The "Dose-Effect" Relationship Between 25-Hydroxyvitamin D and Muscle Strength in Hemodialysis Patients Favors a Normal Threshold of 30 ng/mL for Plasma 25-Hydroxyvitamin D.
OBJECTIVE
Muscle strength is weakened in maintenance hemodialysis patients. Strength is both a measure of a functional parameter and of frailty as it is independently associated with mortality. In the general population, observational studies show that plasma 25-hydroxyvitamin D (25[OH]D) is positively correlated with muscle strength and function. We analyzed the determinants of muscle strength measured by handgrip and 25(OH)D in a maintenance hemodialysis population.


METHODS
In this observational cross-sectional study, data from all hemodialysis patients from our nephrology department were recorded in July 2014. Daily nutritional oral intake, handgrip strength, body composition measured by bioimpedancemetry analysis, as well as biological and dialysis parameters, were obtained from medical files. We used a linear regression model to assess nutritional, biological, and dialysis parameters as well as body composition associated with handgrip strength.


RESULTS
The median age (interquartile range) of the 130 included patients was 77.3 (69.5-84.7) years, 57.7% were men, and 50.8% had diabetes mellitus. Median handgrip strength value (interquartile range) was 14.3 (10.6-22.2) kg. In univariate analyses, the factors associated with handgrip strength were age, gender, albumin, transthyretin, predialysis creatinine and urea, normalized protein nitrogen appearance, lean mass, and muscle mass measured by bioimpedancemetry analysis as well as phase angle, and 25(OH)D. In multivariate analyses, lower age, male gender, higher albumin, higher muscle mass, and 25(OH)D level ≥ 30 ng/mL were independently correlated with muscle strength measured by handgrip.


CONCLUSIONS
This study found a positive correlation between plasma 25(OH)D and muscle strength measured by handgrip in hemodialysis patients. We report a "dose-effect" relationship between 25(OH)D and handgrip strength under 30 ng/mL, which is no more present above 30 ng/mL. Prospective randomized studies are needed to prove that supplementation with cholecalciferol, leading to 25(OH)D levels ≥ 30 ng/mL, improves muscle strength in hemodialysis patients.
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France; Nephrology Dialysis Renal Transplantation Center, APHM, CHU Conception, Marseille, France. Electronic address: stanislas.bataille@ap-hm.fr.
Stanislas
S
Bataille
Institut National de Recherche Agronomique, Unité Mixte de Recherche 1260, Marseille, France; Inserm, Unité Mixte de Recherche 1062, Nutrition, Obésité et Risque Thrombotique, Marseille, France; Faculté de Médecine, Aix-Marseille Université, Marseille, France.
Jean-François
JF
Landrier
Institut National de Recherche Agronomique, Unité Mixte de Recherche 1260, Marseille, France; Inserm, Unité Mixte de Recherche 1062, Nutrition, Obésité et Risque Thrombotique, Marseille, France; Faculté de Médecine, Aix-Marseille Université, Marseille, France.
Julien
J
Astier
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France.
Philippe
P
Giaime
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France.
Jérôme
J
Sampol
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France.
Hélène
H
Sichez
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France.
Jacques
J
Ollier
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France.
Jean
J
Gugliotta
Phocean Nephrology Institute, Clinique Bouchard, Marseille, France.
Marianne
M
Serveaux
Medistats, Marseille, France.
Julien
J
Cohen
Institut National de Recherche Agronomique, Unité Mixte de Recherche 1260, Marseille, France; Inserm, Unité Mixte de Recherche 1062, Nutrition, Obésité et Risque Thrombotique, Marseille, France; Faculté de Médecine, Aix-Marseille Université, Marseille, France.
Patrice
P
Darmon
D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008297:Male; D015596:Nutrition Assessment; D009752:Nutritional Status; D011228:Prealbumin / Q000378:metabolism; D006435:Renal Dialysis; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood
D011228:Prealbumin; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D003404:Creatinine