Why was my CGRP prior authorization denied?

Denials usually trace to one of three things: diagnosis or frequency criteria not met on paper, missing step-therapy history, or disability that isn't documented strongly enough. The first two are about what's in your chart. The third is often a record problem, because logs that end when head pain ends leave out the after-phase days where much of the function loss happens. Your plan's clinical policy lists its exact criteria.

What documentation do I need for CGRP prior authorization?

Plans commonly look for a migraine diagnosis, monthly migraine or headache day counts, the preventives you've tried and why they failed or weren't tolerated, and in many cases a disability measure such as MIDAS or HIT-6. Criteria differ by plan, so ask your clinician's office for the specific policy. The disability piece is the one a thorough daily log, including postdrome days, can make more accurate.

Do postdrome days count as headache days?

No. A day with fog, fatigue, or light sensitivity but no head pain isn't a headache day, and it shouldn't be recorded as one. Those days belong in disability measures instead, which ask about missed or half-productive days at work, at home, and socially.

Does MIDAS include days I wasn't in pain?

MIDAS asks about days migraine caused you to miss activities or cut your productivity by half or more over the past three months. It doesn't require that you were in pain that day. A postdrome day you spent working at half capacity fits the question, if you remember it when you fill out the form.

How far ahead should I start documenting before a CGRP appointment?

MIDAS looks back three months, so a log that covers the full quarter before your appointment gives your clinician the most complete picture. Include the days after each attack in functional terms, like leaving work early or cancelling plans.

What prior authorization actually measures, and why postdrome is the evidence gap

Article · 5 min read

The CGRP evidence gap lives in the days after the headache ends.

A CGRP prior auth is a ruling on how disabling your migraine is. Headache-only logs leave out the days where much of that disability lives.

Two logs, one attack

Two migraine logs cover the same attack. The first reads: pain started Monday night, took a triptan, headache resolved Tuesday afternoon. The second has those exact lines and then keeps going. Wednesday: lost the thread of a sentence twice in a meeting, left early. Thursday: office lights still too sharp, worked half a day from the couch. Friday: back at work.

Same brain. Same attack. Same drug, same dose.

But hand both files to a reviewer deciding whether a CGRP preventive is medically necessary, and they tell different stories. One shows a bad night and a rough afternoon. The other shows most of a work week gone. They're different medical records, even though the biology underneath them didn't change at all.

The second kind of log is rarer than it should be, because most tracking stops the moment the pain does.

The postdrome evidence gap

A CGRP prior authorization is a ruling on how much migraine costs a person. Plans check the diagnosis and the step-therapy history, and those boxes matter. Underneath every criteria sheet, though, sits one question: is this condition disabling enough to justify an expensive preventive?

We call the problem the postdrome evidence gap. The after-phase is where a lot of function loss accumulates. Brain fog that turns a report into an afternoon of rereading. Fatigue that cancels the school pickup. Residual photophobia, a neck that won't turn, a mood that goes flat for a day. And it's precisely the phase headache-only logs are designed to skip.

So the record understates the burden. The reviewer scores the record, not the person.

Why the paperwork framing stops too late

Most advice on CGRP denials treats them as a submission problem. Wrong code, a thin letter of medical necessity, missing dates for the preventives you already tried, a clinician who didn't echo the plan's language. Those failures are real. They're also downstream.

A letter summarizes a chart. It can't cite a Wednesday nobody wrote down.

There's a second trap. Patients tend to fixate on headache-day counts, and that's the one number postdrome can't honestly move. A fog day with no head pain isn't a headache day, and stretching the count to include it would be the wrong fix, clinically and ethically. The place where the after-phase legitimately belongs is the disability measures, which ask what migraine took from your work, your household, and your evenings.

What the instruments actually count

The Migraine Disability Assessment, better known as MIDAS, is five questions about the past three months. Two ask about days you missed work or school, or missed household work, entirely. Two more ask about days your productivity in those areas was cut by half or more. The fifth asks about missed family, social, or leisure time. The answers add up to a grade.

Read those questions again with a postdrome day in mind. The Wednesday you left early is a missed or half-productive work day. The Thursday on the couch is a half-productive one. MIDAS was built to count exactly these days. It just relies on you remembering them across a 90-day window, and fog days are the ones memory blurs first.

The prevalence isn't marginal, either. In a 2016 electronic diary study in Neurology, Giffin and colleagues found 81% of participants reported at least one non-headache symptom after the pain phase.

How plans use these scores varies. The American Headache Society's consensus guidance ties CGRP eligibility at lower attack frequencies to documented disability on scales like MIDAS or HIT-6, and many commercial plans ask for that same kind of disability documentation at initial approval or renewal.

81%

of diary-study participants reported at least one non-headache symptom after the pain phaseGiffin et al., Neurology 2016

2 of 5

MIDAS questions count days when productivity was cut by half or moreMIDAS questionnaire (Stewart, Lipton et al.)

3 months

recall window MIDAS asks you to reconstruct from memoryMIDAS questionnaire (Stewart, Lipton et al.)

MIDAS grading bands. Every half-productive postdrome day that goes unrecalled is a point that never reaches this scale.
MIDAS grade	Total score	Disability level
I	0 to 5	Little or none
II	6 to 10	Mild
III	11 to 20	Moderate
IV	21 or more	Severe

The same attack, scored twice

Walk the opening example through the instrument. The attack, the medication, and the headache days are identical in both logs. What differs is which days exist in the record when someone fills out MIDAS three months later.

Log A supports one half-productive day, maybe. Log B supports that day plus a day of work lost to leaving early and another cut in half by light sensitivity. Now repeat that pattern across every attack in a quarter. The gap isn't a rounding error. It compounds with each attack, and it lands directly in the grade band a reviewer reads.

Nothing in Log B is exaggerated. It simply didn't stop writing.

Hypothetical single attack, identical biology. Headache days are the same in both logs; only the disability-countable days differ.
Day	Log A (stops at pain)	Log B (tracks the after-phase)	What MIDAS can count from it
Mon night	Pain onset, triptan taken	Pain onset, triptan taken	Nothing yet
Tue	Headache resolved by afternoon	Headache resolved by afternoon, foggy evening	Possibly a half-productive work day
Wed	(no entry)	Brain fog, left work early	Missed or half-productive work day
Thu	(no entry)	Residual photophobia, half day from home	Half-productive work day
Fri	(no entry)	Back at work	Nothing

What changes if the gap is real

The evidence for a CGRP file gets built before the file is ever opened. That shifts the work earlier, to the months before a specialist appointment, and it changes what's worth writing down.

Log the after-phase in functional terms. Left work at 2pm. Skipped the grocery run. Worked half a day. Cancelled dinner. Symptom words like foggy and drained are useful, but MIDAS asks about lost and halved days, so the functional note is the one that survives into the score.

Keep the phases separate. Your clinician can see when the pain ended and when you did, and that distinction protects the credibility of your headache-day count. It also helps at renewal, since a shrinking after-phase is its own kind of evidence that a preventive is working.

And ask your clinician directly whether postdrome days are reflected in the disability score in your chart. Plenty of charts carry a MIDAS number that was filled in from memory in the exam room.

Don't pad the headache count

A postdrome day with no head pain is not a headache day. Record it as after-phase function loss. Inflating headache days undermines the whole file; accurate disability documentation strengthens it.

Keeping the attack open

Postdrome was built on the premise in this piece: an attack isn't over when the pain is. The timeline stays open through the after-phase, so Wednesday's fog and Thursday's half day sit in the same record as Monday night's triptan instead of vanishing into memory.

That matters most on the days you can barely look at a screen, which is why Aura Mode keeps logging dim and minimal. Entries stay on your device. When an appointment comes up, you export the record and hand your clinician something closer to what the attack actually cost. It's a one-time lifetime purchase, with no subscription to lapse halfway through a prior-auth cycle.

What we're tracking next

Two things. First, whether insurer clinical policies for CGRP preventives start naming functional measures beyond MIDAS and HIT-6, or loosen disability requirements as first-line use gains ground. Second, how reauthorization criteria treat improvement that shows up in the after-phase rather than in headache-day counts. If plans ever start asking for that explicitly, the patients who already track it will be months ahead.

Start logging the days after the pain, before your next appointment.

Postdrome's timeline keeps an attack open until you log that you're functional again, so the fog on Wednesday and the half day on Thursday live in the same record as the triptan on Monday night. Aura Mode keeps logging usable when light hurts, entries stay on your device, and the full record exports for your clinician. One lifetime purchase, no subscription.

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