Under 38 CFR 3.310, a disability that is proximately due to - or aggravated by - a service-connected condition is itself service-connected. This is the largest category of missed claims, because the second condition often develops years later and does not feel connected to service at all. It is also the theory behind many of our condition guides, such as sleep apnea secondary to PTSD and hypertension secondary to sleep apnea.
For the full picture of how the VA connects any condition to service - direct, presumptive, secondary, and aggravation - see our guide to how VA service connection works.
Frequent secondary pathways
- Sleep apnea secondary to PTSD or to allergic rhinitis
- Hypertension secondary to PTSD or obstructive sleep apnea
- GERD secondary to long-term NSAID use for service-connected pain
- Depression secondary to chronic pain or functional loss
- Opposite-side knee or hip strain secondary to altered gait
- Radiculopathy secondary to a service-connected spine condition
Where veterans start
Every case is different, and there is no obligation at any step. When veterans want to understand what their records actually support, these are the two most common starting points:
- Medical records review
A licensed physician reviews your records for a $250 flat fee and identifies which conditions the available evidence may support. The fee is refunded in full if nothing supportable is identified.
- Nexus letter
When the records support one, a licensed provider writes the medical opinion that addresses the link between your condition and your service or an already service-connected disability.
Causation versus aggravation
Two different arguments are available, and a strong opinion usually addresses both. Causation says the service-connected condition brought the second condition into existence. Aggravation says the second condition existed independently but was made permanently worse. Aggravation claims are rated on the increment of worsening, so establishing the baseline severity matters - which is what a paid medical records review is designed to document before a nexus letter is written. Because a secondary rating combines with your existing ones, you can estimate the combined effect with our VA disability calculator.
The VA claim exam
After the claim is filed, the VA usually schedules a claim exam - often called a C&P exam - where a clinician examines the condition and reports what the rater relies on. Our guide to what to expect at a VA claim exam covers the appointment.