Diabetes, insulin use and Helicobacter pylori eradication: a retrospective cohort study

Background: Diabetic patients may have a higher risk of gastric cancer. However, whether they have a higher incidence of Helicobacter pylori (HP) eradication is not known. Furthermore, whether insulin use in patients with type 2 diabetes may be associated with a higher incidence of HP eradication has not been investigated. Methods: This is a retrospective cohort study. The reimbursement databases from 1996 to 2005 of 1 million insurants of the National Health Insurance in Taiwan were retrieved. After excluding those aged < 25 years, cases of gastric cancer, cases receiving HP eradication before 2005, patients with type 1 diabetes mellitus and those with unknown living region, the reimbursement data of a total of 601,441 insurants were analyzed. Diabetes status and insulin use in patients with type 2 diabetes before 2005 were the main exposures of interest and the first event of HP eradication in 2005 was the main outcome evaluated. HP eradication was defined as a combination use of proton pump inhibitor or H2 receptor blockers, plus clarithromycin or metronidazole, plus amoxicillin or tetracycline, with or without bismuth, in the same prescription for 7-14 days. The association between type 2 diabetes/insulin use and HP eradication was evaluated by logistic regression, considering the confounding effect of diabetes duration, comorbidities, medications and panendoscopic examination. Results: In 2005, there were 10,051 incident cases receiving HP eradication. HP eradication was significantly increased with age, male sex, diabetes status, insulin use, use of calcium channel blocker, panendoscopic examination, hypertension, dyslipidemia, chronic obstructive pulmonary disease, stroke, nephropathy, ischemic heart disease and peripheral arterial disease. Significant differences were also seen for occupation and living region. Medications including statin, fibrate, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and oral anti-diabetic agents were not associated with HP eradication. The adjusted odds ratios for diabetes, insulin use and use of calcium channel blocker was 1.133 (1.074, 1.195), 1.414 (1.228, 1.629) and 1.147 (1.074, 1.225), respectively. Conclusions: Type 2 diabetes and insulin use in the diabetic patients are significantly associated with a higher incidence of HP eradication. Additionally, use of calcium channel blocker also shows a significant association with HP eradication