Improving adherence to medications for heart failure: Medtronic says their CRT does it

Despite relatively few strong research studies supporting methodologies for improving adherence to medications for patients with heart failure, Medtronic's recent press release suggests their cardiac resynchronization therapy (CRT) implants might do the trick.

Medtronic accounced results of a retrospective analysis of administrative claims data of more than 4,500 patients with heart failure at the 2016 Heart Failure Society of America Scientific Meeting, Monday.

The analysis found that the number of patients "fully compliant" to a regimen of guideline-recommended medications "nearly doubled" at twelve months following CRT implants compared to those who did not receive implants.

Why? "Technology may lead to greater medication compliance," says David Stenhaus, MD, medical director for the Cardiac Rhythm and Heart Failure division of Medtronic. "With some heart failure patients, CRT is a turning point in their treatment plan because—in addition to their being monitored more closely—the severity of their symptoms diminish."

If you think Stenhaus's comment doesn't really explain why CRT implants are associated with greater medication adherence, that's because it doesn't.

Let's put this association in context—could the implanted CRT causally improve adherence to medications, or are there too many factors to tell for sure? We're leaning towards the latter.

In a 2012 review published in the American Heart Association journal, Circulation: Heart Failure, authors evaluated sixteen significant studies from 1995-2010 and found only seven interventions that resulted in enhanced adherence to medications.

All seven of the successful studies were categorized as "intensified patient care" interventions, and six of those involved direct patient contact. Only one out of five telephone or telemonitoring programs also included in the category showed enhanced adherence.

If implanting a cardiac resynchronization therapy device leads to more direct patient contact in the form of follow-up visits, of course you would expect to see an association with greater medication adherence.

Stenhaus's comment acknowledges the point, but I guess we'd have to see the data to tell if the benefit of the CRT is truly "in addition to" the effect of more direct patient contact.

The other part of his comment seems to suggest that a reduction in the severity of symptoms resulting from CRT implantation might account for benefits above and beyond patient contact, but you would actually expect the opposite to be the case.

A 2015 review published in Research Reports in Clinical Cardiology by the open access Dovepress suggests that a "feeling that treatment has 'succeeded' as evidenced by decreased or absent symptoms" might lead to non-adherence.

Of course, there's plenty of other confounding factors in medication adherence studies. For example, when comorbidities increase, medication adherence decreases, or when the number of pills taken per day increase, medication adherence increases.

But despite the tenuous meaningfulness of this association, Medtronic is right to bring patient adherence to heart failure medication into the spotlight.

Poor adherence to heart failure medications leads to an increased number of cardiovascular-related emergency department visits and higher health care costs, summarizes a 2009 review in the AHA's journal Circulation, and truly effective and attractive interventions have yet to be identified or widespread.

Poor patient health education is associated with non-adherence, but educational interventions alone are not very effective in improving adherence. "Education is a prerequisite, not sufficient," write the authors of the 2015 review.

So, what do you think? What could improve patient adherence to heart failure medications?

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