Determining the Completeness of Registration and Reporting in Systematic Reviews of Yoga for Health.

Introduction: Yoga is a mind-body practice often used to improve health. Systematic reviews (SRs) of randomized controlled trials on yoga for health are foundational to evidence-based yoga interventions and require rigorous and transparent methods, including preparation of a protocol (e.g., PROSPERO) and following SR reporting guidelines (e.g., Preferred Reporting Items for Systematic Reviews and Meta-Analyses [PRISMA]). Objective: To evaluate the availability of protocols and the completeness of reporting for SRs on yoga for health. Methods: We used a previously assembled database of SRs focused on the use of yoga for health. The authors independently extracted data on protocol availability, PROSPERO registration, and reporting for each PRISMA 2009 checklist item. Discrepancies were discussed or referred to a third author. We used Stata 10 software to produce descriptive statistics and tests for relationships between registration, reporting, and publication year, country, and journal type. Results: We included 147 reviews published between 2005 and 2019. The most common first author country was the United States or Germany (total 67/147; 46%), and the most common journal type was specialty journals (71/147; 48%). Most reviews (116/147; 79%) made no mention of a protocol or registration, and only 15/147 (10%) reviews were linked to an accessible protocol or registration. Most SRs published in 2010 or later mentioned or cited PRISMA (97/139; 70%), and individual PRISMA items were addressed between 10% and 100% of the time. PRISMA reporting improved; over time, but there was no relationship with country or journal type. Discussion: This study identifies a need for increased SR registration for yoga research. The assessment of PRISMA reporting did not evaluate the comprehensiveness with which each item was reported, and while trends are encouraging, there is likely room for improvement. We recommend registering all yoga SRs and following updated PRISMA and recent yoga-specific guidelines for reporting. This may increase transparency, minimize bias, and produce high-quality data to inform evidence-based yoga practices.