Risk of new-onset type II diabetes after appendicectomy

Background Altered immune function after appendicectomy has been associated with autoimmune disease, even though the mechanisms are not clearly elucidated. This study aimed to investigate whether the frequency of new-onset type II diabetes was increased after appendicectomy in a case-control study. Methods This was a retrospective cohort study from the Taiwan Longitudinal Health Insurance Database 2000. The relative risk was compared with that in the general population using population-based data. Each patient was tracked for a 3-year interval to identify those who developed type II diabetes. Cox proportional hazard regression analysis was used to assess the risk of type II diabetes during follow-up. Results A total of 31-512 patients were included in the study, of whom 5252 had an appendicectomy (study cohort) and 26-260 were matched for comparison. Some 714 patients (2·3-per cent) developed type II diabetes during the 3-year follow-up, 161 in the study cohort (3·1-per cent) and 553 in the comparison cohort (2·1-per cent). The adjusted hazard ratio (HR) for type II diabetes in the study cohort was 1·45 (95-per cent c.i. 1·22 to 1·74). This increased risk was most pronounced in men (adjusted HR 1·47, 1·16 to 1·88) and in those with a perforated appendix (adjusted HR 2·28, 1·71 to 3·03), and applied only to patients younger than 65-years of age. Conclusion An increased risk of new-onset type II diabetes within 3-years after appendicectomy was found in patients aged less than 65-years. The risk was highest in men and in those with complicated appendicitis. Appendicectomy increases risk of diabetes.