Objectives: We reported the epidemiology of extrapulmonary tuberculosis (EPTB) in Brunei Darussalam from January 2001 to December 2018. Design or methods: A retrospective cohort study was conducted where sociodemographic and clinical data for all active TB cases were collected. Factors associated with developing EPTB were investigated using logistic regression. Chi-square trend test was used to determine any trends during the 18-year study period. Results: We identified 3,916 TB cases, among which 743 (19.0%) were EPTB cases. Lymphatic (44.8%) and pleural (19.4%) EPTB were most common. The main modes of diagnosis were tissue biopsy (73.6%) and radiologic assessment (18.3%). Treatment success and mortality rate were 79.7% and 7.0%, respectively. Associations with specific EPTB types varies with age-group and gender. Younger age-group (aOR ≥1.94) and females (aOR: 2.45 [95%CI: 1.94,3.11]) had higher adjusted odds of developing lymphatic EPTB, but had lower adjusted odds of developing pleural EPTB [younger age-group (aOR ≤0.54) and female (aOR: 0.41 [95%CI: 0.17,0.90])]. No significant trend differences were observed for overall and specific EPTB types. Conclusions: Understanding EPTB epidemiology is important as it also contributes to the overall TB burden in a country. Future studies could be done to analyse the association between EPTB and presence of co-morbidities.

The authors have declared no competing interest.

This study is funded by Universiti Brunei Darussalam University Research Grant (Ref: UBD/RSCH/URC/RG(b)/2019/011).

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Ethical approval was given by the Medical and Health Research and Ethics Committee, Ministry of Health, Brunei Darussalam (Ref: MHREC/UBD/2019/2).

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