The quality and reliability of short videos about Marfan syndrome on Bilibili and Douyin: a cross-sectional study

Background Marfan syndrome (MS) is a rare, life-threatening connective tissue disorder. Short video platforms are now key health-information sources, yet the quality and reliability of MS-related content remain unclear. Methods In a cross-sectional study, Marfan syndrome videos were retrieved from Bilibili and Douyin on 25 April 2026 using the Chinese keyword “马凡综合征,” from new accounts under anonymous browsing. After screening, data on video characteristics, uploader type, and publicly displayed likes, comments, shares, and collections were extracted. Two reviewers independently scored all eligible videos with Global Quality Scale (GQS), modified Decision-making Information Support Criteria for Evaluating the Reliability of Non-randomised Studies (mDISCERN), Journal of the American Medical Association (JAMA) criteria, and Content Completeness Score (CCS). Descriptive statistics, non-parametric tests, Spearman correlations, and weighted Cohen’s kappa were used. Results 185 videos (103 from Douyin and 82 from Bilibili) were analyzed. The median video duration was significantly longer on Bilibili than on Douyin (126.00 (IQR: 59.00–377.00) vs. 64.00 (IQR: 45.50–103.50) seconds; P < 0.001). Douyin videos had been available for a significantly shorter time since publication (median: 275.00 vs. 747.50 days; P < 0.001), yet their per-day interaction counts remained significantly higher after this adjustment (all P < 0.001). Douyin videos demonstrated significantly higher absolute interaction counts, including likes (median: 2,214.00 vs. 48.00; P < 0.001), comments (240.00 vs. 0.00; P < 0.001), shares (606.00 vs. 5.50; P < 0.001), and collections (475.00 vs. 24.00; P < 0.001). In terms of quality, Douyin videos had higher GQS scores than Bilibili (median: 4.00 vs. 3.00; P < 0.001), whereas Bilibili videos showed higher mDISCERN scores (median: 3.00 vs. 2.00; P < 0.001). No significant differences were observed in JAMA scores ( P = 0.245) or CCS ( P = 0.274). Healthcare professionals accounted for the majority of Douyin content (78.6%), while institutional sources predominated on Bilibili (53.7%) ( P < 0.001). Videos produced by professionals and institutions achieved significantly higher quality and reliability scores compared to individual uploaders. Spearman correlation analysis revealed strong correlations among engagement metrics ( r = 0.84–0.94), but weak or negligible correlations between absolute interaction counts and quality scores ( r = −0.16 to 0.17). Conclusion Marfan syndrome-related videos on Bilibili and Douyin varied considerably in educational quality and reliability; those by healthcare professionals were generally higher quality. Within this sample, observed interaction counts showed weak or negligible associations with quality measures.