Circ study gives scoop on HF drug nonadherence, 'objectively'
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Using a small monitoring device that fits in the cap of a pill vial, researchers tracked the pill-taking patterns of heart failure (HF) patients for six months to identify factors that contribute to medication nonadherence. They found nonadherents were more likely to have attention lapses, excessive daytime sleepiness and multiple dosing, knowledge providers can use to better manage patients.

In a previous study, Barbara Riegel, DNSc, RN, of the University of Pennsylvania School of Nursing in Philadelphia, and colleagues reported that HF patients with excessive daytime sleepiness and cognitive decline were 2.5 times more likely to be nonadherent in taking medications compared with patients without those issues (J Card Fail 2011;17:340-348). That study relied on self-reported claims from patients.

The current study, published online May 30 in Circulation: Heart Failure, Riegel and colleagues developed an objective measure for adherence. They used an electronic monitor, the Aardex Medication Event Monitoring System, placed in the cap of pill containers that collected real-time data that could be downloaded later into a computer. The researchers targeted four components—taking, timing, dosing and drug holidays—to determine adherence and nonadherence. Data were downloaded at three months and six months after enrollment in the study.

The patient population consisted of 202 Stage C chronic HF patients from three sites in the Northeastern U.S. Medications tracked included angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers or beta-blockers. The majority—57.9 percent—of the patients were on a twice-daily dose regimen while 39.1 percent had a once-daily regime and 3 percent took the medications three or more times per day. Of those patients, 65.4 percent were male, 68.3 percent were white, the average patient was 63 years old and had 2.8 comorbid conditions.

They found taking, dosing and timing adherence decreased from the first three-month period to the second three-month period. Using latent growth mixture modeling, they identified two distinct trajectories of nonadherence: a persistent adherence subgroup of 157 patients and a steep decline subgroup of 45 patients. Further analyses showed that lapses in attention, excessive daytime sleepiness and regimens that required two or more medication dosings per day contributed to steep declines in adherence.

“The only therapy-related dimension we identified as important in medication nonadherence was dosing frequency, which has been identified repeatedly as an important factor influencing medication adherence in chronically ill populations,” Riegel et al wrote. Based on those results and other research, they encouraged physicians to streamline dosing schedules if possible. They also noted that poor sleep was likely a contributor to inattention in this patient sample.

There are two groups identified by the authors who would likely would benefit from two different management strategies: “Those with persistent adherence probably need regular encouragement, but no additional intervention resources,” Riegel and colleagues wrote. “The patients with a steep decline in adherence over time may be particularly amenable to an intervention focused more on persistence than execution such as alarms and reminders when medications are due. Screening for patients with lapses in attention and daytime sleepiness can help identify those patients at risk for declining adherence. These patients also need a simplified medication dosing regimen.”

Forty additional patients completed the study but failed to use the monitoring device in the cap correctly for the full six months. Consequently, the study sample of 202 patients was small. The researchers added that future research based on larger sample size would increase precision in the results.   

For more on a related topic, see an article in the August 2010 issue of Cardiovascular Business, which included Riegel and other thought thoughts on reducing HF readmissions