Significance of the decreased risk of dialysis-related amyloidosis now proven by results from Japanese nationwide surveys in 1998 and 2010

Frailty and Duration of Maintenance Dialysis: A Japanese Nationwide Cross-Sectional Study

RATIONALE & OBJECTIVE

Prolonged end-stage kidney disease (ESKD) is a risk factor for frailty, and the number of patients in Japan receiving maintenance dialysis for more than 20 years is large and growing. This study characterized the association of dialysis vintage and frailty among patients receiving dialysis in Japan.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

Patients with ESKD aged over 50 years who received maintenance dialysis in 2018 as represented in the JSDT Renal Data Registry database (n = 227,136).

EXPOSURE

Dialysis vintage categorized as: 0-<5 years, 5-<10 years, 10-<20 years, 20-<30 years, and over 30 years.

OUTCOME

Frailty and bedridden status were defined as graded≥2 and graded 4, respectively, according to the Eastern Cooperative Oncology Group Performance Status scale.

ANALYTICAL APPROACH

Poisson regression models with robust error variance adjusted for potential covariates were used to estimate the adjusted prevalence ratios (APRs) for frailty and bedridden status. Clinical characteristics of patients undergoing dialysis for≥30 years were also described.

RESULTS

Among the study cohort, 5,510 patients (2.4%) had been undergoing dialysis for 30 years or more. The prevalence of frailty in the group with over 30 years of dialysis history was 36.2%, and the rate of being bedridden was 6.4%. Compared with<5 years, dialysis vintages of 5-<10 years, 10-<20 years, 20-<30 years, and over 30 years were associated with frailty (APR, 1.06 [95% CI, 1.05-1.08], 1.10 [95% CI, 1.08-1.11], 1.14 [95% CI, 1.10-1.17], and 1.67 [95% CI, 1.60-1.73]), respectively. Compared with<5 years, dialysis vintages of 5-<10 years, 10-<20 years, 20-<30 years, and over 30 years were associated with being bedridden (APR, 1.17 [95% CI, 1.13-1.22], 1.26 [95% CI, 1.20-1.31], 1.17 [95% CI, 1.08-1.26], and 1.66 [95% CI, 1.49-1.86], respectively.

LIMITATIONS

Patients receiving short-term dialysis may have more unmeasured comorbidities compared with patients receiving long-term dialysis.

CONCLUSIONS

Long-term dialysis therapy, particularly exceeding 30 years, is associated with deterioration of physical function and frailty.

PLAIN-LANGUAGE SUMMARY

End-stage kidney disease increases the risk of frailty. Understanding how long-term dialysis affects physical function may help patients and caregivers plan their lives better. Our research explores the relationship between duration of maintenance dialysis and frailty. We found that longer durations of maintenance dialysis, especially longer than 30 years, were associated with a higher risk of frailty and being bedridden among Japanese patients. The factors responsible for these associations should be the focus of future research.

Carpal tunnel release in the dialysis-dependent population: Incidence and outcomes

Level of evidence

Level III, retrospective case-control study.

Background

The association between dialysis and carpal tunnel syndrome is well-established. As the number of patients living with dialysis-dependent end-stage renal disease (ESRD) increases, it is important that we understand outcomes after carpal tunnel release in this population.

Purpose

To investigate (1) the prevalence of carpal tunnel syndrome (CTS) in dialysis-dependent patients, (2) the incidence of carpal tunnel release (CTR), and (3) the differences in complications after CTR between hemodialysis patients, peritoneal dialysis patients, and matched controls.

Patients and methods

Querying the PearlDiver database, we determined prevalence of CTS and incidence of CTR in dialysis-dependent and control patients. We compared peritoneal dialysis (PD) patients to matched populations of hemodialysis (HD) patients and non-dialysis-dependent controls. Complications were identified, including hospital admission, emergency department visits, infection, revision surgery, and postoperative chronic regional pain syndrome (CRPS).

Results

The rates of CTS and CTR in dialysis patients were significantly increased relative to controls. Dialysis-dependent patients had increased rates of hospital admission within 30 days postoperatively (OR 4.13, P ​< ​.0001 for PD; OR 4.42, P ​< ​.0001 for HD), infection within 6 months postoperatively (OR 2.32, P ​= ​.013 for PD; OR 3.20, P ​< ​.0001 for HD), and need for revision CTR (OR 2.04, P ​= ​.009 for PD; OR 1.62, P ​= ​.037 for HD). Emergency department presentation within 30 days postoperatively was less common in PD vs HD (OR 0.63, P ​= ​.038).

Conclusions

When compared to the control population, patients undergoing dialysis are more likely to be diagnosed with carpal tunnel syndrome, undergo carpal tunnel release, and are at significantly increased risk for perioperative complications.

Supersaturation, a Critical Factor Underlying Proteostasis of Amyloid Fibril Formation

From a physicochemical viewpoint, amyloid fibril formation is a phase transition from soluble to crystal-like sates limited by supersaturation. It occurs only above solubility (i.e., the solubility limit) coupled with a breakdown of supersaturation. Although many studies have examined the role of molecular chaperones in the context of proteostasis, the role of supersaturation has not been addressed. Moreover, although molecular chaperone-dependent disaggregations have been reported for preformed amyloid fibrils, amyloid fibrils will not dissolve above the solubility of monomers, even if agitations fragment long fibrils to shorter amyloid particles. On the other hand, on considering a reversible and coupled equilibrium of interactions, folding/unfolding and amyloid formation/disaggregation, molecules stabilizing native states can work as a disaggregase reversing the amyloid fibrils to monomers. It is likely that the proteostasis network has various intra- and extracellular components which disaggregate preformed amyloid fibrils as well as prevent amyloid formation. Further studies with a view of solubility and supersaturation will be essential for comprehensive understanding of proteostasis.

Ultrasound findings of the sternoclavicular and shoulder joints in patients on maintenance hemodialysis

INTRODUCTION

Ultrasonographic examination of joints is a non-invasive method to detect and monitor Dialysis-associated amyloidosis (DRA).

METHODS

An ultrasonographic examination of the sternoclavicular (SC) and shoulder joints was performed in patients on maintenance hemodialysis (MHD) and those with normal renal function in the control group. The maximum distance (D) of SC, the rotator cuff thickness (RCs), and the echogenic pads (EPs) of the shoulder were evaluated.

RESULTS

Compared with the control group, the MHD group had a higher D of SC, a higher proportion of RCs ≥8 mm, and a higher proportion of EPs positive. Adjust for age and Kt/V, the D of SC was positively related to dialysis vintage, standardized coefficients β = 0.329, p = 0.004. A significant positive correlation existed between the D of SC and the RCs.

CONCLUSION

In addition to the shoulder joint, the sternoclavicular is a suitable site for ultrasonographic detection of DRA.

Dialysis-related Amyloidosis Presenting as a Fever of Unknown Origin: Symptoms and Management

A 74-year-old woman with a 34-year history of hemodialysis presented with an intermittent fever, which later coincided with recurrent bilateral shoulder and hip joint pain. Imaging studies suggested amyloid arthropathy, which was histologically confirmed by a synovial biopsy. Increasing β2-microglobulin clearance during dialysis alone attenuated the intermittent fever and joint pain, but the symptoms did not disappear until the administration of prednisolone 10 mg/day. Reported cases of dialysis-related amyloidosis with a fever imply that changing to blood purification methods with high β2-microglobulin clearance is crucial for controlling the condition long-term, whereas concurrent use of anti-inflammatory agents promptly alleviates the symptoms.

Surgical Treatment of Ischial Ulcers Associated with Deposition of β2-Microglobulin in Two Cases of Dialysis-related Amyloidosis

The accumulation of β2-microglobulin due to long-term hemodialysis is known as dialysis-related amyloidosis, a rare phenomenon that manifests as a subcutaneous mass. Subcutaneous β2-microglobulin amyloidomas are predominantly located on the buttocks. Owing to the load-bearing properties of this location and proximity to the anus, amyloidomas on the buttocks may be prone to pressure ulcers and infection. This report presents two cases of long-term hemodialysis patients who required surgical treatment for infected ulcers caused by buttock amyloidomas. In the first case, treatment failed after the amyloidoma was excised and covered with a single-stage skin flap. In the second case, successful treatment was accomplished by reducing the volume of the amyloidoma, followed by a pause to allow for granulation growth and a two-stage skin graft. Amyloids of this nature are known to be cytotoxic; thus, a robust wound preparation technique should be used until the excision site is fully covered with granulation tissue before wound closure is initiated at the time of surgery. In addition, buttock amyloidomas often extend subcutaneously through the hip joint, and repeated infections may lead to more severe outcomes, such as hip joint infections. The number of dialysis-related amyloidosis patients has been increasing in recent years; thus, we report these case studies to improve patient outcomes in similar cases.

Macromolecular crowding and supersaturation protect hemodialysis patients from the onset of dialysis-related amyloidosis

Dialysis-related amyloidosis (DRA), a serious complication among long-term hemodialysis patients, is caused by amyloid fibrils of β2-microglobulin (β2m). Although high serum β2m levels and a long dialysis vintage are the primary and secondary risk factors for the onset of DRA, respectively, patients with these do not always develop DRA, indicating that there are additional risk factors. To clarify these unknown factors, we investigate the effects of human sera on β2m amyloid fibril formation, revealing that sera markedly inhibit amyloid fibril formation. Results from over 100 sera indicate that, although the inhibitory effects of sera deteriorate in long-term dialysis patients, they are ameliorated by maintenance dialysis treatments in the short term. Serum albumin prevents amyloid fibril formation based on macromolecular crowding effects, and decreased serum albumin concentration in dialysis patients is a tertiary risk factor for the onset of DRA. We construct a theoretical model assuming cumulative effects of the three risk factors, suggesting the importance of monitoring temporary and accumulated risks to prevent the development of amyloidosis, which occurs based on supersaturation-limited amyloid fibril formation in a crowded milieu.

Hemodialysis-Related Amyloidosis in the Tongue

Dialysis-related amyloidosis (DRA) represents a group of relatively rare disorders characterized by the systemic extracellular deposition of insoluble fibrils of amyloid protein in long-term dialysis patients. We describe herein a case of relatively early DRA on the tongue of a long-term dialysis patient. A 67-year-old man with a 39-year history of dialysis was referred for diagnosis of a tongue mass. On examination, a collection of whitish-yellow papules was identified on the ventral surface of the tongue tip. The pathological diagnosis was DRA. Clinicians should be aware that long-term dialysis can cause oral amyloidosis of the tongue.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Association of dialysis-related amyloidosis with lower quality of life in patients undergoing hemodialysis for more than 10 years: The Kyushu Dialysis-Related Amyloidosis Study

BACKGROUND

Dialysis-related amyloidosis (DRA) commonly develops in patients undergoing long-term dialysis and can lead to a decline in activities of daily living and quality of life (QOL), mainly owing to orthopedic complications.

METHODS

First, we determined utility scores of the EuroQol 5-Dimensions 3-Levels (EQ-5D-3L) questionnaire in 1,323 patients with DRA who had undergone dialysis for more than 10 years and compared the score between those with and without DRA. Second, a 2-year follow-up was also performed, in which patients were divided into three groups: those complicated by DRA from the beginning, those with newly developed DRA within the 2-year period, and those not complicated by DRA throughout the survey period; changes in the EQ-5D-3L utility score were compared. In the group already complicated by DRA at the survey baseline, changes in the EQ-5D-3L utility score were compared according to the dialysis treatment method.

RESULTS

A total of 1,314 and 931 patients were included in the first and second studies, respectively. EQ-5D-3L utility scores among patients diagnosed with DRA were significantly lower than scores in those not diagnosed with DRA. The reduction in the EQ-5D-3L utility score over the 2-year follow-up was significantly greater in patients newly complicated by DRA during the follow-up period after enrollment but not in those complicated by DRA from the beginning, as compared with patients not complicated by DRA throughout the survey period. The reduction in utility score tended to be lower in patients routinely treated with a β2-microglobulin adsorption column than in untreated patients with DRA.

CONCLUSION

Complication by DRA in patients undergoing long-term hemodialysis was significantly associated with a decline in QOL.

Dialysis-related carpal tunnel syndrome in the past 40 years

Purpose and method

Patients on hemodialysis develop carpal tunnel syndrome (CTS) due to an accumulation of dialysis-related β2 microglobulin (β2m) amyloid (DRA). In Japan, dialysis technology has progressed remarkably in the past 40 years and has increased the time until patients require surgery for CTS. However, unclear is whether the time from the start of hemodialysis to the first surgery for CTS is associated with β2m clearance by the different hemodialysis techniques. Therefore, we retrospectively evaluated β2m clearance, serum β2m levels, and the change in the length of this period in patients across 4 periods according to the year that first surgery for CTS was performed: period 1, 1982–1989; period 2, 1990–1999; period 3, 2000–2009; and period 4, 2010–2019.

Result

A total of 222 patients who met the selection criteria were included. Mean β2m clearance was −1.8 ± 16.7% in period 1, and improved to 65.4 ± 8.6% in period 3. Accordingly, the serum β2m value after hemodialysis decreased significantly. The time from the start of hemodialysis to the first surgery for CTS was 12.4 ± 2.9 years in period 1 but increased to 21.8 ± 6.3 years in period 3. In multivariable linear regression analysis, the significant factors contributing to β2m clearance were periods 2, 3, and 4. In particular, the relation between removal of β2m and the extension of the dialysis vintage in period 1 and 2 was remarkable compared with periods 3 and 4.

Conclusion

Our findings indicate that improvement of β2m clearance via advances in dialysis technology might result in a significant extension in the time between starting HD and the first surgery for CTS.

Hepatitis C virus and carpal tunnel syndrome in hemodialysis patients: a single center cross-sectional study

OBJECTIVES

Carpal tunnel syndrome (CTS) is a common complication in maintenance hemodialysis (MHD) patients and leads to disabilities and increased risk of mortality. Hepatitis C virus (HCV) infection is associated with inflammatory and oxidative stress, and HCV infection can be cured. This study aimed at evaluating the association of HCV infection with CTS.

METHODS

Using a cross-sectional design, anthropometric and laboratory data were collected. Serum β₂-microglobulin, HCV antibody and HCV-RNA were measured. CTS was diagnosed according to clinical manifestation, electrophysiological test or ultrasonography. The related factors for CTS were analyzed by multivariate logistic regression.

RESULTS

This study included 113 participants, of whom 33 (29.2%) patients were positive for HCV antibody and 18 (15.9%) were positive for HCV antibody and HCV-RNA. Thirty-two (28.3%) patients were diagnosed with CTS. There were significant differences in the dialysis vintage, age of onset of MHD, high-sensitivity C-reactive protein, serum β₂M, anti-HCV-positive, HCV-RNA-positive, HCV load values and urine volume category between the CTS group and non-CTS group (p < 0.05). High-sensitivity C-reactive protein (OR: 1.238, 95% CI: 1.071-1.431, p = 0.004), dialysis vintage (OR: 1.017, 95% CI: 1.008-1.026, p < 0.001) and HCV-RNA-positive (OR: 5.929, 95% CI: 1.295-27.132, p = 0.022) rather than anti-HCV-positive were related factors for CTS.

CONCLUSIONS

High-sensitivity C-reactive protein, dialysis vintage and HCV-RNA replication but not previous HCV-infection were related factors for CTS in MHD patients. Further studies are needed to clarify whether intervention is beneficial for preventing and delaying the progression of CTS in MHD patients with HCV-RNA replication.

Beta-2 microglobulin and all-cause mortality in the era of high-flux hemodialysis: results from the Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Beta-2 microglobulin (β2M) accumulates in hemodialysis (HD) patients, but its consequences are controversial, particularly in the current era of high-flux dialyzers. High-flux HD treatment improves β2M removal, yet β2M and other middle molecules may still contribute to adverse events. We investigated patient factors associated with serum β2M, evaluated trends in β2M levels and in hospitalizations due to dialysis-related amyloidosis (DRA), and estimated the effect of β2M on mortality.

METHODS

We studied European and Japanese participants in the Dialysis Outcomes and Practice Patterns Study. Analysis of DRA-related hospitalizations spanned 1998-2018 (n = 23 976), and analysis of β2M and mortality in centers routinely measuring β2M spanned 2011-18 (n = 5332). We evaluated time trends with linear and Poisson regression and mortality with Cox regression.

RESULTS

Median β2M changed nonsignificantly from 2.71 to 2.65 mg/dL during 2011-18 (P = 0.87). Highest β2M tertile patients (>2.9 mg/dL) had longer dialysis vintage, higher C-reactive protein and lower urine volume than lowest tertile patients (≤2.3 mg/dL). DRA-related hospitalization rates [95% confidence interval (CI)] decreased from 1998 to 2018 from 3.10 (2.55-3.76) to 0.23 (0.13-0.42) per 100 patient-years. Compared with the lowest β2M tertile, adjusted mortality hazard ratios (95% CI) were 1.16 (0.94-1.43) and 1.38 (1.13-1.69) for the middle and highest tertiles. Mortality risk increased monotonically with β2M modeled continuously, with no indication of a threshold.

CONCLUSIONS

DRA-related hospitalizations decreased over 10-fold from 1998 to 2018. Serum β2M remains positively associated with mortality, even in the current high-flux HD era.

Optimized sonoreactor for accelerative amyloid-fibril assays through enhancement of primary nucleation and fragmentation

Ultrasonication to supersaturated protein solutions forcibly forms amyloid fibrils, thereby allowing the early-stage diagnosis for amyloidoses. Previously, we constructed a high-throughput sonoreactor to investigate features of the amyloid-fibril nucleation. Although the instrument substantiated the ultrasonication efficacy, several challenges remain; the key is the precise control of the acoustic field in the reactor, which directly affects the fibril-formation reaction. In the present study, we develop the optimized sonoreactor for the amyloid-fibril assay, which improves the reproducibility and controllability of the fibril formation. Using β₂-microglobulin, we experimentally demonstrate that achieving identical acoustic conditions by controlling oscillation amplitude and frequency of each transducer results in identical fibril-formation behavior across 36 solutions. Moreover, we succeed in detecting the 100-fM seeds using the developed sonoreactor at an accelerated rate. Finally, we reveal that the acceleration of the fibril-formation reaction with the seeds is achieved by enhancing the primary nucleation and the fibril fragmentation through the analysis of the fibril-formation kinetics. These results demonstrate the efficacy of the developed sonoreactor for the diagnosis of amyloidoses owing to the accelerative seed detection and the possibility for further early-stage diagnosis even without seeds through the accelerated primary nucleation.

Renal Rehabilitation: Exercise Intervention and Nutritional Support in Dialysis Patients

With the growing number of dialysis patients with frailty, the concept of renal rehabilitation, including exercise intervention and nutrition programs for patients with chronic kidney disease (CKD), has become popular recently. Renal rehabilitation is a comprehensive multidisciplinary program for CKD patients that is led by doctors, rehabilitation therapists, diet nutritionists, nursing specialists, social workers, pharmacists, and therapists. Many observational studies have observed better outcomes in CKD patients with more physical activity. Furthermore, recent systematic reviews have shown the beneficial effects of exercise intervention on exercise tolerance, physical ability, and quality of life in dialysis patients, though the beneficial effect on overall mortality remains unclear. Nutritional support is also fundamental to renal rehabilitation. There are various causes of skeletal muscle loss in CKD patients. To prevent muscle protein catabolism, in addition to exercise, a sufficient supply of energy, including carbohydrates, protein, iron, and vitamins, is needed. Because of decreased digestive function and energy loss due to dialysis treatment, dialysis patients are recommended to ingest 1.2-fold more protein than the regular population. Motivating patients to join in activities is also an important part of renal rehabilitation. It is essential for us to recognize the importance of renal rehabilitation to maximize patient satisfaction.

Serum total indoxyl sulfate and clinical outcomes in hemodialysis patients: results from the Japan Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Uremic toxins are associated with various chronic kidney disease-related comorbidities. Indoxyl sulfate (IS), a protein-bound uremic toxin, reacts with vasculature, accelerating atherosclerosis and/or vascular calcification in animal models. Few studies have examined the relationship of IS with clinical outcomes in a large cohort of hemodialysis (HD) patients.

METHODS

We included 1170 HD patients from the Japan Dialysis Outcomes and Practice Patterns Study Phase 5 (2012-15). We evaluated the associations of serum total IS (tIS) levels with all-cause mortality and clinical outcomes including cardiovascular (CV)-, infectious- and malignancy-caused events using Cox regressions.

RESULTS

The median (interquartile range) serum tIS level at baseline was 31.6 μg/mL (22.6-42.0). Serum tIS level was positively associated with dialysis vintage. Median follow-up was 2.8 years (range: 0.01-2.9). We observed 174 deaths (14.9%; crude rate, 0.06/year). Serum tIS level was positively associated with all-cause mortality [adjusted hazard ratio per 10 μg/mL higher, 1.16; 95% confidence interval (CI) 1.04-1.28]. Association with cause-specific death or hospitalization events, per 10 μg/mL higher serum tIS level, was 1.18 (95% CI 1.04-1.34) for infectious events, 1.08 (95% CI 0.97-1.20) for CV events and 1.02 (95% CI 0.87-1.21) for malignancy events after adjusting for covariates including several nutritional markers.

CONCLUSIONS

In a large cohort study of HD patients, serum tIS level was positively associated with all-cause mortality and infectious events.

Updates on hemodialysis techniques with a common denominator: The personalization of the dialytic therapy

Hemodialysis (HD) is a life-saving therapy for patients with end-stage renal disease. In dialyzed patients, the prevalence of multi-morbidity is rising driven by various factors, such as the population aging, the incomplete correction of uremia, and the side effects of the dialysis therapy itself. Each dialyzed patient has their own specific clinical and biochemical problems. It is therefore unthinkable that the same dialysis procedure can be able to meet the needs of every patient on chronic dialysis. We have very sophisticated dialysis machines and different dialysis techniques and procedures beyond conventional HD, such as hemodiafiltration (HDF) with pre- and post-dilution, acetate-free biofiltration (AFB), hemofiltration (HF), and expanded HD. Each of these techniques has its own specific characteristics. To solve some intradialytic clinical issues, such as arterial hypotension and arrhythmias, we have biofeedback systems with automatic regulation of the blood volume, body temperature, arterial pressure, as well as potassium profiling techniques in the dialysis bath. New technical innovations, such as citrate-containing dialysate or heparin-coated membranes, could reduce the risk of bleeding. To better address to patient needs, the strengths and weaknesses of each of these systems must be well-known, in order to have a personalized dialysis prescription for each patient.

Beta-2 Microglobulin Amyloidosis: Past, Present, and Future

Almost half a century has elapsed since the first description of dialysis-related amyloidosis (DRA), a disorder caused by excessive accumulation of β-2 microglobulin (B2M). Within that period, substantial advances in RRT occurred. These improvements have led to a decrease in the incidence of DRA. In many countries, DRA is considered a "disappearing act" or complication. Although the prevalence of patients living with RRT increases, not all will have access to kidney transplantation. Consequently, the number of patients requiring interventions for treatment of DRA is postulated to increase. This postulate has been borne out in Japan, where the number of patients with ESKD requiring surgery for carpal tunnel continues to increase. Clinicians treating patients with ESKD have treatment options to improve B2M clearance; however, there is a need to identify ways to translate improved B2M clearance into improved quality of life for patients undergoing long-term dialysis.

Glycated albumin and hemoglobin A1c levels and cause-specific mortality by patients' conditions among hemodialysis patients with diabetes: a 3-year nationwide cohort study

INTRODUCTION

Differences in mortality and cause-specific mortality rates according to glycated albumin (GA) and hemoglobin A1c (HbA1c) levels among dialysis patients with diabetes based on hypoglycemic agent use and malnutrition status remain unclear. Here, we examine these associations using a nationwide cohort.

RESEARCH DESIGN AND METHODS

We examined 40 417 dialysis patients with diabetes who met our inclusion criteria (female, 30.8%; mean age, 67.3±11.2 years; mean dialysis duration, 5.4±4.6 years). The Global Leadership Initiative on Malnutrition criteria were used to assess malnutrition. Adjusted HRs and 95% confidence limits were calculated for 3-year mortality after adjustment for 18 potential confounders. HRs and subdistribution HRs were used to explore cause-specific mortality.

RESULTS

We found a linear association between 3-year mortality and GA levels only in patients with GA ≥18% and not in patients with low GA levels, with a U-shaped association between HbA1c levels and the lowest morality at an HbA1c 6.0%-6.3%. This association differed based on patient conditions and hypoglycemic agent use. If patients using hypoglycemic agents were malnourished, mortality was increased with GA ≥24% and HbA1c ≥8%. In addition, patients with GA ≥22% and HbA1c ≥7.6% had significantly higher infectious or cardiovascular mortality rates. On the other hand, an inverse association was found between GA or HbA1c levels and cancer mortality. Patients with GA ≤15.8% had a higher risk of cancer mortality, especially those not using hypoglycemic agents (HR 1.63 (1.00-2.66)).

CONCLUSIONS

Target GA and HbA1c levels in dialysis patients may differ according to hypoglycemic agent use, nutritional status, and the presence of cancer. The levels may be higher in malnourished patients than in other patients, and a very low GA level in dialysis patients not taking hypoglycemic agents may be associated with a risk of cancer.

TRIAL REGISTRATION NUMBER

UMIN000018641.

Treating Protein Misfolding Diseases: Therapeutic Successes Against Systemic Amyloidoses

Misfolding and extracellular deposition of proteins is the hallmark of a heterogeneous group of conditions collectively termed protein misfolding and deposition diseases or amyloidoses. These include both localized (e.g. Alzheimer’s disease, prion diseases, type 2 diabetes mellitus) and systemic amyloidoses. Historically regarded as a group of maladies with limited, even inexistent, therapeutic options, some forms of systemic amyloidoses have recently witnessed a series of unparalleled therapeutic successes, positively impacting on their natural history and sometimes even on their incidence. In this review article we will revisit the most relevant of these accomplishments. Collectively, current evidence converges towards a crucial role of an early and conspicuous reduction or stabilization of the amyloid-forming protein in its native conformation. Such an approach can reduce disease incidence in at risk individuals, limit organ function deterioration, promote organ function recovery, improve quality of life and extend survival in diseased subjects. Therapeutic success achieved in these forms of systemic amyloidoses may guide the research on other protein misfolding and deposition diseases for which effective etiologic therapeutic options are still absent.

Introduction to clinical research based on modern epidemiology

Over the past 20 years, recent advances in science technologies have dramatically changed the styles of clinical research. Currently, it has become more popular to use recent modern epidemiological techniques, such as propensity score, instrumental variable, competing risks, marginal structural modeling, mixed effects modeling, bootstrapping, and missing data analyses, than before. These advanced techniques, also known as modern epidemiology, may be strong tools for performing good clinical research, especially in large-scale observational studies, along with relevant research questions, good databases, and the passion of researchers. However, to use these methods effectively, we need to understand the basic assumptions behind them. Here, I will briefly introduce the concepts of these techniques and their implementation. In addition, I would like to emphasize that various types of clinical studies, not only large database studies but also small studies on rare and intractable diseases, are equally important because clinicians always do their best to take care of many kinds of patients who suffer from various kidney diseases and this is our most important mission.

Functional impairment attenuates the association between high serum phosphate and mortality in dialysis patients: a nationwide cohort study

BACKGROUND

Both functional impairment and abnormalities in mineral and bone disorder (MBD) parameters are well-known predictors of mortality in dialysis patients. However, previous studies have not evaluated whether functional impairment modifies the association between MBD parameters and mortality.

METHODS

A nationwide prospective cohort study was conducted using data from the Japanese Society for Dialysis Therapy Renal Data Registry collected at the end of 2009 and 2010. The Eastern Cooperative Oncology Group performance status (PS) was used to assess functional status. Cox proportional hazards models were used to assess the associations of baseline functional status, serum phosphate, albumin-corrected calcium and intact parathyroid hormone (PTH) with 1-year all-cause mortality.

RESULTS

By 31 December 2010, 18 447 of 220 054 prevalent dialysis patients (8.4%) had died. Mortality significantly increased with worsening PS grade. PS grade modified the association of serum phosphate levels with mortality (Pinteraction = 0.001). Worsening PS grade attenuated the association of hyperphosphatemia (≥7.4 mg/dL) with mortality, and hyperphosphatemia was no longer significant on mortality among patients with the worst PS grade (hazard ratio = 1.1, 95% confidence interval 0.88-1.39), compared with the level between 3.5 and 4.7 mg/dL. In contrast, hypophosphatemia (<3.5 mg/dL) had a greater adjusted risk of mortality irrespective of PS grade. Serum-corrected calcium (Pinteraction = 0.26) and intact PTH (Pinteraction = 0.17) showed consistent associations with mortality irrespective of PS grade. Findings were robust in several sensitivity analyses.

CONCLUSIONS

Functional impairment was significantly associated with 1-year mortality and attenuated the effect of hyperphosphatemia on mortality among prevalent dialysis patients.

Human amyloidosis, still intractable but becoming curable: The essential role of pathological diagnosis in the selection of type-specific therapeutics

The molecular pathogenesis of human amyloidosis has been elucidated greatly during the last 20 years. Based on the understanding of the molecular mechanisms of amyloid fibril formation and deposition, various kinds of new drugs and therapeutics have been emerging to improve the prognosis of amyloidosis and even cure this disease. In this review article, we first summarize the pathogenesis and state-of-the-art therapeutics of representative types of systemic human amyloidosis, that is, immunoglobulin light chain-related, transthyretin-related, amyloid A-associated and β₂ -microglobulin-related amyloidosis. Next, we describe the essential roles of pathological diagnosis, especially the typing diagnosis of amyloidosis to appropriately guide type-specific therapies of amyloidosis patients. Finally, we introduce the activities of the government-funded group for surveys and research of amyloidosis in Japan, especially the nation-wide pathology consultation system of amyloidosis, which started in April 2018. The nation-wide improvement of the typing diagnosis of amyloidosis is essential for the appropriate treatment and care of amyloidosis patients in Japan.

Chronic intestinal pseudo-obstruction due to β2microglobulin-amyloidosis in a patient on high-flux haemodialysis

Dialysis-related amyloidosis (DRA) or β2microglobulin (β2m)-amyloidosis is a disorder caused by the inability to clear a protein called β2m in patients with chronic kidney disease. It results in deposition of β2m as amyloid fibrils, most commonly in bones and joints. Infrequently, visceral organs may be involved. With modern high-flux haemodialysis, DRA has become a rare disease, yet it may occur. We present a case of DRA in an 86-year-old woman. This case is particularly notable for its rare presentation as chronic intestinal pseudo-obstruction. It is of paramount importance to recognise this entity in order to reduce delay in treatment and avoid patients being frustrated not getting a diagnosis.

Epidemiological survey and risk factor analysis of dialysis-related amyloidosis including destructive spondyloarthropathy, dialysis amyloid arthropathy, and carpal tunnel syndrome

The RDT population, initially at 215 patients, exceeded 300,000 in 2011, with a total of 329,609 patients at the end of December 2016. In our Institute, the number of patients with destructive spondylosis is increasing with the increase in the number of dialysis patients in Japan. We had 14 Cases in the 1990s, and then 82 cases in the 2000s and have already had 131 cases in the 2010s. The purpose of this study was to investigate the incidence of dialysis-related amyloidosis (DRA) such as destructive spondyloarthropathy (DSA), dialysis amyloid arthropathy (DAA), and carpal tunnel syndrome (CTS). In addition, another purpose was to examine the risk factors of the DRA. DAA made its own assessment on radiographs based on stage. Survey items were patient's basic data, laboratory data and X-ray view. Patient's basic data included such as sex, age, height, and weight and RDT-related factors such as kidney disease that led to RDT, age at start of RDT, RDT history, medical history (past and present), and history of surgery. The frequency of DRA was examined by medical history and radiological examination in 199 dialysis patients who obtained informed consent. The patients were divided into two groups according to the presence or absence of DRA, and risk factors of DRA were investigated from the medical history, basic data of patients, and blood tests. Of the 199 patients on regular dialysis therapy, 41 (20.6%) showed DRA. Based on the X-ray images, 21 patients (10.6%) showed DSA, while 22 patients (11.1%) showed DAA. Sixteen patients (8.0%) had CTS, determined through a history of surgery. Regarding overlap of conditions, 14 had both DSA and DAA, 3 had both DSA and CTS, and 2 had both DAA and CTS. There were statistically significant differences between the two groups in the cause of disease in Chronic glomerulonephritis and Diabetic Nephropathy, age at the start of RDT, period of RDT, body weight, blood platelet count, and blood Ca level. When multivariate analysis was performed on these items, statistical differences were recognized only during the dialysis period. In conclusion, long dialysis period was a risk factor for DRA.

Glycated albumin versus hemoglobin A1c and mortality in diabetic hemodialysis patients: a cohort study

Background

For glycemic control in diabetic patients on dialysis it was unclear what level of glycated albumin (GA) was associated with the lowest mortality and GA's utility. Accordingly, we examined the difference in association between GA and hemoglobin A1c (HbA1c) with 1-year mortality in a cohort of the Japanese Society for Dialysis Therapy.

Methods

We examined 84 282 patients with prevalent diabetes who were on maintenance hemodialysis (HD) (female 30.3%; mean age 67.3 ± 11.2 years; mean dialysis vintage 6.4 ± 4.5 years). Of them, 22 441 had both GA and HbA1c. We followed these for a year, 2013-14, using Cox regression to calculate adjusted hazard ratios (HRs) and 95% confidence limits for 1-year mortality after adjusting for potential confounders such as baseline age, sex, smoking and diabetes type.

Results

One-year mortality was lowest in diabetic HD patients who had GA levels of 15.6-18.2% and HbA1c levels of 5.8-6.3%. The associations were linear or J-shaped for GA and U-shaped for HbA1c. Adjusted HRs were significantly higher in patients with GA <12.5% and GA ≥22.9%. This trend flattened in elderly patients, those with higher hemoglobin or those with prior cardiovascular disease. In addition, the C-statistics, Harrell's C and category-free net reclassification improvement to predict 1-year mortality were better when GA was added to the model than when HbA1c was added.

Conclusions

There was a linear or J-shaped association between GA and 1-year mortality, with the lowest mortality at GA 15.6-18.2%. Furthermore, our analyses suggest the potential superiority of GA over HbA1c in predicting mortality.

Positron Emission Tomography Can Support the Diagnosis of Dialysis-Related Amyloidosis

BACKGROUND

The improvements in dialysis have not eliminated long-term problems, including dialysis-related amyloidosis (DRA), caused by Beta-2 microglobulin deposition. Several types of scintigraphy have been tested to detect DRA, none entered the clinical practice. Aim of the study was to assess the potential of PET-FDG scan in the diagnosis of DRA.

METHODS

Forty-six dialysis patients with at least one PET scan (72 scans) were selected out 162 patients treated in 2016-2018. Subjective global assessment (SGA), malnutrition inflammation score (A), Charlson Comorbidity Index (CCI), were assessed at time of scan; 218 age-matched cases with normal kidney function were selected as controls. PET scans were read in duplicate. Carpal tunnel syndrome was considered a proxy for DRA. A composite "amyloid score" score considered each dialysis year = 1 point; carpal tunnel-DRA = 5 points per site. Logistic regression, ROC curves and a prediction model were built.

RESULTS

The prevalence of positive PET was 43.5% in dialysis, 5% in controls (p < 0.0001). PET was positive in 14/15 (93.3%) scans in patients with carpal tunnel. PET sensitivity for detecting DRA was 95% (specificity 64%). Carpal tunnel was related to dialysis vintage and MIS. A positive PET scan was significantly associated with dialysis vintage, MIS and amyloid score. A prediction model to explain PET positivity combined clinical score and MIS, allowing for an AUC of 0.906 (CI: 0.813-0.962; p < 0.001).

CONCLUSIONS

PET-FDG may identify DRA, and may be useful in detecting cases in which inflammation favours B2M deposition. This finding, needing large-scale confirmation, could open new perspectives in the study of DRA.

Possible mechanisms of polyphosphate-induced amyloid fibril formation of β2-microglobulin

Polyphosphate (polyP), which is found in various microorganisms and human cells, is an anionic biopolymer consisting of inorganic phosphates linked by high-energy phosphate bonds. Previous studies revealed that polyPs strongly promoted the amyloid formation of several amyloidogenic proteins; however, the mechanism of polyP-induced amyloid formation remains unclear. In the present study using β₂-microglobulin (β2m), a protein responsible for dialysis-related amyloidosis, we investigated amyloid formation in the presence of various chain lengths of polyPs at different concentrations under both acidic (pH 2.0 to 2.5) and neutral pH (pH 7.0 to 7.5) conditions. We found that the amyloid formation of β2m at acidic pH was significantly accelerated by the addition of polyPs at an optimal polyP concentration, which decreased with an increase in chain length. The results obtained indicated that electrostatic interactions between positively charged β2m and negatively charged polyPs play a major role in amyloid formation. Under neutral pH conditions, long polyP with 60 to 70 phosphates induced the amyloid formation of β2m at several micromoles per liter, a similar concentration range to that in vivo. Since β2m with an isoelectric point of 6.4 has a slightly negative net charge at pH 7, polyPs were unlikely to interact with β2m electrostatically. PolyPs appear to dehydrate water molecules around β2m under the unfolded conformation, leading to the preferential stabilization of less water-exposed amyloid fibrils. These results not only revealed the pH-dependent mechanism of the amyloid formation of β2m but also suggested that polyPs play an important role in the development of dialysis-related amyloidosis.

MRI analysis of carpal tunnel syndrome in hemodialysis patients versus non-hemodialysis patients: a multicenter case-control study

BACKGROUND

Carpal tunnel syndrome (CTS) is common among patients receiving hemodialysis and deeply influences their daily life. Amyloid deposits are considered the main reason for median nerve compression, but its prevalence is unclear. Therefore, to determine the main region of amyloid deposition inside the carpal tunnel, we measured the cross-sectional area (CSA) of each component of the carpal tunnel in preoperative magnetic resonance imaging (MRI).

METHODS

Thirty-five hemodialysis patients (HD group) and age- and sex-matched 35 non-hemodialysis patients (non-HD group), who underwent the first surgery for CTS in registered hospitals from 2005 to 2015, were retrospectively enrolled. CTS was diagnosed from clinical and electromyographic (EMG) findings. The CSA of carpal tunnel, each of the flexor tendons, and the median nerve at the level of the hook of hamate were measured in T1-weighted axial images in preoperative MRI, by using Synapse OP-A software. Statistical analysis was performed using the Student's t test and Pearson's chi-squared test.

RESULTS

The mean age of the HD group was 65.9 years and the dialysis duration was 21.9 (11-35) years. The mean age of the non-HD group was 65.3 years. The CSA of carpal tunnel (p = 0.006), flexor tendon (p = 0.03), and flexor digitorum profundus (FDP) tendon (p = 0.04) were bigger in the HD group. However, the median nerve, the flexor digitorum superficialis (FDS) tendon, and the flexor pollicis longus tendon (FPL) were not significantly different between the two groups. The dialysis duration or age at surgery did not show any strong correlation to each CSA.

CONCLUSIONS

We confirmed that hemodialysis caused expansion of the carpal tunnel due to amyloid deposition as previously described. Hemodialysis also caused expansion of the CSA of the flexor tendon, especially the FDP, possibly because of amyloid deposition inside the tendon. Furthermore, the duration of dialysis or age did not correlate with any CSA, which could be due to the good progress of the beta 2-microglobulin removal technique. Based on our results, FDS excision could be considered in case severe deposition of amyloid in FDP is observed during surgery.

Moving beyond small solute clearance: What evidence is there for more permeable dialyzers and haemodiafiltration?

Dialyzers were initially developed for diffusive clearance of uraemic toxins. Diffusion most effectively clears small uncharged solutes from plasma water, such as urea. Sessional urea clearance targets have been shown to be important for short-term patient survival, but over the longer term, although low-flux dialysis can prolong patient survival, accumulation of middle-sized uraemic toxins, such as β2 microglobulin can lead to disabling arthropathy. Although the introduction of high-flux dialyzers, designed to increase β2 microglobulin clearance, has reduced the prevalence of arthropathy; this has not been translated into a demonstrable significant improvement in patient survival. However, analysis of individual patients recruited into trials of haemo-diafiltration reported that greater convective clearance was associated with better survival, although the individual trials reported mixed outcomes. Most haemodiafiltration trials were not designed to study the effect of convective dose, so although reported patient survival was greater for those receiving greater convective volume exchange, these results could potentially be confounded by patient or center effects. An alternative approach to increasing middle-sized solute clearances would be to use more permeable dialyzers, but as yet there are no trials reporting survival with larger cutoff dialyzers. As such, although there is increasing evidence that increasing middle-sized molecular uraemic solute clearance is associated with improved patient survival, further prospective trials are required to determine whether as with Kt/Vurea there is a threshold effect of how much convective or middle-sized solute clearance is required to improve patient survival.

Prescribing Hemodialysis or Hemodiafiltration: When One Size Does Not Fit All the Proposal of a Personalized Approach Based on Comorbidity and Nutritional Status

There is no simple way to prescribe hemodialysis. Changes in the dialysis population, improvements in dialysis techniques, and different attitudes towards the initiation of dialysis have influenced treatment goals and, consequently, dialysis prescription. However, in clinical practice prescription of dialysis still often follows a "one size fits all" rule, and there is no agreed distinction between treatment goals for the younger, lower-risk population, and for older, high comorbidity patients. In the younger dialysis population, efficiency is our main goal, as assessed by the demonstrated close relationship between depuration (tested by kinetic adequacy) and survival. In the ageing dialysis population, tolerance is probably a better objective: "good dialysis" should allow the patient to attain a stable metabolic balance with minimal dialysis-related morbidity. We would like therefore to open the discussion on a personalized approach to dialysis prescription, focused on efficiency in younger patients and on tolerance in older ones, based on life expectancy, comorbidity, residual kidney function, and nutritional status, with particular attention placed on elderly, high-comorbidity populations, such as the ones presently treated in most European centers. Prescription of dialysis includes reaching decisions on the following elements: dialysis modality (hemodialysis (HD) or hemodiafiltration (HDF)); type of membrane (permeability, surface); and the frequency and duration of sessions. Blood and dialysate flow, anticoagulation, and reinfusion (in HDF) are also briefly discussed. The approach described in this concept paper was developed considering the following items: nutritional markers and integrated scores (albumin, pre-albumin, cholesterol; body size, Body Mass Index (BMI), Malnutrition Inflammation Score (MIS), and Subjective Global Assessment (SGA)); life expectancy (age, comorbidity (Charlson Index), and dialysis vintage); kinetic goals (Kt/V, normalized protein catabolic rate (n-PCR), calcium phosphate, parathyroid hormone (PTH), beta-2 microglobulin); technical aspects including vascular access (fistula versus catheter, degree of functionality); residual kidney function and weight gain; and dialysis tolerance (intradialytic hypotension, post-dialysis fatigue, and subjective evaluation of the effect of dialysis on quality of life). In the era of personalized medicine, we hope the approach described in this concept paper, which requires validation but has the merit of providing innovation, may be a first step towards raising attention on this issue and will be of help in guiding dialysis choices that exploit the extraordinary potential of the present dialysis "menu".

Tendon thickening in dialysis-related joint arthritis is due to amyloid deposits at the surface of the tendon

OBJECTIVES

Beta-2-microglobulin (β2M) dialysis-related amyloidosis (DRA), a disabiliting joint disease, has been initially reported in patients under long-term dialysis. The incidence and prevalence has significantly decreased with the improvement in dialysis techniques. Here, we attempted to clarify the clinical and MRI features to improve the diagnosis.

METHODS

We retrospectively reviewed the files of 19 patients under dialysis treatment referred for suspicion of β2M DRA. The diagnosis was based on MRI criteria (low signal intensity on both T1- and T2-weighted MR sequences). MRI analysis included a scoring of the several joint lesions. Scores were quantified according to a severity scale (0 to 3).

RESULTS

Patients had a mean age of 66.0 ± 10.5 years and mean dialysis duration of 23.7 ± 10.5 years. DRA affected mainly large joints (shoulder in 73.7%, hip in 47.3%) and spine (36.8%). MRI images for 8 shoulders, 8 hips, and 3 spines were analysed. Amyloid synovitis was present in all cases, with high mean scores in the three sites. In all joints, the most common lesions were tendon thickening (68.4%) and bone erosions (68.4%). The mean tendon thickening score was high, particularly at the shoulders and also at the spine. Bone erosions were most frequent in the shoulder and pelvis.

CONCLUSION

In patients under long-term dialysis, β2M DRA involves large joints but also the spine. Special awareness should be drawn by the thickening of the tendon. MRI is required to characterize the pattern of the lesions and to achieve the diagnosis.

Rate of the "burnt-out diabetes" phenomenon in patients on peritoneal dialysis

AIMS

In some diabetes patients on dialysis, glycemic control improves spontaneously, leading to normal HbA1c levels; this phenomenon is known as "burnt-out diabetes." Glycated albumin (GA) might be a better indicator of glycemic control than HbA1c in hemodialysis patients, but it has not been assessed in peritoneal dialysis (PD) patients.

METHODS

This study involved diabetes patients on PD, with HbA1c level and antidiabetes therapy records. First, the "burnt-out diabetes" phenomenon was investigated in patients with HbA1c measurements alone (HbA1c cohort). Then, it was investigated in patients with both HbA1c and GA measurements (GA cohort).

RESULTS

A total of 1296 patients were included in the HbA1c cohort. When "burnt-out diabetes" was defined as HbA1c < 6.0% without treatment, it was noted in 269 patients (20.8%). A total of 413 patients were subsequently included in the GA cohort. "Burnt-out diabetes," using the same definition, was found in 73 patients (17.7%). However, when defined as HbA1c < 6.0% and GA < 16.0% without treatment, "burnt-out diabetes" was found in 45 patients (10.9%).

CONCLUSIONS

Although the "burnt-out diabetes" phenomenon was present in 17.7% of patients with diabetes on PD based on HbA1c, the rate was significantly decreased to 10.9% when taking GA into account.

Doxycycline treatment in dialysis related amyloidosis: discrepancy between antalgic effect and inflammation, studied with FDG-positron emission tomography: a case report

Background

No effective treatment is currently available and dialysis related amyloidosis continues to be invalidating in long-term dialysis patients. A recent case series reported reduction of osteoarticular pain on doxycycline treatment, extending the indications of this drug, used in other uncommon forms of amyloidosis, to dialysis patients. Explanations of the antalgic effect were the anti-inflammatory properties and anti-coiling effects of tetracycline.

Case presentation

Our report regards a 54-year-old woman, who was never transplanted and has been on hemodialysis and hemodiafiltration for overall 37 years, due to renal hypoplasia. In spite of high efficiency hemodiafiltration, she complained of increasing, invalidating osteoarticular pain; history and imaging suggested beta-2 microglobulin amyloid. Positron emission tomography (PET scan) identified metabolically active lesions in the involved settings. Low-dose doxycycline (100 mg/day) was started, leading to a considerable decrease in pain (over 6 months, from 7 to 8 to 4–5 on a 0–10 scale). At 6 months, a PET scan showed unmodified or increased uptake in the involved settings.

Conclusions

In summary, the previously described antalgic effect of doxycycline in dialysis related amyloidosis is confirmed in our case, the first studied using PET scan. The pattern at PET can suggests that the antalgic effect is independent from inflammation and points to other factors, such as interaction with fibril geometry or with bone structure.

High-Performance Membrane Dialyzers and Mortality in Hemodialysis Patients: A 2-Year Cohort Study from the Annual Survey of the Japanese Renal Data Registry

BACKGROUND

Little information is available regarding the type of dialyzer which results in good prognosis. This study is aimed at investigating the association between 7 types of dialyzers and 2-year mortality.

METHODS

We conducted a cohort study using data from a nationwide registry of the Japanese Society for Dialysis Therapy. Subjects were 136,676 patients on maintenance hemodialysis (HD) between 2009 and 2011 who underwent maintenance HD for at least 2 years and were treated with one of the following 7 types of high-performance membrane dialyzers: cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester polymer alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause 2-year mortality, adjusting for potential confounders.

RESULTS

Data were adjusted using basic factors, with PS as a reference group, and the hazard ratio (HR) was significantly higher in CTA, PMMA, PAN, and EVAL groups. Further data adjustment for Kt/V yielded the same results as were obtained from data adjusted for basic factors. After further adjustment for nutrition- and inflammation-related factors, HR was significantly lowered for the PES and PMMA groups compared with the PS group (HR 0.88; 95% CI 0.82-0.94 and HR 0.84 95% CI 0.76-0.93, respectively). After propensity score matching, HR for the PES and PMMA groups was significantly lowered compared with the PS group.

CONCLUSIONS

The use of different membrane types may affect mortality. Further long-term prospective studies are needed to clarify whether the PES and PMMA membranes can improve prognosis.

Multicentre cross-sectional study for bone-articular lesions associated with dialysis related amyloidosis in Japan

AIM

Dialysis-related amyloidosis (DRA) exhibits multiple bone-articular lesions, such as carpal tunnel syndrome (CTS), trigger finger (TF), spinal canal stenosis (SCS), destructive spondyloarthropathy (DSA), bone cysts, and joint pains. DRA leads to a decrease in activities of daily living (ADL). We investigated the initiation of CTS and TF, and evaluated the relationship between walking disturbances and bone-articular lesions or joint pains.

METHODS

A multicentre cross-sectional study was performed. Eighty-two patients with clinical DRA from 20 hospitals in Japan were evaluated.

RESULTS

Of the 82 patients, the first symptom of DRA was CTS in 39 patients (47.6%) and TF in 21 (25.6%). The mean new-onset vintages of 21 earlier cases in the CTS and TF groups were 86.1 ± 36.3 and 133.2 ± 56.4 (mean ± SD) months, respectively (P = 0.0091). The development of SCS and DSA appeared to be later than CTS and TF. Multiple regression analysis revealed that knee joint pain was a significant contributor to walking disturbances.

CONCLUSION

Carpal tunnel syndrome appeared significantly earlier than TF since the initiation of dialysis. In the advanced phase, knee joint pain was a major cause of decreased ADL in patients with clinical DRA.

Dialysis-related amyloidosis: challenges and solutions

Amyloidosis refers to the extracellular tissue deposition of fibrils composed of low-molecular-weight subunits of a variety of proteins. These deposits may result in a wide range of clinical manifestations depending upon their type, location, and the amount of deposition. Dialysis-related amyloidosis is a serious complication of long-term dialysis therapy and is characterized by the deposition of amyloid fibrils, principally composed of β2 microglobulins (β2M), in the osteoarticular structures and viscera. Most of the β2M is eliminated through glomerular filtration and subsequent reabsorption and catabolism by the proximal tubules. As a consequence, the serum levels of β2M are inversely related to the glomerular filtration rate; therefore, in end-stage renal disease patients, β2M levels increase up to 60-fold. Serum levels of β2M are also elevated in several pathological conditions such as chronic inflammation, liver disease, and above all, in renal dysfunction. Retention of amyloidogenic protein has been attributed to several factors including type of dialysis membrane, prolonged uremic state and/or decreased diuresis, advanced glycation end products, elevated levels of cytokines and dialysate. Dialysis treatment per se has been considered to be an inflammatory stimulus, inducing cytokine production (such as interleukin-1, tumor necrosis factor-α, interleukin-6) and complement activation. The released cytokines are thought to stimulate the synthesis and release of β2M by the macrophages and/or augment the expression of human leukocyte antigens (class I), increasing β2M expression. Residual renal function is probably the best determinant of β2M levels. Therefore, it has to be maintained as long as possible. In this article, we will focus our attention on the etiology of dialysis-related amyloidosis, its prevention, therapy, and future solutions.