Association between objectively measured protein intake and muscle status, health-related quality of life, and mortality in hemodialysis patients

Background: Protein intake is known to be associated with muscle mass, health-related quality of life (HRQoL), and mortality in patients with stage 5 chronic kidney disease undergoing dialysis. However, most studies evaluated protein intake based on 24 h dietary recall or food frequency questionnaire, and these methods are prone to bias. Therefore, this study aimed to evaluate the association of objectively measured protein intake with muscle mass and strength, HRQoL, and mortality. Methods: Dietary protein intake was calculated based on the combined (urinary and dialysate) urea excretion rate according to the Maroni formula and indexed to body weight. Muscle mass was calculated based on the combined dialysate and urinary creatinine excretion rate, and muscle strength was assessed by handgrip strength. HRQoL was based on the Short Form 36. Linear and Cox regression were used for the analyses. Results: We included 59 hemodialysis patients (mean age 65 ± 15 years, 37% female, median hemodialysis vintage 15 [6–39] months). Mean protein intake was 0.82 ± 0.23 g/kg/day, and 76% had a low protein intake (