The incidence of idiopathic inflammatory myopathies in the adult Slovenian population
Idiopathic Inflammatory myopathies (IIM) are rare disorders. The aim of our study was to determine the incidence of IIM in a well-defined Slovenian region. This retrospective study was conducted at the Department of Rheumatology, University Medical Centre Ljubljana, the only secondary/tertiary rheumatology center in a region with a population of 704,342 adults. We identified potential IIM cases by searching the electronic patient records for ICD-10 codes M33, M35.1, M35.8, M60, G72, G73, and J84. We included incipient IIM cases between January 2010 and December 2017, who were at the time of the diagnosis, residents of the inspected region. To avoid under-reporting due to miscoded cases, we obtained a list of the patients who had histological patterns consistent with IIM on muscle biopsy from the Institute of Pathology. The annual incidence rate for IIM was calculated. During the eight-year observation period, we identified 65 IIM cases (72.3% female, median (IQR) patient age 64.8 (54.8–73.2) years). The estimated annual incidence of IIM in the studied population was 11.5 (95% CI 9.0–14.6) per 106 adults, in females 16.2 (95% CI 12.1–21.4), and in males 6.6 (95% CI 4.0–10.2) per 106 adults. The incidence rate of IIM in Slovenia is consistent with data from the literature.
KeywordsEpidemiology Incidence Inflammatory myopathy
The study was supported by the Slovenian Research Agency (ARRS) for the National Research Programme P3–0314.
Compliance with ethical standards
Ethics committee approval
The study was approved by the National Medical Ethics Committee.
- 4.Pearson CM (1966) Polymyositis. Annu Rev Med 17:63–82. https://doi.org/10.1146/annurev.me.17.020166.000431 CrossRefGoogle Scholar
- 5.Smoyer-Tomic KE, Amato AA, Fernandes AW (2012) Incidence and prevalence of idiopathic inflammatory myopathies among commercially insured, Medicare supplemental insured, and Medicaid enrolled populations: an administrative claims analysis. BMC Musculoskelet Disord 13:103. https://doi.org/10.1186/1471-2474-13-103 CrossRefGoogle Scholar
- 9.Mendez EP, Lipton R, Ramsey-Goldman R, Roettcher P, Bowyer S, Dyer A, Pachman LM, For the NIAMS Juvenile DM Registry Physician Referral Group (2003) US incidence of juvenile dermatomyositis, 1995-1998: results from the National Institute of Arthritis and Musculoskeletal and Skin Diseases Registry. Arthritis Rheum 49:300–305. https://doi.org/10.1002/art.11122 CrossRefGoogle Scholar
- 12.Tymms KE, Webb J (1985) Dermatopolymyositis and other connective tissue diseases: a review of 105 cases. J Rheumatol 12:1140–1148Google Scholar
- 15.Okada S, Weatherhead E, Targoff IN, Wesley R, Miller FW, for the International Myositis Collaborative Study Group (2003) Global surface ultraviolet radiation intensity may modulate the clinical and immunologic expression of autoimmune muscle disease. Arthritis Rheum 48:2285–2293. https://doi.org/10.1002/art.11090 CrossRefGoogle Scholar
- 17.Patrick M, Buchbinder R, Jolley D, Dennett X, Buchanan R (1999) Incidence of inflammatory myopathies in Victoria, Australia, and evidence of spatial clustering. J Rheumatol 26:1094–1100Google Scholar
- 20.Kendall FP (2005) Muscles: testing and function with posture and pain, 5th ed. Lippincott Williams & Wilkins, BaltimoreGoogle Scholar
- 21.Hoogendijk JE, Amato AA, Lecky BR, Choy EH, Lundberg IE, Rose MR, Vencovsky J, de Visser M, Hughes RA (2004) 119th ENMC international workshop: trial design in adult idiopathic inflammatory myopathies, with the exception of inclusion body myositis, 10-12 October 2003, Naarden, The Netherlands. Neuromuscul Disord 14:337–345. https://doi.org/10.1016/j.nmd.2004.02.006 CrossRefGoogle Scholar
- 22.Lundberg IE, Tjärnlund A, Bottai M, Werth VP, Pilkington C, Visser M, Alfredsson L, Amato AA, Barohn RJ, Liang MH, Singh JA, Aggarwal R, Arnardottir S, Chinoy H, Cooper RG, Dankó K, Dimachkie MM, Feldman BM, Torre IG, Gordon P, Hayashi T, Katz JD, Kohsaka H, Lachenbruch PA, Lang BA, Li Y, Oddis CV, Olesinska M, Reed AM, Rutkowska-Sak L, Sanner H, Selva-O’Callaghan A, Song YW, Vencovsky J, Ytterberg SR, Miller FW, Rider LG, International Myositis Classification Criteria Project consortium, The Euromyositis register and The Juvenile Dermatomyositis Cohort Biomarker Study and Repository (JDRG) (UK and Ireland) (2017) 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Ann Rheum Dis 76:1955–1964. https://doi.org/10.1136/annrheumdis-2017-211468 CrossRefGoogle Scholar
- 23.Hočevar A, Rotar Z, Krosel M et al (2017) Performance of the 2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies in clinical practice. Ann Rheum Dis. https://doi.org/10.1136/annrheumdis-2017-212774