title: Prevalence of sporadic inclusion body myositis and factors contributing to delayed diagnosis.
abstract: The prevalence of sporadic inclusion body myositis (sIBM) is variable in different populations and ethnic groups. A previous survey in Western Australia in 2000 found a prevalence of 9.3 per million population. We have now performed a follow-up survey to determine whether there has since been any change in prevalence. The current prevalence was found to be 14.9 per million population, with a prevalence of 51.3 per million population in people over 50 years of age. This is the highest reported prevalence of sIBM and correlates with a high frequency of HLA-DR3 and the 8.1 major histocompatibility complex ancestral haplotype in this population. Review of a combined cohort of 57 sIBM cases from three Australian centres revealed a high rate of initial misdiagnosis and a mean time to diagnosis of 5.2 years, which suggests that even the latest prevalence figure may be an underestimate, and emphasising the need to increase the level of awareness of the condition among the medical community.
authors.affiliation: Centre for Neuromuscular and Neurological Disorders, Australian Neuromuscular Research Institute (ANRI), University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Perth 6009, Australia. Needhm01@student.uwa.edu.au
authors.forename: Merrilee
authors.initials: M
authors.lastname: Needham
authors.forename: Alastair
authors.initials: A
authors.lastname: Corbett
authors.forename: Timothy
authors.initials: T
authors.lastname: Day
authors.forename: Frank
authors.initials: F
authors.lastname: Christiansen
authors.forename: Vicki
authors.initials: V
authors.lastname: Fabian
authors.forename: Frank L
authors.initials: FL
authors.lastname: Mastaglia
mesh_terms: D001315:Australia / Q000453:epidemiology; D005260:Female; D015803:HLA-DR3 Antigen / Q000235:genetics; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D018979:Myositis, Inclusion Body / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D015995:Prevalence; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D015803:HLA-DR3 Antigen