AHA: Cash for drug adherence study has disappointing result

People with hypertension were twice as likely to take their medicine regularly when offered cash incentives, but that did not translate into improved blood pressure control.

The curious finding was revealed at the American Heart Association (AHA) annual congress in New Orleans over the weekend, and reveals just how hard it can be to anticipate patient behaviour when it comes to taking their medication.

The 400-subject BETTER-BP study was carried out at community health clinics in New York and involved low-income or disabled people with high blood pressure – both groups known to have relatively low rates of compliance with medication use – who reported that they had trouble taking their therapies regularly at enrolment.

The researchers, led by NYU Grossman School of Medicine professor John Dodson, used a smart pill package to measure when participants took out a dose and offered daily cash rewards of between $5 and $50 – by a random draw – if they had opened the pack the previous day.

Participation was reinforced by daily text messaging to tell subjects if they had won any money, and to remind them of a missed opportunity if they had not opened the bottle.

Nearly three-quarters (71%) of participants using the smart bottles took their medication regularly – at least 80% of the time over a six-month period – compared to 34% of a control group who were excluded from the cash reward scheme.

So far, so good, but the surprising finding was that the two groups saw roughly the same level of blood pressure reductions over the study, with an average fall of 6.7 mm Hg with the smart dispenser versus 5.8 mm Hg in the control group.

Moreover, after the study ended, it was found that those participants who improved adherence reverted to their previous behaviour of not consistently taking their medication as prescribed.

Not taking blood pressure medication as directed can increase the risk of complications like heart attack and stroke, so the hope was that a relatively inexpensive scheme such as this could be rolled out more widely and ultimately save health systems money.

The verdict? Dodson told the AHA that the results show that "improving medication adherence is more complex than we thought."

Possible confounders are that blood pressure measurements were taken periodically at clinics, rather than more frequently at home, and the study only tracked one medicine, while patients, in some cases, were taking multiple pills a day to control their blood pressure.

"It is unclear if there was no change because they opened the bottles but didn't take the medication tracked, or if a different medication or lifestyle behaviour not tracked in the study impacted their blood pressure," said Dodson.

It's not unheard of that patients on low incomes take medicines less frequently than advised to avoid even modest co-pays, while having to take multiple pills per day can create confusion that complicates adherence.

"We were also surprised that people did not keep taking their medication as prescribed after the rewards programme ended," added Dodson. "There are still many unknown factors we need to understand in order to help people adopt long-term behaviour changes."