VA secondary conditions: how secondary service connection works

You do not have to trace a condition back to service if you can trace it to something already service connected, so a secondary condition can be service connected even when it never appears in the service records.

Last reviewed October 2026 · Not legal advice, VA.gov always controls

A VA secondary condition is a disability that a service-connected disability caused, or made worse, and VA can service connect it on that basis. VA looks at two routes: causation, where the new condition would not have happened but for the service-connected one, and aggravation, where a condition that is not service connected got worse because of it. Evidence has to show the link, and an aggravation claim also needs a baseline (38 CFR § 3.310).

Once granted, the secondary condition is treated as part of the original service-connected condition. In practice, a veteran may file for the back injury documented in their Service Treatment Records and stop there, while nerve pain down the leg, depression that grew out of years of chronic pain, or stomach damage from years of anti-inflammatories go unclaimed. Each of those may be separately ratable, and none needs a new page from the service records, though each still needs its own evidence.

The two flavors

§ 3.310 covers two distinct situations, and it is worth being explicit about which one you are claiming:

• Causation. The service-connected condition caused the new one. Example: service-connected knee instability changes your gait, and the altered gait produces a hip condition.
• Aggravation. You have a condition that is not service connected, and the service-connected disability made it worse. Here the VA compensates only the worsening above a documented baseline, so establishing that baseline in the record matters. The baseline usually comes from medical records, though M21-1 lets other credible evidence, including lay statements, support it. § 3.310(b) still refers to natural progress. Since Spicer v. McDonough (Fed. Cir. 2023), however, VA's adjudication manual says it no longer considers natural progress in these claims.

What a secondary claim has to show

Three elements:

1. A current diagnosis of the secondary condition.
2. A service-connected primary condition. It can be granted already, or claimed in the same filing; a secondary cannot be granted unless the primary is.
3. Competent evidence of the link, usually a medical opinion that explains how the primary caused the secondary condition or made it worse. If the record shows a current condition and some indication of a link but not enough medical evidence to decide, VA must provide an exam or opinion (38 CFR § 3.159(c)(4)).

Notice what is missing: you do not need an in-service event for the secondary condition. You do not need it in your STRs. It can have appeared fifteen years after you got out. The link runs through the primary condition, not through service.

Common secondary relationships

The table lists examples of secondary theories. None of them is automatic. Every one still needs its own diagnosis and its own medical opinion on your specific facts, but they are examples worth raising with a clinician.

The regulation itself does build in two links. Under § 3.310(c), ischemic heart disease or other cardiovascular disease in a veteran with a service-connected amputation of one leg at or above the knee, or of both legs at or above the ankles, is held to be the result of the amputation. Under § 3.310(d), certain conditions after a service-connected TBI are held to be secondary to it absent clear evidence to the contrary, for example depression that appears within 3 years of a moderate or severe TBI, or within 12 months of a mild one.

The medication pathway is easy to overlook: if the treatment for a service-connected condition damages something else, that damage can be claimed. Ten years of prescribed NSAIDs for a service-connected back, followed by a GERD diagnosis, is a recognized secondary theory, though it still needs a medical opinion on the individual facts.

Where secondary claims fail

No opinion, just a list

A frequent failure is submitting the claim with the relationship asserted but no clinician saying it. "My sleep apnea is secondary to my PTSD" is a theory. You need someone with a medical license to say it is at least as likely as not, and to explain the reasoning.

An opinion with a conclusion and no reasoning

VA's adjudication manual (M21-1) requires every medical opinion to state a rationale, and lists the physician's reasoning among the factors that decide how much weight the opinion gets. A bare "yes, related" offers no analysis to weigh against a C&P examiner's negative opinion that explains itself. The rationale is the substance.

Only causation was addressed

Examiners sometimes answer whether the primary condition caused the secondary, conclude no, and never address aggravation. That is an incomplete opinion. Aggravation is a separate legal theory and an unanswered question is a concrete, addressable defect.

Pyramiding

You cannot be paid twice for the same symptom under two diagnostic codes, § 4.14 prohibits it. Distinct manifestations are fine; the same manifestation dressed in a second code is not. A spine rating for limitation of motion plus a separate rating for radiculopathy of the nerve is normal. Two overlapping mental-health diagnoses producing one set of symptoms will generally be rated together under a single evaluation.

Timing and effective dates

You can file a secondary claim together with the primary or at any point after it is granted, the same week or twenty years later. The effective date generally runs from the date you filed the secondary claim (or a protecting Intent to File, if the complete claim follows within one year), not from the date the primary was granted, so there is a real cost to waiting. The effective dates guide covers the details.

One consequence worth planning around: because ratings combine rather than add, a new rating moves the combined figure more when that figure is still low. Under the combined ratings table in 38 CFR § 4.25, three 10% secondaries take a single 40% rating to 60%, but leave a single 90% rating at 90%. The result depends on the unrounded combined value, so a veteran whose combined rating sits near a rounding line can still move up.

How to work the list

1. Write down every service-connected condition you already have.
2. For each one, list every ongoing problem you have that could plausibly follow from it, including the medications you take for it and their side effects.
3. Get each of those diagnosed if it is not already. No diagnosis, no claim.
4. Ask your treating provider for an opinion on the ones with a real mechanism behind them. Bring the primary's rating decision so they can see what is already service connected.
5. File them together as a fully developed claim rather than trickling them in one at a time.

Be honest in the filtering. A shotgun list of twenty speculative secondaries with no medical support does not help you, and it slows down the ones that are real.

Sources

• 38 CFR § 3.310, Disabilities that are proximately due to, or aggravated by, service-connected disease or injury: the secondary service connection rule, the baseline requirement and deduction for aggravation, and the built-in amputation and TBI links.
• M21-1, Part V, Subpart ii, Chapter 2, Section D, Secondary SC and Aggravation of NSC Disabilities: VA's procedure manual on secondary claims (updated May 1, 2026), including the but-for standard VA applies since Spicer v. McDonough, 61 F.4th 1360 (Fed. Cir. 2023), that VA no longer considers natural progress in aggravation claims, how the baseline is set, and that the baseline is deducted from the current level. Related M21-1 sections: Part V, Subpart ii, Chapter 1, Section A, Principles of Reviewing and Weighing Evidence, which requires a rationale for every medical opinion, and Part V, Subpart iii, Chapter 2, Section B, Conditions of the Auditory System, which grants tinnitus on a direct basis when it is a symptom of service-connected hearing loss.
• 38 CFR § 4.71a, General Rating Formula for Diseases and Injuries of the Spine: the forward-flexion bands used in the worked example, and Note (1), which rates associated neurologic findings such as radiculopathy separately.
• 38 CFR § 4.14, Avoidance of pyramiding: the same manifestation cannot be rated under more than one diagnosis. § 4.25, Combined ratings table: separate ratings combine rather than add, and the combined value is rounded to the nearest 10 only once, after all ratings are combined.
• 38 CFR § 4.119, Diagnostic Code 7913, Note (1): compensable complications of diabetes are evaluated separately unless they are part of the 100% criteria.
• 38 CFR § 3.102, Reasonable doubt: when the evidence is in approximate balance, the doubt is resolved in the veteran's favor, which is why a well-reasoned opinion at the "at least as likely as not" level can be enough.
• 38 CFR § 3.400, Effective dates, General: the effective date is the date VA receives the claim or the date entitlement arose, whichever is later. Under § 3.155(b), Intent to file a claim, a complete claim received within one year of an intent to file is treated as filed on the intent-to-file date.
• 38 CFR § 3.2501, Supplemental claims: VA readjudicates a denied claim, such as a denied primary, when new and relevant evidence is submitted.