VA Secondary Conditions: How Secondary Service Connection Works
A secondary condition is a disability caused or made worse by a condition the VA already rates. Under 38 CFR 3.310, it gets service connected and rated on its own. You need three things: a current diagnosis, a service-connected primary condition, and a medical opinion that the link is "at least as likely as not." Here is how the rule works, the chains veterans most often claim, and what evidence the VA looks for.
TL;DR
- 38 CFR 3.310(a): a disability "proximately due to or the result of" a service-connected condition is itself service connected.
- 38 CFR 3.310(b): if a service-connected condition makes a non-service-connected one worse, the VA rates the added severity above a medical baseline.
- You need a diagnosis, a service-connected primary, and a medical nexus opinion that it is at least as likely as not (50% or more) that the primary caused or worsened the secondary.
- An opinion that only addresses causation and skips aggravation is inadequate (El-Amin v. Shinseki, 26 Vet. App. 136 (2013)).
- Common chains: knee to hip or back, back to radiculopathy, PTSD to sleep apnea or hypertension, diabetes to neuropathy. Each one still needs medical evidence in your file.
What is a secondary condition for VA disability?
A secondary condition is a disability that grew out of a condition you are already service connected for. You do not have to show it started in service. You show it came from, or got worse because of, the primary condition.
The rule is 38 CFR 3.310(a): "disability which is proximately due to or the result of a service-connected disease or injury shall be service connected." Once granted, the secondary condition "shall be considered a part of the original condition," and it gets its own rating that combines into your total.
A primary condition rated at 0% still counts. It is service connected, so it can support a secondary claim.
What is the difference between causation and aggravation?
There are two ways to win a secondary claim. You should argue both when the facts support it.
- Causation (3.310(a)). The service-connected condition caused the new one. Example: a bad knee changed how you walk for years, and a doctor finds that caused your hip condition.
- Aggravation (3.310(b)). You had a condition that was not from service, and a service-connected condition made it worse beyond its natural progress.
The courts built this rule before it was written into 3.310. In Allen v. Brown, 7 Vet. App. 439 (1995) (en banc), the court held that secondary service connection covers aggravation of a non-service-connected condition. In El-Amin v. Shinseki, 26 Vet. App. 136 (2013), the court held that a VA opinion addressing only causation, not aggravation, is not adequate.
What is the baseline rule for aggravation?
For an aggravation claim, the VA only pays for the added severity. Section 3.310(b) says the VA will not concede aggravation unless the baseline level of severity is shown by medical evidence:
- created before the aggravation started, or
- the earliest medical evidence created between the start of aggravation and the evidence showing your current severity.
The VA then rates the baseline and the current level under the rating schedule and subtracts the baseline and any natural progress. What is left is the rating you receive for the aggravation. This makes old treatment records valuable. Gather them early.
What are the most common secondary condition chains?
These are chains veterans often claim. None of them is automatic. Each one depends on your diagnosis, your records, and a medical opinion about your case.
| Service-connected primary | Secondary conditions often claimed | Where to read more |
|---|---|---|
| Knee condition | Hip condition, low back condition, the other knee (from favoring one side) | Knee ratings |
| Back condition | Radiculopathy (sciatica) in one or both legs, bowel or bladder problems | Back ratings |
| PTSD | Sleep apnea, GERD, hypertension, erectile dysfunction (including from medication side effects) | PTSD secondary conditions |
| Tinnitus | Migraines, anxiety or depression | Tinnitus ratings |
| Type 2 diabetes | Peripheral neuropathy, erectile dysfunction, kidney disease, eye conditions | Your treating provider |
Side effects of treatment count too. If a medication for a service-connected condition caused a new problem, that can be a secondary claim under 3.310(a).
Timing does not defeat a secondary claim. In Frost v. Shulkin, 29 Vet. App. 131 (2017), the court held that a secondary condition can be service connected even if it started before the primary condition was service connected.
Some links are already written into the regulation. Under 3.310(c) and (d), certain heart conditions after leg amputations, and certain conditions after a moderate or severe TBI (such as Parkinsonism and unprovoked seizures), are presumed secondary in the absence of clear evidence to the contrary.
Get the Secondary Conditions Map ($37) to see which secondaries to screen for from each primary condition and what evidence each one needs.
What evidence do you need for a secondary claim?
Every secondary claim rests on three elements:
- A current diagnosis of the secondary condition from a medical provider. For sleep apnea, that usually means a sleep study. For radiculopathy, it may mean a nerve test or a documented neurologic exam.
- A service-connected primary condition. Check your rating decision or code sheet to confirm it is service connected.
- A medical nexus opinion that it is "at least as likely as not" (a 50% or greater probability) that the primary caused or aggravated the secondary.
The nexus opinion is where most secondary claims win or lose. A strong opinion rests on an accurate history of your records and explains its reasoning. The court said most of an opinion's weight comes from that reasoning (Nieves-Rodriguez v. Peake, 22 Vet. App. 295 (2008)). A good opinion also addresses both causation and aggravation.
The clinician must review your records and write the opinion in their own words. Nobody should hand a doctor a finished opinion to sign. What you can do is give the clinician an organized packet: the relevant records with page numbers, a timeline, and the legal standard the opinion needs to address.
What else helps a secondary claim?
- Your own statement (VA Form 21-4138) describing when the new symptoms started and how they relate to the primary condition. Write only what you actually experienced.
- Buddy statements (VA Form 21-10210) from people who saw the change, like a spouse who noticed you started snoring and stopping breathing at night.
- Treatment records that mention the connection, such as a provider noting an altered gait from a knee injury.
How do you file a secondary claim?
File on VA Form 21-526EZ, online or by mail, and list the condition as secondary to the service-connected one. Name the primary condition clearly. If you are not ready to file, an Intent to File (VA Form 21-0966) holds your possible effective date for one year (38 CFR 3.155).
If the VA schedules a C&P exam, go to it. Our C&P exam tips explain how to prepare and how to spot an inadequate opinion. To see how a new secondary rating would change your total, use the VA disability calculator.
Frequently asked questions
Can a 0% service-connected condition support a secondary claim?
Yes. A 0% rating still means the condition is service connected, which is what 38 CFR 3.310 requires.
Do I need a doctor's opinion for a secondary claim?
In most cases, yes. The VA needs medical evidence linking the two conditions. The VA may order its own opinion at a C&P exam, and you can also submit an opinion from your own licensed provider.
What does "at least as likely as not" mean?
It means a 50% or greater probability. The opinion does not need to be certain. It needs to show the link is at least as likely as not, with reasoning.
What if the VA denied my secondary claim?
Read the denial for the missing element. If the VA opinion ignored aggravation, that can be an error under El-Amin. You can request a Higher-Level Review, file a Supplemental Claim with new evidence, or appeal to the Board. Filing within one year of the decision protects your effective date (38 CFR 3.2500).
Does a secondary rating combine with the primary?
Yes. It is rated on its own and combined with your other ratings under 38 CFR 4.25, unless it overlaps the same symptoms already rated (38 CFR 4.14).