Secondary conditions are the most-asked-about VA claim strategy. Learn how to prove a secondary service connection, which condition pairings win at the BVA, and what evidence you need.
Secondary service connection under 38 CFR § 3.310 is the single most-discussed claim strategy in veteran communities. A secondary claim argues that a new condition was caused or permanently aggravated by an already service-connected disability. Common winning pairings include sleep apnea secondary to PTSD, radiculopathy secondary to back conditions, depression secondary to chronic pain, GERD secondary to PTSD medications, and erectile dysfunction secondary to diabetes or PTSD. The key to winning a secondary claim at the BVA is a strong medical nexus opinion that specifically addresses causation or aggravation under the 'at least as likely as not' standard. The examiner must explain the medical mechanism — not just state a conclusion. For aggravation claims, the opinion must establish a baseline severity of the secondary condition before aggravation began. Veterans should also submit lay statements describing how the primary condition led to or worsened the secondary condition, along with a timeline showing the progression. The BVA frequently remands secondary claims where the C&P examiner failed to provide an adequate rationale or did not address the aggravation prong of § 3.310(b).