PQA Adherence Measures

The adherence measures examine patients’ fills of medications for particular therapeutic drug classes. Proportion of Days Covered (PDC) is the preferred method to measure adherence; therefore, PQA uses this methodology for its measures that assess patients' adherence to important chronic drug therapies.

Adherence measures assess the percentage of patients covered by prescription claims for the same drug or for another drug 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 for at least two antiretroviral medications.

  • 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)
  • Biguanides (PDC-BG)
  • Dipeptidyl Peptidase (DPP)-4 Inhibitors (PDC-DPP)
  • Sulfonylureas (PDC-SFU)
  • Thiazolidinediones (PDC-TZD)
  • Non-Warfarin Oral Anticoagulants (PDC-NOAC)
  • Long-Acting Inhaled Bronchodilator Agents in COPD (PDC-COPD)
  • Antiretrovirals (this measure has a threshold of 90% for at least 2 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 and persistence for acute therapies of shorter duration. Rather, a different method may be used to better assess whether patients have completed their medication regimens. The Treatment of Chronic Hepatitis C: Completion of Therapy 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.

  • Treatment of Chronic Hepatitis C: Completion of Therapy (HCV)

Primary Medication Nonadherence (PMN) assesses when a new medication is prescribed for a patient, but the patient does not obtain the medication, or appropriate alternative, within an acceptable period of time after it was prescribed.

      • Primary Medication Nonadherence (PMN)
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* Update: August 28, 2018