You wrote the prescription, but will it get filled?

TABLE 2
Prescription characteristics associated with different claims outcomes (N=14,693)*

Discussion

This study used e-prescribing to evaluate nonadherence to the first-fill of an antihypertensive prescription. Our findings that 24.3% of patients did not obtain the first-fill of a medication and that 15.6% of prescriptions remained unclaimed are comparable to those of other research using electronically obtained prescription data.^7,8

In a cross-sectional study of 327 African American adults enrolled in a Medicaid managed care plan, the authors reported that 24.9% (433/1742) of antihypertensive prescriptions were unfilled.⁷ In a study of therapeutically naïve patients, the first-fill failure rate was 17%.⁸ These patients were less likely to fill their antihypertensive prescriptions if they were prescribed loop diuretics or had a higher prescription co-payment. The median co-payment was $2 higher for prescriptions not obtained, compared with those that were obtained (P<.001). This finding was similar to the $2.56 difference we found for mean co-payment.

Higher co-payment was a strong predictor of decreased adherence in other antihypertensive adherence studies.^9,10 In a survey of Medicare patients, the most common reason cited for failing to fill any prescription was that “it would cost too much.”² Prescribing a less costly agent based on an insurer’s formulary may reduce the first-fill failure rate.

Although educating patients about their disease, involving family, and increasing patient participation through self-monitoring of blood pressure all have a positive impact on adherence rates and blood pressure control, physicians are hard pressed for time during an office visit to address such interventions.^11-19 E-prescribing potentially offers a more efficient way to improve antihypertensive medication adherence. A recent ruling by the Centers for Medicare & Medicaid Services (CMS) requires e-prescribing systems to have the capability of providing formulary and benefit transaction, medication history transaction, and fill status notification to prescribers.²⁰ Prescribers can readily access patients’ insurance coverage information. Formulary decision support, as part of an e-prescribing system, has been shown to increase use of formulary products.²¹ Fill status notification allows two-way communication between the prescriber and pharmacy so that prescribers can be made aware if patients fail to fill prescriptions.

Unfortunately, e-prescribing is not yet widely used. Approximately 26% of office-based US physicians use e-prescribing, and only 30% of them take advantage of formulary information.²² E-prescribing authorities believe practices not using the fill status notification probably lack resources needed to manage patients who are nonadherent.²² While it may not be necessary to check whether all patients have obtained their prescription, it may be useful for subgroups of patients, such as those who have received a new diagnosis, whose disease is poorly controlled, who are prescribed new antihypertensive agents, or who are otherwise thought to be nonadherent.

Study limitations. First, claims data serve as a proxy for medication adherence. Even though a patient obtained an antihypertensive prescription according to claims data, this does not guarantee that the patient used the medication.

Second, not all patients had a diagnosis of hypertension designated by specific ICD-9-CM codes. Patients may have been prescribed antihypertensive medications for other indications, such as heart failure, migraine, anxiety, etc. Our results apply to all patients prescribed antihypertensive agents, and although most had hypertension, there may be differences in first-fill rates for those with and without hypertension.

Third, patients were required to fill their prescriptions through insurance. In community pharmacy settings, some prescriptions may be paid for with cash due to the availability of several inexpensive generic antihypertensive medications (eg, a 30-day supply for $4, or 90-day supply for $10).²³ Patients taking advantage of these promotions would result in an overestimation of first-fill failure rate.