A new program that combines cheap, paper-based diagnostics with text-messaging technology could improve tuberculosis (TB) treatment in poor countries. The program, which is the brainchild of engineers, economists, and entrepreneurs at the Innovations in International Health (IIH) project at MIT, rewards patients who adhere to the lengthy TB drug regimens with cell-phone minutes. Called XoutTB, the diagnostics have proved successful in a pilot field test in Nicaragua; a larger trial will begin this month in Pakistan.
TB strikes millions of people across the globe: 9.2 million new cases were diagnosed in 2006, and 1.7 million people died from the disease, according to the World Health Organization. The infection can be effectively treated with antibiotics, but patients need to keep taking the drugs daily for six months or more to completely wipe it out. However, because the drugs can trigger nausea and other side effects, some patients stop taking them when their TB symptoms subside, often one to two months into treatment. “In Pakistan and other countries, low compliance rates are fueling the emergence of drug-resistance strains,” says Rachel Glennerster, executive director of the Poverty Action Lab at MIT.
The main approach to boost compliance has been to institute programs where medical workers monitor patients’ medication, either by visiting their homes every day or by requiring patients to come into a clinic to get their pills.
To get around that problem, Jose Gomez-Marquez, program director for IIH, and his collaborators developed a simple paper-based diagnostic that detects metabolites of the TB drug in urine. The papers are dispensed from a device every 24 hours; when the diagnostic comes in contact with patients’ urine, the metabolite reacts with chemicals embedded in the paper. That reaction reveals a code, which the patient then texts to a central database every day. Those who take the drugs consistently for 30 days are rewarded with cell-phone minutes.
“The beautiful thing about this approach is that it really takes into account all the latest research on the psychology of compliance,” says Glennerster. “What psychologists have found is that people respond to reminders and deadlines, and they are much more responsive to small, immediate incentives than to larger, more distant ones.”
The researchers recently finished a feasibility test in Nicaragua, where they worked with local scientists to improve the accuracy of the test strips, testing them on urine samples collected from TB patients. They also tested the robustness of the devices, making sure that they could be stored reliably and that they worked as well in humid Nicaragua as they did in New England.
The team is launching a larger trial this month in Karachi, Pakistan, in collaboration with the city’s Center for Community Development. The researchers plan to start with 30 patients but aim to eventually test the program on 1,000 people, comparing both compliance and infection rates in those who use the devices and those who have more traditional monitoring.