Effects of dipeptidyl peptidase-4 inhibitor treatment doses on tuberculosis in patients with diabetes: a long-term nationwide population-based cohort study.

Background: To investigate the association of dipeptidyl peptidase-4 inhibitors (DPP4is) treatment doses and tuberculosis (TB) in patients with diabetes.

Methods: We allocated participants into DPP4i users and non-users from the Longitudinal Health Insurance Database. A chi-square test and Wilcoxon's rank-sum test were used to analyze the baseline discrete variables and continuous variable, respectively. The incidence rate was calculated in 1,000 personyears. The hazard ratios (HRs) were adjusted using a multivariate Cox regression model. The effect of DDP4i dosage on TB was analyzed. The Kaplan-Meier method was used to assess the cumulative incidence curves with a log-rank test.

Results: We identified 6,399 DPP4i users and 6,399 non-users. The incidence rate of TB in DPP4i users and non-users was 22.2 and 16.2 per 1,000 person-years, respectively. The HR of TB for DPP4i users relative to non-users was 1.04 (P=0.89). Most of the analysis of factors such as the incidence rate, gender and diabetic comorbidities in our study were non-significant. The risk of developing TB in patients with over 20 average defined daily doses (DDDs) per year was increased by 2.19 times (P=0.048).

Conclusions: In our long-term nationwide population-based cohort study, higher doses of DPP4i (20 average DDDs) could increase TB infection risk in patients with diabetes. To pay more attention to this kind of diabetic patients with DPP4i treatment will be more important for the public health issue of TB prevention.