Pre-Existing Conditions
and Ohio Workers’ Comp
'You already had that problem' is the number-one defense employers use to deny claims. Ohio law doesn't require a perfect body — it requires proof that work made the condition worse.
If you’ve been told your workers’ compensation claim is denied because your injury was “pre-existing,” you’re not alone — and you’re not out of options. Employers and the BWC use the pre-existing condition defense more than any other argument to deny claims, but Ohio law is clear: if work substantially aggravated your condition, you are entitled to benefits. Attorney Mike Gruhin, an OSBA Certified Workers’ Compensation Specialist, has spent over three decades defeating the pre-existing condition defense for injured workers across Ohio.
The substantial aggravation standard
Ohio Revised Code § 4123.01(C)(5) defines the standard for pre-existing conditions in workers’ compensation. An injury is compensable if the work event caused a substantial aggravation of a pre-existing condition. The statute defines substantial aggravation as a worsening that is:
Documented by objective evidence
The aggravation must be supported by objective medical evidence — diagnostic imaging (MRI, X-ray, CT scan), clinical examination findings, nerve conduction studies, or similar verifiable medical data. Subjective complaints alone are insufficient.
Causally connected to the work event
A physician must opine, to a reasonable degree of medical certainty, that the workplace injury or exposure — not the natural progression of the condition — caused the worsening. The causal opinion must specifically address why the work event (not aging, lifestyle, or other factors) is responsible.
The standard is not “the work event was the sole cause.” It is not “the worker had a perfect body before.” The question is straightforward: did the work event make the pre-existing condition detectably and measurably worse? If yes, the claim should be allowed for the aggravation.
How to document substantial aggravation
Winning a pre-existing condition claim requires building a timeline of medical evidence that shows a clear “before” and “after.” Mike Gruhin’s approach focuses on three pillars of documentation:
1. Pre-injury baseline records
Gather all medical records related to the pre-existing condition before the work injury. This includes imaging, office visit notes, physical therapy records, and any prior surgical reports. These records establish the baseline — the condition’s severity before the work event. A 2023 MRI showing mild degenerative disc disease becomes a powerful tool when compared against a post-injury MRI showing a new herniation.
2. Post-injury diagnostic evidence
Obtain new diagnostic imaging and clinical evaluations after the work injury. The key is comparison — showing what changed. A radiologist who directly compares pre- and post-injury imaging and identifies new pathology provides the strongest possible evidence. Ask your doctor to specifically note any new or worsened findings compared to prior studies.
3. Physician causation opinion
Your treating physician (or a specialist retained for this purpose) must provide a written opinion stating, to a reasonable degree of medical certainty, that the work event substantially aggravated the pre-existing condition. The opinion must address the specific mechanism of injury and explain why the work event — rather than natural progression — caused the documented worsening.
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Common pre-existing condition scenarios
Degenerative disc disease + work lifting injury
A warehouse worker with documented mild degenerative disc disease lifts a heavy box and suffers a new lumbar disc herniation. The employer argues the herniation was inevitable. The evidence: pre-injury MRI shows degeneration but no herniation; post-injury MRI shows a new L4-L5 herniation. The treating neurosurgeon opines the lifting event caused the herniation. This is a textbook substantial aggravation — the work event created a new, measurably worse condition on top of the pre-existing degeneration.
Prior knee surgery + slip and fall at work
A factory worker who had ACL reconstruction three years ago slips on an oily floor and re-tears the ligament. The employer’s position: “The knee was already compromised.” Ohio’s response: it doesn’t matter. The worker had returned to full duty, was performing the job without restrictions, and the slip-and-fall caused a new, documented tear. The claim should be allowed for the aggravation.
Prior shoulder impingement + repetitive work
An assembly line worker with mild shoulder impingement develops a full-thickness rotator cuff tear after months of repetitive overhead work. The employer claims the tear is degenerative. The evidence shows the prior impingement was treated conservatively and the worker was functioning normally. The new tear is objectively documented and the treating orthopedist connects it to the repetitive work demands. The substantial aggravation standard is met.
Psychological conditions and workers’ comp
Ohio workers’ compensation covers psychological conditions — including depression, anxiety, and PTSD — when they arise from a physical work injury. This is known as a psychological overlay or psychiatric condition consequential to the physical injury. The condition is added to the existing claim as an additional allowed condition.
For example, a construction worker who suffers a severe spinal cord injury and subsequently develops clinical depression due to chronic pain and inability to work can have depression added to the claim. The psychological condition must be diagnosed by a qualified mental health professional and causally connected to the allowed physical conditions.
Ohio law is more restrictive for purely psychological claims — those without an underlying physical injury. Under O.R.C. § 4123.01(C)(1), a purely psychological condition is compensable only when it arises from specific, identifiable workplace events and is not a “gradual process” occurring over time. Claims based on cumulative workplace stress, management conflict, or general job dissatisfaction are generally not allowed. However, witnessing a traumatic workplace event (such as a co-worker’s death) or being the victim of workplace violence can support a purely psychological claim.
Employer defense tactics
When an employer learns you have a pre-existing condition, they deploy a predictable set of defenses. Understanding these tactics helps you and your attorney prepare:
“Natural progression” defense
The employer’s IME doctor argues the condition would have worsened regardless of the work event — that it was simply the natural progression of age-related degeneration. The counter: objective comparison imaging showing acute changes that are inconsistent with gradual degeneration.
“Failure to disclose” defense
The employer claims the worker hid the pre-existing condition during hiring or failed to disclose it on the FROI. While non-disclosure can create credibility issues, it does not legally bar a substantial aggravation claim. The medical evidence either supports aggravation or it doesn’t.
“Temporary aggravation” defense
The employer argues the worsening was only temporary — a flare-up that resolved on its own — and therefore does not constitute substantial aggravation. The counter: ongoing treatment records, persistent symptoms, and follow-up imaging showing the worsening is not resolving.
The “independent” medical exam
The employer sends you to a doctor of their choosing — an IME physician — who examines you for 15 minutes and writes a report concluding the condition is entirely pre-existing. These reports are often formulaic and conclusory. An experienced attorney like Mike Gruhin knows how to cross-examine IME doctors and expose the weaknesses in their opinions.
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