What Is a VA Secondary Service Connection?

A VA secondary service connection lets you add a new disability to your VA rating by showing that it was caused — or made significantly worse — by a condition you're already service-connected for.

How it works in practice: If your service-connected knee injury changed how you walk, and those changes caused hip and lower back problems over the years — those new problems can be filed as secondary conditions. You're not starting from scratch proving military service caused them. You're showing that your military injury caused a chain reaction.

Common secondary connections:

• Sleep apnea secondary to PTSD (stress and sleep disruption often co-occur)
• Depression or anxiety secondary to chronic pain
• Diabetes complications (nerve damage, vision loss, kidney disease) secondary to service-connected diabetes
• Migraines secondary to TBI
• High blood pressure secondary to PTSD or sleep apnea
• Hip or back problems secondary to a service-connected knee or ankle injury

What you need to file a secondary claim:

1. An already-established service-connected primary condition
2. A current diagnosis of the secondary condition
3. A medical opinion linking the two — a statement from a doctor saying the primary condition "caused or aggravated" the secondary one. This is often called a nexus letter or an Independent Medical Opinion (IMO).

The VA's own C&P exam may provide this link, but if it doesn't — or if the examiner gives a negative opinion — a private nexus letter from your own doctor is often the most important thing you can get for a secondary claim.

Secondary conditions are rated on their own separate scale, and those ratings combine with your existing ratings to increase your overall compensation.