Impact of provider mailings on medication adherence by Medicare Part D members

Bijan J. Borah, Yang Qiu, Nilay D. Shah, Patrick P. Gleason

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Background The Medicare 5-Star Rating System measures and provides incentive for improving Medicare Part D plans through a quality-based payment program. Adherence to medications for chronic conditions is key to the Star ratings. Our objective was to assess the impact of direct-to-provider letters on improving medication adherence. Methods Members of a large US pharmacy benefits manager (PBM) who did not adhere to prescription of oral diabetes (antidiabetics), cholesterol-reducing (statins), or hypertension (renin angiotensin system [RAS] antagonists) drug therapy were identified from the prescriptions claims data of>600,000 continuously enrolled Medicare members. Nonadherence was defined by the Star ratings definition of proportion of days covered (PDC)<80%. The PBM sent letters to prescribing physicians of nonadherent members, requesting that they discuss adherence barriers and potential solutions with their patients. A historical control cohort was constructed from the PBM satisfying the same eligibility criteria as the intervention cohort. Both binary (≥80%) and continuous PDC measures were assessed as outcomes through multivariate logistic regression and difference-in-difference models, respectively. Results Final sample sizes were 21,044; 106,829; and 73,560 patients for antidiabetic, statin, and RAS antagonist use, respectively, with approximately equal number of intervention and control subjects in each drug class. Physician mailing was associated with 11%, 16%, and 7% higher odds of being adherent by members in antidiabetic, statin, and RAS antagonist cohorts, respectively (all P<.001). Conclusions Within limitations of historical controls, physician mailing was associated with improved medication adherence. Implications Physician mailing can be an impactful tool for improving medication adherence. Level of evidence II

Original languageEnglish (US)
Pages (from-to)207-216
Number of pages10
Issue number3
StatePublished - 2016


  • Medicare Part D prescription plan
  • Medicare Star Rating System
  • Medication adherence
  • Prescriber mailing
  • Proportion of days covered

ASJC Scopus subject areas

  • Health Policy


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