The Journey of Sporadic Inclusion Body Myositis Patients Before Diagnosis: A Claims-Based Cohort Analyses (P1.128)

Objective:To elucidate the patient9s journey with sporadic inclusion body myositis (sIBM) in the 3-year period before diagnosis.Background:sIBM is a rare form of progressive inflammatory myositis observed in older patients. Initial diagnoses may often be wrong due to low disease awareness and lack of standard diagnostic algorithm.Methods:A retrospective cohort study using MarketScan claims database included patients aged ≥50 years (at index) with ≥1 inpatient/emergency room (ER) or ≥2 outpatient diagnoses of sIBM (ICD-9-CM 359.71) on different dates ≥7 days apart during the identification period (01/04/2011-31/03/2014). All patients were required to have at least 3 years continuous enrollment for medical and pharmacy benefits before index date, defined as the first diagnosis date in the identification period. Exclusion criteria included a diagnosis of congenital hereditary muscular dystrophy or hereditary progressive muscular dystrophy any time during the study period (01/04/2008-31/03/2014) and a previous sIBM diagnosis in the year prior to index. Descriptive statistics were used to calculate baseline demographic, comorbidities, tests, treatments, resource utilization and costs in the 3-year period before diagnosis.Results:A total of 166 patients were identified; 69[percnt] were male. Mean age was 69 years and mean Charlson comorbidity index was 1.94. Common diagnoses were fibromyalgia (42[percnt]), myopathy (37[percnt]), rheumatic disease (22[percnt]), and polymyositis (20[percnt]), though some may be misdiagnoses. Relevant tests were creatinine phosphokinase assays (49[percnt]), muscle biopsies (28[percnt]), and swallowing function (14[percnt]). Mean number of medications was 16.4 (SD=9.8) for patients with sIBM. Mean outpatient visits (67 [SD=45]) were the most utilized resource compared with ER (1 [SD=3]) and hospitalization visits (1 [SD=1]). Total healthcare costs (medical and pharmacy) were $54,526 (USD) in the 3-year period before diagnosis.Conclusions:sIBM may initially be misdiagnosed. Increased disease awareness and wider recognition of the specific clinical and pathological features of sIBM may lead to earlier diagnosis.Support: Novartis Pharm Disclosure: Dr. Agashivala has received personal compensation for activities with Novartis Pharmaceuticals Corporation as an employee. Dr. Hudson has received personal compensation for activities with Novartis Ireland Ltd. as an employee. Dr. Tsang has received personal compensation for activities with Scott u0026 White Health Plan, University of Texas at Austin and Novartis Pharmaceutical Corporation. Dr. Ozturk has received personal compensation for activities with Novartis as an employee.