Recurrence of TB and associated risk factors among Non-HIV patients in Taiwan

Who

• Study population: 1,875 patients with active tuberculosis (TB) who completed anti-TB treatment at a referral medical center in Taiwan.

• Subgroups:

  • 1,514 (80.7%) with pulmonary TB.

  • 1,342 culture-confirmed pulmonary TB cases.

  • 361 (19.3%) with extrapulmonary TB.

• Demographics: Median age 67 years; 67% male; comorbidities included diabetes (21.2%), malignancy (14.4%), prior TB (11.1%); 34.3% smokers; 9% had cavitary disease; 35.5% sputum smear–positive.

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What

• Focus: Determine TB recurrence rate within 6 years after treatment and identify risk factors for recurrence; evaluate annual recurrence patterns from 2012–2019.

• Major findings:

  • Overall TB recurrence rate: 2.0% (434 per 100,000 person-years).

  • Recurrence highest in the second year post-treatment.

  • Recurrence declined in patients diagnosed after 2017.

  • Independent risk factors for recurrence:

    • BMI < 20 kg/m² (aHR ~4.4–5.0)

    • Prior TB history (aHR ~4.3–4.4)

    • 2-month sputum culture non-conversion (aHR ~3.4–4.4)

  • Recurrence risk increased with cumulative risk factors (10.8% with two; 28.6% with all three).

• Implications: Early culture conversion and nutritional status are key for risk stratification; past TB history strongly predicts recurrence; supports tailored follow-up intensity and resource allocation.

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When

• Diagnosis and inclusion period: January 1, 2012 – December 31, 2019.

• Follow-up duration: Up to 6 years post-treatment, with follow-up ending December 31, 2022.

• Median follow-up: 72 months.

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Where

• Conducted at a single referral medical center in Taiwan, a region with moderate TB burden.

• Data linked with the Taiwan CDC notification database.

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Why

• To identify clinical predictors of TB recurrence to enable risk-stratified and individualized TB management, determine who may need prolonged therapy or closer monitoring, and optimize public health resource deployment.

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How

• Study design: Single-center retrospective cohort.

• Eligibility: Bacteriologically confirmed or clinically diagnosed active TB; completed ≥6 months of guideline-based treatment; excluded those who died or were lost before treatment completion, or had HIV.

• Data collected: Demographics, comorbidities, radiologic findings, microbiology including drug resistance, treatment adherence, and sputum culture conversion at 1 and 2 months.

• Outcome definitions: TB recurrence per WHO criteria (relapse or reinfection).

• Statistical approach:

• Cox proportional hazards regression for risk factor identification.

• Kaplan–Meier survival curves.

• Death treated as a censoring event; recurrence rates expressed per person-years.

• Subgroup analyses for pulmonary and culture-confirmed pulmonary TB.

Source: Hsu, C.M., Wu, C.J., Chang, C.J., Pan, S.W., Tseng, Y.H., Huang, J.R., Su, W.J., Feng, J.Y. and Chen, Y.M., 2025. Recurrence of tuberculosis and associated risk factors among Non-HIV patients in Taiwan: A retrospective cohort study. Journal of Infection and Public Health, p.102912.