Secondary Service Connection: When One Condition Causes Another

What it is

Your body is connected. When one part gets hurt, other parts often pay the price. VA knows this. If you have a service-connected condition, and it causes a new condition, the new one can be service connected too. This is called secondary service connection.

There are two ways it works:

• Caused by. Your service-connected condition directly caused the new one. Example: years of limping on a service-connected knee led to hip arthritis.
• Made worse by (aggravation). You had a condition that wasn't from service, but your service-connected condition made it worse. In that case, VA can rate the extra damage.

Medicine counts too. If a drug you take for a service-connected condition causes a new problem, like stomach issues from pain pills, that can be secondary.

Common examples

• Knee or ankle problems leading to hip or back problems
• A back condition leading to nerve pain down the leg (radiculopathy)
• Diabetes leading to nerve damage in the hands and feet, or kidney problems
• PTSD or depression leading to sleep or weight problems that cause other conditions
• Medicine side effects, like acid reflux or erectile dysfunction

These are examples, not promises. Every case needs medical support.

Who qualifies

You need three things:

1. A current diagnosis of the new condition.
2. An existing service-connected condition.
3. A medical link showing the first condition caused or worsened the second. This is often called a "nexus opinion."

How to apply, step by step

1. Get a diagnosis. Make sure the new condition is written in your medical records with a clear name.
2. Ask your doctor for an opinion. A short letter that says the new condition is "at least as likely as not" caused or worsened by your service-connected condition, with a reason why, is very strong evidence. The reason matters more than the wording.
3. File an Intent to File if you need time to gather evidence. It holds your start date for one year.
4. File the claim on VA.gov (VA Form 21-526EZ). List the new condition and name the service-connected condition you think caused it.
5. Attend your claim exam. The examiner will be asked whether the conditions are linked. Explain when the new problem started and how it relates.
6. Read the decision closely. If VA denies it because of a weak exam opinion, a Supplemental Claim with a better doctor's letter is often the right next step.

Mistakes to avoid

• Not naming the cause. Tell VA exactly which rated condition you think caused the new one. Otherwise VA may only look at whether it happened in service.
• Skipping the "aggravation" angle. Even if you had a problem before, worsening can still be rated.
• Using a vague doctor's note. "Could be related" is weak. A clear opinion with medical reasons is strong.
• Forgetting about medicine side effects. They are a common and valid basis for secondary claims.
• Counting on a bigger total than you'll get. VA combines ratings using "VA math," so adding a 10% condition won't always raise your combined rating.

Related benefits

See our guides on disability compensation, filing your claim, the C&P exam, decision reviews and appeals, and Special Monthly Compensation.