Association Between Inflammatory Bowel Disease and Diabetes Mellitus

The association between inflammatory bowel disease and the risk of other comorbidities has been extensively studied.1Tsai S.Y. et al.Int J Clin Pract. 2015; 69: 228-234Crossref PubMed Scopus (35) Google Scholar,2Chen C.H. et al.Int J Environ Res Public Health. 2018; 15: E513Crossref PubMed Scopus (11) Google Scholar Recently a cohort study from Denmark conducted by Jess et al3Jess T. et al.Clin Gastroenterol Hepatol. 2020; 18: 881-888Abstract Full Text Full Text PDF Scopus (31) Google Scholar published in Clinical Gastroenterology and Hepatology illustrated that people with inflammatory bowel disease were at increased risk of type 2 diabetes mellitus when compared with people without inflammatory bowel disease (incidence ratio, 1.54; 95% confidence interval, 1.49–1.60). These results were consistent with another cohort study from South Korea that found a similar association between inflammatory bowel disease and diabetes mellitus (hazard ratio, 1.135; 95% confidence interval, 1.048–1.228).4Kang E.A. et al.J Clin Med. 2019; 8: E343Crossref PubMed Scopus (42) Google Scholar To test this association in a different population, a preliminary cohort analysis was conducted using the 2005–2012 database of the Taiwan National Health Insurance Program with 23 million people living in Taiwan.5Ministry of Health and Welfare Taiwan2018 Taiwan Health and Welfare Report. Available at:.http://www.mohw.gov.twDate accessed: June 1, 2019Google Scholar,6Lai S.W. et al.Biomedicine-Taiwan. 2018; 8: 23-27Crossref Scopus (8) Google Scholar Patients ≥20 years old who had a diagnosis of Crohn's disease or ulcerative colitis were identified as the inflammatory bowel disease group (based on the International Classification of Diseases, 9th Revision, Clinical Modification, [ICD-9] code 555-556). For each patient with inflammatory bowel disease, 4 sex-matched and age-matched individuals without the diagnosis of inflammatory bowel disease were selected as controls. Patients who had a diagnosis of diabetes mellitus before entering the cohort were excluded from the study. The main outcome was a new diagnosis of diabetes mellitus (ICD-9 code 250). At the end of the cohort study, there was no significant difference in the overall incidence of diabetes mellitus between the inflammatory bowel disease group and the non–inflammatory bowel disease group (1.34 versus 1.30 per 100 person-years; 95% confidence interval, 0.94–1.14; P = .531). The subanalysis illustrated that the incidence of diabetes mellitus was 1.33 per 100 person-years in the Crohn's disease group and 1.46 per 100 person-years in the ulcerative colitis group. The incidence of both diseases did not reach statistical significance when compared with the non–inflammatory bowel disease group (P = .627 and P = .130, respectively). In this preliminary analysis, inflammatory bowel disease was not significantly associated with increased risk of diabetes mellitus, which was contrary to findings from the study by Jess et al.3Jess T. et al.Clin Gastroenterol Hepatol. 2020; 18: 881-888Abstract Full Text Full Text PDF Scopus (31) Google Scholar The contradicting results may be partially explained by the differences in study population and in analysis methods. In the study by Jess et al, the overall incidence of diabetes mellitus was 1.54-fold higher in the inflammatory bowel disease group than in the non–inflammatory bowel disease group (4.67 versus 3.02 per 1000 person-years). The attributable risk caused by inflammatory bowel disease was 1.65 per 1000 person-years. Removal of inflammatory bowel disease may reduce approximately 2 cases of diabetes mellitus per 1000 person-years of follow-up. However, inflammatory bowel disease can neither be prevented nor be cured, but diabetes mellitus can be partially prevented by appropriate interventions such as weight reduction, diet control, and regular exercise. In view of diabetes-related morbidity and mortality, clinicians who participate in the long-term care of people with inflammatory bowel disease should take into consideration aggressive modification of risk factors for diabetes mellitus. Then the risk of developing diabetes mellitus can be further reduced among those people with inflammatory bowel disease. We conclude that the true association between inflammatory bowel disease and diabetes mellitus remains to be determined because of conflicting results between Jess et al’s study3Jess T. et al.Clin Gastroenterol Hepatol. 2020; 18: 881-888Abstract Full Text Full Text PDF Scopus (31) Google Scholar and our preliminary analysis.5Ministry of Health and Welfare Taiwan2018 Taiwan Health and Welfare Report. Available at:.http://www.mohw.gov.twDate accessed: June 1, 2019Google Scholar,6Lai S.W. et al.Biomedicine-Taiwan. 2018; 8: 23-27Crossref Scopus (8) Google Scholar Other real-world data are needed to clarify the association between inflammatory bowel disease and diabetes mellitus. Inflammatory Bowel Diseases Increase Risk of Type 2 Diabetes in a Nationwide Cohort StudyClinical Gastroenterology and HepatologyVol. 18Issue 4PreviewThe intestine regulates glucose homeostasis, but it is not clear whether chronic intestinal inflammation affects risk for type 2 diabetes. We investigated the long-term risk of type 2 diabetes in patients with inflammatory bowel diseases (IBD) in a nationwide cohort study in Denmark. Full-Text PDF ReplyClinical Gastroenterology and HepatologyVol. 18Issue 4PreviewWe are thankful for the opportunity to respond to the letter by Lai et al regarding our results from a Danish nationwide cohort study showing a 54% increased risk of type 2 diabetes in patients with inflammatory bowel disease (IBD). It is important to replicate findings from observational studies to strengthen the causal inference. Without questioning the importance of replication, we here try to explain some of the reasons why the results in the study by Lai et al differ from the results of our study. Full-Text PDF