Evaluation and construction of diagnostic criteria for inclusion body myositis

Abstract

Objective: To use patient data to evaluate and construct diagnostic criteria for inclusion body myositis (IBM), a progressive disease of skeletal muscle. Methods:The literature was reviewed to identify all previously proposed IBM diagnostic criteria.These criteria were applied through medical records review to 200 patients diagnosed as having IBM and 171 patients diagnosed as having a muscle disease other than IBM by neuromuscular specialists at 2 institutions, and to a validating set of 66 additional patients with IBM from 2 other institutions. Machine learning techniques were used for unbiased construction of diagnostic criteria.Results: Twenty-four previously proposed IBM diagnostic categories were identified. Twelve categories all performed with high ($97%) specificity but varied substantially in their sensitivities (11%-84%). The best performing category was European Neuromuscular Centre 2013 probable (sensitivity of 84%). Specialized pathologic features and newly introduced strength criteria (comparative knee extension/hip flexion strength) performed poorly. Unbiased data-directed analysis of 20 features in 371 patients resulted in construction of higher-performing data-derived diagnostic criteria (90% sensitivity and 96% specificity).Conclusions: Published expert consensus-derived IBM diagnostic categories have uniformly high specificity but wide-ranging sensitivities. High-performing IBM diagnostic category criteria can be developed directly from principled unbiased analysis of patient data. Classification of evidence:This study provides Class II evidence that published expert consensusderived IBM diagnostic categories accurately distinguish IBM from other muscle disease with high specificity but wide-ranging sensitivities.

Inclusion body myositis with granuloma formation in muscle tissue

“…All patients met current Sakai 15 clinocopathological diagnostic criteria for IBM [6,11]. Although mediastinal lymph node granulomas were histologically demonstrated in patient 3, other patients demonstrated granuloma formation confined to muscle tissues as determined by intensive examinations.…”

Cytosolic 5′‐Nucleotidase 1A As a Target of Circulating Autoantibodies in Autoimmune Diseases

“…Serum samples were collected from 117 consecutively enrolled patients with a diagnosis of IBM according to data-derived criteria (7) and/or “probable” or “definite” IBM according to the European Neuromusuclar Centre criteria (8), 42 patients with a diagnosis of probable or definite PM according to the criteria described by Bohan and Peter (9,10), 96 patients with SLE, 44 patients with SS, and 42 healthy volunteers. We included sera from 159 of 160 patients with DM who were described in detail in a previous report (11); serum from 1 of these patients was not available for testing in the current study.…”

Inflammatory Muscle Diseases

“…26 Such patients have "clinical inclusion-body myositis" diagnosed on the basis of clinicopathologic correlation. 27,28 Datadriven criteria confirm that finger-flexor or quadriceps weakness, inflammation around nonnecrotic fibers with MHC class I expression, and cytochrome oxidase-negative fibers, even without vacuoles, are specific for the diagnosis of clinical inclusion-body myositis. 27,28 Autoantibodies directed against nuclear RNAs or cytoplasmic antigens are detected in up to 60% of patients with inflammatory myopathies, 6,7,16,29 depending on the case series and the method of detection used.…”