Multiple Sclerosis Prevalence Rates Within a Healthcare Delivery System in Northern California: A Retrospective, Electronic Health Records-Based Study From 2010 to 2016 (P4.2-062)

Objective: To quantify the prevalence of MS in a healthcare delivery system in northern California, USA. Background: Quantifying the prevalence of MS in geographically distinct regions is important to understand its true burden, especially across diverse racial/ethnic populations residing in the same region and with similar access to healthcare. Design/Methods: An electronic health records database from a healthcare system in northern California was used to quantify MS prevalence in adults ≥18 years of age. Individuals who had an International Classification of Disease 9/10 diagnosis of MS between 2010 and 2016 were identified. Overall and annual prevalence rates were based on the total number of patients with encounters during the entire study period and during each year, respectively. Rates were expressed per 100,000 of the population with 95% CI. For comparisons by year, gender, and racial/ethnic groups, rates were age-adjusted using logistic regression. Results: Among 1,508,102 patients in the healthcare system between 2010 and 2016, MS prevalence was 311/100,000 (95% CI: 300–321). There was a significant increase in age-adjusted prevalence from 259/100,000 (95% CI: 249–271) in 2010 to 358/100,000 (95% CI: 344–372) in 2016 (P Conclusions: In a healthcare practice-based setting in northern California, MS prevalence differed by gender and race/ethnicity, and was highest among black women. This study suggests that MS prevalence in northern California is increasing, most notably among non-Hispanic white women. Disclosure: Dr. Romanelli has received research support from Janssen, Regeneron, and Sanofi. Dr. Huang has nothing to disclose. Dr. Lacy has received research support from EMD Serono and Sanofi Genzyme. Dr. Wong has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Sanofi. Dr. Hashemi has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Sanofi . Dr. Smith has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Sanofi. Dr. Smith holds stock and/or stock options with Sanofi.