Sociodemographic and clinical determinants of in-facility case fatality rate for 938 Ebola patients treated in Sierra Leone

Abstract Background The 2013 – 2016 West Africa Ebola Virus Disease (EVD) outbreak recorded the highest incidence and mortality since the discovery of the virus in Zaire in 1976. Studies relating to previous outbreaks usually involved small sample sizes. In this study we are set to identify those sociodemographic and clinical features that predict in-facility mortality among EVD patients using a large sample size. Methods We analysed the anonymized medical records of 938 laboratory-confirmed EVD patients 15 years old and above that received treatment at the 34 Military Hospital and the Police Training School EVD Treatment Centers in Sierra Leone in the period June 2014 to April 2015. We used both univariable and multivariable logistic regression to determine the predictors for in-facility mortality of these patients based on their sociodemographic and clinical characteristics. Results The median age of the EVD cases was 33 years (interquartile range = 25 to 40 years). The majority of the EVD cases were male (59.0%) and had secondary level education (79.3%). A low overall in-facility case fatality rate of 26.4% was shown. The associations between case fatality rates and EVD patients who reported fever, abdominal pain, cough, diarrhoea, vomiting, fatigue, haemorrhage, dysphagia, conjunctival injection, dyspnoea, and skin rash at the time of admission were statistically significant (p < 0.05). Our preferred model with age group of EVD patients and the presence of the symptoms diarrhoea, vomiting, fatigue, dysphagia, conjunctival injection, dyspnoea and muscle pain produced a receiver operating characteristic (ROC) curve with an AUC (area under the curve) value of 0.94. Conclusions The age of EVD patients, as well those patients who reported vomiting, diarrhoea, fatigue, dysphagia, conjunctival injection, dyspnoea and muscle pain have increased odds of dying during treatment and hence will require prompt and intensive treatment at the time of admission. We argue that the high proportion of individuals with higher educational levels may have been a critical determinant for the low case fatality rate.