The role of chronic viral hepatitis on tuberculosis treatment interruption.

BACKGROUND: Tuberculosis (TB) drug-induced liver injury (TB-DILI) usually occurs within 8 weeks of anti-tuberculosis drug initiation. In Singapore, we suspected that the onset of TB drug-induced transaminitis may be confounded with hepatitis C virus (HCV) and hepatitis B (HBV) virus co-infection. OBJECTIVE: To determine the impact of HCV/HBV co-infection on the course of treatment in patients with TB treatment interrupted due to transaminitis. DESIGN: TB patients with treatment interruption during 2013-2014 were identified through the Singapore national TB registry. Case notes of those with transaminitis were perused. RESULTS: Of 3860 TB patients notified, 140 had suspected TB-DILI. Of these, respectively 20/140 (14.3%) and 16/140 (11.4%) were HCV- or HBV-positive. The median time to treatment interruption/transaminitis was 5 weeks vs. 9.9 weeks and 9.6 weeks for transaminitis patients without chronic liver disease and with HCV/HBV co-infection (P < 0.01). Multivariate logistic regression analysis revealed that having HCV/HBV co-infection was associated with treatment interruption occurring beyond 8 weeks (adjusted OR [aOR] 4.06, 95%CI 1.28-12.85); HCV transaminitis patients were more likely to take 10 months to complete anti-tuberculosis treatment (aOR 5.11, 95%CI 1.21-21.67) than those without chronic liver disease. CONCLUSION: TB treatment interruption due to transaminitis in HCV/HBV co-infected patients occurred later than in those without liver disease. Most had completed 2 months of pyrazinamide-containing intensive phase treatment before the onset of transaminitis.

Surveillance of tuberculosis treatment outcomes of Singapore citizens and permanent residents, 2002-2011.

SETTING: Singapore, which had a tuberculosis (TB) incidence rate of 41 per 100,000 resident population in 2011. OBJECTIVE: To report the outcomes of Singapore citizens and permanent residents treated for TB from 2002 to 2011. METHODS: A computerised treatment surveillance module (TSM) was launched in 2001 to track the progress and outcome of TB patients nationally. Physicians were required to submit an electronic or paper return for every patient at each clinic visit. Treatment adherence, drugs prescribed, treatment delivery mode and final outcome, specified as 'completed treatment', 'lost to follow-up', 'death', 'transferred out', 'permanent cessation of treatment' and 'still on treatment/no final outcome', were captured. Quarterly cohort outcomes at 12-15 months after starting treatment were combined to generate annual treatment outcomes. RESULTS: Treatment completion rates increased from 73.4% to 82.8%. The proportion of patients lost to follow-up decreased from 3.4% to 1.7%, while that of patients still on treatment or with no final outcome decreased from 10.5% to 4.4%. The death rate ranged between 10.2% and 11.7%; the majority were not attributed to TB. CONCLUSION: TB treatment completion among Singapore citizens and permanent residents has improved since 2002 as the likely result of the TSM and other initiatives introduced over the past decade.

Notified tuberculosis among Singapore residents by ethnicity, 2002-2011.

SETTING: The National Tuberculosis Programme in Singapore where, among resident cases, higher tuberculosis (TB) rates have been reported in ethnic Malays. OBJECTIVE: To describe the socio-demographic and clinical characteristics of resident TB cases by ethnicity, and to assess whether Malays differ from other groups in terms of the above parameters. DESIGN: Cross-sectional review of records from the tuberculosis registry's electronic database. RESULTS: Among 15 622 resident cases notified, 72.2% were Chinese, 18.7% Malay, 5.8% Indian and 2.9% were from other minorities. Compared to other ethnicities, Malays were more likely to be incarcerated at the time of notification (odds ratio [OR] 3.70, 95%CI 3.03-4.52) and clustered at the same residential address (OR 1.65, 95%CI 1.44-1.89), but were less likely to be aged ≥65 years (OR 0.61, 95%CI 0.54-0.70) or to reside in high-cost housing (OR 0.11, 95%CI 0.07-0.17). In terms of disease characteristics, more Malays had diabetes mellitus (OR 1.54, 1.37-1.73), a highly-positive acid-fast bacilli smear (OR 1.64, 95%CI 1.47-1.83) and cavitary disease on chest X-ray (OR 1.41, 95%CI 1.28-1.55). CONCLUSION: Compared to other ethnicities, reported TB cases among Malays were more severe and were likely to be more infectious. Increased vigilance in case management and contact investigations, as well as an improvement in the socio-economic conditions of this community, are required to reduce TB rates in this ethnic group.

Use of a T cell interferon-gamma release assay to evaluate tuberculosis risk in newly qualified physicians in Singapore healthcare institutions.

BACKGROUND: Surveillance for latent tuberculosis in high-risk groups such as healthcare workers is limited by the nonspecificity of the tuberculin skin test (TST) in BCG-vaccinated individuals. The Mycobacterium tuberculosis antigen-specific interferon-gamma release assays (IGRAs) show promise for more accurate latent tuberculosis detection in such groups. OBJECTIVE: To compare the utility of an IGRA, the T-SPOT.TB assay, with that of the TST in healthcare workers with a high rate of BCG vaccination. METHODS: Two hundred seven medical students from 2 consecutive cohorts underwent the T-SPOT.TB test and the TST in their final year of study. Subjects with negative baseline test results underwent repeat testing after working for 1 year as junior physicians in Singapore's public hospitals. RESULTS: The baseline TST result was an induration 10 mm or greater in diameter in 177 of the 205 students who returned to have their TST results evaluated (86.3%), while the baseline T-SPOT.TB assay result was positive in 9 (4.3%) of the students. Repeat T-SPOT.TB testing in 182 baseline-negative subjects showed conversion in 9 (4.9%). A repeat TST in 18 subjects with baseline-negative TST results did not reveal any TST result conversion. CONCLUSIONS: The high rate of positive baseline TST results in our BCG-vaccinated healthcare workers renders the TST unsuitable as a surveillance tool in this tuberculosis risk group. Use of an IGRA has enabled the detection and treatment of latent tuberculosis in this group. Our T-SPOT.TB conversion rate highlights the need for greater tuberculosis awareness and improved infection control practices in our healthcare institutions.