An ingenious new system has been developed to make sure that patients with tuberculosis (TB) complete their entire course of treatment, thus preventing the emergence and spread of drug-resistant forms of the disease.
XoutTB involves a paper strips embedded with chemicals that detect metabolites of the TB drug isoniazid in a patient’s urine. The strips contain four printed numbers, a certain combination of which react and turn a new colour when exposed to the urine of patients who have taken their medication.
Patients then send a mobile phone text message reporting the numbers on their strip to a central database. Those patients who take the drugs consistently for 30 days are be rewarded with cell-phone minutes.
TB is a preventable but potentially deadly bacterial infection that kills almost 2 million people each year. Rates of TB have increased since the 1980s, in part due to the emergence of drug-resistant strains of the TB bacteria.
Drug resistance is a serious barrier to effective treatment of TB and to the permanent eradication of the disease, so serious that the World Health Organisation this week called the problem “a potentially explosive situation”.
Drug-resistant strains of TB emerge when the antibiotic used to treat the infection fails to kill all of the bacteria it targets. The surviving bacteria become resistant to that particular drug and pass this characteristic on to their descendants, thus spreading the trait.
The major cause of TB drug resistance is inadequate treatment, either because the wrong drugs are prescribed or because people don’t take the entire six-month course of medication. In particular, TB medication has considerable side effects, so to many individuals there seems little incentive or personal gain to be had from taking the whole course of medication.
The new monitoring system, developed by José Gómez-Márquez and colleagues of the Innovations in International Health program at Massachusetts Institute of Technology, provides a clear monetary incentive to encourage patients to take the medications that will improve their health and also indirectly benefit the health of others.