Why a dose change looks like a lost patient
A patient starts a specialty therapy on a titration pack, then moves to the maintenance strength a few weeks later. Clinically, nothing has gone wrong. The patient is doing exactly what the label intends. In many brand reports, though, the patient has stopped on one product and started on another. The starter pack shows a discontinuation, the maintenance strength shows a new patient start, and persistence dips at precisely the week the dose was meant to change.
The cause is rarely the specialty pharmacy or the hub. Each dispense is recorded correctly against the NDC that was shipped. The problem sits in the product layer of the reporting: patients counted by NDC instead of by brand, strengths and pack types that nobody grouped, a new presentation launched mid-year that the dashboard never heard about, and units that cannot be turned into doses or days of therapy without a lookup someone keeps in a spreadsheet.
The fix is a product hierarchy: one owned table that places every NDC under its brand and molecule, labels its strength, form and pack type, and states how its units convert into doses. This article explains where product data breaks, what a hierarchy that holds up contains and how to build one. It sits alongside our guides to payer hierarchies, HCO hierarchies and PDC versus MPR.
Four places product data breaks
Patients counted by NDC
When a report counts patients per NDC and then adds them up, a patient who moves from a starter pack to a maintenance strength is counted twice in one view and as a stop in another.
- Titration step read as a discontinuation
- Strength change read as a new start
- Patient totals above the real number
New NDCs nobody mapped
A new strength, a pen in place of a syringe or a new pack size reaches the specialty pharmacy feed before it reaches the reporting tables. Until someone notices, its fills fall out of the brand or into other.
- Brand volume short in launch weeks of a new presentation
- Fills under unknown product
- Mapping fixed by hand before a QBR
Units that do not mean doses
One NDC holds a 28-day supply, another a single syringe, another a weight-based vial. Without a units-per-dose and days-per-pack rule on each NDC, units and days of therapy cannot be compared across presentations.
- Adherence distorted by default days supply
- Units growth that is a pack mix change
- Forecasts trained on the wrong unit
Every team groups products its own way
Brand groups by indication, finance by pack for pricing and gross to net, the field by what reps detail. NDC formats also differ: the 10-digit code on the label and the 11-digit form used in claims.
- Leading zeros dropped in joins
- Indication guessed from strength
- Brand and finance volumes disagree
What a product hierarchy that holds up looks like
How to put it in place
List every NDC in your feeds
Pull every NDC that appears in specialty pharmacy, hub, distributor and claims data over the last two years, with fill counts, and compare it with the NDCs on your product labels.
Agree the levels and pack roles
Bring brand, patient services, finance and analytics together to agree the hierarchy levels, the pack roles and how a dose change should appear in reports. Write it down with examples.
Add the conversion fields
Record units, doses and intended days per pack for each NDC, with the source and an effective date, and a stated rule for weight-based dosing.
Rebuild patient counts at brand level
Link patients first, then compute starts, persistence and discontinuations at brand level with dose changes as events. Run the old and new numbers side by side for a quarter.
Alert on new NDCs and own the table
Set an alert for unmapped NDCs in every feed and name an owner. Review the table before every new strength, presentation or pack size launches.
Questions leaders ask about product hierarchies
What is an NDC product hierarchy?
Why does persistence drop at the point patients should change dose?
Why do our units and patient numbers grow at different rates?
Can we buy product reference data instead of building a hierarchy?
Who should own the product hierarchy?
Check your product layer with us
Send us the list of NDCs in your specialty pharmacy and hub feeds. We will show which ones are unmapped, where dose changes read as stops, and what a product hierarchy would look like for your brand. More on our work at specialty pharma analytics and automation.
Part of our Pharma Commercial and Patient Analytics hub. Start with our specialty pharmacy analytics.