P.205 Utility of electrical bioimpedance as a biomarker in myotonic dystrophy type I

Abstract

Myotonic dystrophy type 1 (DM1) is frequently associated with endocrinopathies. Body composition analysis by electrical bioimpedance study is useful in the nutritional assessment of these patients. The aim of this study is to investigate its usefulness as a biomarker of clinical progression/severity in DM1. We carried out a cross-sectional study of 47 patients with DM1 attended in the last year who underwent impedancemetry with the InBody S10 device for segmental multifrequency analysis. Muscle weakness was classified according to severity using the muscular impairment rating scale (MIRS). 18 men and 29 women were evaluated. Mean age was 46.11 years. By means of Spearman's Rho correlation, a highly statistically significant concordance was identified between the MIRS scale and the global phase angle (PA) at 50 kHz (p 0.000 and R -0.717) and also with the skeletal muscle mass index (SMMI) (p 0.000 and R -0.549). However, no relationship was observed between MIRS with classical nutritional indicators such as BMI or percentage weight loss. In logistic regression models, PA and SMMI adjusted by age and sex decrease statistically significantly as muscle weakness progresses with high explanatory value. There is a highly significant correlation between clinical severity measured by the MIRS scale and PA and SMMI. PA and SMMI are more sensitive, early and constant as a marker of muscle deterioration than any of the GLIM phenotypic criteria for the diagnosis of malnutrition that are usually related to muscle weakness, thus postulating themselves as a possible useful biomarker of progression in DM1.