title: Increasing incidence of immune-mediated necrotizing myopathy: single-centre experience.
abstract: OBJECTIVE
  Immune-mediated necrotizing myopathy (IMNM) is characterized by the predominant presence of necrotic muscle fibres in muscle biopsy and variable response to immunosuppressive treatment. The aims of this study were to analyse the temporal trend of IMNM incidence in our centre over the past 10 years and to explore the role of statins as possible causative agents.
  
  
  METHODS
  A retrospective evaluation of muscle biopsy results, clinical and laboratory data, including antibody associations of all patients with idiopathic inflammatory myopathy newly diagnosed between 2004 and June 2014, was performed. Available sera were tested for the presence of anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR) autoantibodies.
  
  
  RESULTS
  Of 357 biopsied patients, 233 fulfilled criteria for inflammatory/immune-mediated myopathy, including 27 (11.6%) classified as IMNM. There were no patients with IMNM diagnosed between 2004 and 2007; subsequently, two to three cases of IMNM per year were seen during the period 2008-11, with a substantial increase to 18 cases (66.6% of all IMNM biopsies) in 2012-14. Thirteen of 27 patients (48%) had a history of statin use, 11 (85%) of whom had positive anti-HMGCR antibodies. There was no IMNM patient without a history of statin use who was anti-HMGCR antibody positive.
  
  
  CONCLUSIONS
  Our data show an increasing incidence of IMNM, which is mainly accounted for by anti-HMGCR-positive IMNM associated with the use of statins.
authors.affiliation: Clinical Department, Institute of Rheumatology, Department of Rheumatology, 1st Faculty of Medicine, Charles University in Prague.
authors.forename: Martin
authors.initials: M
authors.lastname: Klein
authors.affiliation: Clinical Department, Institute of Rheumatology, Department of Rheumatology, 1st Faculty of Medicine, Charles University in Prague.
authors.forename: Heřman
authors.initials: H
authors.lastname: Mann
authors.affiliation: Clinical Department, Institute of Rheumatology, Department of Rheumatology, 1st Faculty of Medicine, Charles University in Prague.
authors.forename: Lenka
authors.initials: L
authors.lastname: Pleštilová
authors.affiliation: Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Zámečník
authors.affiliation: Department of Pharmacy and Pharmacology, University of Bath and.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Betteridge
authors.affiliation: Department of Pharmacy and Pharmacology, University of Bath and Rheumatology, Royal National Hospital for Rheumatic Diseases, Bath, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: McHugh
authors.affiliation: Clinical Department, Institute of Rheumatology, Department of Rheumatology, 1st Faculty of Medicine, Charles University in Prague, vencovsky@revma.cz.
authors.forename: Jiří
authors.initials: J
authors.lastname: Vencovský
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D001706:Biopsy; D018153:Czech Republic; D005260:Female; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000276:immunology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects; D015994:Incidence; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000473:pathology*; D009135:Muscular Diseases / Q000453:epidemiology* / Q000276:immunology* / Q000473:pathology; D009220:Myositis / Q000453:epidemiology; D009336:Necrosis; D012189:Retrospective Studies
chemical_list: D001323:Autoantibodies; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; C553220:HMGCR protein, human; D006903:Hydroxymethylglutaryl CoA Reductases
keywords: anti-3-hydroxy-3-methylglutaryl coenzyme A reductase autoantibodies; muscle biopsy; myositis; necrotizing myopathy