Abstract:

Objective: To analyze the epidemiological characteristics and associated risk factors for recurrence of pulmonary tuberculosis (PTB) following successful treatment among patients in Guangdong Province. Methods: A retrospective cohort study was conducted using data from the China Disease Prevention and Control Information System. According to setting inclusion criteria, the clinical information of active PTB patients with etiological confirmation or clinical diagnosis, who were registered in Guangdong Province from January 1 to December 31, 2017 and whose treatment outcomes were “cured” or “completed course”, was automatically matched with all registered PTB cases reported from January 1, 2018 to June 30, 2023. Patients who were matched successfully and met the recurrence definition were selected as study subjects. Clinical data for all recurrent cases was collected and analyzed for its epidemiological characteristics and influencing factors associated with these recurrence by the single factor and multivariable Cox proportional hazards regression models. Results: A total of 1417 recurrent cases meeting the predefined criteria were identified. The crude recurrence rate was 2.67% (1417/53047), and the Kaplan-Meier estimated cumulative recurrence rate was 2.83%. The recurrence incidence density was 0.50 per 100 person-years (1417 recurrences over 283429.25 person-years). Among recurrent cases, the median (IQR) time to recurrence was 1.85 (0.88-3.34) years, with 52.51% (744/1417) of recurrences occurring within the first two years after successful treatment completion. Multivariable Cox regression analysis, based on patient characteristics at the initial PTB diagnosis in 2017, identified the following independent risk factors for recurrence: male sex (adjusted hazard ratio (aHR) =1.380, 95%CI: 1.207-1.578), occupation as farmer or herdsman (aHR=1.587, 95%CI: 1.029-2.450), comorbid diabetes mellitus (aHR=1.287, 95%CI: 1.024-1.616), detected from passive case finding (aHR=1.738, 95%CI: 1.003-3.009), delayed case finding (aHR=1.142, 95%CI: 1.025-1.271), and positive etiological test results (aHR=2.099, 95%CI: 1.886-2.337), while using fixed-dose combination (FDC) drugs (aHR=0.802, 95%CI: 0.717-0.897) and residence in the Pearl River Delta region (aHR=0.665, 95%CI: 0.585-0.755) were identified as protective factors. Conclusion: PTB patients in Guangdong Province remain at risk of recurrence within five years after successful treatment, with over half of the recurrences occurring within the first two years. Enhanced post-treatment follow-up and management are recommended, special attention should be paid to high-risk groups such as males, farmers/herdsmen, patients with comorbid diabetes mellitus and positive for etiology. Active case-finding strategies and standardized use of FDC regimens should be promoted to facilitate early detection, reduce the risk of recurrence, and improve long-term treatment outcomes.

Key words: Tuberculosis, pulmonary, Recurrence, Epidemiological characteristics, Factor analysis, statistical