Before the introduction of diagnostic tests malaria was routinely diagnosed from fever symptoms alone in Africa, meaning that febrile patients were incorrectly diagnosed and treated.
Until 2010 it was World Health Organization (WHO) policy to treat all children with fever in sub-Saharan Africa with antimalarials, leading to both unnecessary drug costs and uncertain outcomes for children with other causes of fever.
Hugh Reyburn, senior lecturer in clinical epidemiology, and Chris Whitty, professor of public and international health, demonstrated the scale of the problem of over-diagnosis in a 2004 study of more than 17,000 patients in 13 hospitals in Tanzania. This study showed that in just over 2,000 patients treated for malaria only 46% had the disease, and among the under fives only 31% tested positive. Of the patients with fever but incorrectly treated for malaria 66% were given no antibiotics and nearly 8% of them died.
Further studies in East and West Africa showed that over-diagnosis was an even greater problem in outpatient settings. Researchers then undertook trials of rapid diagnostic tests but found that clinicians ignored negative test results – despite their accuracy - and prescribed antimalarials in about half the cases.
Economic analyses showed that the tests were cost effective and a further set of anthropological studies was carried out to understand clinicians’ behaviour. These studies showed that behaviour was influenced by peer opinion and a lack of alternative diagnoses. Reyburn and Whitty undertook further studies showing that there was a high burden of bacterial disease among adults and children with fever.
In 2010, WHO changed its policy from one of treating all fevers in Africa as malaria to one where only parasite-test positive cases were treated, recommending the use of rapid diagnostic tests. A British Medical Journal editorial by Rob Newman, then director of WHO’s Global Malaria Programme cited three studies, two of which came from the School.
This policy change is already having an impact – in Senegal, for example, a study found that the change to confirming diagnosis through parasitological tests reduced antimalarial prescriptions among patients displaying fever from 73% to just over 30%. An estimated 516,576 courses of inappropriate prescriptions were averted, saving just over US$1m (£660,000).
The School’s researchers gave a background briefing to the main funder of supplies for malaria diagnosis and treatment – the Global Fund to Fight Aids, Tuberculosis and Malaria. The fund has now introduced the tests in Africa.
The National Audit Office cited the School’s research in a report looking at UK government aid spending and the cost of donating antimalarials unnecessarily.