Elevated Neutrophil-to-Lymphocyte Ratio is an Effective Prognosis Indicator In Extra-Pulmonary Tuberculosis

BACKGROUND: Extra-pulmonary tuberculosis (EPT) may lead to serious outcomes in the absence of an adequate treatment. Factors related to poor prognosis (PP) are still insufficiently understood. The peripheral blood neutrophil to lymphocyte ratio (NLR) has been reported to correlate with the prognosis of many acute or chronic infectious diseases. In this perspective, we aimed to investigate the prognostic relevance of NLR in EPT patients. METHODS: Data were collected from EPT patients, diagnosed between 1990 and 2014. We defined a PP by the occurrence of clinical complications during the hospital-stay or the follow-up. We evaluated the performance of NLR in identifying PP. The Kaplan-Meier method was used to generate complication-free survival curves which were compared by Log rank test according to NLR categories. Cox proportional hazard regression analysis was used to reveal the independent prognostic factors. RESULTS: We included 265 patients with EPT among them 68 cases (25.7%) had a PP. The mean age was 42 ± 19.2 years. Sex ratio was 0.8. EPT incriminated lymph node in 95 cases (35.8%), neuromeningeal sites in 50 cases (19%) and bones in 42 cases (15.8%). Mean value of NLR was significantly higher in the PP group (4.5 ± 3 vs. 3.2 ± 2.5; P = 0.01). NLR had an Area Under the Receiving Operating Curve (AUROC) of 0.63 in predicting PP (P = 0.004). At an optimal cutoff of 2.7, sensitivity and specificity were of 60%. There were 128 cases (48.3%) with a high NLR (≥ 2.7). Positive predictive value of NLR was 67.2% while negative predictive value achieved 80%. Overall, the median complication-free survival was 33 days (CI95% 19.2–46.7). When stratified by NLR cutoff, survival curve analysis showed that the one-month complication-free survival rate was lower in patients with high NLR (45% vs. 55%; P = 0.042). In multivariate Cox regression analysis, high NLR was an independent risk factor of predicting PP in EPT patients (HR=1.7; CI95% 1.1–2.9; P = 0.048). CONCLUSION: In this study, NLR was a useful prognostic factor to predict complications in patients with EPT and may be applied in clinical management of EPT in association with other prognostic indicators in order to identify high-risk patients. DISCLOSURES: All authors: No reported disclosures.