Alexander Keenan,1 Hoa H Le,1 Kavita Gandhi,2 Lola Adedokun,3 Eddie Jones,4 Mia Unsworth,4 James Pike,5 Emily Trenholm4 1Scientific Affairs, Janssen Pharmaceuticals Inc., Titusville, NJ, USA; 2Research and Development, Janssen Pharmaceuticals Inc., Titusville, NJ, USA; 3Research and Development, Janssen-Cilag Ltd, High Wycombe, UK; 4Central Nervous System, Adelphi Real World, Bollington, Cheshire, UK; 5Statistics & Data Analytics, Adelphi Real World, Bollington, Cheshire, UKCorrespondence: Mia Unsworth, Adelphi Real World, Adelphi Mill, Grimshaw Lane, Macclesfield, Bollington, Cheshire, SK10 5JB, United Kingdom, Tel +441625578677, Email mia.unsworth@adelphigroup.comIntroduction: Multiple sclerosis (MS) is a neurodegenerative disease characterized by progressive deterioration of cognitive and physical functioning, reducing activities of daily living and quality of life (QoL). Several treatments are available that modify the course of the disease and reduce the frequency of relapses. Although effective, all treatment options are accompanied by adverse events, and this study aimed to assess the extent to which patients were involved in the choice of treatment.Methods: Data were drawn from the Adelphi Multiple Sclerosis Disease Specific Program (DSP)™, a cross-sectional survey of healthcare practitioners (HCP) and their patients with MS in real-world clinical settings in Europe and the United States (US) between December 2020 and July 2021. HCPs reported patient demographics, clinical characteristics, current and previous treatment, and treatment outcomes. Patients voluntarily completed questionnaires reporting the physical and psychological impact of their MS and its treatment. Regression analysis with inverse probability of treatment weighting was used to compare treatment outcomes in patients actively involved in their current treatment choice with those who were not.Results: Of a total of 692 patients, median age 40 years and 64% female, mostly diagnosed with relapsing-remitting MS, those who were involved in shared decision-making tended to choose oral therapies such as dimethyl fumarate more often than HCPs. MS had greater impact on physical and psychological functioning in patients whose HCP made treatment decisions solely. Patients involved in decision-making reported greater satisfaction with their treatment and a better QoL.Discussion: Because no single optimal therapy exists for patients with MS, treatments should be individualized with consideration of patients’ preferences. Our study shows that shared decision-making is under-utilized in the management of MS and supports the benefits of patient involvement.Conclusion: Patients who have an active role in treatment decision-making show improved wellbeing and QoL, and overall treatment satisfaction.Plain Language Summary: Multiple sclerosis (MS) is a disease that affects the brain, causing symptoms such as blurred vision and problems with movements, thoughts, and feelings. MS is a lifelong condition that becomes worse over time and limits the activities that people can do. There are many treatments that can help to reduce relapses (when symptoms become worse), but all have their benefits and drawbacks. It is often the physician who decides which treatment to use, but we wanted to know if patients would feel better if they were involved in the decision.Using our standardized and validated questionnaires, we surveyed physicians and nurses who treat patients with MS in Europe and the United States of America between December 2020 and July 2021, to assess how they felt about the treatment they chose and its effect on the patient. We also asked the patients themselves how they felt about their illness and treatment, whether they were given the chance to choose which treatment to take, and how their treatment affected their symptoms and overall quality of life.The information provided by both the physicians and their patients was used to compare how patients responded when they were involved in the treatment decisions. We found that patients who were involved in choosing their treatment were more satisfied with their treatment and responded better than those whose physicians decided alone. Therefore, it is important for physicians treating patients with MS to consider their patients’ preferences when deciding which treatment is best for them.Keywords: multiple sclerosis, patient preference, decision-making, shared, multinational, survey