Secondary service connection and aggravation

V.ii.2.D.1.a · Two ways the primary disability can establish secondary service connection

First, a service-connected disability can cause another disability: the additional disability resulted from it, or would not have happened without it. Second, it can make a separate, non-service-connected disability more severe. That includes a condition that would have been less severe if the service-connected disability had not interfered with treatment.

The manual calls this the but-for standard: compare what happened with what would have happened without the service-connected disability. The service-connected condition need not be the only cause. Do not replace this with a stricter proximate-cause test.

Aggravation does not have to be permanent. The current manual also directs VA not to consider natural progression of the non-service-connected disability when deciding this kind of aggravation claim. These instructions reflect Spicer and Ward; do not import the different in-service aggravation test into a secondary claim. The original block links 3.310, 1110, Allen, Spicer, and Ward for the governing authorities.

V.ii.2.D.1.b · A later diagnosis or award does not rule out an earlier causal relationship

There must be evidence that the additional disability resulted from, or would not have occurred without, the primary service-connected disability. But the primary disability did not have to be formally diagnosed or already service connected on the day the additional disability began.

The manual's example involves longstanding back and nerve symptoms that caused a fall and shoulder injury before the nerve condition was formally diagnosed or service connected. Credible history and a supporting medical opinion can establish that sequence. The later diagnosis and award do not, by themselves, defeat causation.

Verify the actual history and current status of the primary disability. Do not assume entitlement to a still-pending primary claim. When a secondary claim predates the primary claim, apply the separate effective-date procedure in V.ii.4.A.3.g; this causation rule does not supply an effective date by itself. The original also links Frost.

V.ii.2.D.1.c · Establish how severe the condition was before the added worsening

For secondary aggravation, the baseline is the condition's severity before the worsening attributable to the service-connected disability. A baseline is required both to establish entitlement on this basis and to determine the evaluation.

Look for medical evidence created before aggravation. If that is not available, consider the earliest medical evidence created between the onset of aggravation and receipt of the evidence establishing current severity. Also consider other credible evidence that helps establish the baseline, including lay evidence.

A lay statement may not establish the baseline by itself, but it can support the finding or show that more evidence needs to be obtained. Do not disregard it simply because it is not a medical report. Follow the lay-evidence procedure in V.ii.1.B.2 and the baseline-development steps that follow.

V.ii.2.D.1.d · Help obtain baseline evidence before deciding that it is missing

The claimant ultimately must provide evidence supporting a baseline, but VA still has its duty to assist. Obtain relevant identified evidence and consider an examination or medical opinion when the examination threshold is met.

The evidence should show severity before aggravation, or as soon afterward as possible while still preceding receipt of the evidence that establishes current severity. Missing a pre-aggravation treatment record does not automatically mean every possible baseline source has failed.

The rating activity makes the legal baseline determination from the whole record. An examiner can provide medical findings and analysis that help with it. When warranted under IV.i.1.B.1.e, request a claims-folder review and an opinion addressing whether the increased manifestations resulted from, or would not have occurred without, the service-connected disability. Do not add an already-established baseline as an extra prerequisite for ordering that warranted assessment.

V.ii.2.D.1.e · Check what the aggravation report actually answers

The report must separately provide the current severity of the claimed condition; an opinion on the required secondary-aggravation relationship; and an adequate medical explanation supporting that opinion.

The relationship question is whether there was any increase that would not have occurred without the service-connected disability, or whether the condition would have been less severe without it. Include interference with or impeded treatment when the record raises that possibility.

A report that only says the primary disability did not cause the secondary condition does not answer a separately raised aggravation question. Likewise, an unexplained conclusion or a permanent-worsening requirement does not satisfy the current instructions. Use the original-request and provider-correction rules to obtain what is missing; do not substitute your own medical conclusion.

V.ii.2.D.1.f · If the baseline still cannot be established after assistance is complete

The manual directs denial of secondary aggravation when no baseline can be established, but only after VA completes the necessary evidence assistance. That can include an examination or opinion when warranted. Missing baseline evidence at the start of development is not the same as an unsupported baseline after development is finished.

Never assume the baseline was zero percent just because the evidence does not establish it. The rating narrative must explain why the degree of aggravation cannot be determined from the available evidence and why the aggravation claim therefore must be denied.

Keep any separate causation or other service-connection theory under review. A baseline is part of this aggravation analysis; failure to establish it does not itself answer a distinct causation question. The original block links the records-assistance, examination, and pre-decision duty-to-assist procedures.

V.ii.2.D.1.g · Calculate the evaluation from the established current and baseline severities

For an aggravation grant, the rating activity determines what schedular percentage represents the established baseline and what percentage represents the current disability. Subtract the baseline percentage from the current percentage to obtain the evaluation attributable to aggravation.

This subtraction still applies when current severity is rated 100 percent, including a temporary total evaluation under 4.29 or 4.30. Do not treat a current total evaluation as automatically erasing the baseline deduction. Apply the correct rating criteria to each supported severity level; the tool does not infer those percentages from a diagnosis.

V.ii.2.D.1.h · Actual worsening can support service connection at zero percent

A condition can genuinely worsen without moving into a higher schedular percentage. When competent, credible evidence establishes worsening from an established baseline because of the service-connected disability, the manual directs a grant at zero percent if baseline and current severity fall in the same schedular evaluation level.

Do not require worsening by at least one full schedular level to establish secondary aggravation. Distinguish this supported zero-percent result from an unknown baseline: an unknown baseline must not be assumed to be zero. The original block links Browder and Hensley for the underlying distinction.