Association between sarcopenia and rheumatological diseases

Muscle strength, not muscle mass, determines the health-related quality of life in Indonesian women with systemic lupus erythematosus

OBJECTIVE

No study evaluated the impact of low muscle strength and mass on the Sarcopenia-related Quality of Life (SarQoL) in women with SLE.

METHODS

This cross-sectional study recruited 145 women with SLE consecutively; muscle strength was measured with a calibrated Jamar handheld dynamometer, muscle mass was measured with appendicular muscle mass index (Tanita MC-780 MAP body impedance analyser) and health-related quality of life with SarQoL Questionnaire. The cut-off points for low muscle strength, low muscle mass and sarcopenia were derived from the Asian Working Group on Sarcopenia 2019. Statistical analysis was conducted with a t-test for mean difference, and logistic regression was used to evaluate for low muscle strength contributing factors.

RESULTS

There was a significant difference in the mean total score of SarQoL in individuals with normal compared with low muscle strength (74.36 vs 64.85; mean difference 9.50; 95% CI 2.10 to 5.33; p<0.001). On the other hand, there was no difference in individuals with normal compared with low muscle mass (71.07 vs 70.79; mean difference 0.28; -5.18 to 5.74; p=0.91). After minimally adjusted with age, we found moderate-severe joint pain (B -9.280; p<0.001) and low muscle strength (B -6.979; p=0.001) to be independently associated with low mean SarQoL total score.

CONCLUSION

There was a lower total SarQoL score in individuals with low muscle strength but not with low muscle mass.

Skeletal Muscle Mass by Bioelectrical Impedance Analysis and Calf Circumference for Sarcopenia Diagnosis

Skeletal muscle mass (SMM) plays an important role in health and physical performance. Its estimation is critical for the early detection of sarcopenia, a disease with high prevalence and high health costs. While multiple methods exist for estimating this body component, anthropometry and bioelectrical impedance analysis (BIA) are the most widely available in low- to middle-income countries. This study aimed to determine the correlation between muscle mass, estimated by anthropometry through measurement of calf circumference (CC) and skeletal mass index (SMI) by BIA. This was a cross-sectional and observational study that included 213 functional adults over 65 years of age living in the community. Measurements of height, weight, CC, and SMM estimated by BIA were made after the informed consent was signed. 124 women mean age 69.6 ± 3.1 years and 86 men mean age 69.5 ± 2.9 years had the complete data and were included in the analysis. A significant positive moderate correlation among CC and SMI measured by BIA was found (Pearson r= 0.57 and 0.60 for women and men respectively (p=0.0001)). A moderate significant correlation was found between the estimation of SMM by CC and by BIA. This suggests that CC could be used as a marker of sarcopenia for older adults in settings in lower-middle-income countries where no other methods of diagnosing muscle mass are available. Although the CC is not the unique parameter to the diagnosis of sarcopenia, it could be a useful procedure in the clinic to identify patients at risk of sarcopenia.