Mass tuberculosis screening among the elderly: A population-based study in a well-confined rural county in eastern China.

BACKGROUND Mass tuberculosis screening has been recommended in certain high-risk populations. However, population-based screening interventions have rarely been implemented. Whether mass screening improves health equity is unknown. METHODS We implemented a mass tuberculosis screening intervention among elderly persons (>60 years old) in Lanxi county, China. Standardized questionnaires, physical examinations, and X-rays were administered to all participants. Systematic testing with computed tomography, smear, culture, or Xpert was performed among persons with an abnormal X-ray. We assessed tuberculosis prevalence per 100,000 persons and constructed multivariable regression models among subgroups that were and were not screened. Medical insurance was categorized as participation in either a basic or more comprehensive coverage program. RESULTS In total, 49,339 individuals participated in the screening, 32% of the elderly population in Lanxi. 115 screened persons were diagnosed with tuberculosis (233 cases per 100,000 persons), significantly higher than persons not screened (168 cases among 103,979 person-years; prevalence-to-case notification ratio: 1.44; 95% CI, 1.14-1.83). This increase was largely driven by diagnosis of asymptomatic disease during mass screening (N = 57; 50% of cases). Participants with basic medical insurance were multiple times more likely diagnosed through mass screening compared to passive detection (Adjusted Odds Ratio, 4.52; 95% CI, 1.35-21.28). CONCLUSIONS In a population-based, mass tuberculosis screening intervention encompassing over 30% of the elderly population in rural China, case finding was 44% higher than background detection, driven by diagnosis of asymptomatic tuberculosis. Importantly, mass screening identified tuberculosis in people with limited healthcare options that were less likely to be found through background detection.