Prevalence Of Inclusion Body Myositis Research Articles

Significance of Sjögren's syndrome and anti-cN1A antibody in myositis patients.

We recently recorded a high prevalence of inclusion body myositis (IBM) in patients with Sjögren's syndrome (SS). Whether myositis patients with SS differ from myositis patients without SS in terms of the characteristics of the myositis is currently unknown. Anti-cytosolic 5'-nucleotidase 1 A (cN1A) has recently been proposed as a biomarker for IBM but is also frequent in SS. Whether anti-cN1A is independently associated with IBM is still an open question. We aimed to assess the significance of SS and anti-cN1A in myositis patients. Cumulative data on all myositis patients (EULAR/ACR 2017 criteria) screened for SS (ACR/EULAR 2016 criteria) in a single centre were analysed. Ninety-nine patients were included, covering the whole spectrum of EULAR/ACR 2017 myositis subgroups and with a median follow-up of 6 years (range 1.0-37.5). The 34 myositis patients with SS (myositis/SS+) were compared with the 65 myositis patients without SS (myositis/SS-). . IBM was present in 24% of the myositis/SS+ patients vs 6% of the myositis/SS- group (P = 0.020). None of the IBM patients responded to treatment, whether they had SS or not. Anti-cN1A was more frequent in myositis/SS+ patients (38% vs 6%, P = 0.0005), independently of the higher prevalence of IBM in this group (multivariate P value: 0.02). Anti-cN1A antibody specificity for IBM was 0.96 (95% CI: 0.87, 0.99) in the myositis/SS- group but dropped to 0.70 (95% CI: 0.48, 0.85) in the myositis/SS+ group. In myositis patients, SS is associated with IBM and with anti-cN1A antibodies, independently of the IBM diagnosis. As a consequence, anti-cN1A has limited specificity for IBM in myositis patients with SS.

Health care costs and comorbidities for patients with inclusion body myositis

Objective: This study identifies the health care costs and utilization, as well as comorbidities, in a Medicare population of inclusion body myositis (IBM) patients.Methods: Medicare patients aged ≥65 years with a diagnosis claim for IBM were identified and matched to a cohort of non-IBM patients based on age, sex, race, calendar year and census region. Generalized linear models were used to estimate health care costs and utilization during the follow-up period.Results: The prevalence of IBM in this population, aged ≥65 years, was 83.7 cases per 1 million patients. Mean 1 year costs for the IBM cohort (N = 361) were $44,838 compared to $10,182 for the matched non-IBM cohort (N = 1805), an excess of $34,656. IBM was significantly associated with multiple unsuspected comorbidities, including hypertension (66% vs. 22%), hyperlipidemia (47% vs. 18%) and myocardial infarction (13% vs. 2%) (all p < .0001).Conclusions: IBM patients utilize more health care resources and incur higher health care costs than patients without IBM. Furthermore, IBM patients were more likely to have multiple comorbidities, including cardiovascular risk factors and events, muscle and joint pain, and pulmonary complications compared to those without IBM.Limitations: The presence of a diagnosis code for a condition on a medical claim does not necessarily indicate the presence of the disease condition because the diagnosis code could be incorrectly entered in the database. Clinical and disease-specific parameters were not available in the claims data. Additionally, due to the observational study design, the analysis may be affected by unobserved differences between patients.

P.189 - Incidence and prevalence of inclusion body myositis in western Sweden

The slowly progressive muscle disease inclusion body myositis (IBM) causing muscle weakness and swallowing difficulties is the most common acquired myopathy in the elderly. To obtain more information of comorbidity, biomarkers and genetic background we aimed to investigate epidemiological aspects of IBM in a population based study. The region Västra Götaland in western Sweden includes approximately 1.5 million inhabitants (data from SCB, Statistics Sweden). Nearly all muscle biopsies performed to diagnose muscle disease in the region have since 1985 been analyzed at the Department of Pathology and Genetics at the Sahlgrenska University Hospital, Gothenburg. Patients were identified by screening all muscle histology reports from 1996 to 2016 for diagnosis myositis or myopathy. An additional approach was to identify all patients with diagnosis IBM at the Neuromuscular Centre at Sahlgrenska University Hospital. All patients living in the region Västra Götaland were included if they fulfilled the ENMC research criteria for clinico-pathologically defined IBM from 2011. The date of the first biopsy fulfilling the ENMC criteria was used as date of diagnosis. A total of 84 patients fulfilled the inclusion criteria. The point prevalence of IBM December 31st 2015 was 27 (95% CI 20–37) per million inhabitants. The incidence rate during the 20-year period varied from 0 (95% CI 0–2.5) to 5.4 (95% CI 2.3–10.1) per million inhabitants and year. Both prevalence and incidence are probably underestimated in our study due to exclusion of patients not fulfilling the strict 2011 ENMC criteria for clinico-pathologically defined IBM. Although inclusion criteria may vary in different studies, the prevalence is similar to a previous study from Norway (33 per million) and higher than a study from the Netherlands (4.9 per million) using the ENMC criteria from 2011 and 1997 respectively. Our well-defined patient cohort will be the basis for further epidemiological studies.

High prevalence of inclusion body myositis in Norway; a population‐based clinical epidemiology study

Knowledge about the occurrence of sporadic inclusion body myositis (sIBM) in the general population is limited. Here, our aim was to identify and characterize every sIBM patient living in southeast Norway (population 2.64 million) from 2003 to 2012. Two sIBM case finding strategies were applied. First, all hospital databases in southeast Norway were screened to identify cases with sIBM-compatible International Classification of Diseases 10 (ICD-10) codes. These cases were then manually chart reviewed. Secondly, all muscle histology reports encoded with inflammation were independently reviewed. Finally, cases were classified according to the 1997 and the 2011 European Neuro-Muscular Centre (ENMC) Research Diagnostic Criteria for sIBM. The combined case finding strategy identified 3160 patients with sIBM compatible ICD-10 codes, and a largely overlapping cohort of 500 patients having muscle biopsies encoded with inflammation. Detailed retrospective review of chart and histology data showed that 95 patients met the 2011 ENMC sIBM criteria and 92 met the 1997 criteria. Estimated point prevalence of sIBM was 33/1000000, equal with both criteria sets. Mean age at diagnosis was 66.9years and mean diagnostic delay was 5.6years. Chart review revealed higher frequencies of dysphagia (94% vs. 65%) and anti-Sjøgren syndrome A antibodies (39% vs. 12%) in female sIBM patients (n=40) than in males. Coexisting rheumatic diseases were present in 25% of sIBM cases, with Sjøgren's syndrome in 10%. An estimated point prevalence of sIBM seven times higher than previously observed in Europe is reported. Our data show considerable diagnostic delay, a major challenge with new sIBM treatments in the pipeline.

P2.41 Prevalence of inclusion body myositis (IBM) in Japanese population

Background: The prevalence of inclusion body myositis (IBM) is variable in different populations and ethnic groups. Previous surveys revealed that the prevalence in Caucasians is 5–15 per million. The prevalence of IBM in Asian people including Japanese has not been elucidated. Method: We estimated the number of IBM by comparing the number of IBM with polymyositis (PM) diagnosed at the National Center of Neurology and Psychiatry (NCNP). The number of PM is calculated from national survey in Japan.

Prevalence of sporadic inclusion body myositis in Western Australia

A 10-year retrospective review was conducted to ascertain the prevalence of inclusion body myositis (IBM) in Western Australia. Seventeen patients with sporadic IBM aged 45–90 years were identified and the prevalence of IBM was calculated to be 9.3 × 10−6. The prevalence was higher in men (10.9 × 10−6) than in women (7.7 × 10−6). The mean age of onset of IBM was 56.6 years, and the mean delay between onset of symptoms and diagnosis was 4.4 years. The age-adjusted prevalence over the age of 50 years was 35.3 × 10−6. The results suggest a higher prevalence of IBM than has previously been reported. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 970–972, 2000

Prevalence of sporadic inclusion body myositis in Western Australia.

A 10-year retrospective review was conducted to ascertain the prevalence of inclusion body myositis (IBM) in Western Australia. Seventeen patients with sporadic IBM aged 45-90 years were identified and the prevalence of IBM was calculated to be 9.3 x 10(-6). The prevalence was higher in men (10.9 x 10(-6)) than in women (7.7 x 10(-6)). The mean age of onset of IBM was 56.6 years, and the mean delay between onset of symptoms and diagnosis was 4.4 years. The age-adjusted prevalence over the age of 50 years was 35.3 x 10(-6). The results suggest a higher prevalence of IBM than has previously been reported.