Development of a clinical scoring system for the diagnosis of smear-negative pulmonary tuberculosis

Abstract

This study developed a clinical score based on clinical and radiographic data for the diagnosis of smear-negative pulmonary tuberculosis (SNPT). SNPT was defined as a positive culture in Ogawa in a patient with two negative sputum smears. Data from patients admitted to the emergency ward with respiratory symptoms and negative acidfast bacilli (AFB) smears was analyzed by means of logistic regression to develop the predictive score.Two hundred and sixty two patients were included. Twenty patients had SNPT. The variables included in the final model were hemoptysis, weight loss, age > 45 years old, productive cough, upper-lobe infiltrate, and miliary infiltrate. With those, a score was constructed. The score values ranged from -2 to 6. The area under the curve for the ROC curve was 0.83 (95% CI 0.74-0.90). A score of value 0 or less was associated with a sensitivity of 93% and a score of more than 4 points was associated with a specificity of 92% for SNPT. Fifty-two point twenty-nine percent of patients had scores of less than one or more than four, what provided strong evidence against and in favor, respectively, for the diagnosis of SNPT. The score developed is a cheap and useful clinical tool for the diagnosis of SNPT and can be used to help therapeutic decisions in patients with suspicion of having SNPT.

Scoring systems using chest radiographic features for the diagnosis of pulmonary tuberculosis in adults: a systematic review

“…After full-text review, 174 articles were excluded for various reasons and 13 articles (all observational studies) were included in the systematic review ( fig. 1) [20][21][22][23][24][25][26][27][28][29][30][31][32].…”

“…Studies that only included patients with possible PTB who were found to be sputum smear negative We identified five studies in this category [26][27][28][29][30]. Four studies were conducted in an inpatient setting for the purpose of determining a clinical rule for respiratory isolation [26,27,29,30]; while one study was performed in an outpatient setting [28] (table 1).…”

“…Four studies were conducted in an inpatient setting for the purpose of determining a clinical rule for respiratory isolation [26,27,29,30]; while one study was performed in an outpatient setting [28] (table 1). As with the previously described set of studies that included all patients with possible PTB, in the univariate analysis the most common radiographic features across studies found to be associated with PTB were upper lobe infiltrates (pooled DOR 3.57, 95% CI 2.38-5.37; five studies) ( fig.…”

“…Of the 13 included studies, 12 studies involved scoring systems that combined clinical and radiographic features [20][21][22][23][24][25][26][27][28][29][30][31] and one study involved validation of 13 clinical prediction rules for inpatient respiratory isolation [32]. This study was included as it retrospectively applied prediction rules from six studies identified by our systematic review to a group of eligible participants with symptoms suggestive of PTB.…”

“…This study also tested rules that were derived from seven other studies, which were excluded from our systematic review as they did not satisfy our reference standard [33,34] or did not use specific features visualised on the chest radiograph as part of the scoring system [35][36][37][38][39]. Seven studies included all patients with possible PTB [20][21][22][23][24][25]32], five studies included patients with possible PTB who were found to have negative sputum smears [26][27][28][29][30], and one study specifically excluded PLWH [31]. Nine studies were performed in high-income countries.…”