Drug benefit sponsors are investing handsomely in copayment reduction programs, drug therapy management, and other clinical interventions to improve medication adherence in disease states with high cost burdens. Medication possession ratio (MPR) is an important outcomes measure for these programs.

MPR is a mathematical formula that approximates patient adherence by measuring the percentage of time a patient has access to medications. It is a commonly used metric for tracking how frequently people take their prescribed medications.

Through retrospective drug claims analysis, MPR looks at medication refill history over a period of time and calculates how many doses of medication a patient obtained during the study period compared to how many doses should have been obtained. See Figure 7 for one example of an MPR formula.

Although MPR does not prove a patient actually took medication as directed, it is widely used and validated as a proxy for drug adherence. Plan sponsors funding programs to improve adherence to specific therapies should request periodic reports that show: 1) average MPR for the targeted populations, and 2) what percent of each targeted population is achieving or exceeding the target MPR. In addition, plan sponsors should work with their PBMs and health plans to obtain separate MPR reports for new-to-therapy patients and continuing patients in each targeted population. It is well known that drop-out rates are higher for patients new to therapy. Reports that show only an aggregate MPR may mask less than desirable adherence rates for new users and the need to focus improvement activities in this segment.

URAC Adopts MPR Metric

URAC’s updated accreditation standards for pharmacy benefit managers (PBMs) and drug therapy management (DTM) organizations include MPR performance measures that reflect the importance of segment-specific reporting. Recently approved 2.0 versions of PBM and DTM standards require organizations to report MPR rates separately for Medicare, Medicaid and commercial populations.

Accredited PBMs also will need to report MPR rates stratified for new users, continuing users, and all users of drugs in three classes of diabetes drugs and five classes of cardiovascular drugs. DTM organizations will need to report MPR rates for new and continuing users as well as all users of drugs in the major classes managed by the DTM.

The new requirements for measuring and reporting MPR will be effective January 1, 2010. Initially, the reporting focus will be on the usefulness of the metrics to an organization’s internal performance improvement. In the second implementation phase, the mandatory measures will undergo an external auditing and verification process. Down the road, the MPR rates reported by accredited organizations will be released on the URAC Website, accessible to employers and other plan sponsors. This multi-phased approach will be implemented over several years. A listing of new performance measures is available in the PBM and DTM fact sheets at www.urac.org. Additional information on MPR as a performance measure will be posted in the near future.

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