Pharmacy Measures Richard A. Hansen, PhD, RPh Department of Health Outcomes Research & Policy Harrison School of Pharmacy
Outline • Pharmacy Quality Alliance (PQA) • Overview (http://pqaalliance.org/) • Examples of measures • Overview of claims-based adherence measures and their interpretation • Medication possession ratio (MPR) • Proportion of days covered (PDC)
Pharmacy Quality Alliance (PQA) • Non-profit alliance with > 100 organizations, established in 2006 • Establish performance measures to improve quality, some of which have been adopted by CMS • PQA develops medication-use measures in areas such as medication safety, medication adherence and appropriateness • Measures target high-priority areas and gaps in existing performance measure sets • Focus on priorities identified through the National Priorities Partnership and National Quality Strategy
Example PQA measures • Percentage of patients with PDC > 80% for chronic medications (e.g., BB, ACE, CCB, statin, oral diabetes drugs, etc) • Percentage of children < 5 receiving antipsychotic medications • Diabetes medication dosing higher than daily recommended dose • Diabetes: appropriate treatment for HTN • Medication therapy for persons with asthma
Adherence / Persistence • Adherence: the extent to which a patient acts in accordance with the prescribed interval and dose of a dosing regimen • Persistence: the duration of time from initiation to discontinuation of therapy
Strengths of Claims-Based Adherence Measurement • Generally performs better than self-report • Reasonably parallels reference standards • More timely and economically efficient than other measurement methods • Pharmacy claims data is generally accurate, or at least more accurate than medical claims since no billing intermediary
Key Assumptions • Having medication supply infers a patient is taking the medication as scheduled • No stock-piling, sharing, etc • Days supply is accurate • People refill medications proximal to the end of previous fills • Treatment is chronic, or at least for a defined period of time
Considerations with Claims-Based Adherence Metrics • OTC use • Purchases outside of insurance • Short measurement intervals • Inpatient hospitalizations • Complex medication use • Switching or augmentation • Dose of drug titration • PRN use
Claims-Based Adherence Metrics Index Days 1-30 Days 31-60 Days 61-90 Days 91-120 Fill 1 DS: 30 Fill 2 DS: 30 Fill 3 DS: 34 Fill 4 DS: 34 • Adherence for single interval • Adherence over evaluation period* • Non-adherence for evaluation period • Persistence
Adherence Over Evaluation Period Continuous Measure of Medication Acquisition (CMA) Medication Refill Adherence (MRA) Medication Possession Ratio (MPR)* Medication Possession Ratio modified (MPRm)* Proportion of Days Covered (PDC)* Compliance Rate (CR) Refill Compliance Rate (RCR) Days Between Fills Adherence Rate (DBR)
Medication Possession Ratio (MPR) Index Days 1-30 Days 31-60 Days 61-90 Days 91-120 Fill 1 DS: 30 Fill 2 DS: 30 Fill 3 DS: 34 Fill 4 DS: 34 Total Days Supplied MPR = Total Days Evaluated MPR: 128/120 = 1.07 (or 1.07:1)
Medication Possession Ratio modified (MPRm) Index (T0) Days 1-30 Days 31-60 Days 61-90 Days 91-120 Fill 1 DS: 30 Fill 2 DS: 30 Fill 3 DS: 34 Fill 4 DS: 34 Total Days Supplied MPRm = X 100 (Last Claim Date – First Claim Date) + Last Days Supply 128 MPRm: X 100 = 89% (110 – 0) + 34
Proportion of Days Covered (PDC) Index Days 1-30 Days 31-60 Days 61-90 Days 91-120 Fill 1 DS: 30 Fill 2 DS: 30 Fill 3 DS: 34 Fill 4 DS: 34 Total Days Supplied PDC = X 100 (capped at 1) Total Days Evaluated PDC: (128/120) X 100 = 100%
Proportion of Days Covered (PDCm)* Index Days 1-30 Days 31-60 Days 61-90 Days 91-120 Fill 1 DS: 30 Fill 2 DS: 30 Fill 3 Day 30 DS: 34 Day 38 Fill 4 DS: 34 Day 96 Day 110
Proportion of Days Covered (PDCm)* Index Days 1-30 Days 31-60 Days 61-90 Days 91-120 Fill 1 DS: 30 Fill 2 DS: 30 Fill 3 Day 30 DS: 34 Day 38 Fill 4 DS: 34 Day 102 Day 110 Days Evaluated – Days without Supply PDC = Total Days Evaluated PDC: (104/120) X 100 = 86.7%
Dichotomous Measure of Adherence • Create indicator for adherent vs. non-adherent based on pre-specified tolerance • Based on period adherence measures • Hard to know what qualifies as “adherent” >= 80% chronic meds >= 95% for HIV • Does this really reflect adherence?
Persistence: Gap Threshold Index • Threshold commonly defined as: • 1.5 times days supply • 7 days (~ MPR of 80% for days supply of 30) • 15 days* Days 1-30 Days 31-60 Days 61-90 Days 91-120 Gap Grace Fill 1 DS: 30 Gap Grace Fill 2 DS: 30 * Gap Grace Fill 3 DS: 34 Fill 4 DS: 34
Combination of Dichotomous Adherence and Gap Limit • Dual requirement for meeting overall adherence threshold with no clinically meaningful gaps in treatment • For example, adherent & persistent: • MPRm >= 80% and no gaps > 15 days
QUESTIONS Contact: rah0019@auburn.edu
