LTBI among Household Contacts of Drug-sensitive Pulmonary TB Patients in Medan, Indonesia [TBN 054]

WHAT

This study examined the prevalence of latent tuberculosis infection (LTBI) among household contacts of pulmonary tuberculosis (TB) patients in Medan, Indonesia. Among 102 household contacts of 62 drug-sensitive pulmonary TB index cases, 30 individuals (29.41%) were diagnosed with LTBI, 60 individuals (58.82%) tested negative, and 12 individuals were diagnosed with active pulmonary TB and excluded from the LTBI analysis. Thus, the final analytic sample included 90 household contacts.

The study also evaluated potential risk factors associated with LTBI, including age, sex, occupation, educational level, nutritional status, comorbidities, smoking behavior, alcohol consumption, and duration of household contact. The majority of participants were female (76.6%), with the most common age group among LTBI cases being 46–55 years, while the non-LTBI group was most commonly aged 26–35 years. Most participants had senior high school education, did not smoke, did not consume alcohol, and reported no comorbidities. Contact duration of ≥5 hours per day was common in both groups.

Bivariate analysis demonstrated that none of the assessed variables were significantly associated with LTBI. Specifically, age, gender, educational level, occupation, nutritional status, comorbidities, smoking, alcohol consumption, and contact duration showed no statistically significant relationship with LTBI occurrence (p > 0.05). These findings suggest that LTBI among household contacts may occur regardless of commonly measured demographic, behavioral, or clinical risk factors.

Overall, the study found a relatively high prevalence of LTBI among household contacts of pulmonary TB patients. The authors concluded that these findings highlight the importance of strengthening contact investigation programs and expanding TB preventive treatment among household contacts, particularly in high-burden urban settings such as Medan.

HOW

This study used a cross-sectional design conducted in Medan, an urban city and the capital of North Sumatra, Indonesia, with a population of approximately 2.47 million people. Pulmonary TB index cases were identified from hospitals, clinics, and community health centers (Puskesmas). Eligible index cases were pulmonary TB patients with sputum positive for Mycobacterium tuberculosis and rifampicin-sensitive results confirmed using the Xpert MTB/RIF test. Verification of index cases was performed using the Indonesian Tuberculosis Information System (SITB).

Household contacts aged 15 years and older who lived in the same household as pulmonary drug-sensitive TB patients and consented to participate were recruited using consecutive sampling between October 1 and December 5, 2023. Family members of extrapulmonary TB patients and individuals diagnosed with active TB during contact investigation were excluded. The minimum sample size calculated using the Lemeshow formula was 99 participants, and 102 household contacts were ultimately enrolled.

Data collection included structured interviews, anthropometric measurements, Interferon-Gamma Release Assay (IGRA) testing, chest X-ray examination, and sputum testing when clinically indicated. Interviews collected demographic information, education, occupation, smoking behavior, alcohol consumption, comorbidities, and duration of contact with the index case. Nutritional status was assessed using body mass index derived from height and weight measurements.

LTBI was defined as a positive QuantiFERON-TB Gold Plus (QFT-Plus) IGRA result with a normal chest X-ray and absence of TB symptoms. Participants with abnormal chest X-ray findings or symptoms suggestive of TB underwent sputum examination using Xpert MTB/RIF testing. Individuals diagnosed with active TB, either microbiologically confirmed or clinically diagnosed, were excluded from the LTBI analysis.

Source: Sinaga, B.Y.M., Siregar, J., Sormin, D.E., Sundari, R. and Samodra, Y.L., 2025. Latent Tuberculosis Infection among Household Contacts of Drug-sensitive Pulmonary Tuberculosis Patients: A Cross-sectional Study from Medan, Indonesia. Acta Medica Philippina, 59(19), p.84-90.

Long-term risk of death after tuberculosis diagnosis and treatment [TBN 053]

What

Tuberculosis (TB) is widely recognized as a treatable and curable disease, yet this study shows that its consequences extend far beyond the active infection phase. Individuals who survive TB continue to face a significantly elevated risk of death for many years after diagnosis and even after completing treatment. This long-term mortality burden is largely overlooked in public health frameworks, with no dedicated guidance from global authorities such as the WHO to address post-TB health risks. The persistence of this risk is thought to arise from a combination of biological damage—such as permanent lung impairment and chronic inflammation—as well as ongoing social and health vulnerabilities, including comorbid conditions and poverty.

The magnitude and duration of excess mortality are substantial. Immediately after TB diagnosis, mortality risk is extremely high, particularly within the first month, and although it declines over time, it remains elevated even 14 years later. Individuals who complete treatment fare better than those newly diagnosed, but still experience roughly double the mortality risk of comparable TB-free individuals over the long term. Importantly, this is not just a relative effect; the absolute number of excess deaths is large, indicating a significant population-level burden that persists well beyond clinical recovery.

This increased mortality risk spans multiple causes of death rather than being limited to TB-related complications. Elevated risks are observed for cardiovascular disease, respiratory conditions, cancer, and metabolic disorders. Certain patterns stand out: respiratory and cancer-related deaths are particularly high shortly after diagnosis or treatment, while cardiovascular mortality becomes more prominent over time. Additionally, deaths from external causes—especially assaults—are also higher among TB-affected individuals, suggesting that social determinants and environmental risks play a meaningful role alongside biological factors.

The impact of TB on mortality is not uniform across populations. Younger adults show higher relative risks, whereas older individuals bear a greater absolute burden of excess deaths. Differences by sex are modest, though slightly higher risks are observed among women in some contexts. Disease severity also matters: individuals with extrapulmonary or mixed forms of TB tend to have worse outcomes than those with pulmonary TB alone. Comorbidities further amplify risk, with diabetes emerging as a particularly important factor—associated with even greater absolute excess mortality than HIV in this study. Notably, household contacts of TB patients also exhibit modestly increased mortality, reinforcing the role of shared socioeconomic and environmental exposures.

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How

This study was designed as a large-scale retrospective cohort analysis using nationwide administrative data from Brazil. It leveraged the “100 Million Brazilian Cohort,” which captures over 130 million individuals enrolled in social welfare programs and represents predominantly low-income populations. These data were linked to national TB notification records and mortality registries, allowing researchers to follow individuals over time and assess long-term outcomes with high completeness and reliability. The study period spanned from 2004 to 2018, providing sufficient duration to evaluate long-term mortality trends.

Two main exposure groups were defined: individuals at the time of TB diagnosis and individuals who had successfully completed TB treatment. Each exposed individual was matched to a TB-free control using exact matching on a wide range of demographic and socioeconomic variables, including age, sex, race or ethnicity, geographic location, housing conditions, and household characteristics. This matching approach was designed to minimize confounding by ensuring that exposed and unexposed groups were highly comparable at baseline, particularly with respect to social determinants of health.

The study focused primarily on “natural deaths,” defined as deaths excluding TB, HIV, and external causes, in order to isolate the indirect and longer-term physiological consequences of TB. Secondary outcomes included all-cause mortality and specific causes of death, such as cardiovascular disease, cancer, respiratory illness, metabolic disorders, and external causes like accidents and assaults. Mortality outcomes were classified using standardized ICD-10 codes, enabling consistent categorization across the dataset.

Participants were followed from the point of TB diagnosis or treatment completion until death, the end of the study period, or (for controls) a subsequent TB diagnosis. Statistical analysis used the Aalen–Johansen estimator to calculate cumulative incidence while accounting for competing risks from different causes of death. Key measures included risk ratios, incidence rate ratios, and absolute risk differences, providing both relative and population-level perspectives on mortality risk over time.

To ensure data quality and interpretability, several exclusion criteria were applied, including removal of individuals with missing key variables, implausible dates, prior TB diagnoses before cohort entry, or extreme ages. Additional subgroup analyses were conducted to examine variation in mortality risk by age, sex, comorbidities, TB type, and household exposure. The study also incorporated analyses of household contacts, allowing for comparison between TB patients and individuals sharing similar living environments, further strengthening the interpretation of both biological and social drivers of long-term mortality.

Source: Cerqueira-Silva, T., Boaventura, V.S., Paixão, E.S., Sanchez, M., Leyrat, C., Ranzani, O., Barreto, M.L. and Pescarini, J.M., 2026. Long-term risk of death after tuberculosis diagnosis and treatment. Nature Medicine, pp.1-8.