Derivation, validation and comparative performance of a simplified chest X-ray score for assessing the severity and outcome of pulmonary tuberculosis
Clinical Respiratory Journal
Department of Internal Medicine and Subspecialties, Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde, Cameroon; Pneumology Service, Yaounde Jamot Hospital, Yaounde, Cameroon; Faculty of Health Sciences, University of Bamenda, Bamenda, Cameroon; Medicine Service, Bertoua Regional Hospital, Bertoua, Cameroon; Department of Medical Imaging and Radiation Therapy, Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde, Cameroon; Non-Communicable Diseases Research Unit, South African Medical Research Council and University of Cape Town, Cape Town, South Africa
Introduction: To derive and validate against the Ralph etal. score, a simplified chest X-ray (CXR) score (SCS) for predicting the outcome of smear-positive pulmonary tuberculosis (SPPTB) among patients with high prevalence of human immunodeficiency virus (HIV) infection. Methods: CXR for 636 SPPTB patients (377 men, median age 31 years) from the Yaounde Jamot Hospital (Cameroon) were examined for the presence of tuberculosis lesions, and estimation of the proportion of lungs affected. SPPTB's evolution was based on sputum smear examination after 2 months of treatments. Logistic regressions were used to derive the SCS with internal validation via bootstrap resampling. Receiver operating characteristic curves (AUC) analyses were used to validate, determine of the optimal cut-offs and compare models' performance. Results: HIV co-infection was present in 191 (30%) patients. Sputum smear non-conversion was found in 45 (7.1) patients after 2 months of treatment. The SCS was expressed as proportion of lung affected plus 23 if cavitation is present. The AUC (95% confidence interval) was 0.718 (0.640-0.795), with little variation in bootstrap validation, and no sizable difference from the Ralph etal. model [0.714 (0.633-0.7860), P=0.717 for the difference). Both models had good calibration (Hosmer-Lemeshow P≥0.183). The optimal cut-off for predicting non-conversion of the sputum at 2 months was 52 for the SCS (sensitivity/specificity 66.7%/62.8%) and 74.5 (62.2%/74.3%) with Ralph etal. score. Conclusions: The outcome of SPPTB among patients with high prevalence of HIV can acceptably be predicted by simple scores comprising baseline CXR variables, including the Ralph etal. score and the SCS from this study. © 2014 John Wiley & Sons Ltd.
ethambutol; isoniazid; pyrazinamide; rifampicin; tuberculostatic agent; adult; area under the curve; Article; chest x ray score; clinical assessment; comparative study; controlled study; disease severity; female; human; Human immunodeficiency virus infection; lung examination; lung parenchyma; lung tuberculosis; major clinical study; male; mixed infection; molecular evolution; outcome assessment; prevalence; priority journal; receiver operating characteristic; scoring system; sensitivity and specificity; smear positive pulmonary tuberculosis; smear positive pulmonary tuberculosis; sputum analysis; sputum smear; thorax radiography; treatment duration; validation study; Cameroon; cohort analysis; complication; Human immunodeficiency virus infection; microbiology; predictive value; reproducibility; severity of illness index; sputum; statistical model; treatment outcome; Tuberculosis, Pulmonary; young adult; Adult; Antitubercular Agents; Cameroon; Cohort Studies; Coinfection; Female; HIV Infections; Humans; Logistic Models; Male; Predictive Value of Tests; Radiography, Thoracic; Reproducibility of Results; ROC Curve; Severity of Illness Index; Sputum; Treatment Outcome; Tuberculosis, Pulmonary; Young Adult