Modeling Low Muscle Mass Screening in Hemodialysis Patients.

INTRODUCTION: Computed tomography (CT) can accurately measure muscle mass, which is necessary for diagnosing sarcopenia, even in dialysis patients. However, CT-based screening for such patients is challenging, especially considering the availability of equipment within dialysis facilities. We therefore aimed to develop a bedside prediction model for low muscle mass, defined by the psoas muscle mass index (PMI) from CT measurement. METHODS: Hemodialysis patients (n = 619) who had undergone abdominal CT screening were divided into the development (n = 441) and validation (n = 178) groups. PMI was manually measured using abdominal CT images to diagnose low muscle mass by two independent investigators. The development group's data were used to create a logistic regression model using 42 items extracted from clinical information as predictive variables; variables were selected using the stepwise method. External validity was examined using the validation group's data, and the area under the curve (AUC), sensitivity, and specificity were calculated. RESULTS: Of all subjects, 226 (37%) were diagnosed with low muscle mass using PMI. A predictive model for low muscle mass was calculated using ten variables: each grip strength, sex, height, dry weight, primary cause of end-stage renal disease, diastolic blood pressure at start of session, pre-dialysis potassium and albumin level, and dialysis water removal in a session. The development group's adjusted AUC, sensitivity, and specificity were 0.81, 60%, and 87%, respectively. The validation group's adjusted AUC, sensitivity, and specificity were 0.73, 64%, and 82%, respectively. DISCUSSION/CONCLUSION: Our results facilitate skeletal muscle screening in hemodialysis patients, assisting in sarcopenia prophylaxis and intervention decisions.

Impact of sevelamer hydrochloride on serum magnesium concentrations in hemodialysis patients.

Serum Mg levels are elevated in patients with renal insufficiency: harmful effects of hypomagnesemia have been reported in patients receiving hemodialysis (HD). In this cross-sectional study, which included 86 HD patients (male : female = 56:30, age 68 ± 12 years), we examined the clinical factors associated with serum Mg levels, with a focus on sevelamer, a phosphate binder widely used to control the hyperphosphatemia of HD patients. The mean serum Mg concentration among our patients was 2.48 ± 0.37 mg/dL (1.02 ± 0.15 mmol/L). Sevelamer was administered to 67 patients (77.9%) at a mean dose of 1.98 ± 1.64 g/day. Sex, diabetes mellitus, cardiovascular disease, anuria, and drugs other than sevelamer were not associated with serum Mg levels. HD duration, serum calcium, albumin, high-density lipoprotein cholesterol, normalized protein catabolic rate (nPCR), creatinine generation rate, and sevelamer dose correlated positively with serum Mg levels, whereas a negative correlation was observed for age and high-sensitivity C-reactive protein. A stepwise multiple regression analysis revealed that age, nPCR, and the dose of sevelamer were independently associated with serum Mg levels. Sevelamer and Mg have been reported to exhibit similar effects, such as an anti-inflammatory effect, inhibition of cardiovascular calcification, and decreased mortality. Therefore, the pleiotropic effects of sevelamer may be partly attributable to the increase in serum Mg levels caused by the drug itself.