SHORT SUMMARY
Background:
With advances in disease-modifying therapies (DMTs), patients with multiple sclerosis (MS) are living longer.
Objective:
This study examined MS prevalence and DMT use among older adults 65 years and above in the US.
Methods:
The study analyzed 2011–2021 Medicare fee-for-service claims data.
Results:
The prevalence rate of MS in older adults increased by 15.49%, from 210.55 (per 100,000) in 2011 to 243.17. Women comprised 75% of the aging MS population, and 90% were White. Over half were prescribed DMTs, mainly interferon-beta and glatiramer acetate.
Conclusions:
The study found an-increasing prevalence of MS among older adults in the US over the past decade, with over half using DMTs. Our findings highlight the need for increasing geriatric care for MS.
Keywords: Multiple Sclerosis, Disease-modifying Therapy, Older Adults, Epidemiology
INTRODUCTION
Multiple sclerosis (MS) is a leading cause of non-traumatic disability and significantly affects the quality of life. Advances in disease-modifying therapies (DMTs) have contributed to improved survival in patients with MS, with recent studies showing that life expectancy is now reduced by approximately 7 to 14 years compared to the general population.1 However, as the MS population ages, new challenges emerge in disease management. With increasing age, patients’ inflammatory activity diminishes, resulting in a decline in relapse frequency and fewer new inflammatory lesions on magnetic resonance imaging.2 Older adults with MS experience a disproportionately greater symptom burden that leads to greater functional impairment.3 Additionally, aging-related comorbidities, polypharmacy, and altered immune responses may influence both disease progression and treatment, especially the optimal use of DMTs in older adults.
Understanding the epidemiology of MS and treatment patterns of DMTs in older adults is important to evaluate the disease burden in this vulnerable population. Globally, about 2.8 million people are living with MS, with a growing proportion of older adults contributing to the rising burden of MS in aging populations.4 Despite global trends, there remains a critical data gap on MS in older adults in the United States (US), especially the prevalence of MS and DMT use. Therefore, this evaluated the prevalence of MS and the utilization of DMTs among older adults 65 years and above in the US using multi-year Medicare data.
METHODS
This study utilized eleven years (2011–2021) of 100% US Fee-for-Service (FFS) Medicare claims data, encompassing Parts A, B, and D, to assess the prevalence of MS among older adults. Medicare Part A provides short-term inpatient hospital stays, Part B supplemental insurance for outpatient care, while Part D covers prescription medications, including DMTs. Medicare enrollees aged 65 years and older with at least one MS-related medical claim (ICD-9/10-CM: 340 or G35) were selected.5 The annual prevalence rate of MS in older adults was calculated among Medicare-aged FFS enrollees, as reported by the Centers for Medicare & Medicaid Services.6
Descriptive analyses were conducted to assess trends in annual prevalence rates by patient characteristics, including age, sex, race, and ethnicity. The utilization rate of available DMTs, including interferon-beta, glatiramer acetate, teriflunomide, dimethyl fumarate, fingolimod, natalizumab, ocrelizumab, and ofatumumab, was assessed throughout the study period.7 Descriptive analyses were performed using SAS version 9.4 (SAS Institute Inc.). The study was approved by the University of Houston’s Institutional Review Board under the exempt category and adhered to STROBE reporting guidelines.8
RESULTS
The number of older adults with MS grew by 67.29%, from 78,486 in 2011 to 123,260 in 2021 (Table 1). The prevalence rate of MS among Medicare-aged FFS enrollees (per 100,000) increased by 15.49%, from 210.55 (95% CI: 209.07–212.02) in 2011 to 243.17 (95% CI: 241.81–244.52) in 2021.
Table 1.
Annual Prevalence of Older Adults with MS among Medicare Enrollees per 100, 000 People in the United States, 2011 to 2021
| 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Number of MS Patients Aged ≥ 65 | 78,486 | 83,423 | 88,213 | 92,985 | 98,360 | 104,013 | 110,164 | 114,846 | 120,327 | 118,425 | 123,260 |
| Total Aged Part A and Part B Medicare Enrollees (In Million) | 37.28 | 38.60 | 39.84 | 41.14 | 42.40 | 43.73 | 45.05 | 46.47 | 47.92 | 49.39 | 50.68 |
| Prevalence of MS in Aged Part A and Part B Medicare Enrollees (per 100,000) | 210.55 | 216.14 | 221.43 | 226.04 | 231.99 | 237.84 | 244.52 | 247.12 | 251.09 | 239.77 | 243.17 |
| 95% CI of Prevalence of MS | (209.07,212.02) | (214.67,217.6) | (219.97,222.89) | (224.59,227.49) | (230.54,233.44) | (236.39,239.28) | (243.08,245.96) | (245.69,248.55) | (249.67,252.51) | (238.4,241.13) | (241.81,244.52) |
| Age | |||||||||||
| Mean ± SD | 73.05±7.12 | 72.76±7.04 | 72.57±6.89 | 72.5±6.77 | 72.45±6.65 | 72.33±6.47 | 72.37±6.43 | 72.36±6.31 | 72.46±6.28 | 72.52±6.2 | 72.65±6.16 |
| Median | 71 | 71 | 71 | 71 | 71 | 70 | 71 | 71 | 71 | 71 | 71 |
| Percentage of MS Patients with Disease-Modifying Therapy | 52.86% | 54.58% | 62.57% | 66.56% | 67.82% | 63.37% | 60.31% | 60.47% | 56.70% | 54.56% | 48.49% |
Throughout the study period, women consistently comprised approximately 74% (range: 73.28% in 2011 to 75.55% in 2021) of the MS population, reinforcing the well-established female predominance in MS epidemiology (Figure 1). Age distribution trends showed a shift toward older age groups. While about 40% of MS patients were aged 65–70 years, the proportion of patients aged 70–75 years increased from 25.21% in 2011 to 30.92% in 2021, and those aged 76–80 years increased from 15.02% to 18.00% over the same period. Despite this shift, the median age of older adults with MS in the Medicare population remained stable at 71 years. The distribution of race stayed stable across the study period, with White patients comprising about 89% of the MS population (range: 88.62% in 2019 to 90.21% in 2011), followed by African Americans (range: 7.19% in 2021 to 7.70% in 2016). More than 50% of older adults with MS were prescribed DMTs, with glatiramer acetate (34.67%) and interferon-beta (32.61%) being the most frequently prescribed DMTs.
Figure 1.
Distribution of Older Adults with MS Enrolled in Medicare in the United States by Age, Sex, and Race/ethnicity, 2011 to 2021
Discussion
This longitudinal study found that the prevalence of older adults with MS increased over the past decade in the US based on the multi-year Medicare data. This can be due to effective treatments, increased MS diagnosis, and overall improvement in chronic care. Similar to the reported MS prevalence rate in other age groups, we also observed a stable sex ratio, with three in four MS patients being females.9 The study found an increasing trend of patients aged 70–80 years, but the median age remained the same. Consistent race and ethnicity patterns among older adults with MS were also observed during the study period, with nine in ten MS patients being white.
Although there is greater availability of DMTs, the utilization of DMT among older people has been consistent over 2011–2021, with over half receiving treatment to manage MS. The DMT usage may reflect the progressive nature of MS in older adults. Interferon-beta and glatiramer acetate were the commonly prescribed DMTs, as these agents were available when they were diagnosed. Even though new DMTs are available, this utilization pattern has been consistent over the past decade. However, the majority of randomized controlled trials investigating DMTs have excluded patients older than 55 years, limiting evidence about their efficacy and safety in this population.10 Patterns of DMT utilization in this population warrant further investigation, particularly given the potential influence of aging-related immunosenescence, comorbidities, and polypharmacy. Although these findings are limited to aged Medicare FFS patients and ability to distinguish MS subtypes, this is the first-ever national study examining the prevalence patterns of MS focused on older adults to understand the burden of the disease and inform geriatric care.
Conclusion
This study found important insights regarding the increasing prevalence of MS among older adults in the US, with a 15.49% rise from 2011 to 2021. The distribution of patient characteristics remained stable, with women comprising about one-third and White patients accounting for 90% of the older adults with MS. More than half of older adults were prescribed DMTs, primarily using interferon-beta and glatiramer acetate. These findings highlight the need for further research on MS management in aging populations, particularly regarding the safety and efficacy outcomes of DMTs to optimize treatment strategies and improve geriatric MS care.
Funding:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: A.A. received funding for this study from the Agency for Healthcare Research and Quality (R01HS029501; PI: Aparasu)
Declaration of Conflicting Interests:
Dr. Aparasu has received research funding from Astellas Inc., Incyte Corp., Gilead, and Novartis Inc. for projects unrelated to the current work. Dr. Hutton reports grants from Novartis, Hoffman-LaRoche, and Sanofi and personal fees from Novartis outside the submitted work. The other authors declare no conflicts of interest for this article.
Data Availability
Since the access to the data is under a contracted data user agreement with the Centers for Medicare & Medicaid services, the authors cannot distribute the underlying data.
REFERENCES
- 1.Scalfari A, Knappertz V, Cutter G, Goodin DS, Ashton R, Ebers GC. Mortality in patients with multiple sclerosis. Neurology. Jul 9 2013;81(2):184–92. doi: 10.1212/WNL.0b013e31829a3388 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Grebenciucova E, Berger JR. Immunosenescence: the Role of Aging in the Predisposition to Neuro-Infectious Complications Arising from the Treatment of Multiple Sclerosis. Curr Neurol Neurosci Rep. Aug 2017;17(8):61. doi: 10.1007/s11910-017-0771-9 [DOI] [PubMed] [Google Scholar]
- 3.Goereci Y, Ellenberger D, Rommer P, et al. Persons with multiple sclerosis older than 55 years: an analysis from the German MS registry. J Neurol. Jun 2024;271(6):3409–3416. doi: 10.1007/s00415-024-12286-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.DiMauro KA, Swetlik C, Cohen JA. Management of multiple sclerosis in older adults: review of current evidence and future perspectives. J Neurol. Jul 2024;271(7):3794–3805. doi: 10.1007/s00415-024-12384-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.St Germaine-Smith C, Metcalfe A, Pringsheim T, et al. Recommendations for optimal ICD codes to study neurologic conditions: a systematic review. Neurology. Sep 4 2012;79(10):1049–55. doi: 10.1212/WNL.0b013e3182684707 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Services CfMM. CMS Program Statistics - Medicare Total Enrollment. 2023. March 6. Accessed November 8, 2024. https://data.cms.gov/summary-statistics-on-beneficiary-enrollment/medicare-and-medicaid-reports/cms-program-statistics-medicare-total-enrollment
- 7.Tomicki S, Pyenson BS. Multiple sclerosis: New perspectives on the patient journey: 2019 update. https://us.milliman.com/en/insight/multiple-sclerosis-new-perspectives-on-the-patient-journey-2019-update
- 8.von Elm E, Altman DG, Egger M, et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol. Apr 2008;61(4):344–9. doi: 10.1016/j.jclinepi.2007.11.008 [DOI] [PubMed] [Google Scholar]
- 9.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. Mar 5 2019;92(10):e1029–e1040. doi: 10.1212/WNL.0000000000007035 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Zhang Y, Gonzalez Caldito N, Shirani A, et al. Aging and efficacy of disease-modifying therapies in multiple sclerosis: a meta-analysis of clinical trials. Ther Adv Neurol Disord. 2020;13:1756286420969016. doi: 10.1177/1756286420969016 [DOI] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Since the access to the data is under a contracted data user agreement with the Centers for Medicare & Medicaid services, the authors cannot distribute the underlying data.