Proportion of days covered as a measure of medication adherence

Medication adherence plays a significant role in specialty pharmacy practice and depends on numerous factors.1 The 2 most common adherence metrics using prescription claims are proportion of days covered (PDC) and medication possession ratio (MPR). Neither accounts for clinically appropriate gaps in therapy nor confirms the medication is administered, and, despite using similar claims data, these metrics do not regularly provide equivalent results. MPR and PDC results are often used to distinguish higher-performing pharmacies and can have a significant impact on specialty pharmacy business performance. Lesser performance can result in restricted access to payer networks and medications, lead to direct and indirect remuneration fees, and negatively impact accreditation scoring.2 As adherence is a significant benchmark for specialty pharmacy performance, a preferred adherence metric, a standardized calculation method, and outcomes-driven thresholds are needed to appropriately assess and compare specialty pharmacy performance. Herein we recommend a preferred adherence metric and...