Untangling AMR: The Relationship between Rapid Diagnostic Testing for Malaria and Antibiotic Prescriptions

26 May 2011
Andrea Titus

A new study provides further evidence that rapid diagnostic tests for malaria (mRDTs) can reduce overuse of antimalarial drugs in malaria endemic countries. mRDTs, when they are high-quality, accessible, and trusted, provide a cost-effective path to accurate malaria diagnosis.

Reducing antimalarial overuse is an essential component in slowing the development of antimalarial resistance.  But this research points out an unintended and unfortunate side effect of improving malaria diagnostics: the potential for an associated jump in antibiotic prescriptions, as more fever-based illnesses could be subsequently misdiagnosed as bacterial infections.

The research team from Switzerland and Tanzania looked at the impact of introducing mRDTs in a variety of health facilities in Tanzania, and found that the intervention did indeed reduce inappropriate antimalarial prescription – the proportion of patients receiving antimalarials fell from 75% to just 20%. 

That antimalarials may currently be overprescribed in endemic countries comes as no surprise.  High child mortality associated with malaria, coupled with limited laboratory and diagnostic resources, has led to a default presumptive treatment for malaria.  This practice even became engrained in the IMCI treatment guidelines (recently amended).  Presumptive treatment and the accompanying overprescription of antimalarial medication, has been “seen as the only practical solution to improve child survival.”  But overuse of the drugs is also known to negatively impact the development of drug resistance.

And in this case, combating antimalarial resistance has some problematic implications for dealing with another area of public health concern: resistance to antibiotics.  The study authors find that the drop in antimalarial prescriptions was accompanied by a 47% jump in antibiotic prescriptions.  It seems that ruling out malaria diminishes the pool of possible causes of illness—a pool that includes bacterial infections.  Antibiotics are another form of presumptive treatment which guards against the significant burden of childhood bacterial infections, including pneumonia.

The take-home message appears to be two-fold.  First, as has been shown before, mRDTs have the potential to greatly improve the appropriate use of valuable antimalarial drugs, though it should be noted that there are significant challenges to widespread implementation of mRDTs.  Training in use of the tests, quality assurance mechanisms, and systems for surveillance and impact assessment need to accompany the intervention.  Second, the intervention must also take into account a broader picture of antimicrobial resistance, which includes antibiotics.  A final note from the study authors:

The downside of mRDT implementation is the shift from anti-malarial wastage to antibiotic wastage due to insufficient knowledge and training on other causes of fever. Deployment of mRDT should therefore move hand in hand with strategies aimed at reducing irrational use of antibiotics at outpatient level, for example through updated IMCI decision charts promoted by innovative approaches for teaching and communication.

Image credit: Flickr: Pranjal Mahna

Antibiotic Resistance