Distortion in the Communication of Nonsignificant Primary Outcomes: The Spin Strategy in Multiple Sclerosis Trials

Spin refers to reporting strategies that highlight the benefits of an experimental treatment or divert attention from nonsignificant primary outcomes. To assess spin in randomized clinic trials (RCTs) on pharmaceutical efficacy in multiple sclerosis (MS) and explore associated factors.

A systematic literature search was conducted in MedLine (PubMed), EMBASE, and Cochrane using database-specific thesauri ("Multiple Sclerosis" and "Drug Therapy") to identify relevant studies. We included multiple sclerosis phase 3 and 4 randomized controlled trials with parallel, superiority designs that were published between 2013 and 2024 reporting nonsignificant primary outcomes. Spin was assessed in title, abstract conclusion, results, discussion, and conclusions. A descriptive analysis was followed by exploratory bivariate logistic regression. Independent variables included trial phase, sample size, drug type, comparison, follow-up time, registration, Consolidated Standards of Reporting Trials (CONSORT) mention, risk of bias (RoB2), journal quartile, first author affiliation, and conflict of interest.

Forty articles met inclusion criteria. Spin appeared in at least one section in 25 articles (62.5%) and in 3 or more in 19 articles (47.5%). The most frequent locations were abstract conclusions, discussion, and conclusions. Spin was significantly associated with smaller sample size (odds ratio [OR] = 7.00, 95% confidence interval [CI] = 1.29-37.91, p = 0.024), non-Q1 journals (OR = 4.38, 95% CI = 1.03-18.63, p = 0.046), and first author affiliation outside Europe or the United States (OR = 5.09, 95% CI = 1.15-22.62, p = 0.032).

Spin is common in MS randomized controlled trials with nonsignificant primary outcomes and may mislead clinical decisions. ANN NEUROL 2026;99:316-327.