Asymptomatic tuberculosis detected in health screening predicts favourable outcome

The clinical and prognostic implications of asymptomatic tuberculosis remain poorly understood.

We conducted a multicentre prospective cohort study to evaluate the association between asymptomatic tuberculosis (TB) and treatment outcomes. Individuals with rifampicin-susceptible pulmonary TB were enrolled from the Cohort Study of Pulmonary Tuberculosis. Asymptomatic TB was defined as the absence of any TB-related symptoms at diagnosis. The primary outcome was a favourable outcome, defined as treatment success without recurrence. Multivariable logistic regression models were used to assess associations between asymptomatic TB and favourable outcomes. The Cox proportional hazards model was applied to evaluate effect of asymptomatic TB on failure to complete treatment within 1 year. Stratified analyses by symptom status and mode of detection were performed to examine stratum-specific effects.

Of 1071 individuals with pulmonary TB, 32.7% were asymptomatic. Compared to symptomatic patients, asymptomatic individuals were younger, less likely to be underweight and more often diagnosed through population health screening rather than clinical presentation or opportunistic testing. Asymptomatic TB was associated with higher likelihood of favourable outcome in multivariable models (adjusted odds ratio (aOR) 1.50, 95% CI 1.04-2.20) and a reduced risk of failing to complete treatment within one year in survival analyses (adjusted hazard ratio 0.66, 95% CI 0.45-0.95). Asymptomatic TB detected through health screening had the most favourable outcomes (aOR 2.41, 95% CI 1.34-4.66).

Asymptomatic TB was significantly associated with treatment success without recurrence and particularly in patients identified through health screening. Our results support symptom-agnostic screening in TB control programmes.