Characteristics of systematic reviews of yoga: a bibliometric analysis of the research

Abstract

Introduction: Yoga is a popular mind-body practice often used for treatment or prevention of health conditions. Many randomized controlled trials (RCTs) and systematic reviews (SRs) of these yoga interventions have conducted in recent years. We aimed to comprehensively identify and describe the characteristics of all available yoga SRs. Methods: 8 databases were searched from inception to November 19, 2019; two authors independently screened and selected records for inclusion. We extracted bibliographic data and research topics for all protocols and reviews. For completed SRs focusing solely on yoga, we extracted information on conclusions (positive, neutral, negative). Results: We identified 319 ongoing and completed SRs of yoga interventions; 157 (49%) focused solely on yoga and 162 (51%) included searches for yoga as part of a broader intervention class (eg, exercise). SRs were published in 2003-2019; 171 (54%) were published in 2016 or later. SRs originated from 32 different countries; 81 (25%) originated from the USA. SRs were most often published in specialty journals (n=158; 50%), CAM journals (n=70; 22%), or SR journals (n=60; 19%). The most common topics were psychiatric (n=71), cancer (n=38), musculoskeletal (n=36), cardiovascular (n=32), metabolic (n=19) and neurological (n=19), while the most common populations included women (n=42), men (n=1), young people (n=11), and older people (n=15). Most SRs focused on yoga stated that yoga had positive effects; only 1 SR had clearly negative conclusions. Conclusion: Many SRs of yoga are conducted as part of a review of a broader class of interventions. There are several SRs of yoga for some conditions (eg, chronic low back pain, breast cancer) and there is likely extensive duplication of SRs covering identical research questions. We will present further information on the characteristics of yoga SRs and suggest how these results taken together may inform the research agenda in yoga. Keywords: Yoga; Systematic review; Randomized controlled trials