PurposeA duodenal bypass after a Roux-en-Y gastric bypass operation for obesity can ameliorate the development of diabetes mellitus (DM). We attempted to determine the subsequent risk of developing DM after subtotal gastrectomy with Billroth II anastomosis (SGBIIA) for peptic ulcer disease (PUD).MethodsWe identified 662 patients undergoing SGBIIA for PUD between 2000 and 2011 from the Longitudinal Health Insurance Database as the study cohort, and we randomly selected 2647 controls from the peptic ulcer population not undergoing SGBIIA and were frequency-matched by age, sex, and index year for the control cohort. All patient cases in both cohorts were followed until the end of 2011 to measure the incidence of DM. We analyzed DM risk by using a Cox proportional hazards regression model.ResultsThe patients who underwent SGBIIA demonstrated a lower cumulative incidence of DM compared with the control cohort (log-rank test, P < .001 and 6.73 vs 12.6 per 1000 person-y). The difference in the DM risk between patients with and without SGBIIA increased gradually with the follow-up duration. Age and sex did not affect the subsequent risk of developing DM, according to the multivariable Cox regression model. Nevertheless, the SGBIIA cohort exhibited a lower DM risk after we adjusted for the comorbidities of hypertension, hyperlipidemia, and coronary artery disease (adjusted hazard ratio (aHR): 0.56, 95% confidence interval (CI): 0.40–0.78). The incidence rate ratio (IRR) of DM in the SGBIIA cohort was lower than that in the control cohort for all age groups (age ≤ 49 y, IRR: 0.40, 95% CI: 0.16–0.99; age 50–64 y, IRR: 0.54, 95% CI: 0.31–0.96; age ≧ 65 y, IRR: 0.57, 95% CI: 0.36–0.91). Moreover, the IRR of DM was significantly lower in the SGBIIA cohort with comorbidities (IRR: 0.50, 95% CI: 0.31–0.78) compared with those without a comorbidity (IRR: 0.65, 95% CI: 0.40–1.04).ConclusionThe findings of this population-based cohort study revealed that SGBIIA was associated with a reduced risk of DM development, and the inverse association was greater in the presence of a comorbidity.