Prognostic Analysis of Patients with Ebola Virus Disease

Abstract

BackgroundThe Ebola virus causes an acute, serious illness which is often fatal if untreated. However, factors affecting the survival of the disease remain unclear. Here, we investigated the prognostic factors of Ebola virus disease (EVD) through various statistical models.Methodology/Principal FindingsSixty three laboratory-confirmed EVD patients with relatively complete clinical profiles were included in the study. All the patients were recruited at Jui Government Hospital, Sierra Leone between October 1st, 2014 and January 18th, 2015. We first investigated whether a single clinical presentation would be correlated with the survival of EVD. Log-rank test demonstrated that patients with viral load higher than 106 copies/ml presented significantly shorter survival time than those whose viral load were lower than 106 copies/ml (P = 0.005). Also, using Pearson chi-square test, we identified that chest pain, coma, and viral load (>106 copies/ml) were significantly associated with poor survival of EVD patients. Furthermore, we evaluated the effect of multiple variables on the survival of EVD by Cox proportional hazards model. Interestingly, results revealed that patient’s age, symptom of confusion, and viral load were the significantly associated with the survival of EVD cases (P = 0.017, P = 0.002, and P = 0.027, respectively).Conclusions/SignificanceThese results suggest that age, chest pain, coma, confusion and viral load are associated with the prognosis of EVD, in which viral load could be one of the most important factors for the survival of the disease.

Age and Ebola viral load correlate with mortality and survival time in 288 Ebola virus disease patients

“…Interestingly, the plasma viral load was closely associated with the survival time in all 288 confirmed EVD patients. Thus, the findings of the present study, in combination with previous reports from this study group, [22][23][24] indicate that older patients and those with high viral loads exhibited a higher fatality rate and shorter survival time, which is in concordance with the findings of Schieffelin et al 20 and Bah et al 21 There are some limitations in relation to the clinical data: (1) the medical records of the hospitalized patients who were Figure 6. Survival curves at the mean of covariate showed that most of the deceased patients died in the first 8 days.…”

“…Non-significantly higher incidences of other symptoms were also found in those who died than in those who recovered. A previous study by this group found age, viral load, and the presence of confusion to be related with survival time and mortality; 22 as the size of this cohort in the early stage of the outbreak was small, further studies were urgently needed. More cases were enrolled after the end of the outbreak and the same results were obtained, consolidating the findings.…”

Post-exposure treatments for Ebola and Marburg virus infections

“…However, these trials do provide valuable information that can be used to improve future clinical validation of experimental therapies, particularly reiteration of the association between high viral load and reduced survival [208][209][210] . A number of studies have correlated nonsurvival at 90% or more if the viral load exceeds 6 log copies per millilitre [210][211][212][213][214] in untreated patients. In a study of 84 patients infected with EBOV in West Africa, all patients with a viral load >7.71 log copies per millilitre of blood died, whereas all those with counts below this threshold survived 215 .…”

Molecular mechanisms of Ebola pathogenesis

“…Association between initial viral load and disease outcome was also reported by the Jui Government Hospital in Sierra Leone, who showed that patients who were admitted with a viral load .10 6 copies/ml had significantly shorter survival times than did patients with viral loads ,10 6 copies/ml. Moreover, advanced age was significantly and negatively associated with survival [81,106]. These observations were confirmed in a second study in which patients with EVD younger than 21 y had a lower CFR than did those older than 45 y [107].…”