 to 0.65) and grip strength (OR: 0.66; 95% CI 0.59 to 0.74). Both estimated GFR (eGFR) were negatively associated with IGF-1, IL-16, 25(OH)D, triglycerides (range of effect size per standard deviation: -0.81 to -0.30), and positively correlated with HDL cholesterol (0.62, 0.31). There was a positive correlation between IGF-1, fasting insulin and ALM as well as grip strength (OR range: 1.04-1.67) and a negative correlation between serum CRP and ALM (OR: 0.95) as well as grip strength (OR: 0.98). Additionally, genetically predicted IL-1β (OR: 0.95) and total cholesterol (OR: 0.96) were negatively associated with ALM. We found evidence that IGF-1 mediates the relationship between eGFR and risk for muscle mass and strength.

CONCLUSIONS

This MR study provides insight into the potential causal mechanisms between renal function and the risk of sarcopenia and proposes IGF-1 as a potential target for the prevention of renal sarcopenia.

Blocking CCN2 Reduces Established Bone Loss Induced by Prolonged Intense Loading by Increasing Osteoblast Activity in Rats

We have an operant model of reaching and grasping in which detrimental bone remodeling is observed rather than beneficial adaptation when rats perform a high-repetition, high-force (HRHF) task long term. Here, adult female Sprague-Dawley rats performed an intense HRHF task for 18 weeks, which we have shown induces radial trabecular bone osteopenia. One cohort was euthanized at this point (to assay the bone changes post task; HRHF-Untreated). Two other cohorts were placed on 6 weeks of rest while being simultaneously treated with either an anti-CCN2 (FG-3019, 40 mg/kg body weight, ip; twice per week; HRHF-Rest/anti-CCN2), or a control IgG (HRHF-Rest/IgG), with the purpose of determining which might improve the trabecular bone decline. Results were compared with food-restricted control rats (FRC). MicroCT analysis of distal metaphysis of radii showed decreased trabecular bone volume fraction (BV/TV) and thickness in HRHF-Untreated rats compared with FRCs; responses improved with HRHF-Rest/anti-CCN2. Rest/IgG also improved trabecular thickness but not BV/TV. Histomorphometry showed that rest with either treatment improved osteoid volume and task-induced increases in osteoclasts. Only the HRHF-Rest/anti-CCN2 treatment improved osteoblast numbers, osteoid width, mineralization, and bone formation rate compared with HRHF-Untreated rats (as well as the latter three attributes compared with HRHF-Rest/IgG rats). Serum ELISA results were in support, showing increased osteocalcin and decreased CTX-1 in HRHF-Rest/anti-CCN2 rats compared with both HRHF-Untreated and HRHF-Rest/IgG rats. These results are highly encouraging for use of anti-CCN2 for therapeutic treatment of bone loss, such as that induced by chronic overuse. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Characteristics of older patients with postmenopausal osteoporosis who developed loss of muscle mass during the COVID-19 pandemic - a case-control study

BACKGROUND

Under the restriction of social activities during the coronavirus disease 2019 (COVID-19) pandemic, there was concern about the loss of muscle mass due to a decrease in physical activity for the elderly. The purpose of this study was to investigate the characteristics of older patients with postmenopausal osteoporosis who developed loss of muscle mass during the COVID-19 pandemic in Japan.

METHODS

A total of 54 patients with postmenopausal osteoporosis were evaluated in this study. Whole-body dual-energy X-ray absorptiometry was performed pre- and post-COVID-19 pandemic to measure trunk and lower limb muscle mass. At the time of the post-COVID-19 pandemic, we conducted a survey to compare lifestyle before pandemic (the frequency of going out, the frequency of meeting acquaintances or families living apart, regular exercise habits, walking time, family structure), and comorbidities between the muscle mass loss (ML) group and the muscle mass maintenance (MM) group. The ML group consisted of patients with at least a 5% decrease in lower limb muscle mass or trunk muscle mass.

RESULTS

A significant difference was found only for the family structure (P = 0.0279); in the ML group, those living alone were the largest group, while in the MM group they were the smallest group.

CONCLUSIONS

The ML group was significantly more likely to live alone than the MM group. The current study showed that loss of muscle mass was more common in patients living alone.

A Sarcopenia Index Derived from Malnutrition Parameters in Elderly Haemodialysis Patients

(1) Background: Persons with chronic kidney disease may have sarcopenia characterized by the loss of muscle mass and loss of muscle strength. However, EWGSOP2 criteria to diagnose sarcopenia are technically challenging, especially in elderly persons on hemodialysis. Sarcopenia may be associated with malnutrition. We aimed at defining a sarcopenia index derived from malnutrition parameters for use in elderly haemodialysis patients. (2) Methods: A retrospective study of 60 patients aged 75 to 95 years treated with chronic hemodialysis was conducted. Anthropometric and analytical variables, EWGSOP2 sarcopenia criteria and other nutrition-related variables were collected. Binomial logistic regressions were used to define the combination of anthropometric and nutritional parameters that best predict moderate or severe sarcopenia according to EWGSOP2, and performance for moderate and severe sarcopenia was assessed by the area under the curve (AUC) of receiver operating characteristic (ROC) curves. (3) Results: The combination of loss of strength, loss of muscle mass and low physical performance correlated with malnutrition. We developed regression-equation-related nutrition criteria that predicted moderate sarcopenia (elderly hemodialysis sarcopenia index-moderate, EHSI-M) and severe sarcopenia (EHSI-S) diagnosed according to EWGSOP2 with an AUC of 0.80 and 0.866, respectively. (4) Conclusions: There is a close relationship between nutrition and sarcopenia. The EHSI may identify EWGSOP2-diagnosed sarcopenia from easily accessible anthropometric and nutritional parameters.

Association Between Protocols of the Sit-to-Stand Test and Lower Limb Muscle Force Output in Patients on Hemodialysis and Subjects Without Chronic Kidney Disease

OBJECTIVE

To evaluate the association of three protocols of the sit-to-stand (STS) test with muscle force output of knee extension (KE) and knee flexion (KF) in patients on hemodialysis and subjects without chronic kidney disease.

METHODS

This cross-sectional study included a hemodialysis group [n = 60, 59.5 (16.8) years, 55% female] and a control group [n = 60, 43.0 (11.8) years, 50% female]. The assessments were performed in 2 days, and the participants were submitted to three protocols of STS test (5-repetition STS, 10-repetition STS and 30-s STS) or muscle force output of the KE and KF evaluation by handheld dynamometer based on randomization.

RESULTS

The hemodialysis group presented reduced muscle force output of the KE and KF, a longer time to perform the 5 STS and 10 STS tests, and a lower number of repetitions in the 30-s STS test. The three STS tests were associated with muscle force output of the KE in the hemodialysis group, in which the 10-repetition STS test showed the best association (R² = 0.47; adjusted R² = 0.42). However, the only association between the STS test and muscle force output of the KE in the control group was found in the 10-repetition STS test (R² = 0.20; adjusted R² = 0.13).

CONCLUSIONS

The three protocols of STS tests were associated with muscle force output of the KE in patients on hemodialysis. However, the 10-repetition STS test was the best protocol to estimate the quadriceps muscle torque in these patients.

The triglyceride-glucose index as a novel marker associated with sarcopenia in non-diabetic patients on maintenance hemodialysis

Objective

Sarcopenia is a common complication in patients with end-stage kidney disease. Insulin resistance is present in non-diabetic patients undergoing maintenance hemodialysis (MHD) and is an important factor leading to sarcopenia. The triglyceride–glucose (TyG) index, a reliable indicator for evaluating insulin resistance, is widely used in clinical practice. The present study investigated the association between the TyG index and sarcopenia in non-diabetic patients undergoing MHD.

Methods

Relevant clinical data of non-diabetic patients undergoing MHD at our center were collected. The TyG index was calculated using the following formula: ln(fasting triglycerides(mg/dL)×fasting blood glucose(mg/dL)/2). Multivariate logistic regression analyses were used to evaluate the associations. The receiver-operating characteristic curve was used to analyze the predictive value of the TyG index in sarcopenia.

Results

Of the 142 patients undergoing MHD who were included, 75 (52.82%) were men, the mean age was 54.05 ± 13.97 years, and 40 (28.17%) patients satisfied the diagnostic criteria for sarcopenia. The TyG index of participants with sarcopenia was higher compared with those without sarcopenia (8.83 ± 0.45 vs. 8.49 ± 0.50, p < 0.001). The prevalence of sarcopenia increased with increasing TyG index tertile (T1, 8.51%; T2, 31.91%; T3, 43.75%; p = 0.001). Logistic regression analysis indicated that the TyG index was an independent risk factor for sarcopenia (odds ratio, 4.21 [95% confidence interval, 1.85–9.59], p = 0.001).

Conclusion

A higher TyG index was associated with an increased risk of sarcopenia in non-diabetic patients undergoing MHD; it may be used as a novel marker to reflect the presence of sarcopenia.

Skeletal Muscle Complications in Chronic Kidney Disease

PURPOSE OF REVIEW

To provide an overview of the recent literature investigating the pathophysiology of skeletal muscle changes, interventions for skeletal muscle, and effects of exercise in chronic kidney disease (CKD).

RECENT FINDINGS

There are multiple CKD-related changes that negatively impact muscle size and function. However, the variability in the assessment of muscle size, in particular, hinders the ability to truly understand the impact it may have in CKD. Exercise interventions to improve muscle size and function demonstrate inconsistent responses that warrant further investigation to optimize exercise prescription. Despite progress in the field, there are many gaps in the knowledge of the pathophysiology of sarcopenia of CKD. Identifying these gaps will help in the design of interventions that can be tested to target muscle loss and its consequences such as impaired mobility, falls, and poor quality of life in patients with CKD.

Effect of low skeletal muscle mass and sarcopenic obesity on chronic kidney disease in patients with type 2 diabetes

OBJECTIVE

This study aimed to investigate the association between low muscle mass or sarcopenic obesity and the risk of incident chronic kidney disease (CKD) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 3123 patients with T2DM with preserved renal function were followed up for incident CKD. Skeletal muscle mass was estimated from bioelectrical impedance analysis. CKD was defined as estimated glomerular filtration rate < 60 mL/min/1.73 m² . Sarcopenic obesity was defined as the coexistence of sarcopenia and abdominal obesity.

RESULTS

During 8.9 years of follow-up, 530 (17.0%) patients developed incident CKD. When patients were divided into three groups based on sex-specific tertiles, lower muscle mass was not associated with an increased risk of incident CKD after adjustment for risk factors. However, when patients were divided into four groups according to the presence of sarcopenia and obesity, sarcopenic obesity was associated with an increased risk of incident CKD (adjusted hazard ratio 1.77; 95% CI: 1.24-2.51; p = 0.001) compared with the other groups.

CONCLUSIONS

Sarcopenic obesity, but not low muscle mass alone, may increase the risk of CKD in patients with T2DM.

Correlation between Glycation-Related Biomarkers and Quality of Life in the General Japanese Population: The Iwaki Cross-Sectional Research Study

The correlation between diabetes-related biomarkers and quality of life (QOL) remains unclear. In this cross-sectional study, we investigated the correlation between diabetes-related biomarkers and QOL in a general Japanese population who underwent health checkups as a part of the Iwaki Health Promotion Project. Male and female participants aged ≥ 20 years from Iwaki District, Hirosaki City, Aomori Prefecture who participated in the 2019 medical evaluation were recruited. QOL was evaluated using the Short Form Health Survey 36 (SF-36). Fasting blood glucose, homeostatic model assessment-estimated insulin resistance (HOMA-IR), hemoglobin A1c (HbA1c), glycoalbumin, and plasma pentosidine were also evaluated as diabetes-related markers. Of the 1065 recruited participants, 1053 completed the clinical and QOL evaluations. Multivariate regression analysis revealed that upregulated diabetes-related markers levels were correlated with decreased SF-36 scores. Blood glucose, HOMA-IR, HbA1c, glycoalbumin, and plasma pentosidine levels were correlated with general health. Moreover, plasma pentosidine levels were correlated with role physical, social functioning, and role emotional in addition to general health. These results indicated that the levels of diabetes-related biomarkers, particularly the levels of plasma pentosidine, a glycation marker, were associated with QOL in our cohort.

The effect of CKD on intertrochanteric fracture treated with proximal femoral nail anti-rotation: A 7-year study

Background

Intertrochanteric fracture is one of the most burdensome osteoporotic fractures in the elderly. Chronic kidney disease is associated with sarcopenia, especially in its advanced stages and, thus may impact functional status. Combining an intertrochanteric fracture with advanced CKD may diminish results after surgical fixation. This study aims to distinguish whether CKD affects the result of intertrochanteric fracture fixation in terms of mechanical and functional outcomes.

Methods

A retrospective study reviews all intertrochanteric fractures treated with PFNA fixation from 2012 to 2018. 445 patients were classified into 5 stages of CKD and divided by eGFR = 90 ml/min/1.73 m² into CKD and non-CKD group and by eGFR = 30 ml/min/1.73 m² into advanced CKD and non-advanced CKD group. The primary outcome was one year Harris Hip Score (HHS). Secondary outcomes were medical complications, surgical complications, and a 1-year mortality rate.

Results

Harris Hip Scores (HHS) were not different between non-CKD and CKD groups (eGFR <90 mL/min/1.73 m²). However, there was a difference between non-advanced CKD and advanced CKD groups (eGFR <30 mL/min/1.73 m²) (p < 0.001). Medical complications were not different, except for sepsis in CKD stage 5 compared with stage 1 (p = 0.023). Even though AO/OTA types were more severe in the advanced CKD group, surgical complications and 1-year mortality were not different.

Conclusion

Advanced stage CKD treated with PFNA fixation is associated with lower functional outcomes at one year. Sepsis is more prone to occur after surgery in CKD stage 5.

Level of evidence

Level III; Retrospective cohort study.

Muscle Wasting in Chronic Kidney Disease: Mechanism and Clinical Implications—A Narrative Review

Muscle wasting, known to develop in patients with chronic kidney disease (CKD), is a deleterious consequence of numerous complications associated with deteriorated renal function. Muscle wasting in CKD mainly involves dysregulated muscle protein metabolism and impaired muscle cell regeneration. In this narrative review, we discuss the cardinal role of the insulin-like growth factor 1 and myostatin signaling pathways, which have been extensively investigated using animal and human studies, as well as the emerging concepts in microRNA- and gut microbiota-mediated regulation of muscle mass and myogenesis. To ameliorate muscle loss, therapeutic strategies, including nutritional support, exercise programs, pharmacological interventions, and physical modalities, are being increasingly developed based on advances in understanding its underlying pathophysiology.

The Role of Bone Muscle Ring Finger-1 (MuRF1), MuRF2, MuRF3, and Atrogin-1 on Microarchitecture In Vivo

Ubiquitin proteasome system was found to contribute to bone loss by regulating bone turnover and metabolism, by modulating osteoblast differentiation and bone formation as well as formation of osteoclasts that contribute to bone resorption. Muscle Ring Finger (MuRF) are novel ubiquitin ligases, which are muscle specific and have not been much implicated in the bone but have been implicated in several human diseases including heart failure and skeletal muscle atrophy. This study is aimed at understanding the role of MuRF1, MuRF2, MuRF3 and Atrogin which are distinct MuRF family proteins in bone homeostasis. Wildtype, heterozygous and homozygous mice of each of the isoforms were used and the bone microarchitecture and mechanical properties were assessed using microCT and biomechanics. MuRF1 depletion was found to alter cortical properties in both males and females, but only trabecular spacing in the females. MuRF2 depletion let to no changes in the cortical and trabecular properties but change in the strain to yield in the females. Depletion of MuRF3 led to decrease in the cortical properties in the females and increase in the trabecular properties in the males. Atrogin depletion was found to reduce cortical properties in both males and females, whereas some trabecular properties were found to be reduced in the females. Each muscle-specific ligase was found to alter the bone structure and mechanical properties in a distinct a sex-dependent manner.

"Sarcopenia and risk of osteoporosis, falls and bone fractures in patients with chronic kidney disease: A systematic review"

BACKGROUND

Chronic kidney disease [CKD] has been suggested to increase the risk of osteoporosis, sarcopenia, falls, and fractures. The aim of this systematic review was to explore the occurrence of osteoporosis, falls, and fractures in patients with sarcopenia and CKD, and to explore the possible association between sarcopenia and osteoporosis, falls, and fractures in patients with CKD.

METHODS

This systematic review was conducted according to the PRISMA guideline. The protocol was registered at PROSPERO. The systematic literature search was conducted in Pubmed [1966 to present] and EMBASE [1974 to present] on December 4, 2020. We searched for articles on CKD and sarcopenia, and then we selected them with outcomes such as osteoporosis, falls, and bone fractures. The risk of bias was assessed with the Newcastle-Ottawa Scale.

RESULTS

Five studies were eligible and included. No studies reported the occurrence of osteoporosis, falls, and bone fractures in patients with CKD and sarcopenia. Sarcopenia had a significant association with low bone mineral density [BMD] and osteoporosis in patients with CKD. The risk of bias assessed with the Newcastle-Ottawa Scale varied from 3-7 stars [median of 7]. Due to the included studies' heterogeneity, a meta-analysis could not be conducted.

CONCLUSION

The occurrence of osteoporosis, falls, and bone fractures in patients with sarcopenia and CKD could not be assessed from the included studies, but an association between sarcopenia and decreased BMD/osteoporosis in patients with CKD was found. The potential mechanistic link between sarcopenia and osteoporosis in CKD needs to be investigated in future studies.

Sarcopenia in Chronic Kidney Disease: A Scoping Review of Prevalence, Risk Factors, Association with Outcomes, and Treatment

Sarcopenia, a condition characterized by loss of skeletal muscle mass and function, has important clinical ramifications. We aimed to map the existing literature about prevalence, risk factors, associated adverse outcomes, and treatment of sarcopenia in individuals with chronic kidney disease (CKD). A scoping review of the literature was conducted to identify relevant articles published from databases' inception to September 2019. Individuals with CKD, regardless of their disease stage and their comorbidities, were included. Only studies with sarcopenia diagnosed using both muscle mass and function, based on published consensus definitions, were included. For studies on treatment, only randomized controlled trials with at least one sarcopenia parameter as an outcome were included. Our search yielded 1318 articles, of which 60 from were eligible for this review. The prevalence of sarcopenia ranged from 4 to 42% according to the definition used, population studied, and the disease stage. Several risk factors for sarcopenia were identified including age, male gender, low BMI, malnutrition, and high inflammatory status. Sarcopenia was found to be associated with several adverse outcomes, including disabilities, hospitalizations, and mortality. In CKD subjects, several therapeutic interventions have been assessed in randomized controlled trial with a muscle mass, strength, or function endpoint, however, studies focusing on sarcopenic CKD individuals are lacking. The key interventions in the prevention and treatment of sarcopenia in CKD seem to be aerobic and resistance exercises along with nutritional interventions. Whether these interventions are effective to treat sarcopenia and prevent clinical consequences in this population remains to be fully determined.

Current status of the assessment of sarcopenia, frailty, physical performance and functional status in chronic kidney disease patients

PURPOSE OF REVIEW

Low physical function, frailty, and sarcopenia are common complications of chronic kidney disease (CKD). In this article, we review the epidemiology and pathogenesis of low physical function, as well as its associations with adverse outcomes in CKD patients. Additionally, we present various traditional and novel methods for assessment of physical function in CKD patients.

RECENT FINDINGS

In nondialysis dependent (NDD) and dialysis-dependent CKD patients, the prevalence of low physical function, frailty, and sarcopenia are substantially higher than in the general population. The potential mechanisms of low physical function, frailty, and sarcopenia in CKD patients are due to various factors including underlying kidney disease, co-existing comorbidities, and certain therapeutic interventions utilized in CKD. Increasing evidence has also uncovered the ill effects of impaired physical function on clinical outcomes in CKD patients.

SUMMARY

Routine assessment of physical function is an under-utilized yet important component in the management of CKD patients. Future studies are needed to determine how prescription of exercise and increased daily physical activity can be tailored to optimize the health and well-being of NDD and dialysis-dependent CKD patients in pursuit of successful aging.

Fibroblast Growth Factor 23 and Klotho Are Associated With Trabecular Bone Score but Not Bone Mineral Density in the Early Stages of Chronic Kidney Disease: Results of the Cross-Sectional Study

This study evaluates bone mineral density (BMD) and trabecular bone score (TBS) in relationship with new markers of chronic kidney disease (CKD), fibroblast growth factor 23 (FGF23), and klotho. The patients in this cross-sectional study were divided as follows: group A -patients in stages G1-3; group B -patients in stages G4 - 5 according to KDIGO. Plasma levels of soluble klotho and FGF23 were determined by ELISA. Bone mineral density (BMD) and trabecular bone score (TBS) were measured. 74 patients with CKD (mean age 68.8 years) were included in the study. Higher levels of FGF23 were observed in group B (N=15) compared to group A (N=59; p=0.001) were observed. FGF23 was higher in group A compared to group B. Significant difference in TBS within the first 3 stages of CKD was observed (mean TBS in G1=1.375 vs. G2=1.340 vs. G3a=1.24; p<0.05) and negative correlation of FGF23 and TBS (R=-0.33; p=0.05) and positive correlation between klotho and TBS (R=0.419; p=0.04) was observed. This study confirmed that FGF23 and klotho are associated with TBS, but TBS reflects a decrease in kidney function only in the first 3 stages of CKD. Thus, FGF23 and klotho together with TBS are promising markers of early trabecular bone impairment in CKD.

Prognostic interplay of kidney function with sarcopenia, anemia, disability and cognitive impairment. The GLISTEN study

BACKGROUND

Interactions between chronic kidney disease (CKD) and several comorbidities may potentially affect prognosis of older hospitalized patients. This study aims at evaluating the prognostic interactions between estimated glomerular filtration rate (eGFR), anemia, sarcopenia, functional and cognitive dysfunction, and 3-year mortality among older patients discharged from acute care hospitals.

METHODS

Our series consisted of 504 older adults enrolled in a multicenter observational study carried out in twelve Acute Geriatric and Internal Medicine wards throughout Italy. CKD was defined as an eGFR< 60 ml/min/1.73 m². Anemia, Short Portable Status Mental Questionnaire (SPMSQ), Basic Activities of Daily Living (BADL), sarcopenia, and Charlson index were considered in the analysis. 3-year survival was investigated by Cox regression and prognostic interactions among study variables were assessed by survival tree analysis. Accuracy of different survival models was investigated by C-index.

RESULTS

eGFR < 30 mL/min/1.73 m², anemia, sarcopenia, SPMSQ ≥ 5, and impairment in 1 or more BADL were significantly associated with mortality. Survival tree analysis showed that patients with eGFR < 35.32 ml/min/1.73 m² and SPMSQ ≥ 5 had the highest risk of mortality [hazard ratio (HR): 5.49, 95%CI: 3.04-9.94] followed by those with eGFR < 35.32 ml/min/1.73 m², hemoglobin < 11.95 g/dL and SPMSQ < 5 (HR:3.65; 95%CI: 2.21-6.02) and those with eGFR 35.32-47.99 ml/min/1.73 m² and sarcopenia (HR:3.65; 95%CI: 1.99-6.69). Survival tree leaf node membership had good accuracy in predicting the study outcome (C-index: 0.73, 95%CI:0.70-0.76).

CONCLUSIONS

Interactions among study risk factors designed distinct risk profiles in older patients discharged from acute care hospitals, that may help identify patients needing targeted interventions and appropriate follow-up after discharge.

Relationship between chronic kidney disease and sarcopenia

Few studies have investigated the relationship between sarcopenia and mild to moderate renal decline. This study aimed to investigate the relationship between chronic kidney disease (CKD) and sarcopenia. In total, 123 patients hospitalized with CKD and 57 healthy volunteers who underwent physical examination during the same period (control group) were analyzed. Body compositions were measured by dual-energy X-ray absorptiometry, and the relative appendicular skeletal muscle index (RASMI) was calculated. Muscular strength was evaluated using hydraulic hand dynamometer. Walking speed within 6 m was measured for muscular function assessment. Single-photon emission computed tomography was performed to measure the glomerular filtration rate of CKD patients, who were then divided into CKD1 (55 patients in CKD stages 1 and 2) and CKD2 (68 patients in CKD stages 3-5). RASMI showed a downward trend with CKD progression (P = 0.001). Multivariate logistic regression analysis showed that age and CKD progression were independent risk factors for sarcopenia. The morbidity of sarcopenia was significantly greater in CKD patients than in healthy volunteers, and the degree of muscle loss was closely related to CKD progression.

Prevalence and Factors Associated with Sarcopenia in Patients on Maintenance Dialysis in Australia-A Single Centre, Cross-Sectional Study

Background: Sarcopenia is associated with significant morbidity and mortality in patients with chronic kidney disease. The prevalence of sarcopenia in the dialysis population varies from 4% to 63%. However, the prevalence and risk factors of sarcopenia in the Australian dialysis population remain uncertain. Aim: To study the prevalence of sarcopenia in patients on maintenance dialysis by using the European Working Group on Sarcopenia in Older People (EWGSOP) diagnostic criteria of sarcopenia and to identify associated risk factors. Methods: We evaluated adult patients on maintenance haemodialysis and peritoneal dialysis in this single-centre cross-sectional study in Australia. Patient’s clinical (age, gender, dialysis modality and diabetic status) and laboratory parameters (serum albumin, calcium, phosphate, 25-hydroxy-vitamin D and parathyroid hormone levels) were investigated. We employed bioimpedance spectroscopy, hand grip dynamometer and the timed up and go test (TUG) to evaluate muscle mass, strength and function, respectively. Results: We evaluated 39 dialysis patients with a median age of 69 years old. The prevalence of sarcopenia was 18%. Sarcopenia was associated with low serum albumin (p = 0.02) and low serum phosphate level (p = 0.04). Increasing age and female sex were potential risk factors for sarcopenia (p = 0.05 and 0.08, respectively). Low lean muscle mass, reduced hand grip strength and prolonged TUG were present in 23.1%, 41% and 40.5%, respectively, of the cohort. The hand grip test had good correlation with lean muscle evaluation and the TUG. Conclusions: Sarcopenia was prevalent in 18% of maintenance haemodialysis patients from an Australian single-centre cohort, with low serum albumin and phosphate as significant risk factors.

T-Score and Handgrip Strength Association for the Diagnosis of Osteosarcopenia: A Systematic Review and Meta-Analysis

BACKGROUND

Osteosarcopenia is a recently identified condition caused by the coexistence of osteoporosis and sarcopenia that affects the frail elderly population, leading to an increased risk of falls and fractures. Given the recent socio-economic interest associated with osteosarcopenia, the aim of this meta-analysis is to provide an overview of the factors potentially involved in its pathogenesis, assessing its population type, prevalence, and associated variables.

METHODS

A comprehensive systematic search for relevant studies, published from 2015 to 2020, was performed by using PubMed, EMBASE, and Cochrane databases. We analysed the variables of age, vitamin D, handgrip, and T-score in four different groups: healthy, osteopenic-osteoporotic, sarcopenic, and osteosarcopenic.

RESULTS

A total of 6504 patients from 16 studies were included in the final meta-analysis. The analysis of the individual variables reveals a statistically significant correlation between the handgrip test data and T-score (p < 0.001).

CONCLUSIONS

The correlation between T-score values and handgrip strength suggests a new potential parameter in the development of predictive models that could be used in clinical practice, highlighting its importance for the diagnosis of osteosarcopenia.

The renal patient seen by non-renal physicians: the kidney embedded in the 'milieu intérieur'

Chronic kidney disease is defined as a decrease in renal function or evidence of kidney injury for >3 months. This represents an oversimplification that may confuse physicians. Thus kidney function is equated to glomerular filtration rate, which represents one of multiple kidney functions. Some potentially more important renal functions are lost earlier, such as the production for the anti-ageing factor Klotho. Overall, these changes modify the emergent properties of the body, altering the relationships between different organs and systems, in a manner that is difficult to predict the response to interventions based on normal physiology concepts, as there is a novel steady state of interorgan relations. In this regard we now discuss the impact of CKD on heart failure; osteomuscular and joint pain and bone fragility and fractures; and osteosarcopaenia as seen by a cardiologist, a rheumatologist and a geriatrician.

Muscle-Bone Crosstalk in Chronic Kidney Disease: The Potential Modulatory Effects of Exercise

Chronic kidney disease (CKD) is a prevalent worldwide public burden that increasingly compromises overall health as the disease progresses. Two of the most negatively affected tissues are bone and skeletal muscle, with CKD negatively impacting their structure, function and activity, impairing the quality of life of these patients and contributing to morbidity and mortality. Whereas skeletal health in this population has conventionally been associated with bone and mineral disorders, sarcopenia has been observed to impact skeletal muscle health in CKD. Indeed, bone and muscle tissues are linked anatomically and physiologically, and together regulate functional and metabolic mechanisms. With the initial crosstalk between the skeleton and muscle proposed to explain bone formation through muscle contraction, it is now understood that this communication occurs through the interaction of myokines and osteokines, with the skeletal muscle secretome playing a pivotal role in the regulation of bone activity. Regular exercise has been reported to be beneficial to overall health. Also, the positive regulatory effect that exercise has been proposed to have on bone and muscle anatomical, functional, and metabolic activity has led to the proposal of regular physical exercise as a therapeutic strategy for muscle and bone-related disorders. The detection of bone- and muscle-derived cytokine secretion following physical exercise has strengthened the idea of a cross communication between these organs. Hence, this review presents an overview of the impact of CKD in bone and skeletal muscle, and narrates how these tissues intrinsically communicate with each other, with focus on the potential effect of exercise in the modulation of this intercommunication.

AGEs accumulation is related to muscle degeneration and vascular calcification in peritoneal dialysis patients

BACKGROUND

Patients with chronic kidney disease (CKD) are affected by dynapenia, sarcopenia, and vascular calcification. Advanced glycation end products (AGEs) may accumulate in peritoneal dialysis (PD) patients and favor sarcopenia via changes in collagen cross-linking, muscle protein breakdown, and the calcification of arterial smooth muscle cells via p38-MAPK activation. The aim of this study is to explore the relationships between AGEs, muscle degeneration, and coronary artery calcification.

METHODS

This was a clinical observational study in patients with CKD undergoing PD, in which serum and skin AGEs (AGEs-sAF), cumulative glucose load, muscle strength and functional tests, muscle ultrasounds with elastography, coronary artery calcium (CAC) quantification, and muscle density by multislice computed tomography were measured.

RESULTS

27 patients aged 48±16 years, dialysis vintage of 27±17 months, had AGEs-sAF levels of 3.09±0.65 AU (elevated in 13 [87%] patients), grip strength levels of 26.2±9.2 kg (11 [42%] patients with dynapenia), gait speed of 1.04±0.3 m/s (abnormal in 14 [58%] patients) and "timed-up-and-go test" (TUG) of 10.5±2.2s (abnormal in 7 [26%] patients). Correlations between AGEs-sAF levels and femoral rectus elastography (R=-0.74; p=0.02), anterior-tibialis elastography (R= -0.68; p=0.04) and CAC (R=0.64; p=0.04) were detected. Cumulative glucose load correlated with femoral rectal elastography (R=-0.6; p=0.02), and serum glycated hemoglobin concentrations correlated with psoas muscle density (R= -0.58; p=0.04) and CAC correlated with psoas muscle density (R=0.57; p=0.01) and lumbar square muscle density (R=-0.63; p=0.005).

CONCLUSIONS

The study revealed associations between AGEs accumulation and lower muscle stiffness/density. Associations that linked muscle degeneration parameters with vascular calcification were observed.

Association Between Gout and Injury Risk: A National Retrospective Cohort Study

The association between gout and injury remains unclear. This study aimed to investigate the injury risk in patients with gout. Using the Longitudinal Health Insurance Database (LHID) from 2000 to 2010 in Taiwan, patients with gout (group CFG) and those without gout (group C) were enrolled for further analysis. The CFG group was separated into two subgroups (with and without medication) to determine whether the risk of injury was reduced with drug intervention. The follow-up period was defined as the time from the initial diagnosis of gout to the date of injury. A total of 257,442 individuals were enrolled in this study, with 85,814 people in group CFG and 171,628 people in group C. Using Cox regression analysis, group CFG showed a significant increase in the risk of injury. Traffic injuries, poisoning, falls, crushing/cutting/piercing injury, and suicides were prominent among these injuries. Furthermore, when urate-lowing drugs were used to treat the CFG group, there were no significant differences in the occurrence of injury. Patients with gout had an increased risk of injury overall, and drug intervention did not lower the risk of injury in these patients.

Association of gait speed and grip strength with risk of cardiovascular events in patients on haemodialysis: a prospective study

Background

Gait speed (GS) and handgrip strength (HGS), both factors associated with frailty and sarcopenia, are reportedly associated with CV events in the general population. However, little is known about the impact of these factors on the outcome of patients on dialysis. This study aimed to evaluate whether evaluation of GS and HGS could be associated the onset of fatal/non-fatal cardiovascular (CV) events in patients on haemodialysis (HD).

Methods

One-hundred-eighty-two patients with end-stage renal disease (ESRD) undergoing HD at four dialysis clinics in April 2015 provided written informed consent to participate in the study. We excluded patients who had physical disability, were unable to walk without help, or had recently experienced CV events. Usual GS over a 4-m walk and HGS were measured at baseline, and 173 patients (men, 124; women, 49) were divided into sex-specific quartiles according to GS and HGS and were followed-up for fatal/non-fatal CV events for a median of 2 years. We examined the association of GS and HGS with CV events and determined cut-off values using Cox regression analysis adjusted for age, sex, HD duration, history of CVD, and diabetes.

Results

During the follow-up period, 46 CV events occurred. Both physical performance factors were significantly associated with CV events. Low GS (< 0.82 m/s for men and 0.81 m/s for women) and weak HGS (< 29.0 kg for men and 19.7 kg for women) were associated with CV events. For low vs. high GS, the hazard ratio (HR) for CV events was 2.29 [95% confidence interval (CI): 1.20–4.33; P = 0.01], and for low vs. high HGS, the HR was 2.15 [95% CI: 1.00–5.04; P < 0.05]. These HRs remained significant after adjusting for confounding factors, such as sex, age, dialysis vintage, history of CV disease, and diabetes.

Conclusions

Slow GS and weak HGS in patients on HD were suggested to be independent predictors of fatal/non-fatal CV events.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1370-6) contains supplementary material, which is available to authorized users.

Chronic kidney disease is associated with low BMD at the hip but not at the spine

Although chronic kidney disease is associated with other bone disorders, osteoporosis can be found in this context, and it is defined based on bone mineral density (BMD), measured by dual-energy X-ray absorptiometry. As CKD progresses, the percentage of normal BMD decreases, whereas that of osteopenia/osteoporosis increases, mostly due to hip involvement, particularly in patients with reduced renal function.

INTRODUCTION

Osteoporosis is a highly prevalent disease in patients with chronic kidney disease (CKD). We investigated the features of bone mineral density (BMD) in patients with assorted kidney diseases and hypothesized that low BMD, as measured by dual-energy X-ray absorptiometry (DXA), would be more prevalent as kidney function decreased and would correlate with biomarkers of mineral and bone disease.

METHODS

DXA obtained from January 1, 2008, to December 31, 2017, clinical, demographic, and biochemical data at the time of image acquisition were recorded. Data from 1172 patients were included in this study (81.3% women, 79.9% white, and 8.1% diabetic).

RESULTS

Osteopenia and osteoporosis in at least one site (total hip or spine) were found in 32.7% and 20.0% of patients, respectively. As CKD progressed, the percentage of patients with normal BMD decreased, whereas the percentage of osteopenia and osteoporosis increased, which was mostly due to the total hip involvement, particularly in patients with estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m². Older age and hyperparathyroidism were independent risk factors for osteopenia/osteoporosis at the total hip; female gender, older age, and higher iCa were independently associated with the risk of osteopenia/osteoporosis at the spine. With eGFR > 90 ml/min as reference, the odds ratios for osteoporosis/osteopenia at the hip were 1.51 (95% CI 1.01-2.24) and 1.91 (95% CI 1.13-3.20) for patients with eGFR 30-60 and 15-30 ml/min/1.73 m², respectively. No CKD stage was significantly associated with the risk of osteoporosis/osteopenia at the spine.

CONCLUSION

Our results highlighted that low BMD in patients with CKD is associated with age and hyperparathyroidism, and affects predominantly the hip.

Association of cystatin C- and creatinine-based eGFR with osteoporotic fracture in Japanese postmenopausal women with osteoporosis: sarcopenia as risk for fracture

Coexistence of chronic kidney disease (CKD) is regarded as a risk for osteoporotic fracture particularly in postmenopausal women, not only because of increased parathyroid hormone level but also uremic sarcopenia. We examined the relationships of cystatin C-based glomerular filtration rate (eGFRcys) and creatinine-based GFR (eGFRcr), as well as their ratio with occurrence of osteoporotic fracture in postmenopausal osteoporotic women. This cross-sectional study included 555 postmenopausal women with osteoporosis. eGFRcr and eGFRcys were simultaneously measured, while occurrence of osteoporotic fracture was obtained by a medical chart review. Patients with osteoporotic fractures (n = 211) exhibited significantly lower levels of physical activity, eGFRcr, eGFRcys, and eGFRcys/eGFRcr ratios, while a higher percentage was CKD stage 3 or more, estimated by eGFRcr or eGFRcys (CKDcys), than those without (n = 344). Lower eGFRcys, but not lower eGFRcr, was independently associated with osteoporotic fracture in the entire cohort and that association was retained in CKDcys patients. Of great interest, higher eGFRcr was associated with osteoporotic fracture independent of eGFRcys in CKDcys patients. Furthermore, lower eGFRcys/eGFRcr ratio was independently associated with osteoporotic fracture in both CKDcys patients and the entire cohort. eGFRcys reduction might be associated with osteoporotic fracture in postmenopausal osteoporotic women, indicating the involvement of renal osteopathy in its occurrence. Furthermore, the association of higher, but not lower, eGFRcr with osteoporotic fracture in CKDcys cases might be explained by underestimation of renal dysfunction by eGFRcr resulting from decreased muscle mass and quality in those patients.

Chronic kidney disease: considerations for monitoring skeletal muscle health and prescribing resistance exercise

Skeletal muscle wasting has gained interest as a primary consequence of chronic kidney disease (CKD) due to the relationship between skeletal muscle mass, mortality and major adverse cardiovascular events in this population. The combination of reductions in physical function, skeletal muscle performance and skeletal muscle mass places individuals with CKD at greater risk of sarcopenia. Therefore the monitoring of skeletal muscle composition and function may provide clinical insight into disease progression. Dual-energy X-ray absorptiometry and bioelectrical impedance analysis are frequently used to estimate body composition in people with CKD within clinical research environments, however, their translation into clinical practice has been limited. Proxy measures of skeletal muscle quality can be obtained using diagnostic ultrasound, providing a cost-effective and accessible imaging modality to aid further clinical research regarding changes in muscle composition. Clinicians and practitioners should evaluate the strengths and limitations of the available technology to determine which devices are most appropriate given their respective circumstances. Progressive resistance exercise has been shown to improve skeletal muscle hypertrophy of the lower extremities, muscular strength and health-related quality of life in end-stage renal disease, with limited evidence available in CKD predialysis. Fundamental principles (i.e. specificity, overload, variation, reversibility, individuality) can be used in the development of more advanced programs focused on improving specific neuromuscular and functional outcomes. Future research is needed to determine the applicability of skeletal muscle monitoring in clinical settings and the feasibility and efficacy of more advanced resistance exercise approaches in those with CKD predialysis.

Muscle wasting in chronic kidney disease

Loss of lean body mass is a relevant component of the cachexia, or protein energy wasting (PEW), syndrome. Reduced muscle mass seems to be the most solid criterion for the presence of cachexia/PEW in patients with chronic kidney disease (CKD), and those with greater muscle mass loss have a higher risk of death. Children with CKD have many risk factors for lean mass and muscle wasting, including poor appetite, inflammation, growth hormone resistance, and metabolic acidosis. Mortality risks in patients with CKD increases as body mass index (BMI) and weight decreases. However, data regarding cachexia/PEW and muscle wasting in children with CKD is scarce due to lack of consensus in diagnostic criteria and an appropriate investigative methodology. Further research is urgently needed to address this important complication in the pediatric CKD setting, which may have fundamental impact on clinical outcomes.

Long-Term Factors Associated With Falls and Fractures Poststroke

Background

Risk factors for poststroke falls and fractures remain poorly understood. This study aimed to evaluate which factors increased risk of these events after stroke.

Methods

Data from 7,267 hospitalized stroke patients were acquired from the Norfolk and Norwich University Hospital Stroke Register from 2003–2015. The impacts of multiple patient level and stroke characteristics and comorbidities on post-discharge falls and fractures were assessed. Univariate and multivariable models were constructed, adjusting for multiple confounders, using binary logistic regression for short-term analysis (up to 1-year post-discharge) and Cox-proportional hazard models for longer term analysis (1–3, 3–5, and 0–10 years follow-up).

Results

The mean age (SD) was 76.3 ± 12.1 years at baseline. 1,138 (15.7%) participants had an incident fall; and 666 (9.2%) an incident fracture during the 10-year follow-up (total person years = 64,447.99 for falls and 67,726.70 for fractures). Half of the sample population were females (50.6%) and the majority had an ischemic stroke (89.8%). After adjusting for confounders: age, sex, previous history of falls, and atrial fibrillation were associated with an increased risk of both falls and fractures during follow-up. Furthermore, chronic kidney disease and hyperlipidemia were associated with an increased risk of falls, while previous stroke/transient ischemic attack increased fracture risk. Total anterior circulation stroke and a prestroke modified Rankin Scale score of 3–5 were associated with decreased risk of both events, with hypertension and cancer decreasing risk of falls only.

Conclusion

We identified demographic, stroke-related, and comorbid factors associated with poststroke falls and fracture incidence. Further studies are required to examine and establish the relationship between reversible factors and further explore the role of preventative measures to prevent poststroke falls and fractures.

Loop diuretics are associated with greater risk of sarcopenia in patients with non-dialysis-dependent chronic kidney disease

Introduction

Sarcopenia, the age-related loss of muscle mass and function, frequently accompanies chronic kidney disease. The aim of this study was to clarify the prevalence and the risk factors for sarcopenia among patients with non-dialysis-dependent chronic kidney disease (NDD-CKD), focusing on the use of drugs.

Methods

We conducted a cross-sectional analysis on a cohort of 260 patients with NDD-CKD in a university hospital, recruited between June 2016 and March 2017. We extracted data on patient gender, age, cause of chronic kidney disease, use of drugs, and comorbidities that could potentially affect the prevalence of sarcopenia. Sarcopenia was diagnosed using the criteria of the Asian Working Group for Sarcopenia. Logistic regression analysis was performed to analyze the association of each factor on the prevalence of sarcopenia.

Results

25.0% of our study subjects had sarcopenia. Multivariable analysis revealed that an increased risk of sarcopenia was significantly associated with age, male gender, body mass index, diabetes mellitus, and loop diuretic use (odds ratio, 4.59: 95% confidence interval, 1.81–11.61: P-value 0.001).

Conclusions

In our cohort, the prevalence of sarcopenia in patients with NDD-CKD was high, and diuretics use, particularly loop diuretic use, was suggested to be a risk factor of sarcopenia. Although loop diuretics are commonly used in patients with CKD, careful consideration of the risk of sarcopenia may be necessary.

Physical Therapy Considerations for Chronic Kidney Disease and Secondary Sarcopenia

Chronic kidney disease (CKD) is a progressive condition that may negatively affect musculoskeletal health. These comorbidities may include malnutrition, osteoporosis, and decreased lean body mass. Secondary sarcopenia due to CKD may be associated with mobility limitations and elevated fall risk. Physical therapists are well-positioned among the health care team to screen for secondary sarcopenia in those with CKD and for the treatment of musculoskeletal comorbid conditions that may affect functional performance. Given the consequences of both low muscle mass and low bone mineral density, appropriate and timely physical therapy is important for fall risk assessment and intervention to minimize the susceptibility to bone fracture. While strength training has been studied less frequently than aerobic training for the management of secondary CKD conditions, evidence suggests that this patient population benefits from participation in strength training programs. However, the provision of a formal exercise prescription by a health care professional, along with formal implementation of an exercise program, may need to be more fully integrated into the standard plan of care for individuals with CKD.

Muscle Atrophy in Chronic Kidney Disease

The renal damage and loss of kidney function that characterize chronic kidney disease (CKD) cause several complex systemic alterations that affect muscular homeostasis, leading to loss of muscle mass and, ultimately, to muscle atrophy. CKD-induced muscle atrophy is highly prevalent and, in association with common CKD comorbidities, is responsible for the reduction of physical capacity, functional independence, and an increase in the number of hospitalizations and mortality rates. Thus, this chapter summarizes current knowledge about the complex interactions between CKD factors and the pathophysiological mechanisms that induce muscle atrophy that, despite growing interest, are not yet fully understood. The current treatments of CKD-induced muscle atrophy are multidisciplinary, including correction of metabolic acidosis, nutritional supplementation, reducing insulin resistance, administration of androgenic steroids, resisted and aerobic exercise, neuromuscular electrical stimulation, and inspiratory muscle training. However, further studies are still needed to strengthen the comprehension of CKD-induced muscle atrophy and the better treatment strategies.

Risk of falls in chronic kidney disease

Chronic Kidney Disease (CKD) is known to be an important risk factor for accidental, low-energy falls especially among elder individuals. The high incidence of falls is a major cause of morbidity and mortality with a substantial annual cost. Patients suffering from CKD are more prone to fall and develop fractures than the general population. Multiple risk factors have been identified and analyzed in order to explain this fact, such as drug combination, diabetes mellitus, orthostatic hypotension, vitamin D deficiency, sarcopenia and anemia, all very common in CKD. In this mini review of published evidence, we tried to search and present a complete aspect of the problem called 'Falls in Chronic Kidney Disease', focusing especially on the risk factors, discussing each one separately and its association with low- energy falls. Concluding, we discuss potential therapies and treatment goals based on the pathophysiology of CKD and accidental falls and propose new fields of investigation.

Clinical relevance of sarcopenia in chronic kidney disease

PURPOSE OF REVIEW

In this article, we review sarcopenia in chronic kidney disease (CKD). We aim to present how definitions of sarcopenia from the general population may pertain to those with CKD, its assessment by clinicians and emerging therapies for sarcopenia in CKD. For this review, we limit our description and recommendations to patients with CKD who are not on dialysis.

RECENT FINDINGS

Poorer parameters of lean mass, strength and physical function are associated with worsening patient-centered outcomes such as limiting mobility, falls and mortality in CKD; however, the magnitude of these associations are different in those with and without CKD. Sarcopenia in CKD is a balance between skeletal muscle regeneration and catabolism, which are both altered in the uremic environment. Multiple pathways are involved in these derangements, which are briefly reviewed. Differences between commonly used terms cachexia, frailty, protein-energy wasting, dynapenia and sarcopenia are described. Therapeutic options in predialysis CKD are not well studied; therefore, we review exercise options and emerging pharmacological therapies.

SUMMARY

Sarcopenia, now with its own International Classification of Diseases, 10th Revision (ICD-10) code, is of importance clinically and should be accounted for in research studies in patients with CKD. Multiple therapies for sarcopenia are in development and will hopefully be available for our patients in the future.

Modified Creatinine Index and the Risk of Bone Fracture in Patients Undergoing Hemodialysis: The Q-Cohort Study

BACKGROUND

Hemodialysis patients are at increased risk for bone fracture and sarcopenia. There is close interplay between skeletal muscle and bone. However, it is still unclear whether lower skeletal muscle mass increases the risk for bone fracture.

STUDY DESIGN

Cross-sectional study and prospective longitudinal cohort study.

SETTING & PARTICIPANTS

An independent cohort of 78 hemodialysis patients in the cross-sectional study and 3,030 prevalent patients undergoing maintenance hemodialysis prospectively followed up for 4 years.

PREDICTOR

Skeletal muscle mass measured by bioelectrical impedance analysis (BIA) and modified creatinine index, an estimate of skeletal muscle mass based on age, sex, Kt/V for urea, and serum creatinine level.

OUTCOMES

Bone fracture at any site.

RESULTS

In the cross-sectional study, modified creatinine index was significantly correlated with skeletal muscle mass measured by BIA. During a median follow-up of 3.9 years, 140 patients had bone fracture. When patients were divided into sex-specific quartiles based on modified creatinine index, risk for bone fracture estimated by a Fine-Gray proportional subdistribution hazards model with all-cause death as a competing risk was significantly higher in the lower modified creatinine index quartiles (Q1 and Q2) compared to the highest modified creatinine index quartile (Q4) as the reference value in both sexes (multivariable-adjusted HRs for men were 7.81 [95% CI, 2.63-23.26], 5.48 [95% CI, 2.08-14.40], 2.24 [95% CI, 0.72-7.00], and 1.00 [P for trend < 0.001], and for women were 4.44 [95% CI, 1.50-13.11], 2.33 [95% CI, 0.86-6.31], 1.96 [95% CI, 0.82-4.65], and 1.00 [P for trend = 0.007] for Q1, Q2, Q3, and Q4, respectively).

LIMITATIONS

One-time assessment of modified creatinine index; no data for residual kidney function and fracture sites and causes.

CONCLUSIONS

Modified creatinine index was correlated with skeletal muscle mass measured by BIA. Lower modified creatinine index was associated with increased risk for bone fracture in male and female hemodialysis patients.

Impact of Skeletal Muscle Mass on Long-Term Adverse Cardiovascular Outcomes in Patients With Chronic Kidney Disease

Sarcopenia, defined as skeletal muscle loss and dysfunction, is attracting considerable attention as a novel risk factor for cardiovascular events. Although the loss of skeletal muscle is common in chronic kidney disease (CKD) patients, the relation between sarcopenia and cardiovascular events in CKD patients is not well defined. Therefore, we aimed to investigate the relation between skeletal muscle mass and major adverse cardiovascular events (MACE) in CKD patients. We enrolled 266 asymptomatic CKD patients (median estimated glomerular filtration rate: 36.7 ml/min/1.73 m²). To evaluate skeletal muscle mass, we used the psoas muscle mass index (PMI) calculated from noncontrast computed tomography. The patients were divided into 2 groups according to the cut-off value of PMI for MACE. There were significant differences in age and body mass index between the low and high PMI groups (median age: 73.5 vs 69.0 years, p = 0.002; median body mass index: 22.6 vs 24.2 kg/m², p <0.001, respectively). During the follow-up period (median: 3.2 years), patients with low PMI had significantly higher risk of MACE than those with high PMI (31.7% and 11.2%, log-rank test, p <0.001). The Cox proportional hazard model showed that low PMI is an independent predictor of MACE in CKD patients (hazard ratio 3.98, 95% confidence interval 1.65 to 9.63, p = 0.0022). In conclusion, low skeletal muscle mass is an independent predictor of MACE in CKD patients. The assessment of skeletal muscle mass may be a valuable screening tool for predicting MACE in clinical practice.