Effect of Type 2 Diabetes Mellitus on the Clinical Severity and Treatment Outcome in Patients with Pulmonary Tuberculosis: a Potential Role in the Emergence of Multidrug-resistance

Background/purpose: A globally increasing trend of type 2 diabetes mellitus (DM), the rising prevalence of tuberculosis (TB) in many countries, and the emergence of multidrug-resistant TB (MDR-TB) in recent years pose a serious challenge for TB control.

Methods: We investigated pulmonary tuberculosis patients with and without type 2 DM (DMTB and TB, respectively) treated at the Chest Hospital, Taiwan, between November 2004 and October 2005.

Results: One hundred and ninety-two new patients (60 DMTB, 132 TB) were regularly treated for a full course (≥ 6 months) and prospectively followed for more than 1 year. The DMTB patients had more severe infections (far-advanced: 45.0%vs. 22.7%, p < 0.01), higher mycobacterial loads (sputum smear: 2.9 ± 1.3(+)vs. 1.9 ± 1.7(+), p < 0.01), higher treatment failure rates (17%vs. 2%, p < 0.01), and longer delayed clearance of mycobacteria than did the TB patients (2.5 ± 3.0 months vs. 1.6 ± 1.4 months, p < 0.01). After one year, three DMTB patients and one TB patient had MDR-TB (5.0%vs. 0.8%, p = 0.056). Bacterial genotyping revealed that the proportion of mycobacterial strains was not significantly different in DMTB and TB patients (Beijing strain: 46.7%vs. 40.6%, Non-Beijing strain: 53.3%vs. 59.4%, p = 0.632).

Conclusion: DMTB patients have more severe TB infections, which require longer treatment and are more likely to develop MDR-TB than are patients with TB alone.