Ryota Matsuzawa

Key Points: Intradialytic renal rehabilitation was associated with higher 3-year survival in patients on maintenance hemodialysis. This association was directionally consistent after multivariable adjustment and propensity score matching. The association seemed stronger in men with severe frailty; no rehabilitation-related adverse events were reported. Background: Frailty and sarcopenia are increasingly common among patients undergoing maintenance hemodialysis. Globally, some countries, including Japan, have recently introduced insurance reimbursement for intradialytic renal rehabilitation, a supervised intradialytic exercise instruction plus nutritional and lifestyle guidance. However, the survival benefit has not been fully evaluated. Methods: We evaluated 708 adult outpatients on dialysis (age, 69.8±11.2 years; men, 59%; and Clinical Frailty Scale ≥6, 13%) at ten institutions across Japan in January 2021 who were retrospectively assessed over a 3-year period, including 228 patients who received intradialytic renal rehabilitation, defined as supervised intradialytic exercise instruction plus nutritional and lifestyle guidance (≥1 session/wk for≥1 month), and 480 who did not receive this intervention. Cox regression models and propensity score matching were used to compare 3-year mortality after adjustment for the Clinical Frailty Scale, comorbidities, laboratory data, and other baseline characteristics. Results: During the follow-up, deaths were observed in 14.9% of the rehabilitation group and 23.1% of the nonrehabilitation group ( P = 0.01). Three-year survival was higher with rehabilitation (84.6% versus 75.6%, P = 0.007), particularly among men and those with severe frailty. In Cox models, renal rehabilitation was consistently associated with lower mortality (crude hazard ratio [HR], 0.59 [95% confidence interval (CI), 0.40 to 0.87]; adjusted HR 0.66 [0.44 to 1.00]). After propensity score matching, the association remained directionally similar (HR, 0.65 [0.40 to 1.05]). Sex-stratified analyses suggested a stronger association among men (adjusted HR, 0.49 [0.27 to 0.89]) than among women (adjusted HR, 0.98 [0.54 to 1.77]), although the formal test for interaction was not statistically significant ( P for interaction = 0.13). Patients meeting exercise-habit criteria (≥2 sessions/wk, ≥30 minutes for ≥1 year) also showed better survival relative to the nonexercise-habit group (adjusted HR 0.60 [0.37 to 0.96], P = 0.03). No adverse events related to rehabilitation were reported. Conclusions: Intradialytic renal rehabilitation may be associated with better survival in patients on maintenance hemodialysis, particularly in men and in those with severe frailty.

Purpose In patients undergoing hemodialysis, poor nutritional status frequently occurs due to depletion of essential nutrients, amino acids, during dialysis sessions. Protein supplementation during dialysis is becoming common to counteract this loss. We compared effects of intradialytic ingestion of fish protein, a novel protein source, with those of the traditionally used whey protein, on blood amino acid levels in patients undergoing hemodialysis. Methods Ten outpatients aged ≥ 60 years undergoing hemodialysis were enrolled in this single-intervention crossover study. Participants underwent three mid-week dialysis sessions with a one-week washout period. During the first session, blood and spent dialysate samples were collected without protein ingestion. In subsequent sessions, participants consumed fish or whey protein soups 30 min after dialysis initiation, followed by blood and spent dialysate sample collection. The effects on amino acid concentrations, including those of branched-chain amino acids (BCAAs), were analyzed using a mixed model for repeated measures. Results Both proteins significantly elevated BCAA concentrations compared with usual care. The effect of fish protein persisted until the end of dialysis (p = 0.016), whereas that of whey protein lasted up to 180 min after dialysis initiation (p = 0.002). Whey protein intake resulted in significantly higher amino acid levels than fish protein intake 30–90 min post-ingestion (p < 0.001), with no differences observed thereafter. Conclusion Both fish and whey protein intake increased amino acid levels compared with usual care. Whey protein induced a rapid increase in levels, whereas fish protein included a slower but sustained increase in levels. Trial registration number and date of registration The study protocol was registered in the UMIN Clinical Trials Registry (UMIN000050805).

Background: Patients with visceral obesity experience an amplified systemic inflammatory response during the perioperative period, increasing infection risk. Significant skeletal muscle loss following invasive cardiovascular surgery presents a considerable clinical challenge. This study aimed to investigate the association between preoperative visceral fat mass and postoperative skeletal muscle loss, emphasizing the clinical utility of computed tomography–based body composition analysis. Methods: This retrospective cohort study included Japanese patients who underwent elective cardiovascular surgery (May 2020 to December 2023). Preoperative computed tomography was used to calculate the visceral fat area, subcutaneous fat area, and psoas muscle area as indicators of skeletal muscle mass. Skeletal muscle loss was assessed by the change in the psoas muscle area between the preoperative period and the first postoperative week. Results: Of the 159 patients included in the final analysis, 69.2% were classified as having visceral obesity. Preoperative visceral fat area was significantly correlated with peak postoperative C ‐reactive protein (CRP) levels ( r = 0.361) and changes in psoas muscle area ( r = −0.374), whereas subcutaneous fat area showed no such correlation. In the multivariate logistic regression analysis, after adjusting for clinical characteristics, including age, body mass index, operative time, preoperative CRP level, EuroSCORE II, and preoperative 6‐min walk distance, higher visceral fat area was significantly associated with postoperative skeletal muscle loss (odds ratio [OR]: 1.01; 95% CI: 1.00–1.02), whereas subcutaneous fat area was not (OR: 1.01; 95% CI: 0.99–1.02). Conclusions: Preoperative visceral fat area measured using computed tomography is a robust predictor of postoperative skeletal muscle loss. Visceral obesity, linked to heightened systemic inflammation, may accelerate muscle degradation through proinflammatory pathways.

Background: Physical inactivity is a significant risk factor for mortality in patients undergoing hemodialysis. Assessment of physical activity is crucial for clinical management and therapeutic decisions in this population. The Human Activity Profile (HAP) questionnaire is widely used to evaluate functional ability across various populations, including those with chronic diseases. Although the HAP is reliable and convenient for use in clinical settings, no validated Japanese adaptation is available. In this study, we aimed to create a Japanese version of the HAP and evaluate its reliability and validity in patients undergoing hemodialysis. Methods: In this cross-sectional study, the Japanese version of the HAP was translated with the permission of the original author. Physical activity was assessed using both the HAP questionnaire and an accelerometer. The total steps and moderate-to-vigorous physical activity (MVPA) time were calculated using an accelerometer. Validity was assessed by evaluating the correlation between the HAP maximum activity score and adjusted activity score (AAS) and objectively measured physical activity levels. Reliability was determined by readministering the HAP questionnaire. Spearman’s rank correlation coefficient and intraclass correlation coefficient (ICC) 2,1 were used to evaluate the validity and reliability, respectively. Results: We included 32 Japanese patients undergoing hemodialysis (mean age 71.7 ± 9.2 years; 19 men). The Japanese version of the HAP AAS correlated with accelerometry-derived data, including both the number of steps and MVPA. The AAS was moderately correlated with MVPA (ρ = 0.64, P < 0.001) and number of steps (ρ = 0.55, P = 0.003). The Japanese version of HAP indicated a high degree of reliability (ICC = 0.84). The cutoff points for HAP were set to identify participants engaging in < 4000 steps per nondialysis day, the minimum recommended physical activity level for patients undergoing hemodialysis, and objectively measure physical activity. The AAS cutoff value was determined to be 50, with an area under the curve of 0.81, a high predictive capability. Conclusions: We demonstrated the robust reliability and validity of the Japanese version of the HAP questionnaire in patients undergoing hemodialysis. Given the strong reliability and validity of the Japanese HAP questionnaire, incorporating this assessment into standard care may be valuable for evaluating the physical activity of patients undergoing hemodialysis.

Background: In the context of cardiovascular surgery, the foremost concern lies in delayed functional recovery, as typified by the acquisition of independent walking after surgery, among older patients with decline in skeletal muscle mass and quality. Computed tomography (CT), which is typically employed for the preoperative assessment of pathological conditions in patients undergoing cardiovascular surgery, is also suitable for screening for potential decline in skeletal muscle mass and quality. The aim of this study was to examine the predictive capabilities of CT‐derived parameters such as muscle mass and muscle quality for the delayed acquisition of independent walking in the postoperative period.Methods: This retrospective study enrolled consecutive Japanese patients who underwent elective cardiovascular surgery between May 2020 and January 2023. In total, 139 patients were included in the analyses. Based on the preoperative CT image, the psoas muscle volume index (PMVI) and psoas muscle attenuation (PMA) were calculated. Information on patient characteristics, including preoperative physical fitness such as handgrip strength/body mass index (GS/BMI), short physical performance battery (SPPB), and 6‐min walking distance (6MWD), were obtained from the medical records. We defined delayed acquisition of independent walking after surgery as the inability to walk 100 m within 4 days after surgery.Results: The median age of the patients was 72 (interquartile: 64–78) years, and 74.8% (104/139) were men; 47.5% corresponded to the delayed group. The areas under the curves of SPPB, GS/BMI, 6MWD, PMVI, and PMA against delayed acquisition of independent walking after surgery were 0.68 [95% confidence interval (CI): 0.59 to 0.77], 0.72 (95% CI: 0.63 to 0.80), 0.73 (95% CI: 0.65 to 0.82), 0.69 (95% CI: 0.60 to 0.78), and 0.78 (95% CI: 0.70 to 0.85), respectively. In the multivariate logistic regression analysis, low PMA was significantly associated with delayed acquisition of independent walking even after adjustment for patient characteristics including physical fitness [model 1: SPPB (OR, 1.14; 95% CI: 1.03–1.25), model 2: GS/BMI (OR, 1.13; 95% CI: 1.03–1.25), and model 3: 6MWD (OR, 1.14; 95% CI: 1.03–1.25)], but PMVI was not.Conclusions: Our study revealed a strong association between PMA, a marker of CT‐derived muscle quality, and the postoperative delay in achieving independent walking in patients who underwent cardiovascular surgery. The technique to obtain information on muscle quality during the time period before surgery may be an option for timely therapeutic intervention in patients who may have delayed acquisition of independent walking after surgery.

To compare the discriminative capabilities for the manifestation of sarcopenia or physical frailty between serum creatinine- and cystatin C-derived indices