Muscle Biopsy: A Requirement for Precision Medicine in Adult-Onset Myopathy.

Yuan-Ting Sun,Po-Yu Lin,Wei-An Liao,Meng-Ju Wu

doi:10.3390/jcm11061580

Yuan-Ting Sun, Po-Yu Lin

Open Access

https://doi.org/10.3390/jcm11061580

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Abstract

Muscle biopsy is a fundamental procedure to assist the final diagnosis of myopathy. With the recent advances in molecular diagnosis, serology tests, and mechanism-based classification in myopathy, the précised diagnosis for myopathy required the applications of multiple tools. This study intends to reappraise the benefit of muscle biopsy in adult-onset myopathy under the setting of an optimized muscle biopsy protocol and comprehensive serology tests. A one-group pretest-posttest study design was used. The pre- and post-biopsy diagnoses and treatments in 69 adult patients were compared. Muscle biopsy yielded 85.5% of definitive diagnoses, including changes in pre-biopsy diagnoses (40.6%) and narrowing down the suspicious myopathies (49.3%). The demographic data and clinical parameters between the group “with change” and “without change” after biopsy were not different. Among those with changes in diagnosis, 39.3% also had a corresponding shift in treatment, which benefits the patients significantly. Regarding the most common adult-onset myopathy, idiopathic inflammatory myopathy (IIM), 41% of patients with pre-biopsy diagnosis as IIM had changes in their IIM subtype diagnosis, and 53% was finally not IIM after muscle biopsy. Although there have been advances in molecular diagnosis recently, muscle biopsy still undoubtedly critically guided the diagnosis and treatment of adult-onset myopathy in the era of precision medicine.

Highlights

Muscle biopsy is a fundamental procedure to assist the final diagnosis of myopathy
A patient who had repeated biopsy, and those identified as non-myopathy diagnoses, medical records of 204 subjects who underwent myopathy workup were reviewed
For evaluating the effects of muscle biopsy, the nested one-group pretest-posttest quasiexperimental design suffered from the limitations of the absence of a control group and the non-random allocation

Summary

Introduction

Muscle biopsy is a fundamental procedure to assist the final diagnosis of myopathy. There have been considerable advances in the diagnosis and treatments for adult-onset myopathy. The newly identified autoantibodies for serology and molecular markers for muscle histopathology [1–4] prompted the change of classifications for idiopathic inflammatory myopathy (IIM) [5,6]. The aforementioned improvements brought about a more precise pre-biopsy diagnosis of myopathy, the essential role of muscle biopsy in the final diagnosis may still not be substituted [17–21]. This study intends to reappraise the benefit of muscle biopsy in adult-onset myopathy under the setting of an optimized muscle biopsy protocol and comprehensive serology tests (Figure 1A). The objective was to evaluate the effect of the invasive procedure, the muscle biopsy, in altering the final diagnosis and treatment of patients who were previously

Methods

Results

Conclusion