Abstract:

Objective: With a dual comparative study on active case finding (ACF) for pulmonary tuberculosis (PTB) patients among migrant population in Tongxiang City, Zhejiang Province from 2024 to 2025, to provide evidences for optimizing regional TB control strategies. Methods: Data on all notified PTB patients in Tongxiang City from 2024 to 2025 were collected from the Tuberculosis Management Information System, a subsystem of the China Information System for Disease Control and Prevention. The first comparison was conducted to explore differences in epidemiological and clinical characteristics between active and passive case finding among the migrant population and the second comparison was performed to study characteristic differences between migrant and local patients among all cases identifed through ACF. Cross-validation was performed by combining the results of the two comparisons to identify coverage gaps in the current ACF system. Results: A total of 175 migrant PTB patients were notified in Tongxiang City from 2024 to 2025, with 66 (37.71%) identified through ACF and 109 (62.29%) through passive case-finding (PCF). The first comparison showed that the proportions of patients residing in industrial core areas (90.91%, 60/66) and with bacteriologically negative results (51.52%, 34/66) in ACF group were higher than those in PCF group (77.98%, 85/109; 26.61%, 29/109) respectively, while the proportion of diagnostic delay (31.82%, 21/66) was lower than that in the PCF group (62.39%, 68/109), with statistically significant differences (χ²=4.837, P=0.028; χ²=11.071, P<0.001; χ²=15.368, P<0.001). Multivariate logistic regression revealed that ACF was a protective factor against bacteriologically positive PTB among migrant patients (OR=0.387, 95%CI: 0.197~0.761). The second comparison showed that a total of 156 patients were identified through ACF during the same period, including 66 migrants (42.31%) and 90 local residents (57.69%). The proportions of patients aged 25-64 years (83.33%, 55/66), working as migrant workers (63.64%, 42/66), residing in industrial core areas (90.91%, 60/66), and with bacteriologically negative results (51.52%, 34/66) among the migrant population were significantly higher than those among the local residents (54.44%, 49/90; 27.78%, 25/90; 74.44%, 67/90; 28.89%, 26/90), with statistically significant differences (Fisher’s exact test, P<0.001; χ²=35.299, P<0.001; χ²=6.820, P=0.009; χ²=8.236, P=0.004). Correspondingly, the local subgroup had statistically significantly higher proportions of elderly patients aged ≥65 years (40.00%, 36/90) and residents of peripheral townships (25.56%, 23/90) than the migrant subgroup (4.55%, 3/66; 9.09%, 6/66). Conclusion: ACF facilitates early identification of bacteriologically negative PTB patients among the migrant population and is associated with a lower proportion of diagnositc delay. There are significant differences in the current ACF coverage characteristics between the migrant population and local residents, with migrants residing in peripheral townships identified as the coverage gap.

Key words: Tuberculosis, pulmonary, Migrant population, Active case finding, Passive case finding, Diagnostic delay