Hippokratia 2004, 8(4):155-160
Gk Sakkas, I Stefanidis, V Liakopoulos, KL Johansen
Dpt of Medicine, niversity of California, San Francisco, CA, USA
Division of Nephology, School of Medicine, University of Thessali, Larissa, Greece
Dpt of Medicine, San Francisco VA Medical Center, San Francisco, CA, USA
Background. Gender has been shown to have an effect on muscle size, strength and performance. However, in patients on dialysis treatment it is not known whether gender plays a role in the degree of muscle wasting and weakness. Preliminary data have shown that male patients are more affected than female counterparts. We sought to determine whether the muscles of the lower leg are differentially affected in males and females with ESRD.
Material and Methods. Six healthy female controls (F-CON) were compared to 24 female dialysis patients (F-RFP) and 13 male controls (M-CON) compared to 27 male dialysis patients for measurements in muscle cross sectional area (CSA) and composition by MRI, isometric leg muscle strength, body composition by DEXA, physical activity by a 3D-accelerometry and physical performance using functional tests. The data were normalized for baseline differences between males and females by dividing the variables for each subject by the mean values of the sex-specific control group. ANOVA was performed to detect statistical differences.
Results. Muscle size in M-RPF group was reduced 13% more than in F-RFP group (p=0.01). Muscle strength was also reduced in M-RFP 5% more than the F-RFP group (p=0.01). Intramuscular fat content was similar in all groups. On the other hand, F-RFP group had 20% more reduction in gait speed than M-RFP group (p=0.01). A similar reduction in physical activity levels, lean body mass and total body fat was found in both dialysis groups. Testosterone concentration was highly correlated with muscle size in M-RFP group (R=0.554, p=0.001).
Conclusions. Male patients have a greater reduction in muscle size and strength than female dialysis patients while female patients have a greater reduction in gait speed. Hormonal changes may be a reason for those differences.