Determination of Kt/V and protein catabolic rate using pre- and postdialysis blood urea nitrogen concentrations

Association Between Potential Renal Acid Load and 10-Year Mortality in Patients on Hemodialysis

OBJECTIVES

Higher dietary acid load (DAL) has been linked to elevated incidence and progression of chronic kidney disease. However, the association between DAL and mortality in patients on maintenance hemodialysis (MHD) has not been evaluated.

METHODS

We retrospectively analyzed baseline laboratory data, self-administered diet history questionnaire results, and 10-year mortality rates in 44 patients (26 men, 67.9 ± 10.4 years) on MHD who participated in a randomized, double-blind, crossover pilot trial of rice endosperm protein supplementation, which was conducted in 2013. DAL was estimated from nutrition intake using potential renal acid load (PRAL), and patients were divided into tertiles using this score.

RESULTS

During the 10-year observation period, 19 patients (43%) died. A higher PRAL score was significantly associated with higher all-cause mortality. The multivariable-adjusted hazard ratio for all-cause mortality in the highest tertile of PRAL versus the lowest tertile was 3.88 (95% confidence interval [CI], 1.10-13.61). Multiple logistic regression analysis showed a significant association between higher PRAL and lower intake of green and yellow vegetables (odds ratio, 5.40; 95% CI, 1.37-21.26) and fruits (odds ratio, 4.76; 95% CI, 1.30-16.76).

CONCLUSIONS

Higher PRAL is positively associated with all-cause mortality, and these associations might be affected by a lower intake of fruits and vegetables in Japanese patients on MHD.

Plasma Metabolite Profiles Between In-Center Daytime Extended-Hours and Conventional Hemodialysis

Key Points

Significant differences in 39 plasma metabolites were observed between patients on extended-hours hemodialysis and those on conventional hemodialysis. Extended-hours hemodialysis had a lower lactate-to-pyruvate ratio and higher branched-chain amino acids than conventional hemodialysis. Extended-hours hemodialysis may have favorable metabolic and nutritional benefits for patients undergoing maintenance hemodialysis.

Background

Protein–energy wasting, characterized by disordered body protein catabolism resulting from metabolic and nutritional derangements, is associated with adverse clinical outcomes in patients undergoing hemodialysis. Extended-hours hemodialysis (≥6 hours per treatment session) offers both enhanced removal of uremic solutes and better fluid management, generally allowing more liberalized dietary protein and calorie intake. The aim of this study was to evaluate the difference in plasma metabolite profiles among patients receiving in-center daytime extended-hours hemodialysis and those receiving conventional hemodialysis.

Methods

Predialysis plasma samples were obtained from 188 patients on extended-hours hemodialysis (21.9 h/wk) and 286 patients on conventional hemodialysis (12.1 h/wk) in Japan in 2020 using capillary electrophoresis-mass spectrometry. Group differences were compared for 117 metabolites using Wilcoxon rank-sum tests with multiple comparisons and partial least squares discriminant analysis. In addition, propensity score–adjusted multiple regression analyses were performed to evaluate group differences for known uremic toxins, branched-chain amino acids, and lactate-to-pyruvate ratio (a possible surrogate marker of mitochondrial dysfunction).

Results

Significant differences were observed in 39 metabolites, largely consistent with the high variable importance for prediction in partial least squares discriminant analysis. Among known uremic toxins, uridine and hypoxanthine levels were significantly higher in the conventional hemodialysis group than in the extended-hours hemodialysis group, whereas trimethylamine N -oxide levels were higher in the extended-hours hemodialysis group than in the conventional hemodialysis group. Patients on extended-hours hemodialysis had higher levels of all branched-chain amino acids and a lower lactate-to-pyruvate ratio than those on conventional hemodialysis (significant difference of −8.6 [95% confidence interval, −9.8 to −7.4]).

Conclusions

Extended-hours hemodialysis was associated with a more favorable plasma metabolic and amino acid profile; however, concentrations of most uremic toxins did not significantly differ from those of conventional hemodialysis.

Association of Ankle-Brachial Index with Quality of Life and Survival Outcomes in Hemodialysis Patients

Background/Objectives: Ankle-brachial index (ABI) is frequently measured in hemodialysis patients due to their high cardiovascular risk, while its potential role as a screening tool for assessing overall physical function and health-related quality of life (QOL) remains unclear. This study aimed to evaluate the association of the ABI with QOL and survival in hemodialysis patients. Methods: This study included 346 hemodialysis patients, categorized into two groups based on their ABI (≤0.9 vs. >0.9). Clinical parameters, QOL (measured using SF-36 and KDQOL questionnaires), and survival outcomes were analyzed. Results: There were 66 (19.1%) patients with an ABI ≤ 0.9 in this study population. Patients with an ABI ≤ 0.9 exhibited significantly older ages, longer dialysis durations, higher prevalence of diabetes mellites and cardiovascular disease, elevated N-terminal pro-brain natriuretic peptide levels, and higher calcitriol use but lower phase angle, skeletal muscle mass index values, health-related QOL domains, and several kidney disease-specific QOL domains compared to those with an ABI > 0.9. Kaplan-Meier analysis revealed significantly higher cumulative mortality in the ABI ≤ 0.9 group (6.6 vs. 2.5 per 100 patient-years, p < 0.001). Conclusions: A low ABI is significantly associated with decreased QOL and higher mortality risk in hemodialysis patients. While traditionally used for PAD screening, the ABI may serve as a practical tool for predicting QOL decline and survival outcomes. Interestingly, the ABI was also linked to muscle attenuation and volume overload. ABI assessment could aid in early risk stratification and guide multidisciplinary interventions, including exercise programs, nutritional support, and cardiovascular risk management, to improve patient care and outcomes.

Longitudinal impact of extended-hours hemodialysis with a liberalized diet on nutritional status and survival outcomes: findings from the LIBERTY cohort

BACKGROUND

Protein-energy wasting (PEW), a unique weight loss linked to nutritional and metabolic abnormalities, is common in patients undergoing hemodialysis (HD) and associated with adverse outcomes. This study investigated whether extended-hours HD combined with a liberalized diet could overcome PEW and improve survival.

METHODS

The body mass index (BMI) and survival outcomes in patients undergoing extended-hours HD were evaluated for up to 8 years using data from the LIBeralized diet Extended-houRs hemodialysis Therapy (LIBERTY) cohort. Extended-hours HD was defined as weekly dialysis length ≥ 18 h.

RESULTS

The LIBERTY cohort included 402 patients who initiated extended-hours HD. An increase in the length and frequency of HD sessions was observed over time, with approximately 70% and 20% of patients undergoing extended-hours HD for > 21 h/week and > 3 sessions/week at 5 years, respectively. The BMI and percentage creatinine generation rate were maintained over time, with no substantial increase in the phosphorus and potassium levels. The estimated BMI initially increased, and thereafter plateaued over time in patients with a baseline BMI < 25 kg/m2, whereas it decreased gradually in patients with a baseline BMI ≥ 25 kg/m2 after several years from baseline. Ninety-one patients died, and 108 discontinued extended-hours HD during the median follow-up period of 6.2 years (interquartile range, 3.5-8.0), yielding a 5-year survival rate of 85%.

CONCLUSIONS

Extended-hours HD with a liberalized diet may help achieve favorable survival outcomes and maintain nutritional status. Thus, it is a promising treatment option for managing PEW in patients undergoing HD.

Prevalence of locomotive syndrome and associated factors in patients receiving hemodialysis

Muscle strength and joint and nervous system functions decline with age and in patients undergoing hemodialysis. The Japanese Orthopaedic Association has defined locomotive syndrome (LoS) as a musculoskeletal disorder primarily caused by aging. Therefore, this study aimed to investigate the prevalence of LoS and identify factors associated with its development in patients undergoing hemodialysis. Patients receiving outpatient hemodialysis at Kurume University Hospital were categorized into LoS and non-LoS groups using the cutoff value of 25-question Geriatric Locomotive Function Scale (GLFS-25). We analyzed differences in malnutrition, biochemical examinations, and Kt/V (a measure of dialysis adequacy) between the 2 groups using Wilcoxon rank-sum tests. Additionally, we evaluated factors that correlated with GLFS-25 through pairwise correlations. Multivariate analysis was performed to determine the independent factors associated with LoS. Nineteen patients were included. The median GLFS-25 score was 18. The LoS group (n = 11) had a significantly higher age (P = .0056) and chloride levels than the non-LoS group (n = 8) (P = .0175). Furthermore, the Nutritional Risk Index for Japanese Hemodialysis patients, creatinine levels, and Kt/V were significantly lower in the LoS group than in the non-LoS group (P = .0156, .0026, and .0163, respectively). The GLFS-25 showed significant correlations with age, total protein levels, C-reactive protein, chloride, creatinine, Nutritional Risk Index for Japanese Hemodialysis patients, and Kt/V (with correlation coefficients of -0.6133, -0.4779, 0.4738, 0.5381, -0.7923, 0.6508, and 0.5747, respectively). Multivariate analysis identified life-space assessment (odds ratio [OR], 3.06; 95% confidence interval [CI], -676 to 674; P < .0001) and age (OR, 31.29; 95% CI, -2061 to 2067; P = .0007) as risk factors for LoS. Age and physical activity were found to be associated with the development of LoS in patients with end-stage renal disease undergoing outpatient hemodialysis at our hospital. This emphasizes the importance of implementing preventative measures for LoS, especially for older and less physically active patients.

Efficacy and safety of intradialytic parenteral nutrition using ENEFLUID® in malnourished patients receiving maintenance hemodialysis: An exploratory, multicenter, randomized, open-label study

The objective of this study was to investigate the efficacy and safety of intradialytic parenteral nutrition (IDPN) using ENEFLUID® (310 kcal, 550 mL) in mild-moderate malnutrition patients receiving maintenance hemodialysis. A total of 40 adult patients with a Nutritional Risk Index-Japanese Hemodialysis (NRI-JH) score of 5-10 were enrolled in this multicenter, randomized, open-label study. Patients in the intervention group received IDPN using ENEFLUID® via the dialysis circuit 3 times a week for 12 weeks; those in the control group did not. The primary endpoint was change in serum transthyretin (TTR). The secondary endpoints were changes in nutritional laboratory tests, nutritional parameters, food intake, plasma amino acids, and blood glucose. For both groups, mean age (72.1±11.4 years) and BMI (20.3±3.0), and median NRI-JH score [7.0 (interquartile range, 6-8)], did not differ. One patient withdrew before intervention, leaving 20 intervention and 19 control patients. Mean (95% confidence interval) change in serum TTR (mg/dL) at 12 weeks did not differ between groups: Intervention, 1.0 (-1.1-3.2); Control, -0.3 (-2.4-1.9); Intragroup difference, 1.3 (-1.7-4.3); P = 0.41. The values reflecting protein intake at 12 weeks compared to those on the study initiation day increased in the intervention group [the changes of blood urea nitrogen, 9.4 (2.6-16.2) mg/dL; P = 0.007, and normalized protein catabolic rate, 0.10 (0.02-0.18) g/kg/day; P = 0.02]. Mean food protein intake (g/kg/day) at 12 weeks increased in the intervention group and decreased in the control group, and differed between groups: Intervention, 0.12 (-0.03-0.28); Control, -0.18 (-0.43-0.08); Inter-group difference, 0.30 (0.00-0.60); P = 0.050. No adverse events occurred. In patients with mild to moderate malnutrition receiving ENEFLUID® for 12 weeks as IDPN, serum TTR was not improved, decreases in protein intake was mitigated, no adverse events occurred. Trial registration Name of the registry: Japan Registry of Clinical Trials Registration number: jRCTs031220296.

Body fluid volume calculated using the uric acid kinetic model relates to the vascular event

PURPOSE

We developed a method to measure the extracellular and intracellular fluid volumes using the kinetics of uric acid in the bodies of Japanese patients undergoing dialysis. In this research, we aimed to assess the prognosis of vascular events using this uric acid kinetic model method.

METHODS

We conducted a retrospective cohort study of 1,298 patients who were undergoing hemodialysis or predilution online hemodiafiltration at the end of December 2019 at 13 institutions in Japan. Information on vascular events was acquired in 2020. Vascular event prognosis was defined as the new incidence of one or more of the following four types of vascular events: myocardial infarction, cerebral infarction, cerebral hemorrhage, or limb amputation. We measured the extracellular fluid volume and intracellular fluid volume after dialysis using the uric acid kinetic model method and determined the association between ECV, ICV, and vascular event risk.

RESULTS

A high extracellular volume was substantially linked to an increased risk of vascular events. In addition, while a crude analysis revealed that a high intracellular volume was associated with a low risk of vascular events, this was not statistically significant after multifactorial adjustment. This result was partly affected by the low measurement accuracy of the serum urea nitrogen level used for the intracellular volume calculation.

CONCLUSIONS

Extracellular volume calculated using the uric acid kinetic model method is a prognostic factor for vascular events in patients undergoing hemodialysis.

Rapid prototyping of multi-compartment models for urea kinetics in hemodialysis: a System Dynamics approach

Models of urea kinetics facilitate a mechanistic understanding of urea transfer and provide a tool for optimizing dialysis efficacy. Dual-compartment models have largely replaced single-compartment models as they are able to accommodate the urea rebound on the cessation of dialysis. Modeling the kinetics of urea and other molecular species is frequently regarded as a rarefied academic exercise with little relevance at the bedside. We demonstrate the utility of System Dynamics in creating multi-compartment models of urea kinetics by developing a dual-compartment model that is efficient, intuitive, and widely accessible to a range of practitioners. Notwithstanding its simplicity, we show that the System Dynamics model compares favorably with the performance of a more complex volume-average model in terms of calibration to clinical data and parameter estimation. Its intuitive nature, ease of development/modification, and excellent performance with real-world data may make System Dynamics an invaluable tool in widening the accessibility of hemodialysis modeling.

Effects of overhydration, Kt/Vurea, β2-microglobulin on coronary artery calcification and mortality in haemodialysis patients

AIM

We studied the effects of overhydration (OH), Kt/Vurea and β2-microglobulin (β2-MG) on coronary artery calcification and mortality in patients undergoing haemodialysis (HD).

METHODS

The Agatston coronary artery calcium score (CACS), postdialysis body composition using bioimpedance analysis, single-pool Kt/Vurea and predialysis β2-MG at baseline were assessed and followed up for 3 years in patients undergoing HD. We performed logistic regression analyses for a CACS ≥400 and Cox proportional hazard analyses for all-cause and cardiovascular mortality.

RESULTS

The study involved 338 patients with a median age of 67 (56-74) years, dialysis duration of 70 (33-141) months and diabetes prevalence of 39.1% (132/338). Patients with a CACS ≥400 (n = 222) had significantly higher age, dialysis duration, male prevalence, diabetes prevalence, C-reactive protein, predialysis β2-MG, OH, extracellular water/total body water and overhydration/extracellular water (OH/ECW) but significantly lower Kt/Vurea than patients with a CACS <400 (n = 116) (p < .05). OH/ECW, Kt/Vurea and predialysis β2-MG were significant predictors of a CACS ≥400 (p < .05) after adjusting for age, dialysis duration, serum phosphate and magnesium. In all patients, cut-off values of OH/ECW, Kt/Vurea and predialysis β2-MG for a CACS ≥400 were 16%, 1.74 and 28 mg/L, respectively. After adjusting for dialysis duration, OH/ECW ≥16%, Kt/Vurea ≥1.74 and β2-MG ≥28 mg/L were significant predictors of 3-year all-cause mortality but not 3-year cardiovascular mortality.

CONCLUSION

Higher OH/ECW, higher predialysis β2-MG and lower Kt/Vurea values are significant risk factors for a CACS ≥400 and 3-year all-cause mortality in patients undergoing maintenance HD.

Anti-SARS-CoV-2 Spike Antibody Response to the Fourth Dose of BNT162b2 mRNA COVID-19 Vaccine and Associated Factors in Japanese Hemodialysis Patients

Background

We assessed the anti-SARS-CoV-2 spike antibody response to four doses of BNT162b2 mRNA COVID-19 vaccine in Japanese hemodialysis patients and determined factors associated with the anti-SARS-CoV-2 spike antibody titer after the fourth dose.

Methods

Fifty-one patients were enrolled in this single-center, prospective, longitudinal study. Change in anti-SARS-CoV-2 spike antibody titers between after the second and fourth doses were evaluated. Multiple linear regression analysis was used to identify factors associated with the anti-SARS-CoV-2 spike antibody titer after the fourth dose.

Results

The anti-SARS-CoV-2 spike antibody titer was higher 4 weeks after the fourth dose compared with 4 weeks after the third dose (30,000 [interquartile range (IQR), 14,000-56,000] vs 18,000 [IQR, 11,000-32,500] AU/mL, p<0.001) and 4 weeks after the second dose (vs 2896 [IQR, 1110-4358] AU/mL, p<0.001). Hypoxia-inducible factor prolyl hydroxylase inhibitor use (standard coefficient [β]=0.217, p=0.011), and the log-anti-SARS-CoV-2 spike antibody titer 1 week before the fourth dose (β=0.810, p<0.001) were correlated with the log-anti-SARS-CoV-2 spike antibody titer 4 weeks after the fourth dose, whereas only the log-anti-SARS-CoV-2 spike antibody titer 1 week before the fourth dose (β=0.677, p<0.001) was correlated with the log-anti-SARS-CoV-2 spike antibody titer 12 weeks after the fourth dose.

Conclusion

Hypoxia-inducible factor prolyl hydroxylase inhibitor use and the anti-SARS-CoV-2 spike antibody titer before the fourth dose were associated with the anti-SARS-CoV-2 spike antibody titer after the fourth dose in Japanese hemodialysis patients.

Anti-SARS-CoV-2 spike antibody response to the third dose of BNT162b2 mRNA COVID-19 vaccine and associated factors in Japanese hemodialysis patients

BACKGROUND

We assessed the anti-SARS-CoV-2 spike antibody response to the third dose of BNT162b2 mRNA COVID-19 vaccine in Japanese hemodialysis patients and determined factors associated with the anti-SARS-CoV-2 spike antibody titer after the third dose of COVID-19 vaccine.

METHODS

Overall, 64 patients were enrolled in this single-center, prospective, longitudinal study. Anti-SARS-CoV-2 spike antibody titers were compared between hemodialysis patients and 18 healthcare workers. Multiple linear regression analysis was used to identify factors associated with the anti-SARS-CoV-2 spike antibody titer after the third vaccination.

RESULTS

There was no significant difference in anti-SARS-CoV-2 spike antibody titer 4 weeks after the third vaccination between hemodialysis patients and healthcare workers (18,500 [interquartile range, 11,000-34,500] vs. 11,500 [interquartile range, 7,918- 19,500], all values in AU/mL; p = 0.17). Uric acid (standard coefficient [β] = -0.203, p = 0.02), transferrin saturation (β = -0.269, p = 0.003), and log-anti-SARS-CoV-2 spike antibody titer 1 week before the third vaccination (β = 0.440, p < 0.001) correlated with the log-anti-SARS-CoV-2 spike antibody titer 4 weeks after the third vaccination. In contrast, only the log-anti-SARS-CoV-2 spike antibody titer 1 week before the third vaccination (β = 0.410, p < 0.001) correlated with the log- anti-SARS-CoV-2 spike antibody titer 12 weeks after the third vaccination.

CONCLUSION

The anti-SARS-CoV-2 spike antibody titer after the third dose of COVID-19 vaccine was comparable between hemodialysis patients and healthcare workers. Uric acid concentration, transferrin saturation, and anti-SARS-CoV-2 spike antibody titer before the third dose were associated with the anti-SARS-CoV-2 spike antibody titer after the third dose in Japanese hemodialysis patients.

Association between Intra- and Extra-Cellular Water Ratio Imbalance and Natriuretic Peptides in Patients Undergoing Hemodialysis

Natriuretic peptides are associated with malnutrition and volume overload. Over-hydration cannot simply be explained by excess extracellular water in patients undergoing hemodialysis. We assessed the relationship between the extracellular and intracellular water (ECW/ICW) ratio, N-terminal pro-B-type natriuretic peptide (NT-proBNP), human atrial natriuretic peptide (hANP), and echocardiographic findings. Body composition was examined by segmental multi-frequency bioelectrical impedance analysis in 368 patients undergoing maintenance dialysis (261 men and 107 women; mean age, 65 ± 12 years). Patients with higher ECW/ICW ratio quartiles tended to be older, were on dialysis longer, and had higher post-dialysis blood pressure and lower body mass index, ultrafiltration volume, serum albumin, blood urea nitrogen, and creatinine levels (p < 0.05). The ECW/ICW ratio significantly increased with decreasing ICW, but not with ECW. Patients with a higher ECW/ICW ratio and lower percent fat had significantly higher natriuretic peptide levels. After adjusting for covariates, the ECW/ICW ratio remained an independent associated factor for natriuretic peptides (β = 0.34, p < 0.001 for NT-proBNP and β = 0.40, p < 0.001 for hANP) and the left ventricular mass index (β = 0.20, p = 0.002). The ICW-ECW volume imbalance regulated by decreased cell mass may explain the reserve capacity for fluid accumulation in patients undergoing hemodialysis.

Decreased Physical and Daily Living Activities in Patients with Peripheral Arterial Disease on Hemodialysis

Decreased physical activity and activities of daily living (ADL) in patients on hemodialysis (HD) are associated with a poor prognosis. Additionally, comorbid peripheral arterial disease is associated with further deterioration. We conducted a cross-sectional study of ADL difficulty and life-space assessment (LSA) in three groups of patients on hemodialysis according to their ankle-brachial index (ABI) values. The 164 patients were divided into ABI Low (ABI < 0.9), Normal (0.9 ≤ ABI < 1.3), and High (1.3 ≤ ABI) groups, and compared using analysis of covariance with LSA and ADL difficulty adjusted for age. The Kihon checklist (KCL) was used to assess the presence of frailty. The LSA was lower in the Low group than in the High group (F = 3.192, p = 0.044). Similarly, the ADL difficulty was significantly lower in the Low group than in the Normal group (F = 3.659, p = 0.028). In the Low group, the proportion of patients with frailty was 47.1% and KCL physical was significantly lower, indicating that patients on HD with a lower ABI had a higher prevalence of frailty and lower LSA and ADL difficulty. In conclusion, patients on HD with decreased ABI values most likely exhibit decline in physical activity and ADL due to frailty and claudication.

Influence of sex differences in maintenance-hemodialysis participants on motivation of exercise therapy implementation: a multicenter cross-sectional study

BACKGROUND

Exercising requires continuing training and maintenance of motivation. Support for exercise continuation by setting sex-appropriate goals is needed. However, this has not been investigated in patients undergoing hemodialysis. This study aimed to investigate sex differences in exercise motivation by analyzing an open-ended questionnaire of patients undergoing hemodialysis.

METHODS

This multicenter, cross-sectional study was conducted among participants undergoing outpatient hemodialysis at 21 dialysis clinics. Before the intradialytic exercise program, a self-reported questionnaire was used to assess exercise purpose using open-label questions. Exercise purpose was analyzed between sexes by quantitative analysis of text, extracting frequently occurring words, creating a co-occurrence network, and constructing concepts. The basic attributes of the two groups were compared using the chi-squared and independent t tests.

RESULTS

The analysis of 669 participants who attended an exercise program showed that the common words for exercise purpose in both sexes were strength, maintenance, walking, exercise, and muscle strength. Significant differences were observed in exercise purpose. Concepts related to the purpose of exercise were categorized into (1) physical function and condition, (2) addressing limitations, and (3) maintaining daily life activities. Physical appearance was important in both sexes. The main purpose of exercise for men was to increase physical fitness and muscle strength, while that for women was to maintain or improve their current functional status and prevent limb weakness. Women had significantly weaker muscle strength and poorer exercise habits than men and had more difficulty in daily life, suggesting that their purpose for exercise was to reduce difficulties in daily life and the burden on family. Women had significantly weaker muscle strength and poorer exercise habits than men and had more difficulty in daily life, suggesting that their purpose for exercise was to reduce difficulties in daily life and the burden on family. Furthermore, fear of falls was higher in women and prevention of falls may be a key for motivation.

CONCLUSION

Exercise purpose in patients undergoing hemodialysis was summarized into the categories of physical function and condition, exercise, and daily life. Men aimed to maintain and increase their current physical status, and women aimed to reduce anxiety regarding their lower limbs and lack of exercise. It is necessary to consider sex differences in exercise purpose when designing exercise regimens and motivating participants.

Association between adrenal function and dialysis vintage in hemodialysis patients

INTRODUCTION

Adrenal insufficiency in hemodialysis patients is commonly encountered in clinical practice. However, its association with end-stage renal disease is unclear. We investigated the relationship between adrenal function and relevant clinical parameters, focusing on dialysis vintage.

METHODS

Altogether, 100 maintenance hemodialysis patients were enrolled (age: 69.8 ± 11.8 years, dialysis vintage: 9.4 ± 9.2 years). Basal serum cortisol levels were measured and their associations with relevant clinical parameters were investigated. Subsequently, hormone stimulation tests were performed to assess adrenal function.

RESULTS

Basal serum cortisol significantly decreased with an increase in dialysis vintage (< 10 years, 11.9 ± 3.7 μg/dL; 10-19 years, 10.9 ± 2.9 μg/dL; ≥ 20 years, 9.7 ± 3.8 μg/dL). Basal cortisol was negatively correlated with dry weight, β2-microglobulin, creatinine, and lymphocyte count and positively correlated with brachial-ankle pulse wave velocity. Significant negative correlations were observed between basal cortisol and dialysis vintage after adjusting for confounding variables in the multivariate analysis. Standard adrenocorticotropic hormone (ACTH) and corticotropin-releasing hormone (CRH) stimulation tests were performed in 17 patients. Seven patients were diagnosed with adrenal insufficiency and all of them had a long dialysis vintage (≥ 10 years). According to the rapid ACTH test, cortisol responses were significantly decreased in patients with long dialysis vintage compared to those with short dialysis vintage (< 10 years). Similar findings were observed in ten patients without adrenal insufficiency. The CRH loading test showed similar tendencies, although the differences were not statistically significant.

CONCLUSIONS

Adrenal function decreased with an increase in dialysis vintage. Long-term dialysis patients might be susceptible to adrenal insufficiency.

Effect of intradialytic exercise on geriatric issues in older patients undergoing hemodialysis: a single-center non-randomized controlled study

PURPOSE

This study investigated the effect of 1 year of intradialytic exercise on older hemodialysis patients with geriatric issues.

METHODS

Forty-six patients aged ≥ 70 years were non-randomly assigned to two groups (exercise group: 27, control group: 19). Intradialytic exercise consisted of 30 min of aerobic exercise using a cycle ergometer, and resistance training comprising four exercises using an elastic tube three times per week for 1 year. Handgrip strength, leg extremity muscle strength, 10-m walk speed, short physical performance battery, serum albumin, Geriatric Nutritional Risk Index (GNRI), geriatric depression scale, frailty, and mobility were each assessed before and after the intervention.

RESULTS

The control group exhibited a significant reduction in handgrip strength, 10-m walking speed, serum albumin, and GNRI after intervention compared to baseline (p < 0.05). Conversely, no significant reductions were observed in the exercise group. The ΔGNRI (effect size, 0.69; 95% confidence interval [CI]  - 5.21, - 0.1; p < 0.05) and Δserum albumin (effect size, 0.72; 95% CI - 0.31, - 0.02; p < 0.05) before and after the intervention declined significantly less in the exercise group than in the control group. Other between-group values were not significantly different. The number of frail patients and patients requiring walking assistance exhibited no significant intra-group or between-group differences before and after the intervention.

CONCLUSION

Intradialytic exercise prevented the worsening of nutritional status and physical function in the exercise group compared to the control group. Exercise therapy during dialysis is an important aspect of patient care that helps prevent functional decline in older patients.

Factors associated with anti-SARS-CoV-2 spike antibody titers after a second BNT162b2 mRNA COVID-19 vaccination in Japanese hemodialysis patients

Background

We investigated factors associated with the anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike antibody titer after the second dose of the BNT162b2 messenger RNA coronavirus disease 2019 (COVID-19) vaccine in Japanese patients undergoing hemodialysis.

Methods

Overall, 75 patients (41 men, 34 women; mean age 71.4 ± 12.2 years) with a hemodialysis duration of 5.7 ± 6.1 [interquartile range, 1.0–8.5] years were enrolled in this single-center, prospective, cross-sectional study. We used multiple linear regression analysis to determine the relationships of the anti-SARS-CoV-2 spike antibody titer with patient demographic and clinical parameters. We also compared the anti-SARS-CoV-2 spike antibody titer between hemodialysis patients and 22 healthcare workers (10 men, 12 women; mean age 48.5 ± 14.4 years).

Results

Autoimmune disease presence (standard coefficient [β] =  − 0.290, p = 0.018), lymphocyte counts (β = 0.261, p = 0.015), hemoglobin levels (β = 0.290, p = 0.009), and blood urea nitrogen concentrations (β = 0.254, p = 0.033) were significantly and independently correlated with the log-anti-SARS-CoV-2 spike antibody titer. The anti-SARS-CoV-2 spike antibody titer was significantly lower in hemodialysis patients than in healthcare workers (3589 ± 3921 [813–4468] vs. 12,634 ± 18,804 [3472–10,257] AU/mL; p < 0.002).

Conclusions

Autoimmune disease presence, lymphocyte counts, hemoglobin levels, and blood urea nitrogen concentrations were associated with the anti-SARS-CoV-2 spike antibody titer after the second dose of the BNT162b2 messenger RNA COVID-19 vaccine in Japanese patients undergoing hemodialysis.

New polymethylmethacrylate membrane, NF-U, improves nutritional status and reduces patient-reported symptoms in older dialysis patients

Introduction

We previously reported the nutritional advantage of polymethylmethacrylate (PMMA) membranes to prevent the progression of malnutrition in dialysis patients. In this study, we examined whether a new PMMA dialyzer, NF-U, has advantages to improve the nutritional condition, patient-reported symptoms, and other clinical parameters in older dialysis patients.

Methods

We selected ten older chronic dialysis patients who were treated with NF-U for improving their worsening nutritional parameters and retrospectively evaluated nutrition and patient-reported symptoms. Patient-reported symptoms were surveyed by our original questionnaire including 20 items of symptom.

Results

Serum albumin concentration, geriatric nutritional risk index, and percent creatinine generation rate increased from 3.01 ± 0.16 to 3.25 ± 0.17 g/dL, 87.7 ± 5.8 to 91.4 ± 6.2, 100.2 ± 21.6 to 111.9 ± 20.9% at 1 and 4 months after switching to NF-U, respectively. For patient-reported outcomes, fatigue and the total score of patient-reported outcomes were improved after switching to NF-U.

Conclusion

Our results suggest that NF-U is a good choice for older dialysis patients to ameliorate their nutritional status and patient-reported outcomes.

Convection volume, β2-microglobulin and α1-microglobulin reduction ratios, and body composition in predilution online haemodiafiltration

AIM

The effect of convection volume (CV) in patients on predilution online haemodiafiltration (Pre-OL-HDF) was evaluated.

METHODS

We conducted a retrospective, cross-sectional study in 126 patients on Pre-OL-HDF. Dialysis conditions, laboratory data, and same day post-dialysis body composition measurements using bioimpedance spectroscopy were assessed. Patients were divided into two groups according to their CV: ≥ median value and < median value. Linear regression analyses for reduction ratios (RRs) of β2-microglobulin and α1-microglobulin, and body composition, were conducted.

RESULTS

Age, dialysis vintage, and CVs of the study patients were 64 ± 12 years, 81 (48-154) months, and 43.2 (38.5-55.9) L/session, respectively. The higher CV (≥ 43 L/session) group (n=66) had significantly higher RRs of β2-microglobulin and α1-microglobulin, lean tissue index, body cell mass index, total body water (TBW), extracellular water (ECW), and intracellular water (ICW) compared with the lower CV (< 43 L/session) group (n = 60; P < 0.01). Serum albumin and fat tissue index were not significantly different between the groups. CV/ECW, CV/TBW, and CV/ICW but not un-adjusted CV, were significant determinants for β2-microglobulin and α1-microglobulin RRs (P < 0.05). Lean tissue and body cell mass indexes, but not the fat tissue index, showed significant associations with CV, and RRs of β2-microglobulin and α1-microglobulin (P < 0.05).

CONCLUSIONS

Among patients on Pre-OL-HDF, higher values in the lean tissue index and body cell mass index were observed in those with higher CV versus lower CV, and CV adjusted to body water may be useful to prescribe individualized conditions for Pre-OL-HDF. This article is protected by copyright. All rights reserved.

Association between salt intake and long-term mortality in hemodialysis patients: A retrospective cohort study

Background

The association between salt intake and clinical outcomes in hemodialysis patients has been controversial. This study aimed to clarify the association between salt intake and mortality in hemodialysis patients.

Method

The present study included patients who underwent hemodialysis from June 1st 2016 to May 31st 2020. Corrected salt intake by ideal body weight was the main predictor of outcomes. Ideal body weight was calculated assuming that the ideal body mass index is 22 kg/m² for the Japanese population. The multivariate Cox proportional hazards model was used to determine the association between corrected salt intake and mortality, adjusting for potential confounders. The outcomes considered were all-cause mortality and cumulative incidence of cardiovascular events at year 4.

Result

A total of 492 adult patients were enrolled in the study. The mean daily salt intake and corrected salt intake at baseline were 9.5 g/day and 0.17 g/kg/day, respectively. The low corrected salt intake group (< 0.13 g/kg/day) demonstrated the highest 4-year all-cause mortality. No association was observed between corrected salt intake and the cumulative incidence of cardiovascular events. In multivariate Cox proportional hazards analysis, only the group with corrected salt intake of 0.16–0.20 g/kg/day was associated with a decreased hazard risk for all-cause death compared with the low corrected salt intake group.

Conclusion

The present study found that a low salt intake was associated with high all-cause mortality in hemodialysis patients. Reduced long-term survival may be attributed to malnutrition resulting from excessive salt restriction.

Characteristics of adrenal insufficiency in hemodialysis patients

Background

Adrenal insufficiency causes abnormal subjective symptoms such as general fatigue, signs such as hypotension, and abnormalities such as hypoglycemia and leads to poor prognosis. However, all these are also observed in hemodialysis (HD) patients without adrenal insufficiency. The morphology of the adrenal glands in HD patients with adrenal insufficiency is unclear. Therefore, this study was performed to clarify the characteristics of adrenal insufficiency in HD patients.

Methods

Seventeen HD patients who had abnormal subjective symptoms and test results indicating adrenal insufficiency and whose serum cortisol levels were less than 18 μg/dL were recruited.

Results

Seven HD patients were diagnosed with adrenal insufficiency. No significant differences were found about abnormal subjective symptoms and images between patients with and without adrenal insufficiency. The levels of serum cortisol and serum cholinesterase were significantly lower in patients with adrenal insufficiency than in those without adrenal insufficiency. A plasma cortisol level of 8.45 μg/dL showed the highest sensitivity and specificity in the receiver operating characteristic curve. The serum cortisol levels were significantly and negatively associated with the plasma ferritin levels in patients with adrenal insufficiency. Multiple linear regression analyses revealed that the serum cortisol levels showed a significant negative association with the plasma ferritin levels after adjustments.

Conclusions

It is difficult to infer adrenal insufficiency in HD patients by subjective symptoms and images of the adrenal glands. Adrenal insufficiency correlates with nutritional and inflammatory status, and the levels of serum cholinesterase and plasma ferritin might reflect their corresponding status.

Smoking and risk of fractures requiring hospitalization in hemodialysis patients: a nationwide cohort study in Japan

BACKGROUND

Smoking is a well-established lifestyle risk factor for fractures in the general population, but evidence specific to hemodialysis populations is lacking. This nationwide cohort study used data from the Japanese Society for Dialysis Therapy Renal Data Registry to examine the association between smoking status and fractures.

METHODS

A total of 154,077 patients (64.2% men; mean age, 68 years) aged ≥20 years undergoing maintenance hemodialysis thrice a week at the end of 2016 were followed for 1 year. Among these, 19,004 (12.3%) patients were current smokers. Standardized incidence rate ratios of hospitalization due to any fracture were calculated and analyzed by multivariable logistic regression analysis, controlling for potential confounders. Propensity score matching and subgroup analyses were also performed as sensitivity analyses.

RESULTS

During the 1-year follow-up period, 3,337 fractures requiring hospitalization (1,201 hip, 479 vertebral, and 1,657 other fractures) occurred in 3,291 patients. The age- and sex-standardized incidence ratio for current smokers was 1.24 (95% confidence interval, 1.12-1.39) relative to non-smokers. Standardized incidence ratios were similar after stratification by age group and sex. Multivariable logistic regression analysis revealed a 1.25-fold higher risk of any fracture requiring hospitalization (95% confidence interval, 1.10-1.42) in current smokers relative to non-smokers in a fully adjusted model. Propensity score matching showed similar results (odds ratio, 1.25; 95% confidence interval, 1.05-1.48). Subgroup analyses for baseline covariates revealed no significant interactions.

CONCLUSIONS

Smoking is a significant risk factor for any fracture requiring hospitalization in hemodialysis patients.

Effects of intradialytic exercise for advanced-age patients undergoing hemodialysis: A randomized controlled trial

Previous reports have shown the benefits of intradialytic exercise to patients undergoing hemodialysis. However, most of those studies assessed the effects of exercise in middle-aged patients and little is known about advanced-age patients undergoing hemodialysis. Therefore, the present randomized controlled trial was performed to determine the effectiveness of exercise therapy in advanced-age patients undergoing hemodialysis. This non-blinded, randomized controlled parallel trial enrolled a total of 101 patients who were randomly assigned to intradialytic exercise (n = 51) or usual care (n = 50) groups. The training program included both resistance and aerobic exercises and was performed three times per week for 6 months. The aerobic exercise intensity was adjusted to a target Borg score of 13 for 20 minutes. Four types of resistance exercises were performed using elastic tubing, with three sets of 10 exercises performed at moderate intensity (13/20 on the Borg scale). The usual care group received standard care. Lower extremity muscle strength, Short Physical Performance Battery score, and 10-m walking speed were the outcomes and were evaluated before the hemodialysis session and after 6 months of training. There were statistically significant improvements in Short Physical Performance Battery score (effect size, 0.57; 95% confidence interval, 0.15‒1.95) in the exercise group relative to the control group. There were no statistically significant differences in lower extremity muscle strength or in the 10-m walking speed between the two groups. These findings suggest that 6 months of intradialytic training could improve physical function in older patients undergoing hemodialysis.

Dialyzer surface area is a significant predictor of mortality in patients on hemodialysis: a 3-year nationwide cohort study

A target Kt/V of > 1.4 and use of a high-flux dialyzer are recommended for patients on hemodialysis. However, there is little information on the relationship between the dialyzer surface area and mortality in these patients. In this nationwide cohort study, we aimed to clarify this relationship by analyzing data from the Japanese Society for Dialysis Therapy for 2010–2013. We enrolled 234,638 patients on hemodialysis who were divided according to quartile for dialyzer surface area into the S group (small, < 1.5 m²), M group (medium, 1.5 m²), L group (large, 1.6 to < 2.0 m²), or XL group (extra-large, ≥ 2.0 m²). We assessed the association of each group with 3-year mortality using Cox proportional hazards models and performed propensity score matching analysis. By the end of 2013, a total of 53,836 patients on dialysis (22.9%) had died. There was a significant decrease in mortality with larger dialyzer surface areas. The hazard ratio (95% confidence interval) was significantly higher in the S group (1.15 [1.12–1.19], P < 0.0001) and significantly lower in the L group (0.89 [0.87–0.92] P < 0.0001) and XL group (0.75 [0.72–0.78], P < 0.0001) than in the M group as a reference after adjustment for all confounders. Findings were robust in several sensitivity analyses. Furthermore, the findings remained significant after propensity score matching. Hemodialysis using dialyzers, especially super high-flux dialyzers with a larger surface area might reduce mortality rates, and a surface area of ≥ 2.0 m² is superior, even with the same Kt/V.

Creatinine generation rate can detect sarcopenia in patients with hemodialysis

BACKGROUND

Sarcopenia is strongly associated with long-term mortality in patients undergoing hemodialysis. The diagnostic modalities used to assess muscle mass, such as bioimpedance analysis and dual-energy X-ray absorption measurement, have limitations for application in patients on hemodialysis. Therefore, there is a need to establish a simple index for assessing muscle mass that can be universally performed in patients on hemodialysis.

METHODS

Patients on maintenance hemodialysis were included in this study. Laboratory tests, skeletal muscle mass measured by bioimpedance analysis, and clinical records were obtained retrospectively. The creatinine generation rate (CGR) was calculated from the pre- and postdialysis blood tests using a kinetic model as the index for whole-body muscle mass. Correlations between the CGR and skeletal muscle mass were investigated, and the cut-off value for muscle wasting was determined. Kaplan-Meier survival analysis was performed to investigate the feasibility of the CGR for predicting long-term survival.

RESULTS

Among the 130 patients included, eight were diagnosed with sarcopenia by bioimpedance analysis. The CGR was positively correlated with skeletal muscle mass (r = 0.454, p < 0.001). Multiple linear regression analysis revealed that age and sex independently influenced the CGR. The patients were classified into two groups according to age- and sex-adjusted CGRs. During a median follow-up period of 32 months, the Kaplan-Meier survival analysis showed that patients with low CGR showed significantly poor long-term prognosis (p = 0.002).

CONCLUSION

The CGR is a simple index for muscle mass and can predict long-term mortality in patients on hemodialysis.

Super high-flux membrane dialyzers improve mortality in patients on hemodialysis: a 3-year nationwide cohort study

Introduction

In Japan, dialyzers are classified based on β₂-microglobulin clearance. Type I dialyzers are classified as low-flux dialyzers (<10 mL/min clearance), type II and III as high-flux dialyzers (≥10 to <30 mL/min and ≥30 to <50 mL/min clearance, respectively), and type IV and V as super high-flux dialyzers (≥50 to <70 mL/min and ≥70 mL/min clearance, respectively). Super high-flux dialyzers are commonly used, but their superiority over low-flux dialyzers is controversial.

Methods

In this nationwide prospective cohort study, we analyzed Japanese Society for Dialysis Therapy Renal Data Registry data collected at the end of 2008 and 2011. We enrolled 242,467 patients on maintenance hemodialysis and divided them into five groups by dialyzer type. We assessed the associations of each dialyzer type with 3-year all-cause mortality using Cox proportional hazards models and performed propensity score matching analysis, adjusting for potential confounders.

Results

By the end of 2011, 53,172 (21.9%) prevalent dialysis patients had died. Mortality significantly decreased according to dialyzer type. Hazard ratios (HRs) were significantly higher for type I, II and III compared with type IV (reference) after adjustment for basic factors and further adjustment for dialysis-related factors. HR was significantly higher for type I, but significantly lower for type V, after further adjustment for nutrition- and inflammation-related factors. These significant findings were also evident after propensity score matching.

Conclusions

Hemodialysis using super high-flux dialyzers might reduce mortality. Randomized controlled trials are warranted to clarify whether these type V dialyzers can improve prognosis.

Dialyzer Classification and Mortality in Hemodialysis Patients: A 3-Year Nationwide Cohort Study

Background: Dialyzers are classified as low-flux, high-flux, and protein-leaking membrane dialyzers internationally and as types I, II, III, IV, and V based on β₂-microglobulin clearance rate in Japan. Type I dialyzers correspond to low-flux membrane dialyzers, types II and III to high-flux membrane dialyzers, and types IV and V to protein-leaking membrane dialyzers. Here we aimed to clarify the association of dialyzer type with mortality.

Methods: This nationwide retrospective cohort study analyzed data from the Japanese Society for Dialysis Therapy Renal Data Registry from 2010 to 2013. We enrolled 238,321 patients on hemodialysis who were divided into low-flux, high-flux, and protein-leaking groups in the international classification and into type I to V groups in the Japanese classification. We assessed the associations of each group with 3-year all-cause mortality using Cox proportional hazards models and performed propensity score matching analysis.

Results: By the end of 2013, 55,308 prevalent dialysis patients (23.2%) had died. In the international classification subgroup analysis, the hazard ratio (95% confidence interval) was significantly higher in the low-flux group [1.12 (1.03–1.22), P = 0.009] and significantly lower in the protein-leaking group [0.95 (0.92–0.98), P = 0.006] compared with the high-flux group after adjustment for all confounders. In the Japanese classification subgroup analysis, the hazard ratios were significantly higher for types I [1.10 (1.02–1.19), P = 0.015] and II [1.10 (1.02–1.39), P = 0.014] but significantly lower for type V [0.91 (0.88–0.94), P < 0.0001] compared with type IV after adjustment for all confounders. These significant findings persisted after propensity score matching under both classifications.

Conclusions: Hemodialysis using protein-leaking dialyzers might reduce mortality rates. Furthermore, type V dialyzers are superior to type IV dialyzers in hemodialysis patients.

Factors associated with dropout from physical function assessment programs among participants receiving maintenance hemodialysis: A retrospective observational cohort study

We aimed to investigate the factors associated with dropout from a physical function assessment program among participants receiving outpatient hemodialysis (HD). The participants were divided into continuation and dropout groups and followed up for 3 years after the initial physical function assessment. Multivariate logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the dropout group to determine the factors associated with dropout from the physical function assessment program. The continuation and dropout groups included 43 and 58 participants, respectively. The continuation group had a significantly higher self-efficacy (SE) and age than the dropout group (p = 0.001, p = 0.047). Multivariate logistic regression analysis indicated that only SE (OR: 1.202, 95% CI: 1.082-1.334) remained a significant predictor after adjustment (p < 0.05). There is a need to evaluate SE to prevent dropout from physical functioning assessment programs.

Analytical Solutions of a Two-Compartment Model Based on the Volume-Average Theory for Blood Toxin Concentration during and after Dialysis

Accurate prediction of blood toxin concentration during and after dialysis will greatly contribute to the determination of dialysis treatment conditions. Conventional models, namely single-compartment model and two-compartment model, have advantages and disadvantages in terms of accuracy and practical application. In this study, we attempted to derive the mathematical model that predicts blood toxin concentrations during and after dialysis, which has both accuracy and practicality. To propose the accurate model, a new two-compartment model was mathematically derived by adapting volume-averaging theory to the mass transfer around peripheral tissues. Subsequently, to propose a practical model for predicting the blood toxin concentration during dialysis, an analytical solution expressed as algebraic expression was derived by adopting variable transformation. Furthermore, the other analytical solution that predicts rebound phenomena after dialysis was also derived through similar steps. The comparisons with the clinical data revealed that the proposed analytical solutions can reproduce the behavior of the measured blood urea concentration during and after dialysis. The analytical solutions proposed as algebraic expressions will allow a doctor to estimate the blood toxin concentration of a patient during and after dialysis. The proposed analytical solutions may be useful to consider the treatment conditions for dialysis, including the rebound phenomenon.

High-performance dialyzers and mortality in maintenance hemodialysis patients

Few data are available regarding the association of dialyzer type with prognosis. In Japan, dialyzers are classified as types I, II, III, IV, and V based on β₂-microglobulin clearance rates of < 10, < 30, < 50, < 70, and ≥ 70 mL/min, respectively. We investigated the relationship of the 5 dialyzer types with 1-year mortality. This nationwide cohort study used data collected at the end of 2008 and 2009 by the Japanese Society for Dialysis Therapy Renal Data Registry. We enrolled 203,008 patients on maintenance hemodialysis who underwent hemodialysis for at least 1 year and were managed with any of the 5 dialyzer types. To evaluate the association of dialyzer type with 1-year all-cause mortality, Cox proportional hazards models and propensity score-matched analyses were performed. After adjustment of the data with clinicodemographic factors, the type I, II, and III groups showed significantly higher hazard ratios (HRs) than the type IV dialyzers (reference). After adjustment for Kt/V and β₂-microglobulin levels, the HRs were significantly higher in the type I and II groups. After further adjustment for nutrition- and inflammation-related factors, the HRs were not significantly different between the type IV and type I and II groups. However, type V dialyzers consistently showed a significantly lower HR. With propensity score matching, the HR for the type V dialyzer group was significantly lower than that for the type IV dialyzer group. Additional long-term trials are required to determine whether type V dialyzers, which are high-performance dialyzers, can improve prognosis.

Quantitative sonographic assessment of quadriceps muscle thickness for fall injury prediction in patients undergoing maintenance hemodialysis: an observational cohort study

Background

Accidental fall risk is high in patients undergoing maintenance hemodialysis. Falls are associated with fatal injury, comorbidities, and mortality. Risk assessment should be a primary component of fall prevention. This study investigated whether quadriceps muscle thickness measured using ultrasonography can predict fall injury among dialysis patients.

Methods

Using an observational cohort study design, 180 ambulatory hemodialysis patients were recruited from 2015 to 2016 from four dialysis clinics. The sum of the maximum quadriceps muscle thickness on both sides and the average of the maximum thigh circumference and handgrip strength after hemodialysis were calculated. Patients were stratified according to tertiles of quadriceps muscle thickness. Fall injury was surveyed according to the patient’s self-report during the one-year period.

Results

Among the 180 hemodialysis patients, 44 (24.4%) had fall injuries during the 12-month follow-up period. When the quadriceps muscle thickness levels were stratified into sex-specific tertiles, patients in the lowest tertile were more likely to have a higher incidence of fall injury than those in the higher two tertiles (0.52 vs. 0.19 and 0.17 fall injuries/person-year). After adjusting for covariates, lower quadriceps muscle thickness was found to be an independent predictor of fall injury (hazard ratio [95% confidence interval], 2.33 [1.22–4.52], P < 0.05). Receiver operating characteristic curves were constructed to determine the optimal cutoffs of quadriceps muscle thickness, thigh circumference, and handgrip strength that best predicted fall injury (quadriceps muscle thickness, 3.37 cm and 3.54 cm in men and women; thigh circumference, 44.6 cm and 37.2 cm in men and women; and handgrip strength, 23.3 kg and 16.5 kg in men and women). Using these cutoff values, the areas under the curve were 0.662 (95% CI, 0.576–0.738), 0.625 (95% CI, 0.545–0.699), and 0.701 (95% CI, 0.617–0.774), for quadriceps muscle thickness, thigh circumference, and handgrip strength, respectively. Quadriceps muscle thickness was a more precise predictor of fall injury than thigh circumference and had similar diagnostic performance as handgrip strength tests in dialysis patients.

Conclusions

Quadriceps muscle thickness can be measured easily at the bedside using ultrasonography and is a precise predictor of fall injury in patients undergoing maintenance hemodialysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02347-5.

Proton pump inhibitors may hinder hypophosphatemic effect of lanthanum carbonate, but not of ferric citrate hydrate or sucroferric oxyhydroxide, in hemodialysis patients

Because end-stage renal disease patients undergoing hemodialysis frequently take acid suppressants for the treatment or prevention of gastrointestinal diseases, it is important to clarify the drug-interactions between acid suppressants and phosphate binders on the control of serum phosphate levels. In the present study, we examined whether the phosphate-lowering effects of three phosphate binders, lanthanum carbonate (LC), ferric citrate hydrate (FCH), and sucroferric oxyhydroxide (SFOH), were affected by proton pump inhibitors (PPIs) in maintenance hemodialysis patients. Laboratory data for 71 patients who had been newly prescribed one of the three phosphate binders were examined. LC at a dosage of 500 ± 217 mg/day significantly decreased serum phosphate levels by −18% in the absence of a PPI (n = 9), while a dosage of 700 ± 230 mg/day only decreased it by −3% in the presence of a PPI (n = 10). Thus, the efficacy of LC in reducing serum phosphate levels was significantly hindered by the presence of PPIs. FCH significantly decreased serum phosphate levels by −18% in the absence of a PPI (n = 7, FCH: 571 ± 189 mg/day) and by −17% in the presence of a PPI (n = 20, FCH: 638 ± 151 mg/day). The decrease in serum phosphate levels by SFOH (393 ± 197 mg/day) was −7% in the absence of a PPI (n = 7), and SFOH at a dosage of 556 ± 316 mg/day significantly decreased serum phosphate levels by −13% in the presence of a PPI (n = 18). These results suggest that the phosphate-lowering effect of LC, but not of FCH or SFOH, is diminished in the presence of PPIs in hemodialysis patients.

One-year intradialytic leg exercises with resistance bands and fat mass increase in elderly hemodialysis patients: a retrospective study

Background

Intradialytic exercises are recommended to be available as a treatment for enhancing physical functioning. However, there have been few reports which evaluated the results of long-term mild intradialytic exercises in elderly patients. The purpose of this study is to investigate the changes in body weight, body composition, and laboratory data in elderly hemodialysis patients after 1-year intradialytic leg exercises with resistance bands.

Methods

A retrospective study. Twenty-one outpatients, aged 65 or older (mean ± SD, 75.2 ± 5.1 years), received intradialytic leg exercises with resistance bands for a year were analyzed. The values of dry weight, body composition, and laboratory data were collected from the year-ago period, at baseline and 1 year after baseline. Fat and muscle mass were evaluated by using a multi-frequency bioimpedance device.

Results

Physical performance changed and body weight increased after 1-year resistance band exercises. However, the participants gained fat mass, not muscle mass. Although the changes in biochemical data related to protein intake were equivocal, triglyceride levels increased significantly after 1-year exercises. An elevation in serum creatinine levels was observed, even if solute clearance increased significantly.

Conclusions

One-year intradialytic leg exercises with resistance bands may have a potential clinical benefit for body mass index even in elderly hemodialysis patients. However, optimal dietary modification is needed to achieve a balanced increase of muscle and fat mass. An increase of serum creatinine levels does not always mean muscle mass hypertrophy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41100-021-00341-z.

Skeletal muscle mass is associated with erythropoietin response in hemodialysis patients

Background

Hyporesponsiveness to erythropoietin stimulating agent (ESA) is associated with poor outcomes in patients with chronic kidney disease. Although ESA hyporesponsiveness and sarcopenia have a common pathophysiological background, clinical evidence linking them is scarce. The purpose of the study was to investigate the relationship between ESA responsiveness and skeletal muscle mass in hemodialysis patients.

Methods

This cross-sectional study analyzed 70 patients on maintenance hemodialysis who were treated with ESA. ESA responsiveness was evaluated by erythropoietin resistance index (ERI), calculated as a weekly dose of ESA divided by body weight and hemoglobin (IU/kg/week/dL), and a weekly dose of ESA/hemoglobin (IU/week/dL). A dose of ESA is equivalated to epoetin β. Correlations between ESA responsiveness and clinical parameters including skeletal muscle mass were analyzed.

Results

Among the 70 patients, ERI was positively correlated to age (p < 0.002) and negatively correlated to height (p < 0.001), body weight (p < 0.001), BMI (p < 0.001), skeletal muscle mass (p < 0.001), transferrin saturation (TSAT) (p = 0.049), and zinc (p = 0.006). In the multiple linear regression analysis, TSAT, zinc, and skeletal muscle mass were associated with ERI and weekly ESA dose/hemoglobin.

Conclusions

Skeletal muscle mass was the independent predictor for ESA responsiveness as well as TSAT and zinc. Sarcopenia is another target for the management of anemia in patients with hemodialysis.

Pre-dialysis Hyponatremia and Change in Serum Sodium Concentration During a Dialysis Session Are Significant Predictors of Mortality in Patients Undergoing Hemodialysis

Background

Previous studies have shown that hyponatremia is associated with greater mortality in hemodialysis (HD) patients. However, there have been few reports regarding the importance of the change in serum sodium (SNa) concentration (ΔSNa) during dialysis sessions. To investigate the relationships of pre-dialysis hyponatremia and ΔSNa during a dialysis session with mortality, we analyzed data from a national registry of Japanese patients with end-stage kidney disease.

Methods

We identified 178,114 patients in the database who were undergoing HD 3 times weekly. The study outcome was 2-year all-cause mortality, and the baseline SNa concentrations were categorized into quintiles. We evaluated the relationships of SNa concentration and ΔSNa with mortality using Cox proportional hazards models.

Results

During a 2-year follow-up period, 25,928 patients died. Each 1-mEq/l reduction in pre-HD SNa concentration was associated with a cumulatively greater risk of all-cause mortality (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.05–1.06). In contrast, a larger ΔSNa was associated with higher all-cause mortality (HR for a 1-mEq/l increase in ΔSNa, 1.02; 95% CI 1.01–1.02). The combination of low pre-HD SNa concentration and large ΔSNa was also associated with higher mortality (HR 1.09; 95% CI 1.05–1.13). Participants with the lowest SNa concentration (≤136 mEq/L) and the highest ΔSNa (>4 mEq/L) showed higher mortality than those with an intermediate pre-HD SNa concentration (137–140 mEq/L) and the lowest ΔSNa (≤2 mEq/L).

Conclusions

Lower pre-HD SNa concentration and higher ΔSNa are associated with a greater risk of mortality in patients undergoing HD.

Effects of exercise therapy on the persistence of physical function, exercise habits, and self-efficacy after cessation of exercise in patients undergoing hemodialysis: A nonrandomized control trial

The present study investigated the sustained effect of exercise therapy discontinuation in patients under hemodialysis with low physical function. Seven subjects in the exercise group and eight in the control group who had low physical function (short physical performance battery; SPPB ≤ 9 points) were included in the study. The exercise group received 6 months of intradialytic exercise, followed by 6 months of observation. We assessed SPPB, grip strength, self-efficacy (SE), and exercise habits in both the groups before and after 12 months. There were statistically significant improvements in SPPB (effect size, 0.58; 95% confidence interval [CI], 0.13-3.55) and SE (effect size, 0.59; 95% CI, 0.25-7.57) in the exercise group relative to the control group. The exercise group displayed more exercise habits than the control group at 12 months. A 6-month period of intradialytic exercise may contribute to the continuation of SPPB and SE after exercise discontinuation.

High serum magnesium levels are associated with favorable prognoses in diabetic hemodialysis patients, retrospective observational study

BACKGROUND

Recent studies have found hypomagnesemia is linked to a heightened risk of cardiovascular events and mortality in hemodialysis (HD) patients; however, the level of serum magnesium (s-Mg) necessary for promoting overall health in these patients and the effects of s-Mg in diabetes HD patients remains to be clarified.

METHODS

HD outpatients (n = 148 under, age ≤ 70 y) were followed over a 6-y period. They were divided into four groups according to their average s-Mg during the first year (L; low level, H; high level) and if they had DM or not (non-DM). The endpoint was mortality and hospitalization for decline of Activities of Daily Living (death/hospitalization). A receiver operating characteristics curve was used in diagnostic tests to identify s-Mg associated with this endpoint. Kaplan-Meier, log-rank test, and a Cox proportional hazards model were used to evaluate prognoses. Fisher's exact test and multiple regressions examined the causes of the endpoints between the four groups and the factors predictive of s-Mg.

RESULTS

s-Mg at 2.7 mg/dL was associated with death/hospitalization. The 5-y survival rate was 38.1%, 86.7%, 73.2% and 87.5%, in the DM/Mg(L), DM/Mg(H), non-DM/Mg(L) and non-DM/Mg(H) groups, respectively (P < 0.001). The Cox proportional hazards model showed significantly lower risk in other groups compared with that in the DM/Mg(L) group [DM/Mg(H); hazard ratio (HR): 0.22, 95% confidence interval (CI): 0.05-0.97, P = 0.046, non-DM/Mg(L); HR: 0.32, 95% CI: 0.15-0.68, P = 0.003, non-DM/Mg(H); HR: 0.17, 95% CI: 0.06-0.44, P < 0.001]. The frequency of the different causes of the endpoints for each group was not significant; s-Mg only associated with age in the DM group.

CONCLUSIONS

s-Mg greater than 2.7 mg/dL associated with a favorable prognosis in HD patients with DM, suggesting that s-Mg is a factor independent of diabetes.

Long-term excess mortality after hip fracture in hemodialysis patients: a nationwide cohort study in Japan

INTRODUCTION

Fracture dialysis patients have a higher risk of 1-year mortality compared with non-fracture dialysis patients. However, it is unclear whether excess mortality persists for more than a year.

MATERIALS AND METHODS

We conducted a nationwide cohort study in 162,360 hemodialysis patients in Japan. Study outcomes were 5-year all-cause mortality and cause-specific mortality. Cox proportional hazards regression was used to examine the association between hip fracture and mortality in two cohorts: the full cohort, which included potential confounders as covariates in multivariable-adjusted regression models, and the propensity score-matched cohort.

RESULTS

Crude mortality rates for fracture patients were double those of non-fracture patients and persisted during the 5-year period. The association between hip fracture and mortality was significant even after adjusting for premorbid conditions (hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.13-1.32). Similar findings were observed in the propensity score-matched cohort of 2410 patients (HR 1.20, 95% CI 1.05-1.36). While cause-specific mortality rates for all categories, with the exception of sudden deaths, were higher for fracture patients relative to non-fracture patients in the full unmatched cohort, only the mortality rate for heart disease was significantly higher for fracture patients relative to non-fracture patients in the propensity score-matched cohort.

CONCLUSION

Excess mortality persisted for many years after hip fracture in hemodialysis patients, and was still present after adjusting for several premorbid conditions and propensity score matching.

Association of normalized protein catabolic rate (nPCR) with the risk of bone fracture in patients undergoing maintenance hemodialysis: The Q-Cohort Study

BACKGROUND & AIMS

Normalized protein catabolic rate (nPCR) is used as a surrogate for daily dietary protein intake and nutritional status in patients receiving maintenance hemodialysis. It remains uncertain whether the nPCR level is associated with the incidence of bone fracture.

METHODS

A total of 2869 hemodialysis patients registered in the Q-Cohort Study, a multicenter, prospective, observational study, were followed up for 4 years. The primary outcome was bone fracture at any site. The main exposure was the nPCR level at baseline. Patients were assigned to four groups based on their baseline nPCR levels (G1: <0.85, G2: 0.85≤, <0.95, G3: 0.95≤, <1.05 [reference], G4: ≥1.05 g/kg/day). We examined the relationship between the nPCR levels and the risk for bone fracture using Cox proportional hazards models.

RESULTS

During the follow-up period, 136 patients experienced bone fracture at any site. In the multivariable analyses, the risk for bone fracture was significantly higher in the lowest (G1) and highest (G4) nPCR groups than the reference (G3) group (hazard ratio [95% confidence intervals]: G1, 1.93 [1.04-3.58]; G2, 1.27 [0.67-2.40]; G3 1.00 (reference); G4, 2.21 [1.25-3.92]). The association remained almost unchanged, even when patients were divided into sex-specific nPCR quartiles, when analysis was limited to patients with a dialysis vintage ≥2 years, assumed to have lost residual kidney function, or when a competing risk model was applied.

CONCLUSIONS

Our results suggest that both lower and higher nPCR levels are associated with an increased risk for bone fracture in hemodialysis patients.

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.

Use of proton pump inhibitors is associated with an increase in adverse cardiovascular events in patients with hemodialysis: Insight from the kids registry

BACKGROUND

Proton pump inhibitors (PPIs) are known to increase the risk of mortality and cardiovascular events in the general population. However, in patients with maintenance hemodialysis, PPI effects are under investigated.

METHODS

We analyzed the risk of PPIs for cardiovascular events using the Kagoshima Dialysis (KIDS) registry, a prospective, multicenter, observational study in patients with maintenance hemodialysis in Japan.

RESULTS

In all, 531 patients were enrolled from June 2015 to December 2018. One-year follow-up data were available for 376 patients (Use of PPIs at baseline (PPI group): 217 patients and without PPIs (No PPI group): 159 patients). The incidence of a composite outcome (all-cause mortality, non-fatal myocardial infarction, or non-fatal stroke) was higher in patients in the PPI group than the No PPI group (15.2% vs. 4.4%; hazard ratio (HR): 3.65, 95% confidence interval (CI): 1.61-8.23, P = 0.002). In the multivariate analysis, even after adjustment for covariates, the use of PPIs was an independent risk factor for a composite outcome (HR: 2.38, 95% CI: 1.02-5.54, P = 0.045). We performed propensity score matching analysis as a sensitivity analysis, showing a consistent result. The incidence of bleeding showed no difference between the two groups (15.7% vs. 11.3%; HR: 1.46, 95% CI: 0.83-2.59, P = 0.19).

CONCLUSIONS

These results indicate that the use of PPIs in patients with maintenance hemodialysis might increase mortality and cardiovascular events without decreasing the risk of bleeding. Therefore, it should always be analyzed if a patient truly needs PPIs.

Influence of albumin leakage on glycated albumin in patients with type 2 diabetes undergoing hemodialysis

Glycated albumin (GA) is recommended as a better glycemic indicator than HbA1c in patients undergoing hemodialysis, because the red blood cell lifespan is generally faster than that in normal subjects. However, GA can be also affected by protein loss in urine and hemodialysis fluid. Therefore, in this study, we investigated the effect of albumin leakage induced by hemodialysis on GA. Nine patients undergoing hemodialysis with a large or small amount of albumin leakage were observed for 9 months in a crossover manner. As a result, it was shown that albumin leakage could affect GA, but the effect was practically small considering the prescription of diabetic drugs. The correlations between HbA1c and blood glucose levels and between GA and blood glucose levels were similar in our study. In conclusion, GA was a reliable indicator, even with the change of hemodialysis modality. The influence of albumin leakage induced by hemodialysis on GA was negligible practically. We should recognize that the preferable glycemic indicator in patients undergoing hemodialysis depends on the hemoglobin and albumin metabolism of each patient.

Gender Differences in Plasma Ghrelin Levels in Hemodialysis Patients

Ghrelin is an orexigenic hormone mainly secreted by the stomach, and it decreases according to the severity of gastric atrophy. Ghrelin has multiple favorable functions, including protein anabolism enhancement, anti-inflammatory activity, and cardiovascular protection, and is associated with survival in hemodialysis (HD) patients. Although the plasma level and role of ghrelin may be different depending on gender, they have not been completely assessed in HD patients. We enrolled 80 (male/female: 51/29) maintenance HD patients. An upper gastrointestinal endoscopic examination was performed for all patients to determine the severity of gastric mucosal atrophy and Helicobacter pylori infection. We measured plasma acyl and desacyl ghrelin levels and assessed the association between ghrelin levels and relevant clinical parameters, including nutrition, inflammation, atherosclerosis, and bone metabolism, by gender. Both acyl and desacyl ghrelin levels in female HD patients were significantly higher than those in male HD patients. When stratified by gastric mucosal atrophy, these gender differences were observed only in patients without gastric atrophy. In female patients, acyl ghrelin level was negatively correlated with age. In male patients, both acyl and desacyl ghrelin levels were positively correlated with bone mineral density. Multiple regression analysis showed significant positive correlations between both ghrelin levels and female gender after adjusting for confounding factors. Plasma ghrelin levels were higher in female HD patients than in male HD patients. The gender difference was more evident in patients without gastric atrophy.

Availability of right femoral vein as a route for tunneled hemodialysis catheterization

Purpose

This study was performed to investigate the primary patency rate and catheter-related problems associated with use of the femoral vein as a route for tunneled hemodialysis catheterization compared with those of the right internal jugular vein as the first-choice route in patients undergoing maintenance hemodialysis.

Patients and methods

Twenty-two patients underwent placement of indwelling tunneled hemodialysis catheters in the right internal jugular vein as the first option for maintenance hemodialysis, and 20 patients underwent placement in the right femoral vein as the second option. The primary patency rate of the catheters and catheter-related problems at 1, 3, 6, and 12 months after placement were investigated.

Results

The 1-, 3-, 6-, and 12-month primary patency rates of the tunneled hemodialysis catheters in the right internal jugular vein were 95.5%, 95.5%, 81.3%, and 58.3%. The primary patency rates of the catheters in the right femoral vein were 95.0%, 89.5%, 86.7%, and 66.7%. There were no statistically significant differences in the primary patency rates at 1, 3, 6, and 12 months or in catheter-related problems between the right internal jugular vein and right femoral vein.

Conclusion

The primary patency rate and catheter-related problems of indwelling tunneled hemodialysis catheters placed in the right femoral vein were not different from those in the right internal jugular vein in patients undergoing maintenance hemodialysis. These results suggest that the right femoral vein might be a useful option for placement of indwelling tunneled hemodialysis catheters in patients undergoing maintenance hemodialysis.