Mo731association Between Skeletal Muscle Mass and Intradialytic Hypotension in Patients Undergoing Maintenance Hemodialysis

Abstract

Background and Aims Patients undergoing hemodialysis showed higher prevalence of sarcopenia than that of the healthy. As an intracellular water reservoir, skeletal muscle mass would be important to predict intradialytic hypotension. This study was designed to reveal the effect of skeletal muscle mass to intradialytic hypotension, which is also an indicator of volume status in patients under hemodialysis. Method 150 patients from three hemodialysis centers in 2016 and 38 patients from one center under maintenance hemodialysis in 2020 were enrolled in this study, and total 177 patients were finally analyzed. We measured skeletal muscle mass, intracellular water, extracellular water, total body water and phase angle in 50 kHz by bio-impedance analysis just after a hemodialysis session. Information including laboratory tests, chest x-ray, handgrip strength, mid-arm circumference and questionnaire to ask the patients’ general condition was collected. Intradialytic hypotension over three months was observed. We analyzed several factors including skeletal muscle mass which would have association with intradialytic hypotension over three months by multivariate logistic regression model. Results Tertile subgroups divided by the ratio of skeletal muscle to body weight defined as skeletal muscle index were compared. Patients in low skeletal muscle index had a higher rate of intradialytic hypotension (41%) while that of intermediate group was 20% and high group was 5%. Patients in low skeletal muscle mass index group was female-dominant, more obese, more diabetic and had lower handgrip strength than higher skeletal muscle index group. In patients who had higher skeletal muscle mass to body weight, the risk of Intradialytic hypotension was decreased (HR: 0.80 [95% CI 0.75-0.88], adjusted HR: 0.73 [95% CI 0.64–0.84]). Comparing tertile groups by skeletal muscle index, patients in the group of higher skeletal muscle mass index showed lower rate of intradialytic hypotension during hemodialysis, which was similar in inverse probability of treatment weighted analysis. Confounders were age, gender, diabetes mellitus, heart failure, ischemic heart disease, the ratio of ultrafiltration amount to body weight and skeletal muscle index. Model including skeletal muscle index and clinical parameters showed highest AUC area (0.877 [95% 0.823-0.930]) when the model including clinical parameters only (AUC area: 0.807 [95% CI 0.735-0.879]) or with each bioimpedance index (skeletal muscle mass to squared height, AUC area: 0.843 [95% CI 0.823-0.931]; the ratio of extracellular water to total water, AUC area: 0.809 [95% CI 0.736-0.883]; the ratio of intracellular water to total water, AUC area: 0.811 [95% CI 0.738-0.885] and phase angle, AUC area: 0.812 [95% CI 0.738-0.886]). Conclusion This study showed correlation between skeletal muscle mass by body weight and intradialytic hypotension. It especially suggested that skeletal muscle mass to weight would be a good predictor of intradialytic hypotension and would be helpful to decide appropriate dry body weight in hemodialysis.