Does popularity reflect quality? A study on the reliability and quality of CAR-T videos on Chinese short-video platforms

Background: Chimeric antigen receptor T-cell (CAR-T) therapy represents a transformative advancement in cancer treatment. While public interest in CAR-T has surged, particularly through short-video platforms like TikTok and Bilibili in China, concerns remain regarding the reliability and quality of health information disseminated through such media. Objective: This study aimed to systematically evaluate the content quality, scientific integrity, and user engagement of CAR-T-related videos on Bilibili and TikTok, and to assess whether high traffic equates to high information quality. Methods: A total of 200 Chinese-language videos (100 per platform) were identified using the keyword "CAR-T." Videos were evaluated using three scoring tools: the DISCERN instrument for reliability, the Global Quality Score (GQS), and a novel CAR-T-specific checklist assessing 12 core domains. Content characteristics, source types, and engagement metrics (likes, comments, shares, and saves) were also extracted and compared across platforms and content types. Results: < 0.001). Videos posted by medical professionals were more common on TikTok (56%) and had higher engagement, but not necessarily higher quality. Bilibili, dominated by academic sources, produced longer videos with more complete and structured information. Correlation analysis revealed strong consistency among quality scoring tools but weak associations between quality and engagement metrics, suggesting a "high popularity-low quality" paradox. Conclusion: CAR-T-related content on Chinese short-video platforms is characterized by a disconnect between popularity and information quality. Effective science communication strategies and platform-level interventions are needed to mitigate misinformation risks and improve the dissemination of high-quality medical content.