If you have a service-connected disability, and that disability has caused or aggravated another condition, that second condition may be ratable as secondary service connection. This is one of the most underutilized pathways in the VA benefits system. Tens of thousands of veterans are living with additional conditions caused by their primary disabilities — and not receiving any compensation for them because they never filed.
What secondary service connection means
Secondary service connection establishes a link between a primary service-connected condition and a secondary condition that was caused or aggravated by it. You don’t need to have injured your secondary condition in service. You need to demonstrate a medical nexus — a medical opinion connecting the dots between your primary condition and the secondary one. Examples: a knee injury (primary) causes hip pain from abnormal gait (secondary); PTSD (primary) causes sleep apnea (secondary, which is among the most commonly linked conditions); a back injury (primary) causes radiculopathy down the legs (secondary).
Common secondary conditions worth claiming
Sleep apnea secondary to PTSD or TBI. Strong medical literature linking both. Sleep apnea is rated at 50% when a CPAP machine is required — that’s a significant monthly payment on its own.
Radiculopathy secondary to back or neck conditions. Nerve pain radiating into arms or legs from a service-connected spinal condition is commonly ratable secondary. Each limb can be rated separately.
Erectile dysfunction secondary to PTSD, TBI, or diabetes. Rated as a separate condition, often at 0% rating but with Special Monthly Compensation (SMC) implications that add significant monthly compensation.
Migraines secondary to TBI. TBI-connected headaches are frequently underrated as migraines — the migraine rating schedule goes higher than the TBI headache rating schedule.
Depression and anxiety secondary to chronic pain conditions. Mental health conditions that develop in response to the stress of living with chronic service-connected pain are claimable.
Building the nexus letter
The nexus letter is the medical opinion that connects your secondary condition to your primary one. It needs to come from a medical professional and state in clear language that the secondary condition is “at least as likely as not” caused or aggravated by the primary service-connected condition. That “at least as likely as not” phrase — 50% probability or greater — is the VA’s standard. Your treating physician can write this letter, or you can obtain an independent medical opinion from a private provider who specializes in VA claims.