A clinical severity scoring system for visceral leishmaniasis in immunocompetent patients in South Sudan

BACKGROUND South Sudan is one of the most endemic countries for visceral leishmaniasis (VL), and is frequently affected by large epidemics. In resource-limited settings, clinicians require a simple clinical tool to identify VL patients who are at increased risk of dying, and who need specialised treatment with liposomal amphotericin B and other supportive care. The aim of this study was to develop and validate a clinical severity scoring system based on risk factors for death in VL patients in South Sudan. METHODS A retrospective analysis was conducted of data from a cohort of 6,633 VL patients who were treated in the Médecins Sans Frontières (MSF) hospital in Lankien between July 2013 and June 2015. Risk factors for death during treatment were identified using multivariable logistic regression models, and the regression coefficients were used to develop a severity scoring system. Sensitivity and specificity of score cut-offs were assessed by receiver operating characteristic (ROC) analysis. RESULTS In multivariable models, risk factors for death in adult VL patients were: anaemia (odds ratio (OR) 4.46 (95% CI 1.58-12.6) for Hb <6g/dL compared with ≥9g/dL), nutritional status (OR 4.84 (2.09-11.2) for BMI <13 kg/m2 compared with ≥16 kg/m2), weakness (OR 4.20 (1.82-9.73) for collapsed compared with normal weakness), jaundice (OR 3.41 (1.17-9.95)), and oedema/ascites (OR 4.86 (1.67-14.1)). For children and adolescents the risk factors were: age (OR 10.7 (6.3-18.3) for age <2 years compared with 6-18 years), anaemia (OR 7.76 (4.15-14.5) for Hb <6g/dL compared with ≥9g/dL), weakness (OR 3.13 (22.8-105.2) for collapsed compared with normal weakness), and jaundice (OR 12.8 (4.06-40.2)). Severity scoring predictive ability was 74.4% in adults and 83.4% in children and adolescents. CONCLUSION Our evidenced-based severity scoring system demonstrated sufficient predictive ability to be operationalised as a clinical tool for rational allocation of treatment to VL patients at MSF centres in South Sudan.