How a lottery system helped 10 patients stay on their medication 24% more often

Incentives: An incentive is any measure that changes the content of a choice in order to motivate people to choose in a certain way. (This contrasts them with nudges, which change the choice architecture—but not the choices themselves—to get people to choose in a certain way.)  

Incentivization: Incentives work, when properly implemented, because humans have a bias towards incentivization—what we choose depends on what rewards or punishments we receive.

Millions of patients have conditions that increase their risk for strokes, bleeding complications, and heart-related problems. These conditions often come with an increased risk for morbidity (long-term suffering from a health condition) and mortality. For most of these patients, preventative blood clot medicine like warfarin can decrease these health complications.

Nonetheless, poor adherence to blood clot prevention pills is fairly common. In one study, researchers found that 40% of patients missed at least 20% of their warfarin doses; and in general, 32-68% of patient time is spent outside of the heathy coagulation range, in large part due to a lack of adherence to their prescribed warfarin regime. This inadequate regulation not only makes patients more susceptible to health complications—it reduces warfarin’s benefit, comes with side effects, and makes physicians more reluctant to prescribe warfarin to these patients in the first place. There is a great need for an intervention that helps patients adhere to their prescribed warfarin regime.

Who did they study?

Volpp et al. ran two pilot tests to see whether a financial incentive could help keep patients on their warfarin regime. The researchers chose lotteries due to their popularity in the United States–over 50% of U.S. adults participate in the lottery at least once per year. Ten patients who had been taking warfarin for at least three months were enrolled in both pilot tests. To participate, all ten signed a written consent form. 

How did they study them?

The researchers made sure they had a home telephone line, and that they could keep track of the pill monitor. Each participant was given an Informedix Med-eMonitorTM System, which tracked and displayed a patient’s medication compartments. The system used a participant’s home telephone line to directly collect data in a centralized database that the study’s administrator could access. 

What did they offer?

In the first pilot study, the expected value of the lottery was $5, with a ⅖ chance of winning $10, and a 1 in 100   chance of winning $100 dollars.  In the second pilot study, the expected value was $3, with a 1/5 chance of winning $10, and a 1/100 chance to win $100. For both studies, patients were enrolled in the lottery only if the Med-eMonitor showed that they had adhered to their warfarin regime, either by taking their prescribed dosage of warfarin or by not taking it when they were not supposed to. 

What did they look for?

The study measured two metrics. First, it measured how long a patient was outside their recommended coagulation levels. (It is unclear if the Med-eMonitor measured or estimated this information.) Second, it measured patient adherence, based on the mean days that the patient opened the correct cabinet and recorded pill taking. To make sure the intervention was effective, each study’s results were then compared with historical group controls or to the patient’s own medical history, which was measured by the Medication Event Monitoring System (MEMS) before the study began.

One way to understand this study’s design is through the “COM-B” framework:

• Capability: patients were both physically and psychologically able to access their medication.
• Opportunity: there were no external physical barriers stopping patients from accessing their medication. The study does not discuss whether there are also any social barriers towards regiment adherence. 
• Motivation: the intervention sought to increase patients’ motivation to follow their prescribed regimen through a financial incentive.
• Behavior: Given the lack of physical and psychological barriers, an increase in motivation was hoped to lead to an increase in warfarin adherence among patients.

First pilot

In the first pilot study, participants’ time in an out-of-range coagulation level was decreased by 27.8% compared to before the intervention. (Notably, in the time period after the intervention, the participants returned to pre-intervention rates.) Additionally, participants also experienced a 19.7% reduction in incorrect pill consumption.

Second pilot

The second pilot study, with a reduced expected value, enjoyed similar results: there was a 24.6% decrease in participants’ time with an out-of-range coagulation level, and incorrect pill consumption reduced by 20.4%.

Limitations

One caveat to note, however, is that the studies’ sample size was small (N = 10) and non-randomized. Therefore, it is unclear whether these promising results would scale in the real-world. The researchers acknowledge that more research is needed before drawing further conclusions.

• Researchers made sure the intervention was safe and effective for participants.
• Participant consent was explicitly gathered, though it is unclear whether the monitor tracked additional data.
• Small, non-randomized sample limits the results’ validity, as well as the diversity of the participant set.

Gold Stars for Staying Home: Rewards and COVID-19

In this intervention, Volpp et al focused on the power that positive incentives—namely, a potential financial reward—could lead patients towards safer behavior. Yet, when it has come to promoting safe behavior during the COVID-19 pandemic, policy makers have largely focused on negative incentives—for instance, the fear of getting ill. In this article, Hannah Chappell argues that positive incentives could also help promote safe behavior among citizens during this ongoing pandemic.     

Should We Pay Students to Go to School?

Earlier, we saw that some studies suggest using financial incentives to increase a student’s time and effort devoted to school. However, some have proposed directly paying students to incentivize them to go to school, in the hopes that this incentive will decrease the number of people who drop out of school. In this article, Tony Jiang outlines where this sort of intervention has been applied (e.g., the Nordic Countries, Mexico, etc.), and its effectiveness in the short-term.