Background: Evidence suggests a causal link between diabetes mellitus and tuberculosis risk. However, to date, few studies have used a prospective design to estimate the impact of diabetes on tuberculosis in a general population. In this study, we prospectively investigated the risk of tuberculosis among persons with diabetes stratified by severity.
Methods: A cohort study was performed that involved 17,715 Taiwanese persons on whom baseline data were collected during Taiwan's 2001 National Health Interview Survey. Participants' subsequent medical care until December 2004 was captured from the National Health Insurance database. The diagnosis and severity of diabetes were established using self-report, International Classification of Diseases, Ninth Revision, Clinical Modification codes, and pharmacy records; incident tuberculosis disease was identified using these codes and pharmacy records. Covariates were obtained through in-person interviews. We used Cox proportional hazards regression analyses to measure the association between tuberculosis and both diabetes and diabetes severity.
Results: Diabetes in general and treated diabetes were significantly associated with tuberculosis (adjusted hazard ratio, 2.09 [95% confidence interval {CI}, 1.10-3.95] and 2.60 [95% CI, 1.34-5.03], respectively). Compared with persons without treated diabetes, participants' risk of tuberculosis increased as the number of complications of diabetes mellitus increased (P = .0016), with >3-fold risk among those with ≥ 2 diabetes-related complications (odds ratio, 3.45; 95% CI, 1.59-7.50). Similarly, the risk increased among those with higher Diabetes Complications Severity Index scores (P = .0002).
Conclusions: The risk of developing tuberculosis increased among those with increasing diabetes severity.