Definition
Medication adherence is the extent to which a patient takes medication as prescribed, including filling and refilling prescriptions on time, and for Medicare Star Ratings it is measured as the share of a period in which the patient had the medication on hand.
Nonadherence takes many forms: a prescription never filled after discharge, a missed refill, doses skipped because of side effects, cost, or confusion. It is a common contributor to avoidable complications and readmissions, and it is often discoverable only by asking the patient.
For Medicare prescription drug plans, three adherence measures feed Star Ratings: adherence to diabetes medications, to hypertension medications (renin-angiotensin system antagonists), and to cholesterol medications (statins). Each is based on proportion of days covered (PDC), the share of days in the measurement period a member had the drug available, with members at 80% or higher counted as adherent. CMS has weighted these measures heavily relative to most others, which gives adherence an outsized influence on a plan's overall rating.
Adherence outreach is clinical in purpose but still subject to calling rules. OptumRx's $1.86M Patterson v. OptumRx settlement (March 2026) involved medication-adherence robocalls placed to wrong numbers, a consent and data-hygiene gap rather than bad intent. See Reassigned Numbers Database.
How Consig handles it
Medication-adherence outreach is one of Consig's health-plan use cases, alongside post-discharge follow-up, aimed at closing care gaps and lifting HEDIS and Star Ratings without added headcount. Identity verification confirms the right member answered before health information is discussed.