Respiratory sarcopenia screening in dialysis patients: cross-sectional and multicentre study protocol

BACKGROUND

Respiratory sarcopenia is characterized by the weakness of respiratory muscles associated with sarcopenia due to aging or systemic diseases such as chronic kidney disease (CKD). Patients with CKD undergoing dialysis are particularly susceptible to respiratory muscle weakness caused by factors such as fluid overload and electrolyte imbalance. This weakness not only affects ventilation but also impairs oxygen uptake and delivery to muscle tissue, potentially leading to severe sarcopenia. Thus, the objective of this study is to conduct a respiratory sarcopenia screening in patients with CKD undergoing haemodialysis (HD) and peritoneal dialysis (PD).

METHODS

This is an observational, cross-sectional and multicentre study conducted between March 2023 and March 2025. The study was approved by the Research Ethics Committee at two centres. Sarcopenia diagnosis is determined based on low handgrip strength and amount of appendicular skeletal muscle mass, assessed through bioelectrical impedance analysis. Respiratory sarcopenia is diagnosed in patients with sarcopenia who have low inspiratory muscle strength, evaluated through a manovacuometry test. The severity of sarcopenia and respiratory sarcopenia is defined, respectively, by low physical performance (measured using the Short Physical Performance Battery and Timed-Up and Go test) and pulmonary performance (measured through spirometry). Thus, this study will include 81 patients undergoing dialysis (41 on HD and 40 on PD) from three participating centres.

DISCUSSION

The literature has been focused on respiratory function in CKD; however, the relationship with sarcopenia remains understudied. We believe that, similar to appendicular skeleton muscles, the axial skeleton muscles are also likely to weaken with the presence of chronic disease, such as CKD.

Pseudoxanthoma Elasticum: An Interesting Model to Evaluate Chronic Kidney Disease-Like Vascular Damage without Renal Disease

Background

Pseudoxanthoma elasticum (PXE; OMIM 264800) is an inherited multisystem disorder associated with accumulation of mineralized and fragmented elastic fibers in the skin, vascular walls, and brush membrane in the eye. Carriers exhibit characteristic lesions in the cardiovascular system, and peripheral and coronary arterial disease as well as mitral valvulopathy often present as a cardiovascular feature of this disease. PXE and chronic kidney disease (CKD) share some common patterns in the vascular damage and in therapeutic approaches as well.

Summary

To date, treating PXE has focused more on careful follow-up examinations with retinal specialists and cardiologist, avoiding long-term anticoagulation. Like CKD, maintaining a low-calcium diet, increasing dietary magnesium, and administering phosphate binders such as aluminum hydroxide or sevelamer may yield a modest benefit. Recently, 4-phenylbutyrate acid (4-PBA) has demonstrated a maturation of ABCC6 mutant effects into the plasma membrane. Moreover, in a humanized mouse model of PXE, 4-PBA administration restored the physiological function of ABCC6 mutants, resulting in enhanced calcification inhibition and thus a promising strategy for allele-specific therapy of ABCC6-associated calcification disorders.

Key Message

Vascular compromise in PXE patients share some components similar to CKD.

Occupational hazards for nursing professionals related to the reuse and single use of the dialyzer

OBJECTIVE

To compare the reports of occupational events recorded by nursing professionals during the periods of reuse and single use of the dialyzer.

METHOD

Retrospective longitudinal study with electronic medical records from nursing technicians of a hemodialysis service. Data were analyzed descriptively and Rate ratio.

RESULTS

During the reuse of the dialyzer, there were seven events from five professionals reporting musculoskeletal disorders, ocular allergies and dermatosis. During single use, two professionals reported low back pain. The rate ratio of medication use was 6.7 days for every 1000 professionals during the reuse period and 1.52 days in the single use period (RR=4.4; 95% CI 2.182-9.805). Anti-inflammatory drugs were the most prescribed, and sick leaves were similar in both periods.

CONCLUSION

Dialyzer reuse was associated with musculoskeletal disorders, ocular irritation, dermatosis and increased use of medications by professionals. Sick leaves were similar on the periods of dialyzer reuse and single use.

Budd-Chiari syndrome secondary to catheter-associated inferior vena cava thrombosis

INTRODUCTION

Patients with chronic kidney disease (CKD) are at increased risk for thrombotic complications. The use of central venous catheters as dialysis vascular access additionally increases this risk. We describe the first case of Budd-Chiari syndrome (BCS) secondary to central venous catheter misplacement in a patient with CKD.

CASE REPORT

A 30-year-old female patient with HIV/AIDS and CKD on hemodialysis was admitted to the emergency room for complaints of fever, prostration, and headache in the last six days. She had a tunneled dialysis catheter placed at the left jugular vein. The diagnosis of BCS was established by abdominal computed tomography that showed a partial thrombus within the inferior vena cava which extended from the right atrium to medium hepatic vein, and continuing along the left hepatic vein. Patient was treated with anticoagulants and discharged asymptomatic.

DISCUSSION

Budd-Chiari syndrome is a rare medical condition caused by hepatic veins thrombosis. It can involve one, two, or all three of the major hepatic veins. It is usually related to myeloproliferative disorders, malignancy and hypercoagulable states. This case calls attention for inadvertent catheter tip placement into hepatic vein leading to this rare complication.

CONCLUSION

Assessment of catheter dialysis tip location with radiological image seems to be a prudent measure after each procedure even if the tunneled dialysis catheter has been introduced with fluoroscopy image.

The pitfall of treating low bone turnover: Effects on cortical porosity

Although it is recognized that cortical bone contributes significantly to the mechanical strength of the skeleton, little is known about this compartment from bone biopsy studies, particularly in CKD patients. In addition, there is no prospective data on the effects of CKD-MBD therapy on cortical porosity (Ct.Po). This is a post hoc analysis on data from a randomized controlled trial on the effects of different phosphate binders on bone remodelling. Therapy was adjusted according to the first biopsy, and included sevelamer or calcium acetate, calcitriol and changes in calcium dialysate concentration. We measured Ct.Po at baseline and one year after. Fifty-two patients (46±13years old, 67% women and 60% white) were enrolled. Ct.Po was already high at baseline in 85% of patients [30% (17, 46)] and correlated with PTH (p=0.001). Low bone turnover was seen in 28 patients (54.9%). After one-year treatment, PTH increased in patients with low turnover, as intended. However, increased Ct.Po was seen in 49 patients (94%). This increase correlated with the delta of phosphate (p=0.015) and the delta of PTH (p=0.03); it was also higher among non-white patients than in white patients (p=0.039). The risk of increase in Ct.Po was 4.5 higher among non-white patients. Adjusted multiple regression analysis showed that the delta of Ct.Po was dependent on delta PTH and race (r(2)=0.193). We concluded that in an attempt to increase bone turnover, the increase in PTH levels might be associated with higher cortical porosity, particularly in non-white patients. Whether this finding leads to a high risk of fracture deserves further investigation.

Effect of cholecalciferol supplementation on urine podocyte-associated messenger RNAs in patients with chronic kidney disease

INTRODUCTION

Vitamin D reduces albuminuria in patients with chronic kidney disease (CKD) but its effects on glomerular podocytes are not entirely understood.

OBJECTIVE

To evaluate if cholecalciferol supplementation reduces the levels of podocyte-associated urine mRNAs in patients with CKD.

METHODS

A total of 27 patients with stages 2 to 4 CKD and suboptimal serum vitamin D [25(OH)D] levels were treated with cholecalciferol for 6 months. Serum 25(OH)D level, estimated glomerular filtration rate (eGFR), proteinuria, and urine mRNA of nephrin, podocin, podocalyxin, transient receptor potential cation channel 6, vascular endothelial growth factor A, and transforming growth factor beta were assessed before and after intervention.

RESULTS

eGFR declined at an average rate of -4.71 mL/min/1.73 m2 (p = 0.010 vs. baseline), being 28 ± 16 mL/min/1.73 m2 at six months. No changes in proteinuria or mineral and bone metabolism parameters were observed after cholecalciferol supplementation. Urinary podocyte-associated mRNAs did not change significantly after treatment. However, patients who achieved 25(OH)D level > 20 ng/mL at six months showed a trend of reduction of urinary nephrin and podocin mRNA levels; in patients with 25(OH)D that remained < 20 ng/mL there was a significant increase in urinary podocalyxin, and a trend of higher expression of urinary nephrin and podocin mRNA.

CONCLUSION

Six months of cholecalciferol supplementation had no effect on urine podocyte-associated mRNA profile of patients with advanced CKD. The protective effect of vitamin D or its analogues on the glomerular podocyte should be investigated in early stages of CKD with a longer treatment period.

Physical activity in chronic kidney disease: a plausible approach to vascular calcification?

Vascular calcification (VC) is a prominent feature that affects up to 40 to 80% of Chronic Kidney Disease (CKD) patients depending on the degree of renal impairment. Though etiology and pathogenesis of the different types of VC are far from being elucidated, it is conceivable that an imbalance between promoters and inhibitors represents the condition that triggers VC deposition and progression. In addition to traditional cardiovascular risk factors, several lines of evidence suggest that specific factors may affect the arterial system and prognosis in CKD. Over the last decade, a few pharmacological strategies aimed at controlling different selected risk factors for VC have been investigated yielding conflicting results. In light of the complicated interplay between inhibitors and promoters as well as the fact that VC represents the result of cumulative and prolonged exposure to multiple risk factors, a more comprehensive risk modification approach such as lifestyle modification or physical activity (PA) may represent a valid strategy to attenuate VC deposition and progression.We herein aim at reviewing the rationale and current evidence on the potential for lifestyle modification with a specific focus on PA as a cost-effective strategy for VC treatment.

Hybrid myocardial imaging for risk stratification prior to kidney transplantation: added value of coronary calcium and epicardial adipose tissue

BACKGROUND

Patient selection and optimal approach to risk stratification prior to kidney transplantation remain uncertain. We sought new predictors of an abnormal myocardial perfusion (MYP) stress test result.

METHODS

Retrospective study of 411 consecutive chronic kidney disease stages 4-5D patients awaiting kidney transplantation referred for risk stratification. PET-CT or SPECT-CT was used to assess MYP and quantify coronary artery calcium (CAC) and epicardial adipose tissue (EAT). Abnormal MYP was defined as a perfusion defect involving ≥5% of the left ventricular myocardium.

RESULTS

Fixed or reversible MYP defects were present in 41 patients (10%). Male sex, smoking, and history of cardiovascular disease were more prevalent; age was higher and CAC and EAT were greater in patients with MYP defects than in those with normal MYP. On multivariate logistic regression, EAT and CAC were independent predictors of abnormal MYP while diabetes mellitus showed a borderline association (P = .08). EAT added incremental diagnostic value to a model including age, CAC and diabetes mellitus [AUC 0.73 (95% CI 0.64-0.81) to 0.76 (95% CI 0.68-0.84; P = .02)]. Furthermore, the model containing EAT showed improved diagnostic discrimination.

CONCLUSIONS

Abnormal MYP on screening stress testing appears to be rare in patients awaiting kidney transplantation suggesting an excess of testing. EAT and CAC may help predict what patients are at higher risk of developing abnormalities of MYP under stress.

Vitamin D status and coronary flow reserve measured by positron emission tomography: a co-twin control study

CONTEXT

Vitamin D insufficiency is associated with increased cardiovascular events in the general population. Additionally, low serum 25-hydroxyvitamin D [25(OH)D] is associated with endothelial dysfunction and arterial stiffness. However, little is known about the association between serum 25(OH)D level and myocardial blood flow.

OBJECTIVE

Our objective was to examine the association between serum 25(OH)D levels and coronary flow reserve (CFR) measured by (13)N-positron emission tomography in asymptomatic middle-aged male twins.

DESIGN

The Emory Twin Study is a cross-sectional study of soldiers from the Vietnam Era Registry.

SETTING

The study was conducted at the General Clinical Research Center, Emory University, Atlanta, GA.

PARTICIPANTS

A total of 368 middle-aged male twins were enrolled for the study. Serum 25(OH)D levels were measured in all subjects and classified as vitamin D insufficiency [25(OH)D <30 ng/ml] or sufficiency [25(OH)D ≥30 ng/ml]. Positron emission tomography with [(13)N]ammonia was used to evaluate myocardial blood flow at rest and after adenosine stress. CFR was measured as the ratio of maximum to rest myocardial blood flow.

MAIN OUTCOME MEASURE

Primary outcome was CFR measurement.

RESULTS

Mean overall serum 25(OH)D concentration was 37.0 ± 21.4 ng/ml; 167 twins (45%) were vitamin D insufficient. CFR was significantly lower in subjects with vitamin D insufficiency compared with subjects with vitamin D sufficiency (2.41 vs. 2.64; P = 0.007), even after adjustment for traditional cardiovascular risk factors, serum PTH, calcium, and phosphorus levels, and season. An abnormal CFR (CFR <2) was more prevalent in subjects with vitamin D insufficiency than with vitamin D sufficiency (31 vs. 20%; P = 0.03). In addition, in vitamin D status-discordant twin pairs, CFR was significantly lower in the vitamin D-insufficient twin than in the vitamin D-sufficient co-twin (2.35 vs. 2.58; P = 0.037).

CONCLUSION

Vitamin D insufficiency is associated with lower CFR in men. This association may help explain some of the increased cardiovascular risk reported in individuals with vitamin D insufficiency.

Cinacalcet: will it play a role in reducing cardiovascular events?

Secondary hyperparathyroidism is a common complication of chronic kidney disease and it is associated with high morbidity and mortality. It is characterized by high parathyroid hormone levels and bone turnover leading to bone pain, deformity and fragility. Furthermore, secondary hyperparathyroidism adversely affects the cardiovascular system and has been associated with cardiovascular calcification and cardiomyopathy. Cinacalcet, a type II calcimimetic, is an effective and well-tolerated oral therapy for the management of secondary hyperparathyroidism. It is an allosteric activator of the calcium-sensing receptor enhancing sensitivity of parathyroid cells to extracellular calcium, which leads to inhibition of parathyroid hormone secretion. The calcium-sensing receptor expression in cardiomyocytes, endothelial cells and vascular smooth muscle cells raises the possibility that this receptor may be implicated in the pathophysiology of cardiovascular disease and constitute a potential therapeutic target. This article reviews the role of the calcimimetic agent cinacalcet in the prevention and progression of cardiovascular calcification and uremic cardiomyopathy in the chronic kidney disease setting.

Secondary hyperparathyroidism status in Brazil: Brazilian census of parathyroidectomy

INTRODUCTION

Secondary hyperparathyroidism (SHP) is a common and serious complication of chronic kidney disease (CKD), with a negative impact on morbidity and mortality. Despite advances in the clinical management of SHP, treatment failure still occurs in a significant number of patients. In such cases, parathyroidectomy (PTx) is indicated.

OBJECTIVE

To have an overview of the prevalence of severe SHP and of its surgical treatment in hemodialysis (HD) patients in Brazil.

METHODS

This was an observational and descriptive study. Data were obtained from questionnaires posted to 660 dialysis units (DU).

RESULTS

Results are expressed in absolute values and percentages, or means and standard deviation, as appropriate. 226 (34%) DU answered the questionnaire, providing data about 32,264 HD patients. The prevalence rate of severe SHP (PTH > 1,000 pg/mL) was 10.7 % (n = 3,463). 68 hospitals countrywide perform PTX. Around 40% of them are university centers. 49 (21.7%) DU reported not to have a specialized medical center to refer their patients with severe SHP. 74 (33%) DU reported that the time interval between surgery indication and its performance was over 6 months. The main recognized obstacles to surgery performance were: difficulty to perform the preoperative exams, lack of head and neck surgeons and the long waiting time.

CONCLUSIONS

Although severe SHP is highly prevalent in Brazil, a significant number of patients do not have access to PTx. Better public health policies and liaison between nephrologists and head and neck surgeons are urgently required to change this reality.

Noninvasive imaging for assessment of calcification in chronic kidney disease

Vascular calcification is highly prevalent in patients with chronic kidney disease and has a progressive course. Several cardiovascular and uremia-related risk factors, such as abnormalities in mineral metabolism, contribute to the development of vascular calcification, although the pathophysiological mechanisms are still unclear. The presence and extent of vascular calcification is associated with an increased risk of cardiovascular events and mortality. By contrast, patients who do not have calcification seem to have a good prognosis, with minimal or no calcification progression over an extended period of time. A number of noninvasive imaging methods are available to detect vascular calcification and may help clinicians to make therapeutic decisions. Cardiac CT remains the reference standard to detect and quantify coronary artery, aortic and cardiac valve calcification. However, the high cost of equipment, the inability to perform in-office testing and the expertise required limit its use on a routine basis. Other imaging methods, such as planar X-ray, ultrasound and echocardiography, are appropriate alternatives to evaluate vascular and valvular calcification. In this review, we discuss the noninvasive imaging methods most frequently used to assess vascular and valvular calcification, with their advantages and limitations.

Cardiovascular imaging in patients with chronic kidney disease

Cardiovascular disease is highly prevalent in chronic kidney disease and has been associated with increased morbidity and mortality. Several morphological and functional tests are available to assess the cardiovascular system. Since structural and functional cardiovascular abnormalities have prognostic implications, their identification may become crucial for the implementation of effective preventive and therapeutic strategies. We review the most frequently used imaging methods to investigate structural and functional cardiovascular changes in patients with chronic kidney disease.

Heritability and seasonal variability of vitamin D concentrations in male twins

BACKGROUND

Serum 25-hydroxyvitamin D [25(OH)D] concentrations can be affected by several environmental and individual factors. It is not clear to what extent genetic influences play a role in determining vitamin D status. Thus far, studies on the heritability of vitamin D have provided conflicting results.

OBJECTIVE

We estimated the heritability of vitamin D concentrations and the effect of season on heritability estimates.

DESIGN

We measured serum 25(OH)D concentrations in 510 middle-aged, male twins (310 monozygotic and 200 dizygotic twins) selected from the Vietnam Era Twin Registry. Generalized estimating equations were used to test the association between 25(OH)D and other study factors. Structural equation modeling was used to estimate the heritability of 25(OH)D.

RESULTS

The twins' mean (±SD) age was 55 ± 2.8 y. The mean (±SD) 25(OH)D concentration was 38.4 ± 23.3 ng/mL with a substantial seasonal variation (a 6.1-ng/mL lower value during the winter than during the summer, P = 0.003). Approximately 70% of the variation in 25(OH)D concentrations during the winter was explained by genetic factors. However, in the summer, 25(OH)D concentrations were not heritable. During the summer, 53% of the variation in 25(OH)D concentrations was due to shared environmental factors, and 47% of the variation in 25(OH)D concentrations was due to unique environmental factors.

CONCLUSIONS

Serum 25(OH)D concentrations are highly heritable during the winter season only. In the summer, environmental conditions (eg, sun exposure) prevail over genetic backgrounds in determining serum 25(OH)D concentrations. This trial was registered at clinicaltrials.gov as NCT00017836.

Heritability of renal function and inflammatory markers in adult male twins

BACKGROUND

Loss of renal function is accompanied by a progressive increase in markers of inflammation; it is unknown whether they share common genetic pathways.

STUDY DESIGN

We evaluated the shared heritability of estimated glomerular filtration rate (eGFR) and markers of inflammation and endothelial activation in 524 twin males from the Vietnam Era Twin Registry; 9 twins were excluded due to incomplete or incorrect data. Models were adjusted for age, race, body mass index, smoking, hypertension, diabetes mellitus, prior coronary artery disease and intercurrent medications.

RESULTS

The mean eGFR was 89 ± 13 ml/min/1.73 m² (range 35-146); eGFR, intracellular adhesion molecule (ICAM) and TNF-α receptor (TNF-αR) were moderately heritable (all ∼50%), while IL-6 receptor (IL-6R) and P-selectin were highly heritable (68 and 76%, respectively). IL-6R and TNF-αR showed a significant inverse association with eGFR (p = 0.04 and p < 0.0001) while the association with ICAM and P-selectin was direct (p = 0.001 and p = 0.06). Bivariate structural equation models showed that the association between eGFR and biomarkers was due to unique environmental factors and there were no shared genetic pathways.

CONCLUSION

We found no shared genetic pathways between renal function and inflammation. Thus, increased inflammation represents a response to declining renal function rather than being a mechanism contributing to renal deterioration.

Coronary calcification and its association with mortality in haemodialysis patients

AIM

Coronary artery calcification (CAC) has been associated with higher mortality in chronic renal disease. The purpose of this study was to assess coronary artery calcium score (CaCs) in haemodialysis patients and to correlate calcium scores with clinical parameters and mortality.

METHODS

A cross-sectional study was conducted in 59 haemodialysis patients. CaCs was assessed by multidetector-row computed tomography and stratified as: CaCs of less than 10 Agatston units (U), no calcification; CaCs of 10-400 U, mild-to-moderate; and CaCs of more than 400 U, severe calcification. The effects of age, haemodialysis duration and biochemical and inflammatory markers on CaCs logarithm were evaluated by multiple linear regression analysis. Cox regression analysis was used to measure the impact of CaCs of more than 400 on 2-year mortality.

RESULTS

Coronary calcifications were detected in 64.5% of patients, and the median of CaCs was 31.7 U (0-589.7) with a range of 0-5790.0 U. Twenty-one (35.5%) patients had mild-to-moderate and 17 (29%) severe CaCs. Patients with severe CaCs were older and showed a higher prevalence of ischaemic heart disease and a higher body mass index (P=0.04). A trend towards higher C-reactive protein levels was found in patients with severe CaCs. Advanced age was the only variable that influenced CaCs logarithm independently. The effect of severe CaCs on 2-year mortality did not persist after adjustment for other covariates.

CONCLUSION

Coronary calcification was highly prevalent in these uraemic patients on chronic haemodialysis. A correlation was evidenced between CaCs and advanced age, but severity of the CAC score did not have an impact on 2-year mortality of this cohort.

Association of waist-hip ratio with diabetes mellitus. Strength and possible modifiers

OBJECTIVE

To characterize the association between central obesity, as measured by the waist-hip ratio (WHR), and non-insulin-dependent diabetes mellitus (NIDDM), considering the effects of sex, age, overall obesity, and family history of diabetes.

RESEARCH DESIGN AND METHODS

Case-control study nested within a community-based survey. We selected 151 subjects with NIDDM and 301 nondiabetic control subjects as a systematic sample of survey screening negative individuals.

RESULTS

Odds ratios for NIDDM, comparing a high WHR (greater than or equal to 0.926 for men, greater than or equal to 0.83 for women) to a low WHR were 4.72 with a 95% confidence interval of 2.39-9.34, and 2.17 with a 95% confidence interval of 1.03-4.58, for women and men, respectively, controlling for age, overall obesity, and a family history of diabetes. Women with high WHRs in the presence of these risk factors are notably at risk for diabetes.

CONCLUSION

Central obesity, as measured by the WHR, is importantly and independently associated with NIDDM.