A secondary condition is a disability that was caused or aggravated by a condition VA has already service-connected. Under 38 CFR 3.310, that secondary condition can be service-connected too — even though it didn't start in service — as long as you can medically link it to the primary. Sleep apnea linked to service-connected PTSD is a classic example.
Why secondaries are where the points hide
When I tell a vet the biggest gains are usually in conditions that didn't start in service, they look at me sideways. But it's true: once you have one service-connected condition, the door opens to everything that condition has caused or made worse. Most veterans stop at their primary and never claim the chain reaction it set off. That's points — and dollars — left sitting on the table.
The catch is that a secondary claim isn't won by saying "these feel related." It's won with a medical link. So the work is matching the right secondary to the right primary, then getting that connection documented.
What "secondary service connection" actually means
There are two ways a condition can be service-connected: directly (it started in service) or secondarily (a service-connected condition caused or worsened it). 38 CFR 3.310 is the secondary path. The condition can show up years after you're out — what matters is the causal chain back to a disability VA already recognizes.
Caused vs. aggravated — both count
People miss half of 3.310. It covers two situations:
- Causation — your service-connected condition caused a new one (e.g., an antalgic gait from a service-connected knee leading to a hip or back condition).
- Aggravation — a condition you'd have anyway is permanently worsened by a service-connected one. VA compensates the degree of worsening over the condition's baseline level before the aggravation.
What you have to prove
A secondary claim needs the same backbone as any service-connection claim, aimed at the link:
- A current diagnosis of the secondary condition.
- An already service-connected primary condition.
- A medical nexus — an opinion that the primary "at least as likely as not" caused or aggravated the secondary.
The nexus is the heart of it. Read how to file your own claim for the mechanics of building and submitting that evidence.
Common secondary chains
Some links come up over and over — sleep apnea connected to PTSD, depression or anxiety secondary to chronic pain, hypertension discussed alongside PTSD, radiculopathy off a service-connected back condition, migraines tied to a head injury. Treat these as starting points to investigate with a provider, not guarantees — your records and a medical opinion decide it.
How to find your likely secondaries
Pick your service-connected condition in the Secondary Conditions Finder to surface commonly linked secondaries, the medical mechanism, and a nexus-strength read. Then, because each new secondary gets its own rating, run the result through the VA Combined Rating Calculator to see how it would actually move your combined number.
Key takeaways
- A secondary is caused or aggravated by an existing service-connected condition (38 CFR 3.310).
- It can be service-connected even though it didn't start in service.
- You need a current diagnosis, a service-connected primary, and a medical nexus linking them.
- Each secondary gets its own rating that then combines with the rest.
Frequently asked questions
- What is a secondary condition in a VA claim?
- A secondary condition is a disability that was caused or aggravated by a disability VA has already service-connected. Under 38 CFR 3.310, the new condition can be service-connected too, even though it didn't begin during service, if you can medically link it to the primary.
- What do I have to prove for a secondary claim?
- Three things: a current diagnosis of the secondary condition, an existing service-connected primary condition, and a medical nexus opinion linking the secondary to the primary. The link is the piece most secondary claims live or die on.
- Does 'aggravation' count, or only conditions the primary caused?
- Both count. 38 CFR 3.310 covers a non-service-connected condition that is permanently worsened (aggravated) by a service-connected one, not just conditions the primary directly caused. VA compensates the degree of aggravation over the condition's baseline level.
- Can a secondary condition raise my combined rating?
- Yes. A newly service-connected secondary gets its own rating, which then combines with your existing ratings using VA math. Whether it raises your overall rating depends on where it lands and how it combines.
Sources
- 38 CFR 3.310 — secondary service connection (caused or aggravated): https://www.ecfr.gov/current/title-38/chapter-I/part-3/subpart-A/section-3.310
- VA — How VA decides service connection: https://www.va.gov/disability/eligibility/
- 38 CFR 4.25 — combined ratings table (how a new secondary combines): https://www.ecfr.gov/current/title-38/chapter-I/part-4/subpart-A/section-4.25
