Prevalence of Patients with Multiple Neurological Autoimmune Diagnoses (P03.155)

Abstract

Objective: To assess the prevalence of patients with multiple neurological autoimmune diagnoses, including “orphan” autoimmune conditions. Background The fact that there are patients with more than one autoimmune diagnosis is appreciated, but quantification of prevalence has been limited. The number of patients with a rare or “orphan” autoimmune disease, by itself, is challenging to assess; therefore, the prevalence of patients with more than one of these conditions is not well understood. Design/Methods: We conducted a retrospective analysis from a geographically-diverse administrative claims database from one of the largest insurers in the US, to assess the prevalence of 12 predefined autoimmune disorders. The prevalence of patients with more than one autoimmune diagnosis was then quantified. Results: Over 38 million enrollees were identified in the database during the period 1 Jan 2001 to 31 Dec 2008. Of these, 444,157 (1.2%) were identified as adults having received at least one autoimmune disorder diagnosis. Once additional methodological criteria were applied to ensure robustness for further analysis, 51,782 adult autoimmune patients remained. These patients were diagnosed with 57,983 autoimmune conditions, representing a multiple diagnosis overlap of 12.0%. The most prevalent diagnosis combination was Dermatomyositis with Polymyositis (40.7% of Dermatomyositis cases); outside of the myosites, patients diagnosed with Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) (65.0%) or Stiff person syndrome (60.8%) were most likely to have an additional autoimmune diagnosis. The most prevalent condition associated with Multiple Sclerosis was Guillain-Barre syndrome (9.7% of MS patients). A substantial proportion of Myasthenia Gravis patients had also received a diagnosis of MS (11.5%) or rheumatoid arthritis (8.9%). Conclusions: There is a significant prevalence of patients with multiple autoimmune disorder diagnoses in the US; often one or more of those disorders are “orphan” in nature. Supported by: Talecris Biotherapeutics. Talecris Biotherapeutics was acquired by Grifols Inc. effective June 1, 2011. Disclosure: Mr. Crescenzi has received personal compensation for activities with Grifols Inc. as an employee. Mr. Crescenzi has received research support from Talecris Biotherapeutics. Dr. Souayah has received personal compensation for activities with Walgreens as a consultant. Dr. Souayah has received research support from Talecris.