Tuberculosis in Bangladesh

In high tuberculosis (TB) burden countries like Bangladesh, lower lung zone TB is often misdiagnosed as pneumonia, lung abscess, bronchial carcinoma, or bronchiectasis due to overlapping clinical and radiological features.

A cross-sectional, observational study was conducted in the Department of Respiratory Medicine at Bangabandhu Sheikh Mujib Medical University (BSMMU) between March 2019 and February 2020. In this study, lower lung field tuberculosis (LLF-TB) on chest X-ray was defined as involvement below a horizontal line drawn across the hila on a posteroanterior (P/A) chest view. Radiological findings recorded included nodular opacities, pleural effusion, bronchiectasis, consolidation, cavitation, and inflammatory changes.

The participants had a mean age of 53.17 ± 14.38 years. LLF-TB among diabetic mellitus (DM) patients was more prevalent in those aged 41–60 years (p = 0.039). Males comprised 78.5% of cases, while females made up 21.5%. Isolated LLF-TB was most commonly observed among smokers.

Among diabetic patients with a disease duration of more than 10 years and those using only insulin without oral hypoglycemic agents (OHAs), LLF-TB prevalence was notably higher (78.6% and 54.2%, respectively).

The most prevalent radiological pattern observed was simultaneous involvement of both upper and lower lobes (38.5%). Isolated LLF-TB was found in 24 out of 117 diabetic TB patients (20.5%). Cavities were seen in 19.6% of cases, and pleural effusion was present in 18.7%. Inflammatory, bronchiectatic, or nodular opacities were noted in 2.6% of patients.

Smear positivity was significantly higher in TB patients with DM compared to non-DM TB patients (83.3% vs. 20.4%, p < 0.001). Conversely, GeneXpert positivity was markedly lower in TB-DM patients than in TB non-DM patients (8.3% vs. 68.8%, p < 0.001).

Elevated erythrocyte sedimentation rate (ESR > 50 mm in the first hour) and poor glycemic control (HbA1c > 7%) were significantly associated with LLF-TB in diabetic patients (83.9% and 79.2%, respectively; p < 0.001).

In conclusion, age over 40 years and diabetic status are significantly associated with the development of isolated LLF-TB. Diabetic patients over 40 years had a 6.8-fold (95% CI: 1.5–30.3) and 3.9-fold (95% CI: 1.1–13.9) increased risk for developing LLF-TB.

Source: Galib, R.K., Paul, S.K., Akter, K., Musa, M.I., Sarker, D.J., Choudhury, S.A.R.A., Paul, S.C. and Chakrabortty, R., 2025. Frequency of Lower Lung Field Tuberculosis in Diabetes Mellitus Patients Attending Tertiary Care Hospital in Bangladesh: A Cross‐Sectional Study. Health Science Reports, 8(1), p.e70413.