Navigating the Wild West of Medication Adherence Reporting in Specialty Pharmacy

Estimating medication adherence through the use of pharmacy claims-based adherence calculations such as medication possession ratio (MPR) and proportion of days covered (PDC) plays a significant role in specialty pharmacy practice. Although MPR and PDC are frequently used in clinical practice, calculation methodologies vary, making meaningful comparisons of adherence rates difficult. In addition, MPR and PDC are increasingly used by insurance companies, pharmacies, accrediting bodies, and drug manufacturers to demonstrate quality differences or clinical benefit across the specialty pharmacy industry. Therefore, recognizing the source and effect of calculation variability is necessary to fully understand reported adherence results. This article highlights the challenges in standardizing adherence methodologies, minimum methodology considerations that should be reported with MPR and PDC results, and key elements to consider when interpreting and applying adherence results. Further, recommendations are provided to promote a more consistent description of calculation methods and to aid pharmacies in adherence measure analysis, interpretation, and application to practice, with a focus on specialty pharmacy programs. A detailed description of methodology as outlined in this article must be provided to ensure reproducibility, external validation, and scientific rigor. In the absence of standardization, specialty pharmacies should be prudent in their use of adherence calculations as a clinical benchmarking tool or comparative quality indicator with outside organizations. Furthermore, specialty pharmacies should consider using current adherence measure calculations to identify and provide targeted interventions to patients with potential adherence problems and strive to better demonstrate ties between adherence measures and direct clinical and cost outcomes. DISCLOSURES: No outside funding supported the writing of this article. Anguiano is a speaker and research consultant for United Therapeutics. The other authors have nothing to disclose.