Epidemiology of extrapulmonary tuberculosis in Brunei Darussalam: a retrospective cohort study.

OBJECTIVES: We reported the incidence and associated factors of extrapulmonary tuberculosis (EPTB). DESIGN: A retrospective cohort study. SETTING: Brunei Darussalam, an intermediate tuberculosis (TB)-burden country with stagnating annual TB rates. PARTICIPANTS: All active TB cases identified in the country between January 2001 and December 2018 (18 years). PRIMARY AND SECONDARY OUTCOME MEASURES: Annual proportions of EPTB (overall and specific) were calculated. Multiple logistic regression was done to investigate factors associated with developing EPTB, when compared with pulmonary TB (PTB). Χ2 trend test was used to determine any trends during the 18-year study period. RESULTS: We identified 3916 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 radiological 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 (adjusted OR (aOR)≥1.94) and women (aOR: 2.45 (95% CI: 1.94 to 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 women (aOR: 0.41 (95% CI: 0.17 to 0.90)). When compared to foreign residents, locals had higher adjusted odds of skeletal (aOR: 4.44 (95% CI: 2.04 to 11.69)), gastrointestinal (aOR: 3.91 (95% CI: 1.84 to 9.66)) and other types of EPTB (aOR: 3.42 (95% CI: 1.53 to 9.14)). No significant trend differences were observed for overall and specific EPTB types. CONCLUSION: Despite being generally non-infectious and less recognised than PTB, understanding EPTB epidemiology is important as it also contributes to the overall TB burden in a country. Examining EPTB cases by their specific anatomical site would provide more information on risk factors. Raising public awareness on the EPTB symptoms and that TB affects lungs and other parts of the body could promote early health seeking behaviour and early EPTB diagnosis.

Contact investigation of tuberculosis in Brunei Darussalam: Evaluation and risk factor analysis.

INTRODUCTION: We evaluated the yield of tuberculosis (TB) contact investigation in Brunei Darussalam, and identified the associated factors for latent TB infection (LTBI) diagnosis, as well as for initiating and completing LTBI treatment. METHODS: Data were extracted and digitalised for all close contacts of pulmonary TB (PTB) cases at the National TB Coordinating Centre from January 2009 to December 2018. Generalising estimating equations logistic regression models were used to determine the associated factors. Manual matching against electronic health records system was done to identify contacts who had progressed to active TB disease. RESULTS: Among 10 537 contacts, 9.9% (n=1047) were diagnosed as LTBI, out of which 43.0% (n=450) initiated LTBI treatment. Among those who initiated, 74.0% (n=333) completed LTBI treatment. Contact factors associated with LTBI diagnosis include being male (adjusted OR (aOR)=1.18 (95% CI 1.03 to 1.34)), local (aOR=0.70 (95% CI 0.56 to 0.88)) and a household contact (aOR=1.59 (95% CI 1.26 to 1.99)). Contacts of index cases who were <60 years old and diagnosed as smear positive PTB (aOR=1.62 (95% CI 1.19 to 2.20)) had higher odds of being diagnosed with LTBI. Local LTBI cases had higher odds of initiating LTBI treatment (aOR=1.86 (95% CI 1.26 to 2.73)). Also, LTBI cases detected from local (aOR=2.32 (95% CI 1.08 to 4.97)) and smear positive PTB index cases (aOR=2.23 (95% CI 1.09 to 4.55)) had higher odds of completing LTBI treatment. Among 1047 LTBI cases, 5 (0.5%) had progressed to active PTB within 1-8 years post-LTBI diagnosis. DISCUSSION: LTBI burden is disproportionately high towards foreign nationals, with higher odds of LTBI diagnosis but lower odds of treatment initiation. Determining the reasons of not initiating LTBI treatment will be useful to help improve LTBI treatment uptake. Establishing digital databases and building TB laboratory capacity for molecular typing would be useful to determine the contribution of LTBI or reactivation towards TB incidence in Brunei.