Conclusions
Increased serum IL-6 and CRP are associated with clinically significant differences in upper and lower extremity muscle strength and may be useful in identifying those at risk for weakness and decreased physical function.
Methods
One hundred thirty-six women with SLE participated in this cross-sectional study. High-sensitivity CRP was analyzed by nephelometry. IL-6 serum levels were analyzed by high sensitivity enzyme-linked immunosorbent assay. Upper and lower extremity muscle strength were assessed by grip strength and peak torque of knee extension and flexion, respectively. Regression analyses modeled associations of CRP and IL-6 with upper and lower extremity muscle strength controlling for age, SLE duration, physical activity, prednisone use, BMI, plaquenil use, and pain.
Results
Higher serum levels of IL-6 and CRP were associated with significantly weaker upper and lower extremity muscle strength even when controlling for covariates. Conclusions: Increased serum IL-6 and CRP are associated with clinically significant differences in upper and lower extremity muscle strength and may be useful in identifying those at risk for weakness and decreased physical function.