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Diagnosis &Treatment Bill Brieger | 01 Jun 2011 05:53 pm

RDTs, unintended consequences?

Results from a recently published study on “Reduction of anti-malarial consumption after rapid diagnostic tests implementation in Dar es Salaam” are being reinterpreted.

The study found that after the introduction of malaria rapid diagnostic tests in urban Tanzania the prescription of artemisinin-based combination therapy (ACT) drugs decreased and was significantly lower in intervention health facilities than the controls, which continued existing clinical diagnostic practices. Of importance, “Adherence to test result was excellent since only 7% of negative patients received an anti-malarial.”

What has given rise to concern, is that when ACT use decreased, there was an increased use of antibiotics used to treat febrile illnesses.  By following up on the story, gathered a more detailed understanding of the implications of the finding that, “antibiotic prescription increased from 49% before to 72% after intervention.”

Valerie D’Acremont, lead author and a senior scientist at the Swiss Tropical and Public Health Institute, Switzerland, explained to that, “Clinicians were handing out antibiotics, instead of anti-malarial drugs, to all patients with fever who tested negative for malaria. ‘They do that to avoid putting patients at risk,’ she told SciDev.Net, ‘especially as there are no diagnostic tools for other diseases such as typhoid or pneumonia.'”

These concerns run counter to the enthusiasm with which RDTs have been greeted by researchers.  For example, Uzochukwu and colleagues found that RDTs are more cost effective in terms of saving lives that clinical diagnosis. Overall costs associated with RDT use was significantly lower than both clinical diagnosis and traditional microscopy.

dscn9149-sm.JPGA study in Burkina Faso showed how real life problems can interfere with research objectives when they tried to compare treatment outcomes between RDT usa and clinical diagnosis. Compliance by prescribers after getting negative RDT results was too low (i.e. they gave malaria treatment even for negative tests) to compare. Health worker acceptance of RDTs is a problem in many countries, but obviously not in the Tanzania study.

The Tanzania experience led to interview Action on Antibiotic Resistance (ReAct) that pointed out the lack of easy to use tests for other febrile conditions (pneumonia, typhoid, viral fevers) in primary care settings as a problem.  Part of the problem is lack of rigorous adherence to clinical algorithms and guidance, and possibly a desire to give anything just to make the patient happy.

Again, the lead author of the Tanzania study was quoted by as saying that, “Ideally, with training and the implementation of clinical guidelines, it’s possible to reduce antibiotic use from 80 per cent to 25 per cent of patients.” Simply put, health care providers can change their behavior.  This need for training and supervision increases as we expand treatment for febrile and other illnesses into the community.  According to MCHIP (USAID) …

Experts agree that 60% of the 9.7 million children who die annually could be spared if we just delivered the life-saving interventions that we already have to families that need them most. These interventions include: antibiotics for pneumonia, dysentery and newborn sepsis; antimalarials; and oral rehydration packets and zinc supplements for diarrhea. Unfortunately the use of these interventions is low in most developing countries because services that deliver them are not accessible, not available, not of good quality, and/or not demanded.

The call therefore is for integrated case management at all level using all the tools currently available. We certainly do not want children to survive because of better malaria case management, while at the same time spurring antibiotic resistance that will threaten those same lives.


One final note – the Tanzania study was based in an urban setting. Urban areas are generally less hospitable to malaria-carrying anopheles mosquitoes. One therefore wonders if the apparent large increase in antibiotic use was a result of fewer expected actual malaria cases in a city? Do we need different guidelines and training to orient health workers to the different ecological settings where malaria is endemic?

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