PND8 Prevalence and Incidence Rates of Multiple Sclerosis in the United States

Abstract

PND8 PREVALENCE AND INCIDENCE RATES OF MULTIPLE SCLEROSIS IN THE UNITED STATES Baser O1, Wang L2, Li T3, Shu Z3, Xie L4 1STATinMED Research/The University of Michigan, Ann Arbor, MI, USA, 2STATinMED Research, Dallas, TX, USA, 3STATinMED (BeiJing) International Healthcare Technology Assessment Co., Ltd., BeiJing, China, 4STATinMED Research, Ann Arbor, MI, USA OBJECTIVES: Multiple sclerosis (MS) is a chronic inflammatory disease with 12,000 new diagnoses per year in the United States. Higher latitude is associated with higher MS prevalence rates, and the female-to-male ratio in MS incidence has been estimated at 2:3 in 2000. This study aims to estimate the prevalence and incidence rate of MS in the United States. METHODS: Patients with an MS diagnosis (International Classification of Diseases Ninth Revision Clinical Modification [ICD-9-CM] code: 340.XX) between January 2006 and December 2010 were identified from a large U.S. claims database. Prevalence rates from 2006 to 2010 were calculated by dividing the number of MS patients by the total number of health plan enrollees in each year. The 2010 incidence rate was calculated by dividing the number of patients with a new MS diagnosis in 2010 by the total number of enrollees in 2010. RESULTS: The prevalence rate remained stable at 0.16% from 2006 to 2008, and then increased in 2009 (0.17%) and again in 2010 (0.19%). In 2010, MS prevalence in women (0.26%) was more than twice the rate than that of the male population (0.09%). To examine regional differences, prevalence rate was also calculated for each U.S. state. Regional prevalence rates ranged from 0.11% (Arkansas) to 0.29% (Rhode Island). The estimated incidence rate for 2010 was 0.03% for the overall population, 0.05% for female, and 0.02% for male patients. Incident cases had an average age of 49 years, and were more likely to suffer from comorbid conditions, such as disturbance of skin sensation, fatigue, and hypertension. Incidence rates by state ranged from 0.01% (Maine) to 0.08% (Michigan). CONCLUSIONS: This study confirms that MS prevalence and incidence rates are higher in female patients, and in regions farther away from the equator.