Analysis of the influencing factors and clinical related characteristics of pulmonary tuberculosis in patients with type 2 diabetes mellitus.

Background: In China, the prevalence of type 2 diabetes mellitus (T2DM) among diabetic patients is estimated to be between 90%-95%. Additionally, China is among the 22 countries burdened by a high number of tuberculosis cases, with approximately 4.5 million individuals affected by active tuberculosis. Notably, T2DM poses a significant risk factor for the development of tuberculosis, as evidenced by the increased incidence of T2DM coexisting with pulmonary tuberculosis (T2DM-PTB), which has risen from 19.3% to 24.1%. It is evident that these two diseases are intricately interconnected and mutually reinforcing in nature.

Aim: To elucidate the clinical features of individuals diagnosed with both T2DM and tuberculosis (T2DM-PTB), as well as to investigate the potential risk factors associated with active tuberculosis in patients with T2DM.

Methods: T2DM-PTB patients who visited our hospital between January 2020 and January 2023 were selected as the observation group, Simple DM patients presenting to our hospital in the same period were the control group, Controls and case groups were matched 1:2 according to the principle of the same sex, age difference ( ± 3) years and disease duration difference ( ± 5) years, patients were investigated for general demographic characteristics, diabetes-related characteristics, body immune status, lifestyle and behavioral habits, univariate and multivariate analysis of the data using conditional logistic regression, calculate the odds ratio (OR) values and 95%CI of OR values.

Results: A total of 315 study subjects were included in this study, including 105 subjects in the observation group and 210 subjects in the control group. Comparison of the results of both anthropometric and biochemical measures showed that the constitution index, systolic blood pressure, diastolic blood pressure and lymphocyte count were significantly lower in the case group, while fasting blood glucose and high-density lipoprotein cholesterol levels were significantly higher than those in the control group. The results of univariate analysis showed that poor glucose control, hypoproteinemia, lymphopenia, TB contact history, high infection, smoking and alcohol consumption were positively associated with PTB in T2DM patients; married, history of hypertension, treatment of oral hypoglycemic drugs plus insulin, overweight, obesity and regular exercise were negatively associated with PTB in T2DM patients. Results of multivariate stepwise regression analysis found lymphopenia (OR = 17.75, 95%CI: 3.40-92.74), smoking (OR = 12.25, 95%CI: 2.53-59.37), history of TB contact (OR = 6.56, 95%CI: 1.23-35.03) and poor glycemic control (OR = 3.37, 95%CI: 1.11-10.25) was associated with an increased risk of developing PTB in patients with T2DM, While being overweight (OR = 0.23, 95%CI: 0.08-0.72) and obesity (OR = 0.11, 95%CI: 0.02-0.72) was associated with a reduced risk of developing PTB in patients with T2DM.

Conclusion: T2DM-PTB patients are prone to worse glycemic control, higher infection frequency, and a higher proportion of people smoking, drinking alcohol, and lack of exercise. Lymphopenia, smoking, history of TB exposure, poor glycemic control were independent risk factors for T2DM-PTB, and overweight and obesity were associated with reduced risk of concurrent PTB in patients with T2DM.