Treatment outcome of Singapore residents with pulmonary tuberculosis in the first year after introduction of a computerised treatment surveillance module.

INTRODUCTION: A key intervention of the Singapore Tuberculosis Elimination Programme (STEP) was the introduction in 2001 of a computerised treatment surveillance module (TSM) for the real-time monitoring of the treatment progress of the country's notified tuberculosis (TB) cases until a final outcome. We report the treatment outcome as at December 31, 2002 for the cohort of Singapore residents with new and relapsed pulmonary TB in whom treatment was commenced in 2001. METHODS: Each TB notification will activate the TSM, which requires a return on the patient's treatment progress, treatment delivery mode and the treating physician's management decision at each clinic visit to the STEP Registry until an outcome is reached. RESULTS: There were 1,354 Singapore residents with new or relapsed pulmonary TB who started treatment in 2001. Of these, 620 (45.8 percent) underwent directly-observed therapy (DOT) at their nearest polyclinic. As at December 31, 2002 , 79 percent of patients completed treatment, nine percent died (two percent from TB), nine percent interrupted treatment (they were either lost to follow-up or refused treatment), 1.8 percent were still on treatment, 0.6 percent left the country, and 0.5 percent had permanent cessation of treatment due to drug reactions. Factors associated with treatment completion were Chinese ethnicity (odds-ratio [OR] 1.5, 95 percent confidence interval [Cl] 1.1-2, p-value is 0.02), age younger than 65 years (OR 1.8, 95 percent Cl 1.3-3.0, p-value is 0.003) and the use of DOT (OR 3.1, 95 percent Cl 2.3-4.1, p-value is less than 0.05). CONCLUSION: The findings from the TSM's first year provide a baseline for future programme evaluation.

Contact screening and latent TB infection treatment in Singapore correctional facilities.

SETTING: Singapore, a city-state with a tuberculosis (TB) incidence rate of 47 per 100000 population in 2000. OBJECTIVES: 1) To report our experience with contact investigation and latent TB infection (LTBI) treatment in high-risk contacts with unknown human immunodeficiency virus (HIV) status in correctional facilities (CFs) (prisons/drug rehabilitation centres); and 2) to compare the yield of contact screening in this setting with that in the community (household/family) setting. METHODS: The tuberculin skin test (TST) readings of 704 CF contacts screened from 1999 to 2001 were compared with those of 2729 household/family contacts who underwent screening in 2000. RESULTS: Respectively eight (1.1%) and 20 (0.7%) active TB cases were detected among the CF and community contacts. A significantly higher proportion of CF contacts had first (non-conversion) TST readings > or =15 mm (39% vs. 22%, OR 2.3; 95%CI 1.9-2.7; P < 0.001), and 10-14 mm (26% vs. 18%, OR 1.6; 95%CI 1.3-2.0; P < 0.001) and TST conversion (43% vs. 20%, OR 2.9; 95%CI 1.7-4.9; P < 0.001). LTBI treatment was started in 65% of the CF contacts screened; 87% completed treatment. CONCLUSION: We found a high LTBI rate among CF contacts, presenting an opportunity for intervention.

Factors associated with transmission of severe acute respiratory syndrome among health-care workers in Singapore.

Between 1 and 22 March 2003, a nosocomial outbreak of Severe Acute Respiratory Syndrome (SARS) occurred at the Communicable Disease Centre in Tan Tock Seng Hospital, Singapore, the national treatment and isolation facility for patients with SARS. A case-control study with 36 cases and 50 controls was conducted of factors associated with the transmission of SARS within the hospital. In univariate analysis, contact with respiratory secretions elevated the odds ratio to 6.9 (95 % CI 1.4-34.6, P= 0.02). Protection was conferred by hand washing (OR 0.06, 95% CI 0.007-0.5, P=0.03) and wearing of N95 masks (OR 0.1, 95% CI 0.03-0.4, P=0.001). Use of gloves and gowns had no effect. Multivariate analysis confirmed the strong role of contact with respiratory secretions (adjusted OR 21.8, 95 % CI 1.7 274.8, P=0.017). Both hand washing (adjusted OR 0.07, 95 % CI 0.008-0.66, P=0.02) and wearing of N95 masks (adjusted OR 0.1, 95% CI 0.02-0.86, P=0.04) remained strongly protective but gowns and gloves had no effect.

Treatment of latent TB infection for close contacts as a complementary TB control strategy in Singapore.

OBJECTIVE: To describe our initial experience with treatment of latent tuberculosis infection (LTBI) for close contacts of infectious TB cases in Singapore, an intermediate TB burden country with mass BCG (re)vaccination since the 1950s. METHODS: Screening of 5699 contacts of 1374 index cases notified in 1998 was carried out at the TB Control Unit. RESULTS: Seventy-five per cent (4239) completed tuberculin skin testing (TST). Fifty-three cases of TB disease were detected (0.9% yield). Twenty-one per cent (895/4239) of the TST-screened contacts were started on LTBI treatment, comprising 92% (810/883) of contacts with TST > or = 15 mm, 5% (64/1195) of those with TST 10-14 mm and 1% (21/2161) of those with TST < 10 mm. The regimen utilized was isoniazid for 6 months in adults and 9 months in children. Eighty-one per cent completed treatment. The incidence of isoniazid-induced hepatitis was 0.45%. Over the ensuing 4 years, one case of active TB was reported among those treated for LTBI, and 10 cases (five without TST readings) were notified among contacts who did not receive treatment. CONCLUSIONS: Where good case-finding and treatment of TB disease exist, and where resources permit, LTBI treatment for close contacts is feasible as a complementary TB control strategy in an intermediate TB burden country with a BCG-vaccinated population.

Hepatotoxicity of tuberculosis chemotherapy under general programme conditions in Singapore.

SETTING: The Singapore Tuberculosis (TB) Control Unit, a high volume national referral centre. OBJECTIVES: To determine the incidence, clinical course and outcome of TB drug-induced hepatitis (DH) and the risk factors associated with DH under general programme conditions. DESIGN: A retrospective review of adult patients started on TB treatment in 1998. RESULTS: There were 55 cases of DH in the cohort of 1036 patients treated in 1998. The median time to diagnosis of DH was 38 days. Factors significantly associated with DH were abnormal baseline transaminases/ bilirubin (OR 2.1, 95%CI 1.1-4.3, P = 0.02), age >60 years (OR 1.97, 95%CI 1.14-3.34, P = 0.01) and female sex (OR 1.9, 95%CI 1.07-3.4, P = 0.02). Ethnicity, self-reported alcohol consumption and body weight were not associated with development of DH. All three patients with fatal DH had received pyrazinamide-containing regimens. Treatment was re-introduced in 48 patients and successfully completed in 45 patients. The median time to reinstitution of TB treatment was 23 days. CONCLUSION: The incidence of TB drug-induced hepatitis was 5.3%. Age >60 years, abnormal baseline transaminase/bilirubin levels and female sex were risk factors associated with the development of TB drug-induced hepatitis.