Writing the secondary nexus letter

The structure is identical to the direct nexus letter with one critical difference: instead of pointing to an in-service event, the doctor points to your service-connected primary condition.

Key opinion language

• “It is at least as likely as not that the veteran’s [secondary condition] was CAUSED BY the service-connected [primary condition].” (Causation theory)
• “It is at least as likely as not that the veteran’s [secondary condition] was AGGRAVATED BEYOND ITS NATURAL PROGRESSION by the service-connected [primary condition].” (Aggravation theory)
• “It is at least as likely as not that the veteran’s [secondary condition] was caused by medications prescribed to treat the service-connected [primary condition].” (Medication side-effect theory)

Pro tip

Have the doctor address BOTH causation AND aggravation, even if only one applies. If VA rejects causation, they may still grant on aggravation. Use phrasing like:

“It is at least as likely as not that the veteran’s [condition] was either caused by OR aggravated beyond its natural progression by the service-connected [primary].”

Use the generator

The secondary nexus letter generator walks you through the inputs and outputs a clean draft you can hand to your physician.

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