Creatine supplements in patients with idiopathic inflammatory myopathies who are clinically weak after conventional pharmacologic treatment: Six-month, double-blind, randomized, placebo-controlled trial.
OBJECTIVE
To test the hypothesis that oral creatine supplements with exercise are more effective than exercise alone in improving muscle function in patients with established dermatomyositis or polymyositis receiving chronic medical therapies who are clinically weak yet stable.


METHODS
In a 6-month, 2-center, double-blind, randomized controlled trial, patients were randomized to receive oral creatine supplements (8 days, 20 gm/day then 3 gm/day) or placebo. All patients followed a home exercise program. The primary outcome was aggregate functional performance time (AFPT), reflecting the ability to undertake high-intensity exercise. Secondary outcomes included a functional index measuring endurance and muscle bioenergetics on (31)P magnetic resonance spectroscopy ((31)P MRS). Patients were receiving stable immunosuppressive treatment and/or corticosteroids.


RESULTS
A total of 37 patients with polymyositis or dermatomyositis were randomized (19 to creatine, 18 to placebo); 29 completed 6 months. Intent-to-treat analyses demonstrated that AFPT improved significantly at 6 months with creatine (median decrease 13%, range -32-8%) compared with placebo (median decrease 3%, range -13-16%; P = 0.029 by Mann-Whitney U test). A completer analysis also showed significant benefits from creatine (P = 0.014). The functional index improved significantly with both creatine and placebo (P < 0.05 by paired Wilcoxon's rank sum test), with a significant benefit between groups in the completer analysis only. Phosphocreatine/beta-nucleoside triphosphate ratios using MRS increased significantly in the creatine group (P < 0.05) but not in the control group. No clinically relevant adverse events were associated with creatine.


CONCLUSIONS
Oral creatine supplements combined with home exercises improve functional performance without significant adverse effects in patients with polymyositis or dermatomyositis. They appear safe, effective, and inexpensive.
Chung
Yuen-Li
YL
King's College London School of Medicine, and the MRC Clinical Science Centre, Hammersmith Hospital, Imperial College School of Medicine, London, UK. ychung@sgul.ac.uk
Alexanderson
Helene
H
Pipitone
Nicoló
N
Morrison
Catherine
C
Dastmalchi
Maryam
M
Ståhl-Hallengren
Christina
C
Richards
Selwyn
S
Thomas
E Louise
EL
Hamilton
Gavin
G
Bell
Jimmy D
JD
Lundberg
Ingrid E
IE
Scott
David L
DL
D000284:Administration, Oral; D003401:Creatine / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects; D015444:Exercise; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects; D018908:Muscle Weakness / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D009220:Myositis / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes; D010919:Placebos; D016896:Treatment Outcome
D010759:Phosphorus Isotopes; D010919:Placebos; D010725:Phosphocreatine; D003401:Creatine