A World Health Organization (WHO)-coordinated retrospective study, published in the New England Journal of Medicine, provides evidence that supportive care, especially rehydration and correction of metabolic abnormalities, may contribute to patient survival.
The study analyzed clinical data on 37 confirmed Ebola patients admitted for treatment at hospitals in Conakry, Guinea’s capital and most densely populated city. The cases occurred during the first month of West Africa’s first outbreak of Ebola virus disease. Fourteen of the patients were heathcare workers. The majority (12) acquired their infection in a healthcare setting.
The study benefitted from careful and thorough daily data collection, laboratory records, and case histories put together by clinicians from the Ministry of Health, Médecins sans Frontières (MSF), and WHO.
One of the patients had negative results on an RT-PCR test, but was positive for IgG antibodies on ELISA. This finding underscores WHO recommendations for repeat testing before a suspected case can be discarded as “negative” or a recovered patient can be discharged from a treatment centre.
The majority (65%) of patients were male, countering assumptions that women, who are more likely to provide home care for patients and prepare bodies for funerals and burials, are more frequently exposed and infected.
Patients presented at hospital from three to seven days after symptom onset, most commonly with fever (in 84 percent), fatigue (in 65 percent), diarrhea (in 62 percent), vomiting in 21 patients (57 percent), and a heartbeat that was moderately faster than normal. Of these patients, 28 percent developed hiccups, a non-specific but distinctive feature of Ebola, at some point during their hospital stay.
To replace fluids lost through severe diarrhea, 36 patients (97 percent) received oral rehydration solution. Additional intravenous fluid resuscitation was given to 28 (76%) patients.
One patient with acute kidney injury, probably caused by profound diarrhoea-related dehydration, improved following the administration of approximately five litres of intravenous crystalloid fluids per day for three days.
As a precaution, antibiotics were administered to 37 patients (100 percent) to combat potential bacterial infections associated with their gastrointestinal illness. Seven patients received antimalarial medication and four had that diagnosis strengthened by a positive rapid diagnostic test.
Despite this treatment, 16 patients (43 percent) died, on average within five days after hospitalization. This case fatality rate is lower than that recorded at other sites during the current outbreaks, also in Guinea, and in previous outbreaks caused by the Zaire species of Ebola virus.
For example, another retrospective study of 106 patients from Sierra Leone, published last week in the New England Journal of Medicine, documented a case fatality rate of 74 percent.
High-quality supportive care is thought to have contributed to the larger number of survivors. However, two limitations compromised the quality of bedside care: staff were too few in number; and the duration of time spent providing care at the bedside was too little, due to dehydration and over-heating of clinicians wearing personal protective equipment.
These limitations suggest that survival rates, under more favourable hospital conditions, might be even higher.
Factors that may have influenced survival from Ebola:
The study population was too small to allow firm conclusions about which specific interventions increased the prospects of survival.
The amount of circulating viral load was higher in those who died than in survivors; those patients with the highest levels of virus were most likely to die.
One of the strongest determinants of survival appears to be patient age. Patients older than 40 years were nearly 3.5 times more likely to die than those aged less than 40. The association between an older age and a higher risk of death was found regardless of whether the patient had co-morbidities or not.
Evidence of substantial fluid loss and profound electrolyte derangement associated with severe diarrhoea appears to increase the risk of a fatal outcome. More aggressive supportive care, especially intravenous rehydration, is thought to improve the prospects of survival.
Along with fluid management, enhanced levels of clinical assessment and diagnostic testing may be ways to further improve survival beyond what has been seen elsewhere and in previous outbreaks of Ebola virus disease.