The VA quietly revised a piece of its adjudication manual that controls how raters decide secondary service connection claims — specifically when a service-connected (SC) disability aggravates a non-service-connected (NSC) disability. The change appears in M21-1, Part V, Subpart ii, Chapter 2, Section D (V.ii.2.D), changed May 1, 2026, and updates the language to conform to the Federal Circuit's decision in Spicer v. McDonough, 61 F.4th 1360 (Fed. Cir. 2023). The underlying regulation, 38 CFR 3.310, has not been rewritten, but the way VA adjudicators are now instructed to apply it has shifted. If you have a current claim involving a condition that was made worse by a service-connected condition — or you're thinking about filing one — this update changes the framing of how your evidence gets weighed. Below is a plain-English breakdown of what the manual revision says, who it touches, and how to position a claim under the updated guidance.

What Secondary Service Connection and Aggravation Mean

Secondary service connection is the legal pathway that lets you get a disability rating for a condition that wasn't directly caused by service, but was caused — or made worse — by a condition that was caused by service. It lives in 38 CFR 3.310. There are two flavors:

  1. Direct secondary service connection — your SC condition causes a new condition. Classic example: service-connected diabetes leads to peripheral neuropathy.
  2. Aggravation under 3.310(b). You already have a non-service-connected condition, and it would be less severe but for a service-connected condition. Since May 1, 2026, VA no longer asks whether the worsening went beyond natural progress, and the worsening does not have to be permanent.

The aggravation prong has always been the harder of the two. The rule requires you to establish a baseline level of severity for the NSC condition before the SC condition started aggravating it, then show the current level of severity, and then show the increase is due to the SC condition. Before May 2026, VA also asked whether the increase went beyond the natural course of the disease and treated aggravation as permanent worsening; the manual change removed both. In practice, VA raters have applied that framework inconsistently, sometimes denying claims because the baseline was poorly documented or because the medical opinion didn't use the exact magic words.

The M21-1 is the internal procedures manual VA employees use to process claims. It doesn't have the force of regulation, but it controls day-to-day decision-making. When the manual changes, your claim outcome can change with it.

What This Update Actually Changes

According to the VA's published guidance, the revision to M21-1, Part V, Subpart ii, Chapter 2, Section D updates the language on secondary service connection and aggravation of an NSC disability by an SC disability "in accordance with the holding in Spicer v. McDonough." The change is targeted at the analytical framework adjudicators use when applying 38 CFR 3.310(b).

What that means in practice: the manual now reflects the court's interpretation of how aggravation is to be established and how the evidentiary burden is properly applied. The Spicer decision addressed how VA must treat the relationship between an SC condition and the worsening of a separate, non-service-connected condition, and the manual update brings VA's internal procedures into alignment with that ruling. In practice, the manual now asks whether the NSC condition would be less severe but for the SC condition, including when the SC condition got in the way of treating it. VA no longer considers natural progress, and the worsening does not have to be permanent. A baseline from medical evidence is still required, and VA rates the difference between the baseline and the current severity.

The key takeaway: if your claim was previously denied — or if you're filing now — VA adjudicators are required to use the updated framework. That includes how they read medical opinions, how they handle baseline-versus-current-severity questions, and how they decide whether the NSC condition would be less severe but for the SC condition, without weighing natural progression.

For the full revision history and the manual section itself, see the VA's M21-1 change tracker: https://www.knowva.ebenefits.va.gov/system/templates/selfservice/va_ssnew/help/customer/locale/en-US/portal/554400000001018/topic/554400000004657/VA-Changes-By-Date.

Because the underlying regulation (3.310) hasn't been rewritten, this isn't a brand-new benefit category. It's a procedural recalibration. But procedural recalibrations frequently shift outcomes — particularly in cases that turned on how the rater interpreted ambiguous medical evidence.

Who Should Pay Attention

You should read this update carefully if any of the following describe your situation:

  • You have a denied secondary aggravation claim. If VA denied a claim that your SC condition aggravated an NSC condition — particularly if the denial cited weak baseline evidence, lack of a clear medical nexus, or natural progression — the updated framework may change the analysis on a supplemental claim or appeal.
  • You have a service-connected condition and a separate, untreated or undiagnosed worsening condition. Common pairings include service-connected knee or back conditions altering gait and aggravating hip, opposite-knee, or lumbar conditions; service-connected mental health conditions aggravating hypertension or GI conditions; service-connected sleep apnea aggravating cardiovascular conditions; service-connected medication regimens aggravating kidney or liver function.
  • You have a pending claim that hasn't been decided yet. Raters working your claim should be applying the updated manual. If you have new evidence that addresses baseline severity or the nexus between your SC condition and the worsened NSC condition, now is the time to submit it.
  • You're preparing a Higher-Level Review or Board appeal. The updated guidance is the standard the reviewer should be applying. Pointing to the revised section can frame your argument.

This update does not, by itself, grant anyone a rating. It changes how VA is required to analyze the claim.

What to Do Next

Concrete steps you can take:

  1. Pull your last decision letter. Read the reasons-and-bases section. If your secondary aggravation claim was denied, identify the specific rationale — was it baseline evidence, the medical opinion, or a finding of natural progression?
  2. Identify the right filing lane. If you're within one year of the decision, you generally have options including a Supplemental Claim with new and relevant evidence, a Higher-Level Review, or a Board appeal. Each lane has different rules. An accredited VSO or attorney can help you pick.
  3. Get a medical opinion that addresses the updated framework. A strong private medical opinion (sometimes called a nexus letter or DBQ-supported opinion) should explicitly address: (a) the baseline severity of the NSC condition before the SC condition started aggravating it, (b) the current severity, and (c) the medical reasoning on the current question: whether the condition would be less severe but for the SC condition, including any effect on treatment.
  4. Submit new and relevant evidence. For a Supplemental Claim, new and relevant evidence is the threshold. Old records you never submitted, updated imaging, specialist notes, and a new medical opinion all qualify.
  5. Don't go it alone on complex secondary aggravation theories. Consult an accredited VSO or VA-accredited attorney for case-specific strategy.

Evidence That Strengthens a Claim Under This Rule

For a secondary aggravation claim under 38 CFR 3.310(b), the strongest evidentiary record usually includes:

  • Baseline documentation of the NSC condition. Imaging, exam findings, functional assessments, or treatment notes from before the alleged aggravation began. The earlier and more detailed, the better.
  • Longitudinal records showing progression. Continuous treatment notes that track the NSC condition over time so a clinician can show when the worsening began and how it tracks the SC condition.
  • A private medical opinion or IME that explicitly identifies baseline severity, current severity, and the mechanism by which the SC condition has aggravated the NSC condition. Opinions that simply state "it is at least as likely as not" without explanation tend to get discounted.
  • Specialist evaluations. Orthopedic, cardiology, pulmonology, psychiatric, or other specialist input is often more persuasive than primary care notes on technical aggravation questions.
  • Lay statements from you, family, or fellow service members describing functional changes you've observed, particularly when medical records are sparse.

Evidence that ties facts to the regulatory elements — not just "my back hurts more now" — moves the needle.

Common Mistakes to Avoid

  • Filing a bare claim without a medical opinion addressing aggravation. The rater isn't required to develop your theory for you.
  • Confusing causation with aggravation. They are two separate paths under 3.310. Be clear which one your evidence supports.
  • Ignoring baseline severity. Without a baseline, the rater cannot calculate the degree of aggravation, even if everything else is in order.
  • Submitting a generic nexus letter that doesn't answer the but-for question: would the condition be less severe but for the SC condition? Raters look for that specific issue.
  • Missing appeal deadlines after a denial. The decision review options have strict timelines.
  • Assuming the manual update automatically reopens your claim. It doesn't. You still have to file in the right lane.

Source & Getting Help

The revision is documented in the VA's M21-1 change tracker: VA Changes By Date. The affected section is M21-1, Part V, Subpart ii, Chapter 2, Section D (Secondary Service Connection and Aggravation of Non-Service-Connected Disabilities), and the underlying regulation is 38 CFR 3.310. Claim Raven's secondary service connection guide covers the current rule in full.

For a personalized read on whether this update affects a denial in your file, use Ask Raven to query the rule against your situation, or run Raven Scan on your decision letter to identify whether secondary aggravation was analyzed under the prior framework. For legal advice on appeals, supplemental claims, or filing strategy, consult an accredited VSO or VA-accredited attorney.