Results of a study on the prevalence of pulmonary tuberculosis among people with type 2 diabetes mellitus

Abstract

Backround: The continuous annual increase in the prevalence of diabetes mellitus (DM) poses significant challenges not only within our nation but also globally in the control and management of tuberculosis. Aim: This study aimed to determine the incidence of pulmonary tuberculosis among individuals with type 2 diabetes mellitus (T2DM) residing in six central districts of Ulaanbaatar and to investigate associated factors. Materials and Methods: A cross-sectional study design was employed. Participants aged 18 years and older diagnosed with T2DM and receiving care at endocrinology clinics in six central districts of Ulaanbaatar were selected using systematic random sampling. Presumptive TB cases were identified through a structured questionnaire and chest X-ray. Sputum specimens were collected and subjected to smear microscopy and Xpert MTB/RIF assay for tuberculosis detection. Cases confirmed by laboratory diagnosis, currently undergoing tuberculosis treatment and previously treated cases as per questionnaire data were classified as tuberculosis cases, and prevalence was calculated. Results: A total of 1,644 individuals with T2DM were enrolled in the study, of whom 836 (50.9%) were female, with a mean age of 58 years (range 19–89). The overall prevalence of presumptive TB cases was 10.5% (n=172; 95% CI, 9.0–12.0). Among 112 suspected cases from whom sputum samples were obtained, 10 (8.9%; 95% CI, 4.9–15.7) were laboratory-confirmed for M.tuberculosis. Notably, 7.2% (6 cases; 95% CI, 3.4–14.9) of asymptomatic individuals with abnormal X-ray findings were diagnosed with tuberculosis. According to questionnaire responses, 9 participants (0.5%; 95% CI, 0.3–1.0) were undergoing tuberculosis treatment, and 53 (3.2%; 95% CI, 2.5–4.2) reported a previously treated TB cases. The overall prevalence of tuberculosis among individuals with diabetes was 4.4% (n=72; 95% CI, 3.5–5.5). Stratification by age and sex revealed a significantly higher prevalence among males (5.9%; n=48; 95% CI, 4.5–7.8) compared to females (2.9%; 95% CI, 1.2–4.2) (p=0.002), indicating a twofold increased risk of tuberculosis in males. Although no statistically significant differences in tuberculosis prevalence were observed across age groups (p>0.05), a declining trend in prevalence with older age was noted. Conclusion: The prevalence of tuberculosis among individuals with type 2 diabetes was 4.4% (n=72; 95% CI, 3.5–5.5), with a significantly higher rate in males (p=0.002) and a decreasing trend with increasing age. Among asymptomatic individuals exhibiting radiographic abnormalities, 7.2% were confirmed to have tuberculosis via laboratory testing.