Construction and Validation of a Predictive Model for Culture Results of Mycobacterium Tuberculosis in Superficial Lymph Nodes

Background: To establish and validate a nomogram for predicting the culture results of Mycobacterium tuberculosis in superficial lymph nodes.

Methods: The clinical data of patients with superficial lymph node tuberculosis admitted to Xi'an City Chest Hospital from November 23, 2018, to May 30, 2024, were selected and divided into a training set and a validation set according to a ratio of 7:3. Influencing factors were identified through multivariate logistic regression analyses. Using R version 4.3.2, we developed a predictive model and generated a nomogram based on this model. The performance of the nomogram was evaluated using receiver operating characteristic (ROC) curves, calibration curve analysis (CCA), and decision curve analysis (DCA).

Results: The positive rate of superficial lymph node tuberculosis culture was 23.0% (103/446). Multivariate Logistic regression analysis showed that anti-tuberculosis treatment duration (OR=0.98, 95% CI: 0.97 ~ 0.99), initial treatment or retreatment (OR=0.12, 95% CI: 0.05 ~ 0.28), and adenosine deaminase (OR=1.12, 95% CI: 1.03 ~ 1.22) were independent factors affecting the culture results of Mycobacterium tuberculosis in superficial lymph nodes. The areas under the ROC curves were 0.86 (95% CI: 0.82-0.91) for the training set and 0.89 (95% CI: 0.84-0.95) for the validation set. The P values of calibration curves were 1.000 and 0.961, respectively, and the predicted values were in good agreement with the actual values. The threshold probabilities of clinical decision curves were 3%~64% and 1%~68%, respectively.

Conclusion: The positive rate of Mycobacterium tuberculosis culture in superficial lymph nodes is low. The increase in retreatment patients and anti-tuberculosis treatment time are obstacle factors for Mycobacterium tuberculosis culture positivity, while an increase in adenosine deaminase is a promoting factor for Mycobacterium tuberculosis culture positivity. The nomogram model established based on these factors can be used to predict the results of Mycobacterium tuberculosis culture in superficial lymph nodes.