Epidemiology of sporadic inclusion body myositis

Curr Opin Rheumatol. 2016 Nov;28(6):657-60. doi: 10.1097/BOR.0000000000000327.


Purpose of review: In this review, we describe recent progress in the clinical epidemiology of sporadic inclusion body myositis (IBM).

Recent findings: In a population-based, retrospective study from Norway, performed with a denominator population of 2.6 million; and with cases defined by the 1997 and/or 2011 European Neuro-Muscular Centre Research Diagnostic criteria, the estimated point prevalence of IBM was 3.3/100 000. Mean time from symptom onset to diagnosis was 5.6 years, longer than in earlier studies. The male to female ratio was 3 : 2, and the mean age at diagnosis 67 years, very similar to figures reported this year from a nationwide, Dutch myopathy registry. Coexisting rheumatic diseases were recorded in 25% of Norwegian IBM cases, with Sjøgren's syndrome as the most commonly encountered. Mortality was increased in IBM, with a standardized mortality rate of 1.7, but there was no indication of increased cancer risk.

Summary: Population-based data indicate that the prevalence of IBM in Europe is higher than expected from previous studies. Diagnostic delay appears to be a persisting problem in IBM; a major challenge with promising new therapies on the horizon.

Publication types

  • Review

MeSH terms

  • Delayed Diagnosis
  • Europe / epidemiology
  • Humans
  • Myositis, Inclusion Body / diagnosis
  • Myositis, Inclusion Body / epidemiology*
  • Prevalence
  • Retrospective Studies
  • Sjogren's Syndrome / diagnosis
  • Sjogren's Syndrome / epidemiology