CVS Caremark study addresses correlation between out-of-pocket co-pay, Rx abandonment

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CVS Caremark study addresses correlation between out-of-pocket co-pay, Rx abandonment

By Antoinette Alexander - 11/16/2010

WOONSOCKET, R.I. — There is a direct correlation between the amount of a patient's out-of-pocket co-pay and prescription abandonment, according to the findings of a CVS Caremark-sponsored study published this week in the Annals of Internal Medicine. The study also found that e-prescriptions are more likely to be abandoned at retail compared with handwritten prescriptions.

The new study by Harvard, Brigham and Women's Hospital and CVS Caremark researchers found a direct correlation between the amount of a patient's out-of-pocket co-pay and likely abandonment of the prescription, with patients having a co-pay of $50 almost four times more likely to abandon a prescription at a pharmacy than those paying $10. The study also found that e-prescriptions are 65% more likely to be left abandoned at a retail pharmacy by patients than are handwritten prescriptions.

"Sticker shock is an important driver of prescription abandonment," stated lead author of the study William Shrank of Brigham and Women's Hospital and Harvard. Shrank said the study also outlined and validated a simple prediction rule that pharmacists can apply to help them assess whether patients are at risk to abandon their prescriptions.

"This research gives us new insight into an area of nonadherence that we did not have before, and shows we have opportunities to change patient behavior," added Larry Merlo, president and COO of CVS Caremark. "We need to be more attentive to reasons why patients may be abandoning prescriptions and work to help them stay on their medications. We continue to be a strong proponent of e-prescribing because we recognize the benefits it can provide, such as improving the accuracy and quality of prescription delivery and reducing paperwork to make pharmacy care more efficient."

Researchers reviewed all prescriptions dispensed at CVS/pharmacy locations between July 1 and Sept. 30, 2008. Of the prescriptions that were abandoned, more than half were never filled at any pharmacy, while some were filled at other pharmacies at a later date. The team concluded that the pharmacy industry would benefit from learning more about prescription abandonment, which the team said is an addressable factor impacting patients' adherence to their medications.

The researchers said the higher rate of abandonment for e-prescriptions appeared to occur because patients with written prescriptions must proactively brought the request for medications to the pharmacy, while patients with e-prescriptions are not required to take any step to begin the prescription-filling process. In addition, the rate of e-prescription abandonment appeared high because pharmacies are able to track the prescriptions as abandoned versus paper prescriptions that never actually are brought to a pharmacy.

The researchers said that if the 3.27% abandonment rate observed during the study period was applied to the 3.6 billion prescriptions filled at pharmacies in 2008, approximately 110 million prescriptions would be abandoned.


Furthermore, researchers outlined a predictive model for pharmacists to apply to help them recognize likely candidates for abandonment that includes:

  • Reviewing the individual's benefit plan and tiered co-pays. The study said cost is the strongest predictor of abandonment. The data showed a 1.4% prescription abandonment rate for patients with co-pays of $10 or less, a 3.4% rate for patients with co-pays between $30 and $40, and a 4.7% rate for patients with co-pays of $50;

  • Understanding past pharmacy behavior. Patients with first-fill prescriptions are three times more likely to abandon prescriptions than those who are refilling their medication;

  • Identifying the age of the patient. Younger patients are more likely than older patients to abandon their medications; and

  • Reviewing the drug class. The study found that opiates, antiplatelets and statins were the least likely to be abandoned, while insulin and proton-pump inhibitors were more likely to be abandoned.



The study is the work of CVS Caremark's previously announced three-year collaboration with Harvard University and Brigham and Women's Hospital to research pharmacy claims data to better understand patient behavior around medication adherence.


Past industry studies showed one-quarter of people receiving prescriptions never filled their first prescriptions, and patients with such chronic diseases as diabetes and coronary artery disease adhere to their ongoing medication regimen about half of the time. Nonadherence to essential medications is a frequent cause of preventable hospitalizations and patient illness, with costs to the U.S. healthcare system estimated at about $300 billion annually.