Bacteriological confirmation rate among notified pulmonary TB patients in China is among the lowest in the world. This study was to understand the yield of bacteriological confirmation using different testing strategies and patient-level factors associated with bacteriological confirmation among pulmonary TB patients in Tianjin, China between 2017 and 2018.
A retrospective study was conducted, enrolling pulmonary TB patients reported to National TB Information Management System (TIMS) in Tianjin during 2017–2018. Bacteriological confirmation was defined as a positive result by any of the followings: smear microscopy, culture, or nucleic acid amplification test. Individual characteristics were compared between patients with positive and negative bacteriological results using contingency tables and χ2 test. Multivariable logistic regression was applied to analyze factors associated with bacteriological confirmation, calculating adjusted odds ratios (aOR) and 95% confidence intervals (CI) (α = 0.05).
Of 6,364 reported patients, 4,181 (65.7%) were bacteriologically confirmed. Positivity proportion was 43.1% (2,746/6,364) for smear microscopy, 57.7% (3,380/5,853) for culture, 61.7% (1,608/2,605) for Xpert MTB/RIF and 73.4% (1,824/2,484) for combination of the three. Occupation as un-employed (aOR = 1.5, 95% CI: 1.0-2.2) and a farmer (aOR = 1.7, 95% CI: 1.1–2.8) compared with a student; diagnosis by inpatient hospitals compared with TB clinics (aOR = 3.4, 95% CI: 2.6–4.4); delay ≥ 2 weeks for TB care (aOR = 1.4, 95% CI: 1.1–1.8); cough (aOR = 2.2, 95% CI: 1.8–2.8); blood sputum (OR = 1.5, 95% CI: 1.0-2.2); cavitation on chest X-ray (OR = 3.3, 95% CI: 2.5–4.3); bilateral lung lobes affected (aOR = 1.7, 95% CI: 1.4–2.2) were factors associated with bacteriological confirmation.
Combination tests was an effective way to improve bacteriological confirmation among pulmonary TB patients. Being unemployed, farmers, delay for TB care, and more severe in TB condition were factors associated with bacteriological confirmation among the patients. We recommend combination of bacteriological tests and sputum collection intervention to improve bacteriological confirmation for pulmonary TB patients, especially who are in early stage of the disease or with conditions tend to be bacteriologically negative.