New Estimate Shows Prevalence of MS Has Increased Steadily, Is at Highest Level

In the past 5 decades, there has been a steady rise in the prevalence of multiple sclerosis (MS), according to estimates using a validated algorithm across 5 large US administrative health claims (AHC) data sets. The research was published in Neurology.

The algorithm identified adult cases of MS between 2008 and 2010 using data sets that included private and government-sponsored insurance programs. Previous estimates have suggested that between 300,000 and 400,000 individuals in the United States are affected by MS.

“These estimates do not reflect the changing demographics of the United States or potential changes in the ascertainment of MS due to modifications in the diagnostic criteria and new treatment options,” the authors noted.

The diagnostic algorithm the authors used to identify people with MS in the AHC data sets required at least 3 MS-related hospitalizations, outpatient visits, or prescriptions for an MS disease-modifying therapy within a 1-year period. If a claim for natalizumab was for a patient who also had an International Classification of Diseases, Ninth Revision code for inflammatory bowel disease, then that claim was not included. The algorithm was tested in a Canadian population of individuals with and without MS claims and the researchers found that the sensitivity was 96.0% and the specificity was 99.5%.

They determined the prevalence by identifying all persons who met the definition for MS in any 1 of the 3 study years. The 3-year prevalence estimates were stratified by age, sex, and region.

The AHC data sets used captured 125 million people 18 years or older. Over the 3 years, the average annual increase in prevalence of MS was 6.3%. The MS prevalence estimate in 2010 over the 3 years for the combined data sets was 199.84, which corresponds to a total of 470,053 people in the United States with MS.

After the authors adjusted the estimate for the uninsured and applied a lower-bound inflation factor, as well as an upper-bound inflation factor, they estimated that the 2010 prevalence for MS cumulated over 10 years was anywhere from 265.1 to 309.2 per 100,000 people, or a total of 623,437 to 727,344 people with MS.

By region, the Northeast had the highest prevalence (377.4 per 100,000) and the South had the lowest prevalence (272.6 per 100,000). The prevalence for women remains higher (450.1 vs 159.7 per 100,000).

“The US national MS prevalence estimate for 2010 is the highest reported to date and provides a contemporary understanding of the disease burden,” the authors concluded.

Reference

Wallin MT, Culpepper WJ, Campbell JD, et al. The prevalence of MS in the United States: a population-based estimate using health claims data. Neurology. 2019;92(10):e1029-e1040. doi: 10.1212/WNL.0000000000007035.