Urinary Klotho Excretion: A Key Regulator of Sodium Homeostasis in Chronic Kidney Disease Stage 2-4.

BACKGROUND Soluble alpha-klotho (klotho) is considered an important regulator of mineral homeostasis in patients with chronic kidney disease (CKD). Since the mineral transport proteins are located on the apical membrane of renal tubular cells, we hypothesized that urine klotho may also be involved in their homeostasis. We aimed to investigate the associations between serum and urine klotho and their impacts on mineral homeostasis in patients with stage 2 to 4 CKD. MATERIAL AND METHODS Serum, spot urine, and 24-h urine of klotho were measured by using enzyme-linked immunosorbent assay. Fractional excretion of sodium, potassium, calcium, phosphate, magnesium, and klotho were calculated. RESULTS A total of 53 patients with CKD stages 2 to 4 were enrolled in this cross-sectional study. The mean age was 71.1±10.5 years, and 68% were men. Linear regression analysis showed that serum log-transformed klotho was negatively associated with log-transformed fractional excretion of klotho (log-FEKlotho) (ß=-0.085, P=0.02), showing that urinary klotho excretion could negatively regulate serum klotho levels. Moreover, our multivariate stepwise regression showed log-fractional excretion of sodium was positively associated with log-FEKlotho (ß=0.138, P=0.032). This implied urinary klotho excretion positively regulated urinary sodium excretion. CONCLUSIONS Our study showed that urine klotho excretion resulted in decreased serum klotho levels and enhanced urinary sodium excretion in patients with CKD stages 2 to 4. In addition to serum klotho, we found, for the first time, that urine klotho also played a significant role in sodium homeostasis.

A New Predictive Equation for Estimating Serum Ionized Calcium Levels in Patients on Chronic Hemodialysis.

BACKGROUND Circulating calcium mainly carries out its physiologic function in its ionized form (iCa). Clinically, iCa is usually estimated by multiplying the total calcium (TCa) level by 0.5 in the general population, but this method is not accurate when applied to patients on long-term hemodialysis (CHD). Accordingly, this study aimed to develop a predictive function for iCa in patients on CHD by incorporating TCa and other additional variables. MATERIAL AND METHODS This was a retrospective cross-sectional study consisting of 2 cross-sectional datasets: a derivation set including 469 CHD patients in June 2019, and a validation set including 446 CHD patients in September 2019. The derivation set's data were analyzed using the stepwise model selection of machine learning with 10-fold cross-validation to develop a predictive function for iCa. This predictive function was then applied to the validation set's data, and the predictive function's estimated iCa was compared with the actual laboratory iCa by using the paired-samples t test and intraclass correlation coefficient. RESULTS After analyzing the routine laboratory data parameters of patients in the derivation set, the following 5 variables were included in the predictive function of iCa: blood urea nitrogen, creatinine, phosphate, TCa, and albumin. This predictive function was applied to the validation set to yield an estimated iCa level that was not significantly different from the laboratory-measured iCa level of the validation dataset (P=0.676) with an excellent ICC of 0.905. CONCLUSIONS We developed a new predictive function that accurately measures the iCa in patients on CHD by using routine laboratory data.

Phosphate burden induces vascular calcification through a NLRP3-caspase-1-mediated pyroptotic pathway.

AIMS: The aim of this study is to clarify the role of NLRP3 inflammasome in phosphate burden-induced vascular smooth muscle cell (VSMC) calcification. MAIN METHODS: VSMC calcification was induced using a high concentration of inorganic phosphate. After pharmacological inhibition or genetic silencing of the NLRP3 inflammasome, pyroptosis, or potassium efflux, the cells were examined by RT-qPCR, immunofluorescence, and western blotting to identify the NLRP3-mediated pathway for VSMC calcification. KEY FINDINGS: Calcified VSMCs with α-smooth muscle actin (α-SMA) disarray presented features of pyroptosis, including caspase-1 maturation, cleaved gasdermin D (GSDMD), and a high supernatant level of lactate dehydrogenase A. Pharmacological inhibitions of caspase-1 and pyroptosis attenuated VSMC calcification, whereas interleukin-1ß receptor antagonism did not. Unlike canonical NLRP3 activation, osteogenic VSMCs did not upregulate NLRP3 expression. However, NLRP3 genetic silencing or inhibitions, which targets different domains of the NLRP3 protein, could ameliorate VSMC calcification by aborting caspase-1 and GSDMD activation. Furthermore, potassium efflux through the inward-rectifier potassium channel, and not through the P2X7 receptor, triggered NLRP3 inflammasome activation and VSMC calcification. SIGNIFICANCE: In the present study, we identified a potassium efflux-triggered NLRP3-caspase-1-mediated pyroptotic pathway for VSMC calcification that is unique and different from the canonical NLRP3 inflammasome activation. Therefore, targeting this pathway may serve as a novel therapeutic strategy for vascular calcification.

Impact of Pre-Transplant Parathyroidectomy on Graft Survival: A Comparative Study of Renal Transplant Patients (2005-2015).

BACKGROUND Hyperparathyroidism poses significant risks for patients prior to kidney transplantation. However, the outcomes of patients who undergo parathyroidectomy before renal transplantation compared to those without such a procedure remain uncertain. This real-world data study aimed to examine the clinical outcomes of both patient groups. MATERIAL AND METHODS Using the Taiwan National Health Insurance Research Database, we conducted a retrospective cohort study on patients who underwent renal transplantation between January 2005 and December 2015. The patients were divided into two groups: a case group (n=294) with parathyroidectomy and a control group (n=588) without the need for parathyroidectomy before kidney transplantation. The groups were matched based on age, sex, dialysis vintage, and baseline characteristics at a 1:2 ratio. Hazard ratios (HR) were estimated using the Cox regression model. The main outcomes assessed were graft failure, mortality, and major adverse cardiovascular events (MACE) recorded until December 2019. RESULTS During a mean follow-up period of 6 years, a significant difference was observed in graft failure (HR 1.40; 95% confidence interval 1.10-1.79, p=0.007) between the two groups. After further adjustment, graft failure remained significant (HR 1.52; 95% CI 1.07-2.15, p=0.019). Additionally, machine learning-based feature selection identified the importance of parathyroidectomy (ranked 9 out of 11) before kidney transplantation in predicting subsequent graft failure. CONCLUSIONS Our study demonstrates that severe hyperparathyroidism requiring parathyroidectomy before kidney transplantation may contribute to poor post-transplant graft outcomes compared to patients who do not require parathyroidectomy.

Protective Effect of BCG and Neutrophil-to-Lymphocyte Ratio on Latent Tuberculosis in End Stage Renal Disease.

INTRODUCTION: Bacillus Calmette-Guérin (BCG) vaccination has been reported to be protective against latent tuberculosis infection (LTBI) in the general population. The aim of this study was to investigate the protective effect of BCG vaccination against LTBI in adult patients with end-stage renal disease (ESRD) and renal transplants. METHODS: Patients aged ≥ 20 years with ESRD who received hemodialysis (HD), peritoneal dialysis (PD) or kidney transplant were enrolled from January 2012 to December 2019 at a medical center and a regional hemodialysis center. Patients with active tuberculosis (TB), previously treated TB, active immunosuppressant therapy or human immunodeficiency virus infection were excluded. LTBI status was determined by QuantiFERON-TB Gold In-tube (QFT-GIT). RESULTS: After the exclusion of indeterminate results of QFT-GIT, 517 participants were enrolled and 97 (18.8%) were identified as having LTBI. Participants with LTBI were older (55.1 ± 11.4 vs. 48.5 ± 14.6 years, p < 0.001) and had a significantly higher proportion receiving HD than those without LTBI (70.1% vs. 56.7%, p = 0.001). The percentage with BCG scars was higher in the non-LTBI group than in the LTBI group (94.8% vs. 81.4%, p < 0.001), whereas the neutrophil-to-lymphocyte ratio (NLR) (≥ 2.68) was significantly higher in the LTBI group (62.8% vs. 45.5%, p = 0.02). By multivariate logistic regression analysis, presence of BCG scar and high NLR were independent protective factors against LTBI [adjusted OR: 0.19 (0.063-0.58, p = 0.001) and 0.50 (0.28-0.89, p = 0.02)]. CONCLUSION: The prevalence of LTBI was as high as 18.8% in patients with end-stage kidney disease or kidney transplant. BCG vaccination and high NLR might have protective effects against LTBI in patients with renal failure or transplant.

Evaluation of the Impact of Remote Monitoring Using the Sharesource Connectivity Platform on Adherence to Automated Peritoneal Dialysis in 51 Patients.

BACKGROUND This study from a single center in Taiwan aimed to evaluate the impact of remote patient monitoring (RPM) using the Sharesource connectivity platform on adherence to automated peritoneal dialysis (APD) in 51 patients. MATERIAL AND METHODS We analyzed data on 51 patients with end-stage renal disease (ESRD) under APD. They were treated with a traditional APD machine HomeChoice (phase 1), changed to new APD machine HomeChoice Claria for 12 weeks (phase 2), then connected to the Sharesource platform for another 12 weeks (phase 3), and were followed up for 1 year. The non-adherence rate was compared between the 3 phases. The secondary outcomes included peritonitis rate, hospitalization rate, and hospitalization days, 1 year before and after receiving a new APD machine. Patients were subdivided into good and poor adherence (>1 episode of non-adherence in phase 1) groups for further analysis. RESULTS The average non-adherence rates were 10.5%, 5.1%, and 4.9% in phases 1, 2, and 3, respectively, although differences were not significant. Serum potassium (P<0.0001) and C-reactive protein (CRP) (P=0.026) levels significantly decreased in phase 3. The 1-year peritonitis rate, hospitalization rate, and number of days of hospitalization showed no significant changes. Subgroup analysis revealed that the non-adherence rate in the poor adherence group decreased from 48.4% in phase 1 to 14.2% and 12.4% in phases 2 and 3, respectively (P=0.007). CONCLUSIONS Remoting monitoring using the Sharesource connectivity platform increased dialysis adherence in APD treatment, especially in patients with poor adherence. Serum potassium level and inflammation status were also improved by this system.

High intact fibroblast growth factor 23 levels associated with low hemoglobin levels in patients on chronic hemodialysis.

Introduction: A negative association between C-terminal fibroblast growth factor 23 (cFGF23) and hemoglobin (Hb) levels has been reported in patients with predialysis chronic kidney disease. In dialysis patients, the dominant form of serum FGF23 is intact FGF23 (iFGF23); however, its association with the Hb level remains unclear. Therefore, simultaneously monitoring iFGF23 and cFGF23 levels is crucial. In this study, we investigated the associations between both forms of FGF23 (iFGF23 and cFGF23) and renal anemia in chronic hemodialysis (CHD) patients. Methods: We included 166 CHD patients from two hospitals in this cross-sectional, observational study. The primary predictors were serum iFGF23, cFGF23, and iFGF23/cFGF23 levels. The main outcome was the Hb level. Results: Among the CHD patients included, 60.8% were men with a mean age of 59.4 ± 12.7 years. In the crude analysis, iFGF23 and iFGF23/cFGF23 levels showed a significant negative association (-0.27, p = 0.004 and -0.22, p = 0.034, respectively) with the Hb level. Even after adjusting for multiple variables (a parsimonious model), every increment of natural log transformation by 1 for (ln)iFGF23 and ln(iFGF23/cFGF23) levels showed a negative correlation with the Hb level (estimate: -0.27 [95%CI: -0.44, -0.10, p = 0.001]; -0.19 [95%CI: -0.37, -0.01, p = 0.042], respectively), whereas both were positively associated with erythropoietin-stimulating agent (ESA) hyporesponsiveness (odds ratio [OR]: [95%CI: 2.30, 1.26-4.17], p = 0.006; 1.95 [95%CI: 1.08-3.50], p = 0.025). Moreover, these abovementioned associations were more dominant in patients with diabetes who used angiotensin receptor blockers. Discussion: In conclusion, a negative association between serum iFGF23 or iFGF23/cFGF23 level and the Hb level was observed in our CHD patients. Meanwhile, a higher iFGF23 or iFGF23/cFGF23 level may predispose patients to ESA hyporesponsiveness.

All-Cause Standardized Mortality Ratio in Hemodialysis and Peritoneal Dialysis Patients: A Nationwide Population-Based Cohort Study.

Patients with end-stage renal disease (ESRD) are at a higher mortality risk compared with the general population. Previous studies have described a relationship between mortality and patients with ESRD, but the data on standardized mortality ratio (SMR) corresponding to different causes of death in patients undergoing hemodialysis (HD) and peritoneal dialysis (PD) are limited. This study was designed as a nationwide population-based retrospective cohort study. Incident dialysis patients between January 2000 and December 2015 in Taiwan were included. Using data acquired from the Taiwan Death Registry, SMR values were calculated and compared with the overall survival. The results showed there were a total of 128,966 patients enrolled, including 117,376 incident HD patients and 11,590 incident PD patients. It was found that 75,297 patients (58.4%) died during the period of 2000-2017. The overall SMR was 5.21. The neoplasms SMR was 2.11; the endocrine, nutritional, metabolic, and immunity disorders SMR was 13.53; the circulatory system SMR was 4.31; the respiratory system SMR was 2.59; the digestive system SMR was 6.1; and the genitourinary system SMR was 27.22. Therefore, more attention should be paid to these diseases in clinical care.

Serum Intact Fibroblast Growth Factor 23 Levels Are Negatively Associated with Bone Mineral Density in Chronic Hemodialysis Patients.

(1) Background: Fibroblast growth factor 23 (FGF23) is predominantly secreted from bone and plays an important role in mineral balance in chronic kidney disease. However, the relationship between FGF23 and bone mineral density (BMD) in chronic hemodialysis (CHD) patients remains unclear. (2) Methods: This was a cross-sectional observational study that involved 43 stable outpatients on CHD. A linear regression model was used to determine risk factors for BMD. Measurements included serum hemoglobin, intact FGF23 (iFGF23), C-terminal FGF23 (cFGF23), sclerostin, Dickkopf-1, α-klotho, 1,25-hydroxyvitamin D, intact parathyroid hormone levels and dialysis profiles. (3) Results: Study participants had a mean age of 59.4 ± 12.3 years, and 65% were male. In the multivariable analysis, cFGF23 levels showed no significant associations with the BMD of the lumbar spine (p = 0.387) nor that of the femoral head (p = 0.430). However, iFGF23 levels showed a significant negative association with the BMD of the lumbar spine (p = 0.015) and that of the femoral neck (p = 0.037). (4) Conclusions: Among patients on CHD, higher serum iFGF23 levels, but not serum cFGF23 levels, were associated with lower BMD values of the lumbar spine and femoral neck. However, further research is required to validate our findings.

Electrochemical Skin Conductance by Sudoscan in Non-Dialysis Chronic Kidney Disease Patients.

BACKGROUND: Peripheral neuropathy is prevalent among patients with chronic kidney disease (CKD). Sudoscan non-invasively detects polyneuropathy by measuring electrochemical skin conductance (ESC). We conducted a study on sudomotor function in CKD patients across various stages based on their estimated glomerular filtration rate (eGFR). METHODS: In this cross-sectional study of 700 CKD patients, all underwent Sudoscan. Pathological ESC was defined as hands < 40 µS or feet < 50 µS. Clinical neuropathy scores including Michigan Neuropathy Screening Instrument (MNSI) and Douleur Neuropathique en 4 questionnaire (DN4) were obtained. RESULTS: Among participants, 344 had diabetes and 356 did not. Hands and feet ESC decreased with CKD progression (median (IQR) in stage 1-2, 3, 4-5: 54.0 (39.0-68.0), 45.5 (30.0-63.0), 41.8 (26.5-60.5), p trend < 0.001; 64.5 (53.5-74.0), 60.5 (43.0-72.5), 55.0 (39.0-69.8), p trend < 0.001). Pathological hands and feet ESC increased in later CKD stages (stage 1-2, 3, 4-5: 26.6%, 40.9%, 45.7%, p trend < 0.001; 21.7%, 34.0%, 40.6%, p trend < 0.001). Positive hands and feet ESC-eGFR correlation existed irrespective of diabetes. Diabetic patients had lower hands and feet ESC than non-diabetics as CKD progressed. However, multivariate regression found no significant ESC-eGFR association. Sudoscan correlated with clinical neuropathy scores. CONCLUSION: Pathological sudomotor function was common in non-dialysis CKD stages 4-5. Diabetic patients had worse function. Sudomotor dysfunction progressed with renal disease but eGFR was not an independent risk factor.

The use of a low-flux hemo-dialyzer is associated with impaired platelet aggregation in patients undergoing chronic hemodialysis.

In patients with chronic hemodialysis (HD), both abnormal thrombotic and bleeding events are commonly observed. Uremic platelet dysfunction is one of the important attributing factors. Moreover, HD may also result in aggregation dysfunction of platelets during the therapeutic procedure. However, how the HD process affects platelet and coagulation function is unknown and dialyzer membrane flux could have an impact on it. We aimed to compare the impacts of low-flux and high-flux HD on the platelet function of patients undergoing chronic HD. This was a cross-sectional study conducted in the HD unit of E-Da hospital in Taiwan. A total of 78 patients with maintenance HD three times per week for more than one year, including 40 with high- and 38 with low-flux hemodialysis, were recruited. Their platelet functions were evaluated using an in vitro platelet function analyzer (PFA-100) before and after the HD session. Of the 78 patients undergoing HD, 60 (76%) had prolonged pre-dialysis collagen/epinephrine (CEPI) and collagen/adenosine diphosphate closure times. Those receiving low-flux dialyzer had a significant increase in CEPI closure time (pre-dialysis 212.3 ±â€…62.1 seconds. post-dialysis 241.5 ±â€…64.3 seconds, P = .01), but not collagen/adenosine diphosphate closure time, after HD. After adjusting confounding factors, only the low-flux dialyzer demonstrated an independent association with the prolonged CEPI closure time after HD therapy (odds ratio = 23.31, 95% CI: 1.94-280.61, P = .01). We observed that impaired platelet aggregation is prevalent in patients undergoing chronic HD. Therefore, the use of low-flux dialyzers may further worsen platelet aggregation after dialysis. Patients with uremic bleeding diathesis should take precautions. We suggest that further studies using flow cytometry should be conducted to explore the mechanism of dialysis flux and platelet activity during HD.

Antibody Response and Adverse Events of AZD1222 COVID-19 Vaccination in Patients Undergoing Dialysis: A Prospective Cohort Study.

This study observed the antibody response and adverse events of AZD1222 (Oxford/AstraZeneca) vaccination in dialysis patients. A prospective cohort study was conducted in E-Da Healthcare Group hospitals between 1 July and 30 November 2021. Patients receiving hemodialysis (HD, n = 204) or peritoneal dialysis (PD, n = 116) were enrolled alongside healthy subjects (control, n = 34). Anti-SARS-CoV-2 S1 RBD IgG antibodies were measured before the first vaccination (T0), four to six weeks afterwards (T1), one week before the second dose (T2), and four to six weeks afterwards (T3). Adverse events were recorded one week after each dose. The positive IgG rates in the HD (T1: 72%; T2: 62%) and PD (T1: 69%; T2: 70%) groups were lower than the control group (T1: 97%; T2: 91%), with lower median antibody titers. At T3, the positive antibody response rates (HD: 94%; PD: 93%; control: 100%) and titers were similar. Titers were higher after the second dose in all groups. Adverse events were more severe after the first dose and less common with HD than PD or controls. Dialysis patients exhibited lower antibody responses than controls after the first dose of the AZD1222 vaccine but achieved similar responses after consecutive vaccination. Age, health status, two vaccine doses, and alcohol consumption may influence antibody levels.

Corrigendum: The Protective Effects of Lipid-Lowering Agents on Cardiovascular Disease and Mortality in Maintenance Dialysis Patients: Propensity Score Analysis of a Population-Based Cohort Study.

[This corrects the article DOI: 10.3389/fphar.2019.00079.].

Serum osteocalcin concentration as an independent biomarker of osteoporosis in patients with chronic kidney disease.

OBJECTIVES: Osteocalcin, an osteoblast-derived hormone, is associated with the development of osteoporosis and arteriosclerosis in the general population. However, its role on the pathogenesis of osteoporosis and vascular calcification in patients with chronic kidney disease (CKD) is unclear. Here, we investigated the connection between osteocalcin, bone mineral density (BMD), and abdominal aortic calcification (AAC) in CKD patients. MATERIALS AND METHODS: In total, 95 patients with stage 2 to stage 5 CKD were enrolled. Serum osteocalcin levels were measured using an electrochemiluminescence immunoassay. BMD was determined by dual-energy X-ray absorptiometry, and AAC scores were generated from lateral lumbar radiograph findings. RESULTS: 95 patients were assigned into normal bone density (30.5%, n = 29), osteopenia (45.3%, n = 43), and osteoporosis (24.2%, n = 23) groups. The osteoporosis group was characterized by older age, higher female-to-male ratio, phosphorous levels, calcification scores, osteocalcin levels, and intact parathyroid hormone (PTH) levels, while with lower hemoglobin levels as compared to normal and osteopenia groups. Multivariate multinominal regression analysis showed age, female sex, intact PTH, and serum osteocalcin level were independent determinants of osteoporosis severity in CKD patients. Furthermore, serum osteocalcin level is positively correlated to intact PTH in multivariate linear regression model, indicating that osteocalcin might be a bone turnover marker in patients with CKD. Multivariate stepwise linear regression analysis revealed that age, diabetes mellitus, poorer renal function, rather than osteocalcin, have independent associations with AAC score. CONCLUSION: Elevated serum osteocalcin levels could be considered as a marker of osteoporosis rather than that of vascular calcification in patients with CKD.

Hazardous Effect of Low-Dose Aspirin in Patients with Predialysis Advanced Chronic Kidney Disease Assessed by Machine Learning Method Feature Selection.

Background: Low-dose aspirin (100 mg) is widely used in preventing cardiovascular disease in chronic kidney disease (CKD) because its benefits outweighs the harm, however, its effect on clinical outcomes in patients with predialysis advanced CKD is still unclear. This study aimed to assess the effect of aspirin use on clinical outcomes in such group. Methods: Patients were selected from a nationwide diabetes database from January 2009 to June 2017, and divided into two groups, a case group with aspirin use (n = 3021) and a control group without aspirin use (n = 9063), by propensity score matching with a 1:3 ratio. The Cox regression model was used to estimate the hazard ratio (HR). Moreover, machine learning method feature selection was used to assess the importance of parameters in the clinical outcomes. Results: In a mean follow-up of 1.54 years, aspirin use was associated with higher risk for entering dialysis (HR, 1.15 [95%CI, 1.10-1.21]) and death before entering dialysis (1.46 [1.25-1.71]), which were also supported by feature selection. The renal effect of aspirin use was consistent across patient subgroups. Nonusers and aspirin users did not show a significant difference, except for gastrointestinal bleeding (1.05 [0.96-1.15]), intracranial hemorrhage events (1.23 [0.98-1.55]), or ischemic stroke (1.15 [0.98-1.55]). Conclusions: Patients with predialysis advanced CKD and anemia who received aspirin exhibited higher risk of entering dialysis and death before entering dialysis by 15% and 46%, respectively.

Association between ADAMTS13 deficiency and cardiovascular events in chronic hemodialysis patients.

A mild decrease of ADAMTS13 (a disintegrin and metalloprotease with thrombospodin type 1 motif 13) could attribute to stroke and coronary heart disease in general population. However, the role of ADAMTS13 in hemodialysis (HD) patients remains to be explored. This cross-sectional and observational cohort study enrolled 98 chronic HD patients and 100 normal subjects with the aims to compare the ADAMTS13 activity between chronic HD patients and normal subjects, and to discover the role of ADAMTS13 on the newly developed cardiovascular events for HD patients in a 2-year follow-up. Our HD patients had a significantly lower ADAMTS13 activity than normal subjects, 41.0 ± 22.8% versus 102.3 ± 17.7%, p < 0.001. ADAMTS13 activity was positively correlated with diabetes, triglyceride and hemoglobin A1c, and negatively with high-density lipoprotein cholesterol levels in HD patients. With a follow-up of 20.3 ± 7.3 months, the Cox proportional hazards model revealed that low ADAMTS13, comorbid diabetes, and coronary heart diseases have independent correlations with the development of cardiovascular events. Our study demonstrated that chronic HD patients have a markedly decreased ADAMTS13 activity than normal subjects. Although ADAMTS13 seems to correlate well with diabetes, high triglyceride and low high-density lipoprotein cholesterol levels, ADAMTS13 deficiency still carries an independent risk for cardiovascular events in chronic HD patients.

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

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

Effects of ketoanalogues on skeletal muscle mass in patients with advanced chronic kidney disease: real-world evidence.

OBJECTIVE: Ketoanalogue (KA) supplementation in patients with chronic kidney disease (CKD) on a restricted protein diet has been shown to maintain their nutritional status in clinical trials. However, a gap existed between the findings of the clinical trials and the real-world practice. The aim of this prospective observational study was to evaluate the KA effect on skeletal muscle mass in patients with stage 4-5 CKD. METHODS: Among 170 patients with CKD screened, 148 were recruited. Patients were defined as KA or non-KA users. During a 12-mo follow-up, skeletal muscle and body fat mass were measured via bioelectrical impedance analysis at baseline, 6 mo (n = 108), and 12 mo (n = 85). RESULTS: Among the patients (mean age, 66.5 ± 12.9 y), KA users tended to maintain skeletal muscle and body fat mass, whereas non-KA users had a significantly reduced muscle mass (P = 0.011) and body fat gain (P = 0.004). Stratified by median age, in patients ≥68 y of age, non-KA users yielded the most significant muscle mass reduction and fat mass gain, whereas KA users revealed no changes in skeletal muscle and fat mass. CONCLUSION: In real-world practice, we concluded that KA supplementation favorably prevents skeletal muscle mass loss and fat mass gain in elderly patients with stage 4-5 CKD.

The Association of Urinary Sclerostin and Renal Magnesium Handling in Type 2 Diabetic Patients with Chronic Kidney Disease.

INTRODUCTION: Sclerostin could enhance renal excretion of calcium (Ca) and phosphate (P). The association between sclerostin and magnesium (Mg) has not yet discovered. In patients with type 2 diabetes mellitus (T2DM) or chronic kidney disease (CKD), higher serum sclerostin and altered renal excretion of Ca, P, and Mg were detected. Therefore, we tried to evaluate if there was any association between sclerostin and fractional excretion of Ca, P, and Mg (FeCa, FeP, and FeMg) in T2DM with CKD. METHODS: In this prospective cohort study, 43 T2DM patients without CKD or with CKD stage 1-5 were enrolled. Values of parameters, including serum and urine sclerostin, were collected at baseline and 6 months later. For baseline data, the Mann-Whitney U test, χ2 test, or Spearman's correlation were used. For multivariate repeated measurement analysis, generalized estimating equation (GEE) model was utilized. RESULTS: Patients with lower estimated glomerular filtration rate had higher serum sclerostin, FeP, FeMg, and lower FeCa. By correlation analysis, serum sclerostin was negatively associated with FeCa (p = 0.02) and positively associated with FeP (p = 0.002). The urine sclerostin to creatinine ratio (Uscl/Ucre) was positively correlated with FeP (p = 0.007) and FeMg (p = 0.005). After multivariate analyses by GEE model, serum sclerostin was still inversely associated with FeCa, while Uscl/Ucre was significantly associated with FeMg. On the other hand, FeP lost its associations with serum sclerostin or Uscl/Ucre. CONCLUSION: In our study population of T2DM patients with or without CKD, the inverse correlation between serum sclerostin and FeCa could not be explained by the calciuric effect of sclerostin. In addition, a newly discovered positive association between urinary sclerostin and FeMg indicated a possible role of urinary sclerostin in regulating renal Mg handling especially over distal convoluted tubules.

Inverted U-Curve Association between Serum Indoxyl Sulfate Levels and Cardiovascular Events in Patients on Chronic Hemodialysis.

BACKGROUND: Protein-bound uremic toxins are associated with cardiovascular disease and mortality in patients with chronic kidney disease. We investigated their association with clinical outcomes in patients undergoing chronic hemodialysis (CHD). METHODS: A prospective cohort study was conducted on 86 Taiwanese patients undergoing CHD. The predictors were indoxyl sulfate and p-cresyl sulfate concentrations, with each analyzed as three tertiles. Outcomes were cardiovascular events and all-cause mortality. RESULTS: During a 25-month follow up period, there were 23 cardiovascular events and seven all-cause mortality events. In the crude survival analysis, the second indoxyl sulfate tertile was shown to be a powerful predictor of cardiovascular events compared with the third tertile (hazard ratio (HR), 3.14; 95% confidence interval (CI), 1.10-8.94), and the first tertile was shown to have a poor but insignificant cardiovascular outcome (HR, 1.09; 95% CI, 0.30-4.00). Moreover, the predictive power of the second indoxyl sulfate tertile for cardiovascular events remained after adjustment for confounders (HR, 5.42; 95% CI, 1.67-17.60). CONCLUSIONS: An inverse U-curve relationship was observed between the total serum indoxyl sulfate level and cardiovascular events in our CHD patients. A large-scale study is needed to confirm this relationship.