How Do Secondary VA Claims Work: Nexus, C&P Exam, and Appeals

Secondary VA claims let you get compensation for a new health condition that was caused or worsened by a disability the VA has already rated, and winning one comes down to proving the medical link — the nexus — between the two. The new condition does not have to have started during your service; it has to be tied, through a qualified medical opinion, to a disability that is already service-connected.¹

What Counts as a Secondary Condition

Federal regulation gives the VA authority to grant service connection for a condition that was caused by, or aggravated by, a disability you already have rated. When the VA grants secondary service connection, it treats the new condition as part of your original service-connected disability for compensation purposes.² There are two paths, and they carry different evidence burdens.

Causation

The most straightforward path is showing that your rated condition directly caused a brand-new health problem. A service-connected knee injury forces you to walk differently, and the altered gait eventually damages your opposite hip. The hip problem did not exist before, and your rated knee disability is the reason it developed. In a causation claim, the medical opinion needs to tie the new diagnosis entirely to your primary disability.²

Aggravation

The second path covers situations where you already had a non-service-connected condition, but your rated disability made it measurably worse beyond its natural course. The VA will not grant aggravation-based service connection without medical evidence establishing a baseline: the severity level of the non-service-connected condition before the worsening began.² The VA then measures the difference between that baseline and your current severity, subtracting any worsening attributable to natural progression. You only receive a rating for the portion of increased severity caused by your service-connected disability.

The baseline requirement makes aggravation claims harder to prove than causation claims. If you have older medical records showing the non-service-connected condition before it worsened, gather them. They give your doctor the foundation to establish the baseline the VA requires.

Proving the Claim: The Three Elements

Every secondary claim needs three things. A current diagnosis of the secondary condition from a licensed provider. An existing VA-rated disability (even a 0% non-compensable rating counts). And a medical nexus opinion linking the two.³

The nexus is a written opinion from a qualified provider stating that your secondary condition is “at least as likely as not” related to your primary disability. That phrase reflects the VA’s benefit-of-the-doubt standard: when the evidence for and against is roughly equal, the VA resolves that doubt in your favor.⁴ In practice, if the opinion places the probability at 50% or higher, you have met the standard.⁵

Adjudicators look for specific reasoning tied to your individual medical history, not generic statements about what conditions can cause. A strong nexus opinion explains the physiological pathway: how your particular primary disability led to or worsened the secondary condition in your body. Medical professionals often cite peer-reviewed research to support that reasoning. Without an individualized explanation, the VA frequently denies the claim because the legal connection remains unproven.

Conditions the VA Commonly Grants as Secondary

Certain pairings appear again and again because the medical links are well-documented. Recognizing them can help you spot conditions worth claiming.

Orthopedic overcompensation. An injury to one limb forces a shift in weight or gait, leading to pain or degeneration in the opposite limb or the back. A service-connected knee disability can cause low back arthritis or damage to the other knee over time.
Diabetes and peripheral neuropathy. Service-connected type II diabetes frequently leads to nerve damage in the hands and feet. The VA regularly grants secondary service connection for peripheral neuropathy when the medical evidence ties it to diabetes.
Hypertension and cardiovascular or renal conditions. VA-rated high blood pressure can lead to heart disease, stroke, or kidney problems, but the claim requires medical evidence showing the blood pressure condition contributed to the secondary diagnosis.
Mental health and gastrointestinal disorders. PTSD and major depression are linked to irritable bowel syndrome and gastroesophageal reflux disease. The Board of Veterans’ Appeals has granted secondary service connection for both IBS and GERD stemming from PTSD.
Tinnitus and migraines. Service-connected ringing in the ears has been linked to recurring headaches, and the VA has granted secondary service connection when supported by an adequate medical opinion.

These are common examples, not a closed list. Any condition your doctor can link to a rated disability through sound medical reasoning is eligible.

Filing the Claim

Lock In Your Effective Date First

Before you finish gathering evidence, submit an intent to file. That notifies the VA you plan to file and locks in a potential effective date, which is the start date for any benefits awarded. Submit an intent to file on April 2 and complete your claim on July 15, and any benefits are retroactive to April 2.⁶ You have one year from that date to submit the full claim. Without an intent to file, the effective date is generally when the VA receives the completed application, or the date your condition arose, whichever is later.⁷ You can submit it online, by phone, or by mailing VA Form 21-0966.

The Application

You file a secondary claim on VA Form 21-526EZ, the same application used for all disability compensation claims.⁸ Identify the new condition clearly as secondary and name the already-rated disability it stems from. Getting the primary condition wrong on the form can trigger processing delays or an administrative denial.

The Nexus Letter

The nexus letter is the single most important document in a secondary claim. It should include the provider’s credentials, a detailed review of your medical history, and the explicit opinion that the secondary condition is at least as likely as not caused or aggravated by your primary disability.³ The provider should confirm they reviewed both your private records and your VA treatment records. A well-reasoned letter from a specialist in the relevant field carries significant weight.

Nexus letters from private providers typically cost between $250 and $1,500, and complex cases can run higher. The VA does not reimburse the cost.

Medical Records and DBQs

Compile private medical records from every non-VA provider who has treated the secondary condition. If you received care at a VA Medical Center, give the VA the location and treatment dates so they can pull the records internally.

You can also ask your private doctor to complete a Disability Benefits Questionnaire for the secondary condition. DBQs are standardized VA forms that capture the specific clinical findings the VA uses to assign a rating, so a completed DBQ from your own doctor delivers evidence in exactly the format the examiner needs.⁹ The provider must complete all identification fields and sign and date the form. The VA does not reimburse this cost either.

The C&P Exam

After the VA receives your application, they typically schedule a Compensation and Pension exam. A VA-contracted physician verifies your diagnosis, assesses how the condition limits your daily life and ability to work, and provides a medical opinion on the connection to your rated disability.¹⁰ The examiner uses the criteria in the VA’s Schedule for Rating Disabilities to determine the appropriate percentage.¹¹

Attend every scheduled exam. If you miss an exam for an original compensation claim, the VA rates your claim on whatever evidence is already in your file, which may not be enough for a favorable decision. Miss an exam for a supplemental or increased-rating claim, and the VA will deny it outright.¹²

You cannot get the exam results at the appointment or directly from the examiner. To obtain the final report, submit a Freedom of Information Act or Privacy Act request using VA Form 20-10206. You can file it online, by mail, or in person at a VA regional office.¹⁰ If the examiner made factual errors or gave an inadequate opinion, seeing the report early helps you plan next steps.

How a New Rating Combines With Your Existing One

Adding a secondary condition does not mean the VA adds the new rating to the existing one. The VA uses a combined ratings table that applies each successive rating to whatever percentage of “whole person” health remains after the previous rating.¹³

Say you have 50% for a knee disability and the VA grants 30% for a secondary back condition. The 50% leaves you at 50% of full health. The 30% back rating is applied to that remaining 50%, which is 15%. Your combined value is 65%, which the VA rounds to 70%. Simple addition would give 80%. The combined method always produces a lower figure.

When secondary conditions affect both sides of the body — for example, a service-connected right knee causing a secondary left knee problem — the VA applies a bilateral factor, combining the ratings for both sides and adding 10% of that combined value before continuing the calculation.¹⁴

The VA also prohibits “pyramiding,” which is rating the same symptom twice under different diagnoses. If your primary and secondary conditions share overlapping symptoms, those symptoms only count once.¹⁵ Each rated condition must involve distinct functional limitations, so your medical evidence should clearly distinguish the symptoms of each.

Because the combined method compresses your total, a secondary rating that pushes you across a rounding threshold, say from 64% to 70%, can produce a meaningful jump in monthly compensation. Rates for 2026 (effective December 1, 2025) run from $180.42 per month at 10% to $3,938.58 per month at 100% for a single veteran with no dependents, and veterans rated at 30% or higher receive additional compensation for qualifying dependents. All VA disability payments are tax-free.¹⁶

If the VA Denies Your Secondary Claim

You have three decision review options. For most benefits, you have one year from the date on the decision letter to request a Higher-Level Review or a Board Appeal. You can file a Supplemental Claim at any time, but filing within one year preserves your original effective date.¹⁷

Higher-Level Review

A Higher-Level Review asks a more senior adjudicator to re-examine the same evidence already in your file. Choose it if you believe the original reviewer misapplied the law or misjudged the evidence, but you do not have new evidence to submit. You cannot add new records, statements, or medical opinions to a Higher-Level Review.¹⁸

Supplemental Claim

A Supplemental Claim is the right choice when you have new and relevant evidence that was not in your file before. “New” means information the VA has not yet considered; “relevant” means it proves or disproves something about your claim. For a denied secondary nexus, a stronger nexus letter from a specialist or a newly completed DBQ typically qualifies.¹⁹

Board of Veterans’ Appeals

You can also appeal directly to the Board, which offers three docket options:²⁰

Direct Review. The fastest Board option. A Veterans Law Judge reviews only what is already in your file. Best when you believe the law was misapplied.
Evidence Submission. You have 90 days after filing to submit additional evidence before the judge reviews the case.
Hearing. You appear before a Veterans Law Judge, usually by video, to present your case. Longest wait, but you get to explain your situation directly.

Match the lane to the reason for denial. If the denial rested on a weak nexus opinion and you now have a stronger one, a Supplemental Claim is usually the most efficient route. If the evidence was solid but the decision looks legally wrong, a Higher-Level Review or a Direct Review Board appeal is the better fit.

1
Veterans Affairs. Eligibility for VA Disability Benefits
2
eCFR. 38 CFR 3.310 – Disabilities That Are Proximately Due To, or Aggravated By, Service-Connected Disease or Injury
3
Veterans Affairs. Evidence Needed for Your Disability Claim – Section: Secondary Service-Connected Claim
4
eCFR. 38 CFR 3.102 – Reasonable Doubt
5
Office of the Law Revision Counsel. 38 USC 5107 – Claimant Responsibility; Benefit of the Doubt
6
Veterans Affairs. Your Intent to File a VA Claim
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eCFR. 38 CFR Part 3 Subpart A – Effective Dates
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Veterans Affairs. About VA Form 21-526EZ
9
Department of Veterans Affairs. Disability Benefits Questionnaires (DBQs) Fraud Prevention
10
Veterans Affairs. VA Claim Exam (C&P Exam)
11
eCFR. 38 CFR Part 4 – Schedule for Rating Disabilities
12
eCFR. 38 CFR 3.655 – Failure to Report for Department of Veterans Affairs Examination
13
eCFR. 38 CFR 4.25 – Combined Ratings Table
14
eCFR. 38 CFR 4.26 – Bilateral Factor
15
eCFR. 38 CFR 4.14 – Avoidance of Pyramiding
16
Veterans Affairs. Current Veterans Disability Compensation Rates
17
Veterans Affairs. Decision Reviews FAQs
18
Veterans Affairs. Higher-Level Reviews
19
Veterans Affairs. Supplemental Claims
20
Department of Veterans Affairs. Veteran Choices for Type of Board Appeal Influences Wait Times