By: Peter Metzger, Soshana Clerizier, David McCue, & Kelsey Murphy
Tuberculosis (TB) is one of the top three global infectious diseases; one third of the world’s population – approximately 2.2 billion people – bears either an active or latent infection. The disease is caused by the bacterium Mycobacterium tuberculosis, a pathogen which usually infects the lungs and spreads through the air from persons with active respiratory TB. Without treatment, a contagious, active TB infection is fatal, accounting for about 1.3 million deaths annually.
Since 1990, the global incidence rate of tuberculosis has continued to rise, and World Health Organization (WHO) data indicate that case detection rates were still as low as 67% in 2008. Once diagnosed, global treatment success rates have been as high as 86% in 2007, when default rates were especially low. Unfortunately, patients continue to default on the standard 6-month first-line TB treatment regimen.
Failure to complete the full TB treatment course has dampened cure rates, and has induced bacterium resistance to first-line drugs. Multi-drug resistant tuberculosis (MDR-TB) accounts for 3.6% of incident TB cases worldwide. High-incident countries report that up to 22% of all TB cases are MDR-TB. In South Africa , the prevalence of MDR-TB among new TB cases has exceeded 10%, and continues to grow despite continued public health control efforts.
Drug resistance poses both a serious human and economic cost worldwide. The introduction of a single MDR-TB case into a community threatens to infect the entire population with a MDR-TB strain. A limited drug supply and acquisition costs mean that a second-line treatment course for MDR-TB costs over 100 times more than the standard first-line treatment; additionally, second-line treatment success rates are considerably lower than first-line treatments. Both second-line treatment plans and MDR-TB diagnostic tests are considerably more time-consuming, extending treatment to 24 months or more. Currently, less than 2% of estimated worldwide culture-positive MDR-TB patients are treated according to WHO recommendations, and only 7% of all estimated patients are diagnosed and notified.
MDR-TB is a highly preventable illness, making it one of the most logical targets for TB intervention. Proactive reduction of drug resistance requires increased adherence to treatment regimens and uninterrupted access to first-line drugs. Texts for TB aims to address these two concerns simultaneously with mobile technology. Globally, SMS treatment reminders have proven successful in combating HIV and TB in pilot studies. In Kenya, HIV patients who received SMS support had significantly improved ART adherence and rates of viral suppression compared to control subjects. In a South African pilot study, only 1 in 138 TB patients receiving SMS medication reminders defaulted on treatment.
Texts For TB is a planned TB-treatment intervention that is designed to complement and enhance existing health-care infrastructure to prevent the development of MDR-TB. The central tenet of Texts for TB is: treatment is prevention. Current first-line drugs are efficacious against normal TB, but require effective administration and patient adherence to drug regimes. Patients default during treatment plans for two main reasons: patients choose to stop treatment (Figure 1.4); and patients attempt to procure the next drug installment but encounter a drug stockout (Figure 1.5).
Texts for TB employs mobile phone technology to mitigate both problems. Texts for TB provides every patient that presents with TB at a clinic and enrolls in the treatment program a cell phone (Figure 1.1) and 250 SMS texts per month for free. In exchange, patients are required to abide by Texts for TB requirements.
Clinicians will input patient drug regimes into a program database running open-source software FrontlineSMS (Figure 1.7) that tags patient cell phone numbers with treatment plan information. Patients subsequently receive automated, interactive text messages for every dose of medication required under the treatment plan (Figure 1.6). These interactive messages require that patients actively affirm their receipt of the reminder and compliance with the drug plan (Figure 1.8).
Texts for TB also requires that patients report drug stock-outs. Patients will text a national database when they encounter a drug stock-out and are unable to procure their medications (Figure 1.8). Drug availability data from patients will provide a means of rapidly responding to drug stock-outs (Figure 1.9-10). Thus, Texts for TB mitigates patient default rates by incentivizing and enabling adherence to treatment plans and improving distribution of TB drugs.
The Khayelitsha Township just outside the metropolitan area of Cape Town, South Africa is the ideal location for the initial roll-out of Texts for TB. Khayelitsha is the largest informal urban community in Africa, with a population of 500,000. This fast growing township has the world’s fastest growing and highest rates of TB. For every 100,000 people in Khayelitsha there are 1,600 infected with TB (1.6%) and approximately 10% of TB patients develop MDR-TB. To make matters worse, 70% of TB patients have an HIV co-infection. Khayelitsha is in dire need of immediate and effective intervention. Texts for TB has the potential to succeed in Khayelitsha because there is an existing health infrastructure upon which Texts for TB can build. There are 3 day-hospitals and 8 local clinics spread throughout the area that treat TB, among other illnesses. Vodacom, MTN, and Virgin Mobile all provide cellular coverage to over 95% of the South African population. Additionally, 76% of households in Khayelitsha have access to electricity for charging their phones, supporting the feasibility of the plan working in Khayelitsha. Once the success of the program in Khayelitsha is accessed, the plan can be translated to other informal urban environments in South Africa and around the world.
MDR-TB is a growing proportion of TB cases worldwide, representing an increasing global human and economic cost. Fortunately, the development and spread of MDR-TB is preventable through adequate first-line treatment of TB. Increased mobile phone penetration can be used to realize the potential for more effective TB treatment programs. Texts for TB enables and reinforces collaborative interaction amongst patients, clinicians, and government drug delivery programs to stop MDR-TB.
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