Ultrasound Assessment of Sarcopenia in Patients With Sarcoidosis

Sarcoidosis can cause sarcopenia like other chronic diseases. Ultrasonography is a simple method, which has been used frequently in recent years. We aimed to evaluate the sarcoidosis patients with ultrasonography for sarcopenia and to compare the results of ultrasonography with the accepted standard method, bioelectrical impedance analysis (BIA).

BIA and handgrip test were applied to all patients diagnosed with sarcoidosis. The patients were classified according to the presence of probable sarcopenia with their handgrip results and the presence of sarcopenia with the appendicular skeletal muscle mass index calculated with using BIA. Ultrasonography was applied to each patient and the thickness of seven different muscle groups of the patients were evaluated. The ability of muscle thickness values measured by ultrasonography to predict sarcopenia was compared with the reference standard test BIA.

Forty patients (women/men = 31/9) were included in our study. The mean age was 53.2 ± 12.5 years. A statistically significant positive correlation was observed between handgrip strength and gastrocnemius medialis (GM), rectus femoris (RF) cross-sectional area, rectus abdominis (RA), external oblique (EO), transversus abdominus (TA), and diaphragm thicknesses. Therefore, there was a significant correlation between fat free mass index with RA, EO, and TA muscles. According to the ROC analysis, statistically significant muscle groups predicting sarcopenia were found as GM, RF cross-sectional area, EO, and IO. Again, according to the ROC analysis, it was seen that the thicknesses of GM, RA, EO, IO, and TA muscles corrected for BMI predicted probable sarcopenia with quite high sensitivity and specificity.

Muscle thicknesses measured by ultrasonography are helpful for the diagnosis of sarcopenia that may develop in chronic diseases such as sarcoidosis. Further studies with higher number of patients are needed to validate the results of the present pilot study.