Open Issues

This page tracks open issues/questions/concerns about the draft implementation guide and its components. It should be deleted if/when the IG is released.

Representing Drug Tiers

There is not a single, standard set of drug tiers, but most insurers group medications into 3, 4, 5, or 6 tiers. How should this be represented? A single set of codes which all plans would need to map to? Several code sets for the different tiers? The combination of a code set for the number of tiers in the formulary and a separate code set for the specific tier of each medication? Use subsections to represent each tier?

Use of Composition vs. List

The Composition resource was used to model a list of all the formularies that an insurer maintains. Each formulary is (itself) a list of Medication resources. Should each formulary be a profiled List resource instead (e.g., List instead of Composition.section)?

Need for New LOINC Codes

There aren't many good LOINC codes for administrative health items. This IG may require some new ones:

  • The current FormularyList profile uses LOINC 82215-5 (Medical equipment or product list) as the FormularyList.section.code
  • There is no existing LOINC code that would represent a collection or list of formularies, which would be helpful for FormularyList.type

Public Formularies vs. Patient-Specific Formularies

Insurers regularly make medication formularies public, but the prices (co-pays and coinsurance amounts) are generally excluded from these formularies or assigned by drug tiers. This IG models the implementation for public formularies similar to what is already available, but it could be advantageous to patients if insurers were able to make specific formulary amounts available to patients, based on the plans in which they are enrolled (or are intersted in purchasing). Should co-pay and coinsurance amounts also be included, to allow for this type of exchange?

Consistency in RxNorm Code Selection

While the IG specifies RxNorm as the preferred code system for medications, there are many ways to represent drug components, drug packs, etc. (see RxNav). This may lead different insurers to map similar medications to different RxNorm codes. Further guidance may be required on this subject.

RxNorm Codes to Use

Based on brief research, this may be an appropriate way to assign RxNorm codes for medications in formularies:

Drugs Distinguished By Generic Brand
Ingredient Only Ingredient [IN/MIN] Brand Name [BN]
Ingredient and Components/Packaging Clinical or Drug Pack [SCD/GPCK] Branded Drug or Pack [SBD/BPCK]

Practically, the QHP formulary for asks for every possible SBD/BPCK and SCD/GPCK RxNorm code that could be associated with each covered medication to make sure that users searching for a specific packaging of a medication are able to find it. This may be a more reasonable approach.

Consistency in Drug Classification Representation

Many formularies visually segment their lists of covered medications using classification categories based on their expected use in patient care (e.g., 'Inflammatory Conditions', 'Sexual Dysfunction', 'Musculoskeletal', etc.).

The WHO maintains the ATC classification code set, which may be useful here. ATC classes may be derived from RxNorm codes (since there is a classification hierarchy included with each RxNorm code), but it will be useful to have these classification codes explicit in the payload.

TODO: Should implementers use partial ATC codes with a specific level of ATC (e.g., A for Alimentary tract and metabolism [1st level, anatomical main group] versus A10 for Drugs used in diabetes [2nd level, therapeutic subgroup] versus A10B for Blood glucose lowering drugs, excl. insulins [3rd level, pharmacological subgroup])? If so, which level (2nd level seems promising...)? Also, how do they use the RxNorm code to derive the proper ATC class (or classes)

Reconciliation with the QHP Formulary API Format for maintains an active list of QHP formularies that are collected via a non-FHIR API documented on github. QHPs will need a transition plan to switch from providing data in a JSON using that format to building one according to this IG. Also, the team that built the formulary API may have lessons learned that could be included in this IG.