Adverse event reporting in randomized trials of spinal manipulative therapy: a scoping review of practices and characteristics

BACKGROUND: Despite the availability of guidelines such as the Consolidated Standards of Reporting Trials (CONSORT) Harms extension, adverse event (AE) reporting in randomized controlled trials (RCTs) of spinal manipulative therapy (SMT) remains inconsistent and incomplete. Many trials fail to provide essential AE details hindering the accurate assessment of SMT-related risks. Mapping the current landscape of AE reporting and identifying deficiencies is critical to improving transparency and advancing patient safety in SMT research and practice. PURPOSE: To provide a comprehensive overview of AE reporting in randomized controlled trials (RCTs) investigating high-velocity, low-amplitude SMT for spinal pain, including AE types, characteristics and reporting practices. STUDY DESIGN/SETTING: Scoping review based on a previous systematic review. METHODS: We searched PubMed and Epistemonikos for systematic reviews indexed up to February 2022 and conducted an updated systematic search in MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Physiotherapy Evidence Database, and Index to Chiropractic Literature from January 1, 2018, to September 12, 2023, with a final update on March 8, 2026. Eligible studies were RCTs involving SMT for spinal pain in adults, including multimodal SMT trials. Studies were included if published in English, Spanish, Portuguese, French, German, Norwegian, Swedish, or Danish. AE data were extracted in three steps: whether AEs were mentioned, collected, and reported. For studies reporting AEs, detailed data on type, severity, duration, onset, relatedness, and additional care were categorized into meaningful subgroups. Summary statistics and visualizations were used to describe reporting patterns. RESULTS: Of 253 included RCTs, 55% mentioned AEs, 53% collected them, and only 28% reported their occurrence. AE characteristics were inconsistently reported, with wide variation in terminology and classification. Pain-related AEs were most common, typically described as mild in severity. However, characteristics such as duration, onset, and additional care required were often omitted. Relatedness was also inconsistently assessed. CONCLUSION: AE reporting in SMT RCTs remains suboptimal and inconsistent with established standards. Improved adherence to standardized reporting frameworks, such as the CONSORT Harms extension, and a cultural shift toward treating AE monitoring as a core component of trial design are urgently needed to enhance transparency and strengthen patient safety.