PQA Adherence Measures

The adherence measures examine individuals’ prescription claims for specific classes of medication therapy. Proportion of Days Covered (PDC) is the preferred method to measure medication adherence; therefore, PQA uses this methodology for measures that assess individuals' adherence to important chronic drug therapies.

Adherence measures assess the percentage of patients covered by prescription claims for the same medication (or similar medication) in the same therapeutic class, within the measurement year. The PDC threshold is the level above which the medication has a reasonable likelihood of achieving the most clinical benefit. Clinical evidence provides support for a standard PDC threshold of 80%. However, the PDC: Antiretroviral Medications measure requires 90% threshold.

  • Proportion of Days Covered Composite (PDC-CMP)
  • Diabetes All Class (PDC-DR) (NQF #0541)
  • Renin Angiotensin System Antagonists (PDC-RASA) (NQF #0541)
  • Statins (PDC-STA) (NQF #0541)
  • Beta-blockers (PDC-BB)
  • Calcium Channel Blockers (PDC-CCB)
  • Adherence to Direct-Acting Oral Anticoagulants (PDC-DOAC)
  • Long-Acting Inhaled Bronchodilator Agents in COPD (PDC-COPD)
  • Antiretrovirals Medications (PDC-ARV)
  • Non-infused Biologic Medications Used to Treat Rheumatoid Arthritis (PDC-RA)
  • Non-infused Disease Modifying Agents used to Treat Multiple Sclerosis (MS) (PDC-MS)

The PDC method, although preferred for chronic therapies, may not be the most appropriate method to assess adherence for acute therapies of shorter duration. Rather, a different method may be used to better assess whether patients have completed their medication regimens. For example, The Treatment of Chronic Hepatitis C: Completion of Therapy (HCV) measure assesses the percentage of patients who initiated antiviral therapy for treatment of chronic hepatitis C, and who completed the minimum intended duration of therapy with no significant gap(s) in therapy. The Persistence to Basal Insulin (PST-INS) measure assesses the percentage of individuals who were treatment persistent to basal insulin during the measurement year.

  • Treatment of Chronic Hepatitis C: Completion of Therapy (HCV)
  • Persistence to Basal Insulin (PST-INS)
Download an Overview of PQA Measures
Download the PQA Sociodemographic Status (SDS) Risk Adjustment FAQs
Ask about PQA Measures
Learn More about the PQA Measure Development Process

Updated April 19, 2022