Learn what documentation is needed for migraine prior authorization, from diagnosis records and step therapy notes to headache diaries and functional impairment scores.
Knowing what documentation is needed for migraine prior authorization is the first practical step toward getting it approved, and it matters more than most patients realize. Insurers review prior authorization requests against a specific checklist, and a submission that is missing even one core document can produce a denial that has nothing to do with whether the treatment is medically appropriate. The clinical case might be solid. The paperwork just has to prove it.
This article focuses specifically on the documents themselves: what they are, why each one matters to the reviewer, where the data comes from, and what separates a complete submission from a thin one. For the full renewal process, see the guide on CGRP prior authorization renewal.
Every prior authorization request for a migraine preventive, particularly a CGRP-targeted therapy, is trying to answer three questions for the insurer's reviewer: Is the diagnosis legitimate? Were less expensive treatments tried first? Is this specific medication medically necessary? The documentation package needs to answer all three, in writing, with enough specificity that a reviewer who has never met you can reach an approval decision.
The core documents fall into a predictable pattern across most commercial plans, though eligibility requirements and specific thresholds vary by insurer. Always confirm exact requirements with your insurer or your prescriber's office before assuming any particular standard applies to your plan.
A formal diagnosis of migraine must appear in the record, along with the type (episodic or chronic) and the documented frequency. Episodic and chronic migraine carry different clinical thresholds that affect what criteria a prior authorization needs to meet. The diagnosis should come from the treating clinician, typically a neurologist or headache specialist, and be reflected in the chart notes submitted with the PA.
Before treatment begins, the insurer needs a pre-treatment baseline: how many migraine days per month did you have? This number becomes the "before" in the before-and-after comparison that justifies both initial coverage and any future renewal. Without a documented baseline, a prescriber cannot demonstrate response to treatment later.
This is where patient data becomes critical. Clinical visit notes rarely contain month-by-month migraine frequency with the precision insurers want. A headache diary or migraine log from the one to three months before starting treatment gives the prescriber actual numbers to cite rather than estimates. See how to count monthly migraine days for guidance on what to track and how.
Most commercial plans and many Medicaid programs require evidence that you tried and failed at least two or three older, less expensive preventive medications before they will approve a CGRP therapy. This is called step therapy or fail-first policy. The documentation burden here is significant because vague records frequently trigger denials.
A strong step therapy failure note includes:
A weak note says only that a drug was tried without those details. The reviewer has no basis for confirming that the trial was adequate.
Validated disability measures like the MIDAS (Migraine Disability Assessment) and HIT-6 (Headache Impact Test) translate the lived experience of migraine into a standardized score that reviewers can interpret and compare. For initial prior authorizations, a baseline score establishes how much the condition is affecting your daily function. For renewals, an improved score alongside reduced migraine frequency makes a much stronger case than frequency data alone.
If your clinician has not administered one of these tools, ask before a PA submission. The scores need to come from your prescriber's office, but you can prompt the conversation. The measure CGRP progress guide covers how these tools work and what they measure.
| Document | Source | What It Establishes |
|---|---|---|
| Formal migraine diagnosis and type | Clinician chart notes | Legitimate indication for preventive treatment |
| Pre-treatment monthly migraine day count | Patient diary and clinician notes | Baseline disease burden |
| Step therapy records (medications, doses, duration, failure reason) | Clinician chart notes and prescription history | Compliance with fail-first requirements |
| Baseline MIDAS or HIT-6 score | Clinician-administered assessment | Functional impairment level before treatment |
| Acute medication usage (rescue medication days per month) | Patient diary and pharmacy records | Supplementary burden evidence |
| Letter of medical necessity | Prescribing clinician | Clinical justification for the requested therapy |
A prior authorization submission comes from your prescriber's office, not from you directly. But the data behind that submission has two sources, and both matter.
Clinician-supplied data includes the diagnosis, the step therapy history, and any disability scores administered in clinic. The prescribing physician writes the letter of medical necessity and signs off on the submission.
Patient-supplied data is the migraine log: dates, duration, severity, acute medications taken, and any relevant triggers or notes. This is the source of the baseline migraine day count and the ongoing tracking data that shows treatment response. Clinicians generally do not reconstruct this month-by-month without it. When you arrive at an appointment with organized diary records, your prescriber can use those specific numbers in the submission rather than estimating.
The CGRP renewal report shows how structured tracking data maps directly to what a renewal submission needs, which illustrates the same principle for initial PAs.
Step therapy documentation is the most common source of easily preventable denials. The difference between a strong and a weak failure note comes down to specificity.
Weak: "Patient tried propranolol, did not work."
Strong: "Propranolol 80mg daily, 12-week trial. Patient experienced less than 25% reduction in monthly migraine days with persistent side effects including fatigue and exercise intolerance. Discontinued due to inadequate efficacy and tolerability."
The strong version gives a reviewer everything needed to confirm that the trial was adequate, the outcome was documented, and the reason for discontinuation was clinically valid. The weak version raises the question of whether the trial was long enough, at a therapeutic dose, and whether the outcome was actually measured.
If you have been taking preventive medications for years and switched plans recently, those prior trials need to appear in the records your prescriber submits. Pharmacy fill history and prior clinical notes can help reconstruct this. Ask your prescriber's office specifically whether step therapy history from previous providers or plans has been obtained.
Most PA denials for migraine preventives come from a handful of predictable gaps, not from the insurer deciding the treatment is inappropriate. The most common:
The prescriber's office handles the submission, but what you bring to appointments shapes what they have to work with. Before a PA submission, ideally in the appointment where you and your clinician discuss starting or continuing a preventive:
The migraine reduction calculator can help you quantify your frequency change from baseline to present in percentage terms, which is exactly the format many PA reviewers are looking for.
If you have questions about what your specific plan requires, call the member services number on your insurance card or ask your prescriber's office. Requirements vary enough across plans that general guidance only takes you so far.
The documentation a prior authorization needs is not invented at submission time. It accumulates month by month from the records you keep between appointments. A patient who has tracked migraine days, acute medication use, and symptom severity consistently from the start of treatment has the raw material for a complete, specific, defensible submission. One who has not is relying on estimates. Consistent tracking, even a simple daily log, converts into the exact numbers that reviewers are looking for and that prescribers need to make the strongest possible case. Understanding how migraine tracking connects to coverage costs gives more context on why this habit pays off over time.
Educational, not medical advice. Migraine Tracker: CGRP Log is a personal tracking tool, not a medical device. It does not diagnose, treat, or provide medical advice. Always talk to your clinician.
Most insurers require a formal migraine diagnosis, documented monthly migraine day frequency, evidence of prior preventive treatment failure (step therapy), and often a functional impairment score such as MIDAS or HIT-6. Patient-recorded headache diary data supports and strengthens all of these.
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