Contact with pharmacist can improve adherence to new anticoagulant, study finds

The proportion of patients with a prescription for dabigatran who take their tablets as instructed varies widely and can be improved by more appropriate selection of patients and monitoring by a pharmacist, a study reported in JAMA has found.1

US researchers questioned whether patients’ adherence to target-specific oral anticoagulants, including dabigatran, could be improved. They noted that a previous study had reported that suboptimal adherence to dabigatran was associated with increased risk of stroke and death. Unlike warfarin, this new generation of anticoagulants does not require regular monitoring, so contact with patients is much less than that experienced by those on the more traditional drug.

To investigate adherence the researchers examined how patients who had dabigatran prescribed from October 2010 to September 2012 were managed by anticoagulant clinics at Veterans Health Administration sites across the United States. Interviews with staff included questions about how they selected patients, what they told them about their medicines, and how they monitored the patients—for example, whether a dedicated pharmacist was available to monitor adverse events and adherence to drugs. Altogether, information was gathered on 4863 patients treated at 67 veteran sites and from pharmacists at 41 locations.

Adherence—defined as the proportion of days covered (dispensed pills divided by non-hospitalised days)—of at least 80% was found to vary from 42% to 93% across the sites studied, with a median proportion of adherent patients of 74%, giving a median odds ratio of 1.57 after adjusting for measured confounding factors.

Researchers found that more appropriate patient selection, based on past adherence to medicines, led to better dabigatran adherence (relative risk 1.14 (95% confidence interval 1.05 to 1.25)), as did pharmacist led monitoring, such as determining how drugs were taken and stored and establishing the frequency of missed doses with timely laboratory testing (1.25 (1.11 to 1.41)).

The authors said that their results may have been biased because they could not obtain data from all eligible sites and could not verify that dispensed medicines were taken.

“Our results highlight the importance of selecting patients and monitoring strategies to translate the efficacy of TSOACs [target-specific oral anticoagulants] in randomized trials to clinical practice,” they wrote. “Prior studies have described variation in patient performance on warfarin across sites, further highlighting the importance of management strategies in improving patient performance to anticoagulants.”

They added that the higher adherence rates associated with provision of dedicated monitoring, even for a short time, were potentially due to consistent contact with patients.

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