You wrote the prescription, but will it get filled?

Despite numerous studies on adherence, there is little research on the first-fill rate of antihypertensive prescriptions. Our study took advantage of the recent increase in electronic prescribing (e-prescribing) and used data from e-prescribing physicians to determine the first-fill failure rate of antihypertensive prescriptions and to assess which factors predict first-fill failure.

This retrospective study reviewed claims from a Mid-Atlantic managed care organization (MCO). We included adult members with continuous medical and pharmacy coverage who were prescribed an antihypertensive in 2008 by an e-prescribing physician. First-fill failure occurred when the patient did not obtain the antihypertensive medication due to either a denial by the MCO or reversal by the dispensing pharmacist. (Pharmacists reverse claims when a patient fails to pick up a medication.) Multivariate regression analysis determined the clinical and demographic factors associated with failure to fill.

The cohort consisted of 14,693 antihypertensive prescriptions, prescribed by 164 e-prescribing physicians for 7061 unique members. There were 2289 out of 14,693 prescriptions (15.6%) that went unfilled, affecting 24.3% of patients. Of the prescriptions not obtained, 1466 (64%) were denied by the MCO and 823 (36%) were reversed. Significant factors associated with first-fill failure were new diagnosis of hypertension, new antihypertensive agent, higher co-payment, and enrollment in a health maintenance organization or preferred provider organization.

Patients newly diagnosed with hypertension and those prescribed a new antihypertensive were at particularly high risk for not obtaining their medication. Because nearly a quarter of patients did not obtain their initial fill of an antihypertensive prescription, future research should determine efficient and cost-effective systems to address first-fill failure in primary care.