Dual Antiplatelet Therapy: A Phone Call Away from Near-Perfect Adherence

Patients implanted with a drug-eluting stent who received a series of phone calls from nurses had much higher levels of adherence to dual antiplatelet therapy than patients who received usual follow-up care.

Many patients struggle with adherence to their drug regimen, and compliance can be especially difficult for patients who have had an acute coronary syndrome (ACS) event and are placed on 5 or more new medications. Some of these patients are discharged on the same day they are admitted, and either do not receive drug counseling or are in no condition to understand the drug counseling they are offered. Poor adherence to dual antiplatelet therapy (DAT)—missing more than 5 days of treatment—increases the risk of stent thrombosis and death. Small delays and temporary interruptions in therapy can also have dire consequences.

Clinical researchers at the Quebec Heart and Lung Institute in Canada hypothesized that a simple phone call might improve adherence to DAT after drug-eluting stent (DES) implantation. Between June 2009 and June 2010, they randomized 300 patients immediately after DES implantation into an intervention group and a control group and followed them for 1 year. Of the patients, 73% received the DES in the context of ACS.

Nurses telephoned patients in the intervention group within 7 days of the DES implantation and at 1, 6, and 9 months. In their phone calls, the nurses emphasized the importance of medication adherence. Control patients were followed as per usual clinical practice and did not receive the phone calls. The researchers collected pharmacy data documenting prescription fills and refills. The primary end point was the proportion of days covered with aspirin and clopidogrel during the year after discharge. As a secondary outcome measure, the researchers calculated persistence of aspirin and clopidogrel treatment, with non-persistence defined as a refill gap of longer than 14 days.

The researchers reported their results in a study published online on February 23, 2013, in Heart. At 6 months, 99% of patients in the intervention arm were adherent to their clopidogrel and aspirin prescriptions, compared with 94% in the control group. At the study’s end, more than 87% of intervention-group patients had been persistently adherent to aspirin and clopidogrel, while approximately 57% of patients in the control group had had treatment interruptions of at least 14 days.

“Near-perfect drug adherence and persistence is what physicians really expect with DAT after DES implantation,” the study authors write. “However, median adherence scores were around 90% at 1 year in the control group. This represents 10% of the year without DAT, or roughly 36 days. Although we acknowledge that this period is spread over the year, such non-adherence is expected to result in a lower antiplatelet effect.”

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.