Effect of diabetes mellitus on muscle size and strength in patients receiving dialysis therapy
Background. Diabetes mellitus (DM) is a potential contributor to the muscle abnormalities and poor physical functioning of the dialysis population. Methods: Thirty-three dialysis patients without DM (non-DM group) were compared with 25 dialysis patients with DM (DM group). Measures were made of cross-sectional area and composition of the leg muscles by using proton T(1-)weighted magnetic resonance imaging; body composition by means of dual-energy X-ray absorptiometry; leg muscle strength by means of isokinetic knee extension; isometric dorsiflexor maximum voluntary contraction by means of force plate; physical activity by means of 3-dimensional accelerometry; and functional capacity by using various functional tests. Results:The DM group was older, weaker, more atrophic, and had a greater amount of intramuscular fat compared with the non-DM group. However, when the overall analysis was adjusted for age and sex, there were no differences between the 2 groups with respect to muscle cross-sectional area, leg strength, or physical activity. To further account for sex and age differences, a paired analysis was performed after matching patients by age (within 5 years) and sex (N = 16/group). In the matched analysis, only intramuscular fat and leg adipose tissue were different between the 2 groups. Conclusion: DM is associated with more fat within muscles of dialysis patients, but is unrelated to muscle size or strength. Demographic differences between the DM and non-DM groups on dialysis therapy likely are responsible for the general perception that patients with DM are more debilitated.