Abstract:

Objective: To analyze the incidence and influencing factors of close contacts of active pulmonary tuberculosis patients in Kashgar, Xinjiang Uygur Autonomous Region, and to provide a scientific basis for the development of close contact screening strategies. Methods: Data of 11411 active pulmonary tuberculosis (TB) patients registered and reported in Kashgar, Xinjiang Uygur Autonomous Region were collected, excluding 58 deaths, no close contacts, and incomplete information, 11353 active TB patients were actually included as indicated cases, from January to June 2018 reported in the “Tuberculosis Management Information System”, a subsystem of the “China Disease Prevention and Control Information System”. Close contacts were identified through household interviews and face-to-face questionnaires, cohorts were established, general demographic information were obtained, and screening for suspicious symptoms of TB, chest X-ray and sputum smear, etc.. The comprehensive diagnosis was made by a team of experts from the designated TB medical institution, and close contacts not diagnosed with active TB were followed up for three years (once a year). Multifactorial logistic regression was used to analyze the risk factors of the occurrence of active TB in close contacts. Results: A total of 25577 close contacts were identified in 11353 indicated cases, with an average of approximately 2.25 close contacts traced per indicated case. Active TB was detected in 2106 cases during the 3-year follow-up period, with an incidence rate of 8.26%. Multifactorial logistic regression analysis showed that male (OR (95%CI): 1.396 (1.260-1.546)), primary treatment (OR (95%CI): 1.605 (1.413-1.824)), and age 15-34 years (OR (95%CI): 1.318 (1.033-1.682)) or 35-54 years (OR (95%CI): 3.054 (2.717-3.432)) were independent risk factors for the development of active TB in the close contacts. Close contacts with a history of previous TB disease (OR (95%CI): 22.447 (18.570-27.134)), age ≤14 years (OR (95%CI): 2.792 (2.224-3.507)) and ≥55 years (OR (95%CI): 2.089 (1.777-2.457)), and social relationships with the indicated case’s were parents (OR (95%CI): 6.521 (4.284-9.926)), spouse (OR (95%CI): 6.311 (4.478-8.894)), children (OR (95%CI): 6.708 (4.739-9.495)), grandchildren (OR (95%CI): 10.003 (6.702-14.930)), siblings (OR (95%CI): 4.851 (3.171-7.422)), grandparents (OR (95%CI)=9.976 (4.083-24.375)), relatives (OR (95%CI)=2.456 (1.363-4.428)), and village doctors (OR (95%CI): 7.166 (2.110-16.339)), were all independent risk factors for the development of active TB among them. Conclusion: The incidence of active TB is high among close contacts in Kashgar. In patient management and health education, emphasis should be focused on male, newly treated, and middle-aged and young patients; meanwhile, screening and follow-up should be focused on close contacts with a previous history of TB, the elderly, the young and those who with close social relations with the patients.

Key words: Tuberculosis,pulmonary, Contact tracing, Factor analysis, statistical