RT Journal Article
SR Electronic
T1 Adipose Depots, Not Disease-related Factors, Account for Skeletal Muscle Insulin Sensitivity in Established and Treated Rheumatoid Arthritis
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP jrheum.140224
DO 10.3899/jrheum.140224
A1 Hiba AbouAssi
A1 K. Noelle  Tune
A1 Brian Gilmore
A1 Lori A.  Bateman
A1 Gary McDaniel
A1 Michael Muehlbauer
A1 Janet L.  Huebner
A1 Helen M.  Hoenig
A1 Virginia B.  Kraus
A1 E. William  St. Clair
A1 William E.  Kraus
A1 Kim M.  Huffman
YR 2014
UL http://www.jrheum.org/content/early/2014/06/25/jrheum.140224.abstract
AB Objective In prior reports, individuals with rheumatoid arthritis (RA) exhibited increased insulin resistance. However, those studies were limited by either suboptimal assessment methods for insulin sensitivity or a failure to account for important determinants such as adiposity and lack of physical activity. Our objectives were to carefully assess, compare, and determine predictors of skeletal muscle insulin sensitivity in RA, accounting for adiposity and physical activity. Methods Thirty-nine individuals with established (seropositive or erosions) and treated RA and 39 controls matched for age, sex, race, body mass index, and physical activity underwent a frequently sampled intravenous glucose tolerance test to determine insulin sensitivity. Inflammation, body composition, and physical activity were assessed with systemic cytokine measurements, computed tomography scans, and accelerometry, respectively. Exclusions were diabetes, cardiovascular disease, medication changes within 3 months, and prednisone use over 5 mg/day. This investigation was powered to detect a clinically significant, moderate effect size for insulin sensitivity difference. Results Despite elevated systemic inflammation [interleukin (IL)-6, IL-18, tumor necrosis factor-α; p < 0.05 for all], persons with RA were not less insulin sensitive [SI geometric mean (SD): RA 4.0 (2.4) vs control 4.9 (2.1)*10-5 min-1/(pmol/l); p = 0.39]. Except for visceral adiposity being slightly greater in controls (p = 0.03), there were no differences in body composition or physical activity. Lower insulin sensitivity was independently associated with increased abdominal and thigh adiposity, but not with cytokines, disease activity, duration, disability, or disease-modifying medication use. Conclusion In established and treated RA, traditional risk factors, specifically excess adiposity, play more of a role in predicting skeletal muscle insulin sensitivity than do systemic inflammation or other disease-related factors.