Prevalence of Diabetes Mellitus in Patients with Tuberculosis: A Prospective Cohort Study

Background: Diabetes mellitus (DM) and poor glycemic control significantly increase the risk of tuberculosis (TB) and adverse outcomes after TB treatment. However, DM screening is not universally performed. Method: Patients diagnosed with TB were enrolled and tested for fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) within 3 months after TB diagnosis. Results: A total of 216 patients with TB were included. Median (IQR) age was 60 years (53-73), and 57% were male. The prevalence of DM was 42.6%. Patients with TB with DM were more likely to have other comorbidities (76% vs 52%, p<0.001), a higher proportion of positive sputum acid-fast bacilli (AFB) (27% vs 11%, p=0.001), and a positive culture for Mycobacterium tuberculosis in bronchoalveolar lavage (10% vs 3%, p=0.045) compared to those withour DM. Patients with TB with DM had a lower cure rate at 6 months (30% vs 57%, p=0.001), a higher death rate at 6 months (14% vs 3%, p=0.016), and a higher proportion of treatment complications (22% vs 10%, p=0.014) than those without DM. Having pre-existing underlying impaired fasting glucose (odds ratio [OR] 8.03, p<0.001) and positive sputum AFB (OR 7.41, p<0.001) were associated with newly diagnosed DM cases among patients with TB. Conclusions: The prevalence of DM in patients with TB in our study's setting was unexpectedly high. Patients with TB with DM had unfavorable outcomes compared with those without DM. We recommend routinely screening for DM in all patients with newly diagnosed TB.