To analyze the effect of metformin on the eradication rate of Helicobacter pylori (H.pylori) in patients with type 2 diabetes mellitus and the potential relationship between metformin use and serum interleukin-8 (IL-8).

One hundred patients with T2DM complicated with H.pylori infection admitted to Huai′an Hospital of Xuzhou Medical University from January 2018 to November 2019 were randomly divided into either group A (n=50) or group B. In addition, 50 patients with H.pylori infection alone admitted in the same period were included in group C. All the patients in three groups were treated with quadruple therapy (amoxicillin, clarithromycin sustained release tablets, omeprazole, and colloidal pectin bismuth). On this basis, group A was treated with metformin combined with insulin, while group B was treated with insulin only. The eradication rate and adverse reactions in the three groups were compared. Meanwhile, 20 patients were randomly selected from the three groups, and serum IL-8 levels were detected by enzyme-linked immunosorbent assay. The Chi-square test was used to compare the eradication rate of H.pylori and the incidence of adverse reactions in the three groups. Analysis of variance was used to compare IL-8 levels, and q-test was used for pairwise comparison between groups. The factors affecting the eradication rate of H.pylori were investigated by binomial Logistic regression analysis.

The H.pylori eradication rate in group A [94.00% (47/50)] was significantly higher than those in group B [78.00% (39/50)] and group C [80.00% (40/50)] (χ²=5.316, P=0.021; χ²=4.332, P=0.037), while there was no statistical difference between group B and group C (χ²=0.060, P=0.806). There was no statistically significant difference in the incidence of adverse reactions (nausea, vomiting, hypoglycemia, abdominal discomfort, and constipation) between the metformin group (group A) and the groups without metformin (group B and group C). Serum IL-8 level in group A was significantly lower than those of group B and group C [(163.02±22.11) pg/ml vs (294.00±29.89) pg/ml and (306.11±35.17) pg/ml; q=4.172 and 4.797; P=0.005 and 0.001, respectively], although there was nosignificant difference between group B and group C (q=0.386, P=0.786). Logistic regression analysis showed that metformin was a factor affecting the eradication rate of H.pylori (OR=0.195, 95%CI=0.051-0.748, P=0.017).

Metformin is the potential influential factor of the H.pylori eradication rate, and it increases the H.pylori eradication rate in T2DM patients with H.pylori infection, and decreases serum IL-8 level. Metformin-added anti-Hp quadruple therapy does not increase the incidence of adverse effects.