The hidden burden: a regional study revealing the substantial burden and distinct epidemiology of asymptomatic pulmonary tuberculosis in Southern China.

BACKGROUND

The clinical spectrum of pulmonary tuberculosis (PTB) ranges from symptomatic to asymptomatic disease, yet the burden and epidemiology of asymptomatic PTB remain poorly characterized. This study aims to elucidate the prevalence, detection methods, and associated features of asymptomatic PTB in southern China through a large-scale comparative analysis.

METHODS

We conducted a regional cross-sectional study using data from China’s Tuberculosis Information Management System (2022–2024). A total of 102,274 PTB patients were classified as symptomatic or asymptomatic according to World Health Organization criteria. Descriptive statistics and χ² tests were used to compare demographics, case detection pathways. A multivariable logistic regression model was performed to examine the factors independently associated with asymptomatic presentation.

RESULTS

Among all cases, 34.0% (n = 34,741) were asymptomatic. This proportion was consistently higher in the developed Pearl River Delta region than in non-PRD regions. Asymptomatic rates were elevated among younger age groups (15–25 years: 44.5%), migrant populations (39.0%), and high-risk groups (38.3%). Although passive case finding accounted for 97.9% of all cases, active case finding identified a markedly higher proportion of asymptomatic PTB (82.4%). Multivariable analysis revealed that the influence of key factors, such as previous TB history (aOR, 1.75, 95%CI,1.64–1.87) and co-morbidities (aOR, 1.74, 95%CI,1.64–1.84) on symptomatic presentation was significantly modified by regional economic development.

CONCLUSION

This study reveals a substantial, under-ascertained reservoir of asymptomatic PTB in China, which is systematically missed by passive detection strategies. The higher yield of ACF and the identified demographic and regional disparities highlight the urgent need for a strategic shift towards proactive, targeted, and contextually adapted screening interventions to interrupt transmission effectively.