When a Medicare beneficiary with Part D coverage fills a prescription, the prescription drug plan submits a record to CMS. The PDE file includes all transactions covered by the Medicare prescription drug plan for both Prescription Drug Plans (PDPs) and Medicare Advantage Prescription Drug Plans (MA-PDs).

The Medicare Part D Drug Characteristics file refers to a set of variables that are appended to the Medicare Part D Event file (PDE). Researchers need to request the specific variables required for their study and CMS must approve the release.

The Medicare Part D Formulary file is a suite of five sub-files: Formulary, Excluded Drug, Over-the-Counter Drug, Indication-based Formulary, and Part D Senior Savings (PDSS) Model that contain information on how the plan covers the prescription drugs filled (as described in the Part D Drug Event (PDE) file.

The Part D Pharmacy Characteristics file provides information about the pharmacy identified as the source of the drug for each Part D Event (PDE) prescription fill record.

The Medicare Part D Prescriber Characteristics file contains descriptive information for the prescriber identified on a Part D Event file record.

The Plan Characteristics file contains Medicare Advantage plan and Prescription Drug Plan information separated into six subfiles.

The subfiles are:

• Plan Base
• Premium
• Tier
• Service Area
• Plan Crosswalk
• SNP Contract

This file includes beneficiary-level information for participants in the Part D Medication Therapy Management (MTM) program, required of CMS Part D plans. Eligible beneficiaries include those enrolled in Part D plans with multiple chronic disease, those taking multiple Part D drugs and those likely to have expenditures exceeding a specified level as described by federal regulations.

This Medicare Part D file identifies beneficiaries covered by the Low Income Subsidy (LIS) program for Part D Plan enrollment.