Malaria policymakers and clinicians are concerned about the clinical, financial and public health harms associated with over-treating malaria.
Over-treatment happens when a person who doesn’t have malaria is given antimalarial drugs unnecessarily. This could be a person who has malaria-like symptoms such as fever.
About 88% of the world’s malaria cases are found in Africa. As a result, over-treatment of malaria is most common on the continent.
There are three main issues with over-treatment.
The first is that because malaria has been so prevalent there is a danger that all fevers are diagnosed as being caused by the disease. This means that other serious infections could be missed. This is particularly true as the number of malaria cases has dropped in many countries.
Second, the currently recommended first-line antimalarial drugs – artemisinin-based combination therapies – are not cheap. Their unnecessary use leads to a waste of resources.
And third, in some countries, resistance against these drugs has emerged. They therefore need to be used sparingly.
To help overcome this problem the use of rapid diagnostic tests should be expanded. The tests have been around for at least six years and have changed the way that malaria is diagnosed. They can detect the presence of malaria within minutes and can be used in basic health care services in remote places.
In 2010 the World Health Organisation recommended that countries switch to this method of universal testing before treatment can begin.
There has been a rapid scaling up of the use of the tests in recent years. Nevertheless, over-treatment of malaria remains a problem.
Why over-treatment happens
Up until about 15 years ago, policymakers such as the World Health Organisation promoted a strategy known as “presumptive treatment of malaria”. This meant that in areas where diagnostic testing was unavailable, patients with fever were treated with antimalarials.
This happened whether or not there were signs of any other illnesses. As a result, there was a substantial overuse of chloroquine, the drug used to treat malaria before artemisinin. Chloroquine was cheap and well tolerated by the body.
Previous health worker training emphasised the danger of missing a case of malaria and sending a child home without treatment. This ingrained a belief in health workers and is likely to take time to change. They will require evidence based reassurance that the new policy of testing before treating is safe.
In our paper we analysed three scenarios that can lead to over-treatment. When:
treatment is based on symptoms and no tests done;
negative test results are ignored and treatment is administered; or
tests erroneously give positive results and treatment is administered.
Studies have highlighted how these scenarios play out. In Uganda, around two-thirds of people seek malaria treatment from retail drug stores, where testing is rarely done. This seems to be true in other African countries.
In Kenya, over-the-counter malaria medicines are the most-popular first response to fever in children and adults with acute illnesses.
Another reason for not testing is a shortage of rapid tests. Surveys of facilities in Tanzania, Mozambique and the Democratic Republic of Congo estimated that between 50% and 62% did not have rapid diagnostic tests in stock.
Even when the tests are available, in some instances they are not universally used. In one Tanzanian study staff reverted to presumptive treatment when the patient workload was high or there were staff shortages.
Why rapid diagnostic tests are the answer
Rapid diagnostic tests are accurate and can reduce over-treatment by 95% if they are available and used correctly. They are conducted next to the patient and the results are made available within minutes. There is no need to send blood samples to a laboratory, which can take several days and delay treatment.
But successful universal use of the test will need different interventions across public, private and retail sectors. The latest World Health Organisation data shows that the use of diagnostic testing across the continent increased from 41% in 2010 to 65% in 2014. But this only reflects use in the public-sector health facilities. Many people still seek anti-malarial treatment from retail drug stores as a first response to fever.
There are three processes that can improve the use of these tests.
First, improving the management at healthcare centres would mean they don’t run out of rapid diagnostic tests.
Second, technology can help. This was evaluated in rural districts in Tanzania and Kenya. The use of mobile phones, particularly SMS services, and the internet means that health low stocks can be notified. The quality assurance of the tests can also be improved.
Third, the rapid diagnostic tests should be subsidised. Previously, a subsidyfor artemisinin successfully increased its availability in the private sector. Research has proposed that a similar approach could improve the use of rapid diagnostic tests.