Many Lower-Income Patients Fail to Stick With Clopidogrel After PCI

About one-third of lower-income patients do not comply with clopidogrel therapy in the year after receiving DES, despite the drug being provided at a nominal cost, a study conducted within a single health system suggests.

Take Home: Many Lower-Income Patients Fail to Stick With Clopidogrel After PCI

Further research is needed to better understand the reasons why patients do not adhere to prescribed treatments and to develop new strategies to combat the problem, Sandeep Das, MD, MPH, of the University of Texas Southwestern Medical Center (Dallas, TX), and colleagues report in a paper published online this week in the American Journal of Cardiology.

Prior studies looking at the issue of compliance with clopidogrel therapy have been limited by short follow-up and the use of self-reported data, according to the researchers. Also, no previous study has focused on the “urban poor, who may face unique challenges in adhering to a treatment plan,” they say.

To explore the issue, Das and colleagues retrospectively evaluated clopidogrel refill data in patients implanted with DES between 2008 and 2011 at the Parkland Health and Hospital system in Dallas. Clopidogrel was provided at discharge and then at a “nominal cost” after discharge through the Parkland Health Plus program, which provides taxpayer-subsidized assistance for uninsured, low-income people living in Dallas County.

The analysis included 369 patients (mean age 55 years; 34% women) who had at least 1 year of follow-up and did not have physician-recommended discontinuation of clopidogrel, a switch to a different P2Y12 inhibitor, receipt of alternative health insurance, or prescriptions sent to an outside pharmacy. The cohort was multiethnic, with 39% identifying as Hispanic, 26% as white, and 26% as black; 26% said Spanish was their primary language.

The most common indication for PCI was stable angina (53%), followed by NSTEMI/unstable angina (39%) and STEMI (8%).

Nonadherence Common

The median time to failure to obtain a clopidogrel refill after allowing for a 5-day grace period (primary outcome) was 153 days. Cumulative failure to get at least 1 refill was 23% for the first refill, 52% at 6 months, and 68% at 1 year.

Looking at the proportion of days covered, only 21% of patients had 100% coverage through 1 year. About one-third (34%) had coverage less than 80%, is the level considered nonadherent.

Compared with adherent patients, those with less than 80% coverage were more likely to be black, have English as the preferred language, and have comorbid heart failure, an ejection fraction below 40%, CAD, and a history of smoking. There were, however, no independent predictors of nonadherence after multivariate adjustment.

If Not Cost, Then What?

Cost is often provided as a reason for poor compliance with medication regimens, but that did not seem to be a contributing cause in the current study because of the provision of clopidogrel at little to no cost. Das and colleagues note that that is consistent with the findings from the MI-FREEE study, in which eliminating copays for recommended therapies—including statins, beta-blockers, ACE inhibitors, and angiotensin receptor blockers—had only a modest effect on adherence in patients discharged after MI.

“Adherence to clopidogrel, which was not provided free of charge in the MI-FREEE trial, was estimated between 69%-71%, similar to the rates of clopidogrel adherence seen in our study,” the authors write. “These data are conflict with the idea that high medication costs are the dominant barrier to adherence; although the financial burden of medication costs is a likely contributing factor to nonadherence, there are additional important factors which need to be better understood and addressed.”

They say the findings are consistent with prior research showing that both financial and cultural obstacles influence adherence and suggest that low health literacy and “insufficient and ineffective communication at [a] patient’s level of understanding” also play a role.

Eric Peterson, MD, of the Duke Clinical Research Institute (Durham, NC), agreed in an interview with TCTMD. Adhering to a change in behavior—like taking medication every day—is difficult for everybody, and “part of that is the education that we give our patients,” he said.

“How much information are we giving them about the potential risks and benefits of taking a medication, in this case one that can prevent stent thrombosis and heart attack? We don’t emphasize it enough,” he said.

He raised the issue of shared accountability when it comes to a patient taking his or her prescribed medications.

“What if I was in part held accountable a little bit to whether my patients took their medicines long-term or not? And in that way, the more I educated my patients, the more I gave systems of support that would allow those patients to consistently take their medicines, the better their adherence would be and then ultimately the better my performance would be,” Peterson said. “What if we lived in a system like that?”

Studies like these, he concluded, “reinforce the need for better work to try to intervene on patients.”


Khalili H, Singh R, Wood M, et al. Premature clopidogrel discontinuation after drug-eluting stent placement in a large urban safety-net hospital. Am J Cardiol. 2015;Epub ahead of print.

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  • Das did not make any statement regarding conflicts of interest.
  • Peterson reports no relevant conflicts of interest.

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