Adherence measurement can help patients achieve better outcomes.
A focus on quality measurement—coupled with significant redesign in reimbursement and patient care—has become a dominant theme over the past 2 decades within the US health care system. Increased quality measurement has resulted in improved patient outcomes, as well as decreased spending in some specific disease areas. Every sector of health care, including pharmacy, has been impacted by this new approach to quality.
In the past, pharmacy reimbursement has centered on a fee-for-service system based on the number of prescriptions dispensed to patients. In the evolving system, pharmacy reimbursement will be increasingly linked to performance on a defined set of medication-based metrics. This includes both pay-for-performance systems and limited networks. The initial measures used to evaluate programs include adherence and medication safety metrics developed by the Pharmacy Quality Alliance (PQA).
Pharmacy Quality Alliance
After the rollout of the Medicare Part D program in 2006, then-Centers for Medicare & Medicaid Services (CMS) administrator Mark McClellan, MD, recognized the need to measure and evaluate the performance of Part D health plans as related to medication management. The PQA was born based on vision and need. The PQA is a nonprofit organization that strives to facilitate such improvements in health care quality through promotion of appropriate medication use, and the development of strategies for measuring and reporting performance information related to medications and medication management. Today, PQA represents more than 150 pharmacy stakeholders from a variety of fields—community pharmacy, pharmaceutical manufacturers, health plans, pharmacy benefit managers, academic universities, government agencies, long-term care facilities, health solution vendors, associations, and many more.
PQA originally created measures related to appropriate and safe medication use for inclusion in the evaluation of Medicare pharmacy plans. PQA had seen uptake of its measures in the Medicare Star Ratings, with 5 measures included and an additional 4 utilized as display measures. Over PQA’s 8-year history, the utilization of PQA measures has expanded to areas outside of Medicare as well. PQA continues to create measures not only for use at the health plan level, but also for use by community pharmacies, long-term care facilities, and integrated care teams.
How to Calculate Adherence
High adherence is considered to be a proportion of days covered (PDC) of >80% for most medication classes. One exception is antiretrovirals, where the target adherence goal is PDC >90%. PDC is 1 of 2 key measure calculations of adherence that are utilized in health care: the other is the medication possession ratio (MPR). MPR can be calculated through various methods to obtain a summation of the days’ supply of medication, which commonly results in an overestimation of a patient’s adherence. The lack of standardization in a definition only further complicates this issue. PDC is calculated according to fill dates and day supply, along with measuring for full persistence across the measurement period, not stopping after the last fill as MPR does. The utilization of PDC allows for a more accurate, conservative reflection of a patient’s adherence level. Because of its accuracy, consistent definition, conservative estimations, and extended application to multiple medications, PDC is considered by PQA to be the preferred method of adherence calculation.
Additionally, and equally as important, PDC is considered to be the most appropriate methodology for calculating adherence by a variety of entities, including the National Quality Forum (NQF), the Centers for Medicare & Medicaid Services (CMS), the National Committee for Quality Assurance, URAC, and the Center for Clinical Standards and Quality, for use in health insurance exchanges. PQA encourages all pharmacies to align their adherence calculation methods with national standards.