WOONSOCKET, R.I. — A new study by researchers at CVS Caremark Corp., Harvard University, and Brigham and Women’s Hospital revealed that 24% of patients given a new medication by their doctor didn’t fill the prescription.
CVS Caremark announced the research on Wednesday and said the findings were published this week in the American Journal of Medicine.
According to the company, most prior research of patients who don’t adhere to their medications examined patient behavior after filling a first prescription. The advent of electronic prescribing, however, enables the tracking of initial prescriptions that may have been undetected and gives health care providers a broader look at patients who never fill their new prescriptions.
The newest CVS Caremark-sponsored study evaluated more than 423,000 e-prescriptions written in 2008 by 3,634 doctors for more than 280,000 patients from all 50 states. The study team 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 six months to identify primary nonadherence.
"CVS Caremark is looking at this issue from every angle," study co-author Troy Brennan, executive vice president and chief medical officer of CVS Caremark, said in a statement. "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."
Medication nonadherence, especially for chronic conditions, means that patients miss an opportunity to improve their health and avoid long-term complications, noted Michael Fischer of Brigham and Women’s and Harvard Medical School, the lead author of the study.
"While some recent research has used e-prescribing data to evaluate primary nonadherence, 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 nonadherence than seen in earlier studies," Fischer stated.
Factors highlighted by the researchers as predictive of primary nonadherence included the following:
• Out-of-pocket cost of medications. Patients who received prescriptions for medications that were not included on their health care formulary — and were more expensive because co-pays would be higher — are more likely not to fill their first prescription.
• Integration of the doctors’ health information systems. Prescriptions sent directly to pharmacies or mail-order systems are more likely to be filled than e-prescriptions that doctors print out and give to patients.
• Socio-economic factors. The researchers determined by reviewing ZIP codes and census data 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%. Medications for hypertension or diabetes saw primary non-adherence rates in excess of 25%.
This latest study stems from a three-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.
