Muscle ultrasound in Spondyloarthritis patients receiving biologic disease-modifying anti-rheumatic drugs early in treatment

Objective: This study evaluated muscle ultrasound in spondyloarthritis (SpA) patients receiving biologic disease-modifying anti-rheumatic drugs (b-DMARDs) early in treatment. Methods: A prospective study was conducted with 110 b-DMARD-naive SpA patients. The baseline and control muscle strength, physical performance tests, ultrasonographic muscle parameters, and disease activity scores of 67 controlled patients were examined. Results: During the follow-up period, there were significant improvements in the thickness of the gastrocnemius medialis (GM) muscle (p<0.001), the length of the GM fascicle (p=0.031), the thickness of the rectus femoris (RF) muscle (p<0.001), the cross-sectional area of the RF (RFCSA) muscle (p<0.001), the thickness of the rectus abdominis (RA) muscle (p<0.001), the thickness of the transverse abdominis (TA) muscle (p=0.004), and the thickness of the external oblique (EO) muscle (p=0.042). Besides, ASDAS-CRP scores were related to GM muscle thickness, RFCSA, and TA muscle thickness percent changes in patients whose disease activity regressed from high to moderate (respectively; p=0.030, p=0.040, p=0.002). Conclusion: Muscle ultrasound examination can show muscle mass improvement in SpA patients during treatment.