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

Abstract

IntroductionWe 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.MethodsData 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.ResultsAmong 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.DiscussionLTBI 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.

The yield of tuberculosis contact investigation on relapsed TB patients and analysis of associated risk factors: Singapore’s experience

“…During the 5-year study period, TBI yield was 14.3% and TB disease yield was 0.7%, respectively, among close contacts of relapsed TB cases. This finding of TBI positivity is high in a country with TB incidence rate of 30.7 cases per 100,000 population when compared to high-income setting in South-East Asia where a TB incidence of 57 per 100,000 population with TBI positivity of 9.9% [ 9 ]. This finding in our study was largely contributed by non-residents as TBI positivity among non-residents was higher than that of residents (16.0% vs. 13.7%) among all screened contacts although it did not reach the statistical significance.…”

“…Studies have been done globally to evaluate the yield of contact investigation done for newly diagnosed TB cases and the factors associated with increased yield [9][10][11]. A study done in a highincidence country showed that retreatment index TB cases were 7.6 times higher yield of TB disease among their contacts than new cases [12].…”

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

“…A plausible explanation is that on initial suspicion of EPTB diagnosis, foreign workers may opt to refuse further diagnostic tests and be sent back to their home country, due to the monetary costs involved. Foreign residents make up 28% of Brunei’s labour force, with a significant proportion employed as low-skilled workers in construction, wholesale and retail trade 25 26. Foreign workers are required to undergo medical check-up on the start and renewal of their employment contract, and those diagnosed with active TB (PTB or EPTB) would be asked to return to their home country for treatment 17.…”

Epidemiology of Extrapulmonary Tuberculosis in Brunei Darussalam: A retrospective cohort study

“…A plausible explanation is that upon initial suspicion of EPTB diagnosis, foreign workers may opt to refuse further diagnostic tests and be sent back to home country, due to the monetary costs involved. Foreign residents makes up 28% of Brunei’s labour force, with significant proportion employed as low-skilled workers in construction, wholesale and retail trade [22,23]. Foreign workers are required to undergo medical check-up upon start and renewal of their employment contract, and those diagnosed with active TB (PTB or EPTB) would be asked to return to their home country for treatment [24].…”