# Evaluation of Sarcopenia in Patients with Monoclonal Gammopathy of Undetermined Significance

## TL;DR

This study finds that nearly a third of patients with MGUS have sarcopenia, suggesting a possible link between muscle loss and this blood disorder.

## Contribution

The study is the first to evaluate sarcopenia prevalence in MGUS patients and identify associated clinical factors.

## Key findings

- Sarcopenia was confirmed in 34.15% of MGUS patients.
- Male patients with sarcopenia showed significantly lower hand grip strength and muscle mass indices.
- Low muscle function scores were associated with higher age and lower Lambda light-chain levels.

## Abstract

Background: We aimed to determine the prevalence of sarcopenia in patients with monoclonal gammopathy of undetermined significance (MGUS) and to evaluate the links between MGUS and sarcopenia. Methods: Eighty-two patients with a diagnosis of MGUS were enrolled in the study. Muscle strength was measured using the handgrip dynamometer. Physical performance was assessed by assessing gait speed over a 6-minute walking test. Muscle mass was determined using a bioelectrical impedance analyzer. Results: Sarcopenia was confirmed in 34.15% of patients. Male predominance was demonstrated in MGUS subjects with sarcopenia, particularly patients with low hand grip strength, low appendicular skeletal muscle mass (ASMM), or low ASMM index (p < 0.001, 0.013, and 0.001, respectively). Higher age and lower serum free light-chain Lambda levels were shown in MGUS patients with low muscle function scores compared to normal scores (p < 0.001, and 0.014, respectively). In addition, having a low ASMM score was related to low body mass index and high-risk group (p = 0.020, 0.033, respectively). Conclusions: We demonstrated that the frequency of sarcopenia is high in patients with MGUS. Whether sarcopenia has a possible role as a factor contributing to the pathogenesis of MGUS should be supported by further studies containing longitudinal data.