WOONSOCKET, R.I. — Twenty-four percent of patients given a new medication by their doctor did not fill the prescription, according to a new study by researchers at Harvard University, Brigham and Women's Hospital and CVS Caremark.
The newest CVS Caremark-sponsored study, which was published this week in the American Journal of Medicine, evaluated more than 423,000 electronic 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.
Most prior research of patients who do not take medications as prescribed looked at patient behavior after filling a first prescription. The advent of e-prescribing provides the opportunity to track initial prescriptions that previously may have been undetected and gives healthcare providers a broader look at patients who never fill their new prescriptions, the study authors noted.
"When patients don't take their medications, especially for chronic conditions, they miss an opportunity to improve their health and avoid long-term complications," stated 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."
"CVS Caremark is looking at this issue from every angle," added Troyen A. Brennan, EVP 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."
Among the factors highlighted by the researchers as predictive of primary nonadherence are:
The out-of-pocket cost of medications: 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;
The integration of the doctors' health information systems: Prescriptions directly sent to pharmacies or mail-order systems are more likely to be filled than e-prescriptions that doctors print out and give to patients;
Socioeconomic 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; and
The 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 is another result of 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.
Annual excess healthcare costs due to medication nonadherence in the United States are estimated to be as much as $300 billion annually.