Time to sputum conversion in patients with pulmonary tuberculosis: A score to estimate the infectious period

• Published in: Journal of clinical tuberculosis and other mycobacterial diseases Vol. 31; p. 100361
• Main Authors: Ramirez-Hidalgo, Maria, Trujillano-Cabello, Javier, Espluges-Vidal, Adrià, Reñé-Reñé, Mercé, Santín, Miguel, Sánchez-Montalvá, Adrián, Bernet-Sánchez, Albert, Gros-Navés, Laura, Falguera, Miquel
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2023; Elsevier
• Subjects: Conversion; Predictor factors; Pulmonary tuberculosis (PTB); Score; Sputum conversion; OR; ROC; DOT; DM; Pulmonary tuberculosis (PTB); Conversion; Sputum conversion; AUC; PTBSCore; Predictor factors; Score; NLR; PTB; COPD; PTB, Pulmonary Tuberculosis; PTBSCore, Pulmonary Tuberculosis Sputum-Conversion score; DM, Diabetes Mellitus; AUC, Area Under the Curve; NLR, Neutrophil-to-lymphocyte Ratio; COPD, Chronic Obstructive Pulmonary Disease; ROC, Receiver Operating Characteristic; DOT, Directly Observed Therapy; OR, Odds Ratio
• ISSN: 2405-5794; 2405-5794
• DOI: 10.1016/j.jctube.2023.100361

•Time for culture conversion in treated PTB is uncertain and can be delayed.•Patients can have predicatble risk factors associated with late conversion.•Using a simple score could help clinicians to make decisions about isolation period. Patients with pulmonary tuberculosis (PTB) disease and positive sputum cultures are the main source of infection. Culture conversion time is inconsistent and defining the length of respiratory isolation is challenging. The objective of this study is to develop a score to predict the length of isolation period. A retrospective study was carried out to evaluated risk factors associated with persistent positive sputum cultures after 4 weeks of treatment in 229 patients with PTB. A multivariable logistic regression model was used to determinate predictors for positive culture and a scoring system was created based on the coefficients of the final model. Sputum culture was persistently positive in 40.6%. Fever at consultation (1.87, 95% CI:1.02–3.41), smoking (2.44, 95% CI:1.36–4.37), >2 affected lung lobes (1.95, 95% CI:1.08–3.54), and neutrophil-to-lymphocyte ratio > 3.5 (2.22, 95% CI:1.24–3.99), were significantly associated with delayed culture conversion. Therefore, we assembled a severity score that achieved an area under the curve of 0.71 (95% CI:0.64–0.78). In patients with smear positive PTB, a score with clinical, radiological and analytical parameters can be used as a supplemental tool to assist clinical decisions in isolation period.