Objectives Studies on the association between metformin use and the risk of oesophageal cancer (OC) have generated controversial findings. This updated meta-analysis was conducted to reassess the effects of metformin on OC.
Methods A comprehensive search strategy was conducted to select relevant studies from origination to February 2021. Heterogeneity was evaluated through the Q test and I2 statistics. HRs and 95% CIs were pooled through either random-effect or fixed-effect models. Meta-regression, subgroup analyses, sensitivity analysis and publication bias diagnosis were also performed.
Results Seven studies with 5 426 343 subjects were included. Metformin use was associated with reduced risk of OC (HR=0.69, 95% CI 0.54 to 0.87, p<0.001). Sensitivity analysis suggested that the results were relatively stable.
Conclusion Metformin is associated with a reduced risk of OC. More well-designed studies are still needed to further elaborate on these associations.
PROSPERO registration number CRD42021237127.
- clinical pharmacology
- adult gastroenterology
- oesophageal disease
- adult oncology
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information. Not applicable.
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Contributors CS designed the study, performed literature search, collected the data, performed statistical analysis, interpret data and wrote the manuscript. YC performed literature search, collected the data, statistical analysis, interpret data and wrote the manuscript. LH and XC performed literature search, collected the data, statistical analysis and wrote the manuscript. YW performed literature search, statistical analysis, interpret data, revised the manuscript and provided critical opinion. NHK, SK and FQ provided critical opinion and revised the manuscript. CB and KYK revised the manuscript. RM, CCD and QZ provided critical opinion, participated in literature search and revised the manuscript. All authors approved the final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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