Objective  To analyze the causal relationship between gastroesophageal reflux disease (GERD) and chronic obstructive pulmonary disease (COPD) based on the bidirectional two-sample Mendelian randomization (MR).

Methods  Genetic variation information of GERD and COPD was obtained from Genome-Wide Association Studies (GWAS) and used as instrumental variables. Inverse variance-weighted (IVW), weighted median and MR-Egger methods were used for MR analysis, and sensitivity analysis was performed to validate the robustness of the results.

Results  A significant positive correlation was observed between genetically predicted GERD and the incidence risk of COPD, but there was no statistical association between COPD and the incidence risk of GERD. Positive IVW result showed that the odds ratio (OR) was 1.305 7, the 95% confidence interval (95%CI) was 1.114 4 to 1.529 8, and the P value was 0.000 9; the reverse IVW result showed that the OR was 0.982 3, the 95%CI was 0.917 4 to 1.051 9, and the P value was 0.610 4. Sensitivity analysis did not find any potential bias.

Conclusion  MR analysis shows that GERD is a risk factor for COPD, and treating GERD may help prevent or delay the progression of COPD.