Low methodological quality of systematic reviews on acupuncture: a cross-sectional study

BACKGROUND: While well-conducted systematic reviews (SRs) can provide the best evidence on the potential effectiveness of acupuncture, limitations on the methodological rigour of SRs may impact the trustworthiness of their conclusions. This cross-sectional study aimed to evaluate the methodological quality of a representative sample of SRs on acupuncture effectiveness. METHODS: Cochrane Database of Systematic Reviews, MEDLINE, and EMBASE were searched for SRs focusing on the treatment effect of manual acupuncture or electro-acupuncture published during January 2018 and March 2020. Eligible SRs must contain at least one meta-analysis and be published in English language. Two independent reviewers extracted the bibliographical characteristics of the included SRs with a pre-designed questionnaire and appraised the methodological quality of the studies with the validated AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews 2). The associations between bibliographical characteristics and methodological quality ratings were explored using Kruskal-Wallis rank tests and Spearman’s rank correlation coefficients. RESULTS: A total of 106 SRs were appraised. Only one (0.9%) SR was of high overall methodological quality, zero (0%) was of moderate-quality, six (5.7%) and 99 (93.4%) were of low-quality and critically low-quality respectively. Among appraised SRs, only ten (9.4%) provided an a priori protocol, four (3.8%) conducted a comprehensive literature search, five (4.7%) provided a list of excluded studies, and six (5.7%) performed meta-analysis appropriately. Cochrane SRs, updated SRs, and SRs that did not search non-English databases had relatively higher overall quality. CONCLUSIONS: Methodological quality of SRs on acupuncture is unsatisfactory. Future reviewers should improve critical methodological aspects of publishing protocols, performing comprehensive search, providing a list of excluded studies with justifications for exclusion, and conducting appropriate meta-analyses. These recommendations can be implemented via enhancing the technical competency of reviewers in SR methodology through established education approaches as well as quality gatekeeping by journal editors and reviewers. Finally, for evidence users, skills in SR critical appraisal remain to be essential as relevant evidence may not be available in pre-appraised formats. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12874-021-01437-0.