Proving Major Cause Of Preexisting Conditions

If you are treating a patient whose need for treatment has more than one cause, can you quantify the amount each cause contributes? If your patient has a history of a condition, or even a previously undetected condition, in the same area as a recent work injury, can you state whether the injury has “combined” with it? And can you quantify the causal role of each in the patient’s present disability and need for treatment?


More specifically, if a 50-year-old mill worker comes to you for a back injury Suffered at work and tests reveal that, as with most people of his age, degenerative changes have occurred in his spine (which were unknown or unsymptomatic before the injury), are you prepared to quantify how this condition compares with the work injury in causing the need for back surgery?

The potential impact of “preexisting conditions” on Oregon workers cannot be overstated. It could literally destroy the protective and remedial purposes of Workers Compensation laws and wreak financial catastrophe on workers such as the 50-year-old mill worker with a back injury.

So, we revisit “preexisting conditions,” as now defined in workers compensation law. Doctors are increasingly being called upon to quantify the relative causal contributions of recent work injuries and work-related diseases as compared to “preexisting conditions” (defined in our Winter 1996, Vol. 3 issue), which “predispose” a worker to the disability or need for treatment for which a workers’ compensation claim has been made.

One of the troubling aspects of the new legal definition of “preexisting condition” is how open-ended it is. After listing specific examples, it says, “…or similar condition that contributes or predisposes a worker to disability or need for treatment …”.

One may argue that a person’s height “predisposes” him to a head injury on the job that a shorter worker would have avoided. Indeed, one could argue that having any body part predisposes one to suffering injury! Also, since most people suffer age-related degeneration in the spine, it means that the older a worker is, the more likely he/she will be legally disqualified from workers’ comp benefits for a back injury. Thus, if the degenerative changes noted are normal for someone of your patient’s age, this observation could he made: a denial may arguably be unconstitutionally discriminatory based on the patient’s age.

Also, remember that the issue centers around the patient’s disability or need for treatment, not necessarily a diagnosed condition. This distinction can be crucial.

Simply stating that a work injury precipitated the disability or need for treatment does not make it the major cause of the resulting “combined condition,” disability or need for treatment. You must call it the major (51% or more) cause. Nor is your medical opinion that the work injury pathologically worsened the preexisting condition legally sufficient to conclude that the work injury in question is the major contributing cause. The quantitative contribution of each cause must be weighed to establish the primary (major) cause of the worker’s need for treatment.

The practical result is that the major cause is simply the one which the doctor says it is. It is more a question of philosophy than medicine. Under this law, major cause, like beauty, is in the eye of the beholder, in this case the doctor. If you as the qualified treating physician believe that the work injury is the major cause, then you should say so and explain your position. If a person was asymptomatic before an injury, then the major cause of the need for treatment can be the industrial exposure, regardless of “pre-existing condition.”

In other words, even though a pre-existing condition exists, the inquiry is whether or not the occupational exposure is the major cause of the need for treatment. If the industrial event is the cause of a worsening of a condition, it may well be the major cause of disability or need for treatment. If the need for treatment comes in major part from symptoms supported by objective findings caused by the industrial event, it should be paid for by workers’ compensation insurance.

This article was prepared by Robert L. Chapman