Primary drug resistance among tuberculosis patients with diabetes mellitus: a retrospective study among 7223 cases in China.

Background: Given the high burden of tuberculosis (TB) and diabetes mellitus (DM) in China and the worse outcome of TB-DM cases (refers to TB patients with diabetes), and drug-resistant tuberculosis cases (DR-TB), it is of great significance to explore the association between diabetes and primary DR-TB for TB elimination target in China. We assessed the clinical characteristics, drug-resistance profile, and increased risk of resistance among TB-DM patients across China from 2004 to 2017.

Method: 7223 cases with drug-susceptibility data were collected from Shandong, China. Categorical baseline characteristics of new TB cases were compared by DM status using Fisher's exact or Pearson Chi-square test. Univariable analysis and multivariable logistic models were used to estimate the association between diabetes and different drug-resistance profiles and the risk factors of primary drug resistance among TB-DM cases.

Result: Of 7223 newly diagnosed TB patients, 426 (5.90%) were TB-DM cases. TB-DM csaes were more likely to be older，accompanied by higher body mass index (BMI) and hypertension than TB-no DM cases (refers to TB patients without diabetes). The rates of DR-TB (21.83% vs 16.96%), polydrug resistant TB (PDR-TB, 6.10% vs 3.80%), isoniazid (INH)+streptomycin (SM)-resistant TB (4.93% vs 3.13%), and SM-resistant TB (16.20% vs 11.7%) among TB-DM group were higher than TB-no DM group, <0.05. DM was significantly associated with any DR-TB (adjusted (aOR):1.30; 95% CI, 1.02-1.65), SM-related resistance (aOR: 1.43; 95% CI, 1.08-1.88), PDR-TB (OR: 1.57; 95% CI, 1.04-2.36; aOR: 1.59; 95% CI, 1.04-2.44), compared with pan-susceptible TB patients (<0.05).

Conclusion: Our study indicated that TB-DM groups had a higher proportion of drug resistance than TB groups, and diabetes was identified as a risk factor of total DR, PDR, SM resistance and INH+SM resistance among newly diagnosed TB cases. Good management of diabetes and TB infection screening program among DM patients might be necessary for improving TB control in China.