LAUSR

RATIONALE Systematic reviews (SRs) provide best evidence on effectiveness of treatment strategies for asthma. Carefully conducted SRs provide high-quality evidence for supporting decision-making, but trustworthiness of conclusions can be hampered by limitation in rigour. OBJECTIVES We aimed to appraise methodological quality of a representative sample of SRs on asthma treatments in a cross-sectional study. METHODS A cross-sectional study was conducted to identify SRs on asthma treatment published between 2013 and 2019, by searching the Cochrane Database of Systematic Reviews, EMBASE, MEDLINE, and PsycINFO. SRs including at least one meta-analysis on asthma treatments were included. Methodological quality of included SRs was assessed with the AMSTAR 2 instrument. Factors associated to methodological quality were explored using multivariate regression analysis. RESULTS 136 SRs were included and appraised, with majority being non-Cochrane reviews (71.3%). Only 12 (8.8%) were of high overall quality, respectively 9 (6.6%), 32 (23.5%), and 83 (61.0%) were of moderate, low, and critically low overall quality. More specifically, no SRs (0.0%) conducted a comprehensive literature search, only 3 (2.2%) justified on why a particular primary study design was selected, 37 (27.2%) reported sources of funding among included studies, and 54 (39.7%) provided lists of excluded studies with justification. Cochrane reviews (adjusted odds ratio [AOR]: 36.56, 95% confidence interval [CI] 10.49-127.42) and SRs published after 2017 [AOR: 4.52, 95%CI: 1.73-11.83]) were positively associated with higher methodological quality. CONCLUSIONS Methodological quality of SRs on asthma treatments are suboptimal. Future SRs should improve with conducting comprehensive literature search; justifying study design selection, providing a list of excluded studies, and reporting funding sources of included studies.