"I already had diabetes. Does that ruin my claim?"

The rule

You do not have to be healthy to be covered. If work caused or contributed to your disability, that portion is compensable, and a pre-existing condition that made you more vulnerable does not defeat the claim.

What the carrier will do instead is apportion — attribute part of your permanent disability to the non-industrial condition under Labor Code §§ 4663 and 4664, reducing what it owes.

Why most apportionment opinions fail

Under Escobedo, an apportionment opinion must be substantial evidence. That means the physician has to explain how and why the non-industrial factor caused a specific percentage of the permanent disability.

A sentence that says "50% apportioned to pre-existing degenerative disease" and stops is not substantial evidence. It is a conclusion without reasoning, and it does not survive a proper challenge.

A very large number of apportionment opinions are exactly that sentence. What makes one hold up.

And note the direction of travel: after Lindh, an asymptomatic pre-existing condition — including a genetic predisposition — can support apportionment. So the argument is real and it has to be met on the reasoning, not dismissed.

Conditions that come up most

Diabetes — relevant to healing, neuropathy, infection risk, and amputation. It also makes some injuries far worse, and worsening caused by the industrial injury is compensable even where the underlying condition is not.

Degenerative disc disease and arthritis — present in most adults over forty and used constantly. That page.

Prior surgeries and prior injuries, including a prior award, which raises § 4664(b) and a presumption that the prior disability continues.

Obesity, hypertension, and cardiac conditions, particularly in heat and exertion cases.

The thing to do, and it is counterintuitive

Disclose everything, early, in your own words.

People hide prior conditions out of fear they will be used against them. They will be found — the records exist, and they will be obtained. Disclosed late, they look like concealment and they damage your credibility, which in a disputed case is close to the whole case. Disclosed early, they are just facts, and they may be the most valuable facts you have.

Because here is the other side of it: where a pre-existing disability combines with a new work injury to leave you far more disabled than either alone, the Subsequent Injuries Benefits Trust Fund exists to pay that difference. Disability apportioned away from your employer is often precisely the disability SIBTF is designed to address. How that works.