The prevalence, risk factors, and public health consequences of peripheral lymph node-associated clinical and subclinical pulmonary tuberculosis.

OBJECTIVES

Relatively little is known about the prevalence, risk factors, and public health consequences of peripheral lymph node (PLN)-associated pulmonary tuberculosis (PTB).

METHODS

We developed a 10-year (2010-2019) population-based cohort of PLNTB patients in Canada. We used systematically collected primary source data and expert reader chest radiograph interpretations in a multivariable logistic regression to determine associations between sputum culture positivity and demographic, clinical, and radiographic features. Public health risks were estimated among contacts of PLNTB patients.

RESULTS

There were 306 patients with PLNTB, among whom 283 (92.5%) were 15-64 years of age, 159 (52.0%) were female, and 293 (95.8%) were foreign-born. Respiratory symptoms were present in 21.6%, and abnormal chest radiograph in 23.2%. Sputum culture positivity ranged from 12.9% in patients with no symptoms and normal lung parenchyma to 66.7% in patients with both. Respiratory symptoms, abnormal lung parenchyma, and HIV-coinfection (borderline) were independent predictors of sputum culture positivity (odds ratio [OR] 2.24 [95% confidence interval [CI] 1.15-4.39], P = 0.01, OR 4.78 [95% CI 2.41-9.48], P < 0.001, and OR 2.54 [95% CI 0.99-6.52], P = 0.05), respectively. Among contacts of sputum culture-positive PLNTB patients, one secondary case and 16 new infections were identified.

CONCLUSION

Isochronous PTB is common in PLNTB patients. Routine screening of PLNTB patients for PTB is strongly recommended.