Identifying unanswered questions and setting the agenda for future systematic research in Multiple Sclerosis. A worldwide, multi-stakeholder Priority Setting project.

Background: Eliciting the research priorities of people affected by a condition, carers and health care professionals can increase research value and reduce research waste. The Cochrane Multiple Sclerosis and Rare Disease of CNS Group, in collaboration with the Cochrane Neurological Sciences Field, launched a priority setting exercise with the aim of prioritizing pressing questions to ensure that future systematic reviews are as useful as possible to the people who need them, in all countries, regardless of their economic status.

Method: Sixteen high priority questions on different aspects of MS were developed by members of a multi-stakeholder priority setting Steering Group (SG). In an anonymous online survey translated into 12 languages researchers, clinicians, people with MS (PwMS) and carers were asked to identify and rank, 5 out of 16 questions as high priority and to provide an explanation for their choice. An additional free-text priority research topic suggestion was allowed.

Results: The survey was accessible through MS advocacy associations' social media and Cochrane web pages from October 20, 2020 to February 6, 2021. 1.190 responses (86.73% of all web contacts) were evaluable and included in the analysis. Responses came from 55 countries worldwide, 7 of which provided >75% of respondents and 95% of which were high and upper-middle income countries. 58.8% of respondents live in the EU, 23% in the Americas, 8.9% in the Western Pacific, 2.8% in the Eastern Mediterranean and 0.3% in South Eastern Asia. About 75% of the respondents were PwMS. The five research questions to be answered with the highest priority were: Question (Q)1 "Does MRI help predict disability worsening of PwMS?" (19.9%), Q5 "What are the benefits and harms of treating PwMS with one disease-modifying drug compared to another?" (19.3%), Q3 "Does multidisciplinary care by teams of different social and health professionals improve health outcomes and experiences for PwMS?" (11.9%), Q16 "Does psychological health affect disease progression in PwMS?" (9.2%) and Q10 "What are the benefits and harms of exercise for PwMS?" (7.2%). The multivariable logistic regression analysis indicated a significant influence of geographic area and income level on the ranking of Q1 and a marginal for Q16 as top a priority after accounting for the effect of all other predictors. Approximately 50% of the respondents indicated that they had an important additional suggestion to be considered.

Conclusion: This international collaborative initiative in the field of MS offers a worldwide perspective on the research questions perceived as pivotal by a geographically representative sample of multiple stakeholders in the field of MS. The results of the survey could guide the prioritization of research on pharmacological and non-pharmacological interventions which could be meaningful and useful for PwMS and carers, avoiding the duplication of efforts and research waste. High quality systematic reviews elicited by priority setting exercises may offer the best available evidence and inform decisions by healthcare providers and policy-makers which can be adapted to the different realities around the world.