CVS Study Finds that a Quarter of New Prescriptions Aren't Filled

A new study by researchers at Harvard University, Brigham and Women’s Hospital, and CVS Caremark indicates that 24% of patients who are given a new medication do not fill the prescription.

Previous studies looking at medication non-adherence focused on primarily patient behavior after filling a first prescription. Technologies such as electronic prescribing grant researchers the opportunity to track initial prescriptions that may have been previously undetected and give health care providers a broader look at patients who never fill their new prescriptions.

In the CVS Caremark-sponsored study, which is published in the November issue of the American Journal of Medicine, investigators evaluated more than 423,000 e-prescriptions written in 2008 by 3634 doctors for more than 280,000 patients from all 50 states. Lead author Michael A. Fischer, MD, MS, of Brigham and Women’s and Harvard Medical School, and colleagues matched the e-prescriptions with resulting claims data, or in the case of those not filling the prescription, used the lack of a claim within 6 months to identify primary non-adherence.

“When patients don’t take their medications, especially for chronic conditions, they miss an opportunity to improve their health and avoid long-term complications,” said Dr. Fischer in a statement. “While some recent research has used e-prescribing data to evaluate primary non-adherence, we were able to study a nationwide sample of patients. Our finding that 24% of patients are not filling initial prescriptions reflects slightly higher primary non-adherence than seen in earlier studies.”

Among the factors highlighted by the researchers as predictive of primary non-adherence are:

  • Out-of-pocket costs. Patients who received prescriptions for medications that were not included on their health care formulary—and were therefore more expensive because co-pays would be higher—are more likely not to fill their first prescription.
  • Integration of health information systems. Prescriptions sent directly to pharmacies or mail-order systems are more likely to be filled than e-prescriptions that physicians print out and give to patients.
  • Socioeconomic factors. A review of zip codes and census data showed that patients who live in higher income areas are more likely to fill prescriptions for new medications.
  • Type of medications. Prescriptions written for infants are almost always filled and antibiotics are filled at a rate of 90%, whereas medications for hypertension or diabetes saw primary non-adherence rates in excess of 25%.

“CVS Caremark is looking at this issue from every angle,” said Troyen A. Brennan, MD, MPH, executive vice president and chief medical officer of CVS Caremark, and a study co-author. “This study reviewed factors that might cause patients to ignore that first fill, so we can arm health care providers with information to proactively address the problem.”

This latest study is another result of a 3-year research collaboration between CVS Caremark, Brigham and Women's Hospital, and Harvard that aims to develop a better understanding of patient behavior, with a special focus on medication adherence.