Development of the Core Outcome Set for Herbal Medicine Treatment of Lumbar Disc Herniation (COS‐HM‐LDH) in Korean Medicine Practice

BACKGROUND: Lumbar disc herniation (LDH) is a common cause of low back pain and disability. Herbal medicine (HM) is increasingly used for LDH in Korean medicine (KM) practice, but evidence synthesis is limited by inconsistent outcome selection and reporting. We aimed to develop a core outcome set (COS) to standardize reporting in HM studies of LDH in KM practice. METHODS: The study followed the Core Outcome Set-STAndards for Development (COS-STAD), with reporting guided by the Core Outcome Set-STAndards for Reporting (COS-STAR). Candidate outcomes were identified through a systematic review of Korean (OASIS, ScienceON) and international (PubMed, CENTRAL) databases from inception to December 2024, supplemented by clinical practice guidelines and textbooks. Outcomes were refined into predefined domains and potential effect modifiers (EMs) were identified. A two-round Delphi survey with experts was conducted, followed by a Delphi survey with KM clinicians to assess feasibility in practice. A structured consensus meeting was held to finalize the COS. RESULTS: Of 1426 records, 122 studies were included. Ninety-six outcomes were refined to 75 distinct outcomes across six domains, alongside 15 EMs. Delphi participation included 25 experts in Round 1, 23 experts in Round 2, and 10 KM clinicians in the clinician Delphi survey. The final Core Outcome Set for Herbal Medicine Treatment of Lumbar Disc Herniation (COS-HM-LDH) comprised 13 outcomes and 10 EMs. CONCLUSION: COS-HM-LDH provides a standardized minimum set of clinically important LDH outcomes and EMs for HM trials and real-world studies in KM practice, improving consistency and comparability across studies.