Closing the Gap: Identifying Rates and Reasons for Nonadherence in a Specialty Population

Adherence to specialty and nonspecialty medications is often calculated using pharmacy claims data. However, specialty medication regimens are complex and may require periods of intentional gaps in therapy. Common adherence calculations are insufficient in identifying reasons for gaps in therapy. Because adherence reporting is a growing measure of quality care for specialty pharmacy accreditation and payer and manufacturer contracts, a better understanding of the rates and reasons for nonadherence within a specialty population is needed.

The objective was to identify rates and reasons for misidentified and true nonadherence in patients who are prescribed specialty medications.

A single center, retrospective cohort study was conducted using pharmacy claims data between March 2017 and February 2018. Medication adherence was calculated using proportion of days covered (PDC). Electronic medical records of a random 10% sample of nonadherent patients (PDC<80%) were manually reviewed to identify reasons for nonadherence. Patients were then classified as either (a) misidentified as nonadherent (i.e., a provider-directed discontinuation or disruption of treatment that varies from the prescribed administration schedule or transfer of the prescription to an external pharmacy) or (b) truly nonadherent (discontinuation or disruption of treatment that varies from the prescribed administration instruction that is not directed or recommended by the provider or health care team).

Of the 7,488 included prescription records from 18 specialty areas, 1,059 met criteria for nonadherence. 105 prescription records (representing 105 unique patients) were manually reviewed; most of these patients (58%) were truly nonadherent, driven by inability to contact patients for refills (59%). However, 40% were misidentified as nonadherent, most due to provider-directed medication holding (69%). Two percent of patients were nonadherent for unknown reasons.

Many patients classified as nonadherent based on pharmacy claims experienced gaps in therapy due to medically appropriate reasons. Methods to better measure and identify true nonadherence are needed to efficiently and adequately affect specialty medication adherence behavior.

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