Can a Risk Factor Become Causative in California?

By Robert G. Rassp, Esq.

This article is guaranteed to give you a headache or at least make your head spin. Now, the only risk factor for head spinning I have is a propensity to write these articles when I am bored and I do not want to do real work. So what is causing your headache? Reading this article? Too little sleep last night? Had too many drinks last night? All stressed out? All of those are risk factors for causing a headache. “Headaches” take a 3% WPI rating in Chapter 13 of the AMA Guides. So what is directly causing your impairment due to the headache?

During the California Society of Industrial Medicine and Surgery (CSIMS) annual summer educational program, we were asked to attend and participate in a break out session for physicians who specialize in internal medicine. During both the break out session and the plenary session on apportionment, the number one question on the minds of all physicians is what is the role of risk factors on the question of apportionment of permanent disability as required under Labor Code sections 4663 and 4664?

Both Labor Code sections require physicians to determine how much permanent disability is directly caused by an industrial injury and how much is caused by “other factors” such as pathology, pre-existing or subsequent injuries or retroactive work restrictions. See Escobedo vs. Marshalls (2005) 70 Cal. Comp. Cases 604. Then the physician shall “parcel out” percentages of disability to each industrial injury if there are successive industrial injuries to the same part of body that become permanent and stationary at the same time. See Benson vs. WCAB (2009) 74 Cal. Comp. Cases 113.

Physicians need to only consider two published cases in order to determine apportionment from a strictly medical standpoint – Escobedo and E.L. Yeager vs. WCAB (Gatten) 71 Cal. Comp. Cases 1687 (2006). The Gatten case simply states that a medical report constitutes substantial evidence on apportionment if the physician indicates approximately what percentage of permanent disability is directly caused by an industrial injury and what percentage is caused by other factors based on reasonable medical probability and the physician's experience, knowledge, education, abilities and skills.

But what about the influence of such risk factors as obesity, age, gender, race, smoking, and genetics? How do these risk factors play into consideration of apportionment in alleged industrial injuries to the heart, hypertension, diabetes and other internal medical conditions? Six and a half years after SB 899 was enacted, there are no WCAB en banc, Court of Appeal or Supreme Court published decisions that address the role of risk factors in apportionment in a case involving an internal medical condition such as heart disease, hypertension or diabetes.

However, from a medical standpoint, a risk factor is not a pathology; rather, it is a possible contributing factor to causation of a disease process. See the WCAB panel decision of American Airlines vs. WCAB (Milivojevich) (2007) 72 Cal. Comp. Cases 1415 (writ denied) wherein hyperlipidemia (high cholesterol) was only a risk factor but not causative of heart disease and apportionment was not permitted).

Remember, the Escobedo and Gatten cases involved injured workers who had orthopedic medical conditions that included degenerative disc disease or degenerative joint disease and those cases did not involve risk factors such as what could affect an internal medical condition like heart disease, high blood pressure or diabetes. In cases that involve claims of industrial injury to the heart, hypertension and aggravation of diabetes the decisions in Escobedo and Gatten may not give any guidelines as examples.

We know that if you put 100 people in the same room who are considered “obese” or who have a 20-pack-a-year smoking history or who are African-American men or people over the age of 60 from Eastern European descent, you cannot predict with reasonable medical probability who within any such homogenous group would develop heart disease, hypertension or diabetes. Similarly, in a room with 100 women over the age of 80, you cannot predict with reasonable medical probability which ones are able to play a game of tennis, based on diagnostic imaging of everyone's spine and which ones cannot due to degenerative arthritis. Isn't degenerative arthritis a pathology and not a risk factor? So you can see how complicated this whole area of apportionment due to pathology or risk factors is and how it takes physicians down a slippery slope.

You may argue that stress is a “risk factor” as well and if you put 100 people in a room who are in stressful jobs you cannot predict with reasonable medical probability who in that group will develop heart disease, hypertension or diabetes. However, there is the argument that stress is a pathology, too, since we know there are biochemical reactions to physical and emotional stress, i.e., an increase in catecholamines that affect blood pressure, heart rate and the vascular system.

We know that a risk factor is not a “pathology” because risk factors for anything are based on statistical probabilities and epidemiological data. Individuals with a risk factor such as obesity, old age, gender, smoking, sedentary lifestyle, etc. has nothing to do with predicting whether any given individual will develop a medical condition, disease process or impairment of function.

Physicians are scientists by training, education, experience and skill. They want exactitude for the diagnosis, treatment, prognosis, causation of a medical condition and reasonable scientific certainty for outcomes. The medical-legal issue of apportionment of permanent disability is a troubling area for physicians to get their arms around because it is a non-scientific albatross. There is no exactitude in the final analysis of “approximately what percentage of permanent disability is directly caused by the industrial injury and what percentage of permanent disability is caused by other factors.” There is also confusion over what causes an industrial injury and what causes permanent disability, which are two separate medical-legal analyses required by physicians in every case.

All physicians can do is use his or her best clinical judgment based on the history of the patient and the physician's analysis of all pertinent facts. There is a comfort zone emerging among physicians who specialize in internal medicine and who evaluate industrial injury cases that there is a point at which a risk factor does become causative of impairment. This is a moving target in any given case and probably depends upon how long a person has had a risk factor occurring, how many risk factors for a given medical condition is occurring at the same time and if there is any evidence that risk factors played a role in the person's family history.

So if a injured worker is claiming cumulative injury to his heart and hypertensive cardiovascular disease due to 20 years of industrial stress and strain, if his or her parents both had heart disease and hypertension, it is reasonable that a physician could consider a risk factor of family history as partially causative of impairment due to heart disease and hypertension. The opposite is also true - if there is no family history of heart disease or hypertension then there cannot be apportionment to that risk factor because there is no evidence of the risk factor in the first place.

Can you even say that a person with certain risk factors causes an impairment to be worse for him or her than if he or she did not have a risk factor? This is too speculative for any physician to say because there has to be evidence that a risk factor became causative of impairment.

The additional problem physicians have with the question of apportionment under Labor Code section 4663 and the determination of overlap under Labor Code section 4664 is the legal requirement that the physician determine what permanent disability “is directly caused” by the industrial injury. Attorneys know the term, “direct causation” to usually mean “proximate cause” or “but for “x” occurring, “y” would not have occurred as and when it did. In other words, “but for the industrial injury, the impairment would not have occurred how and when it did.”

We know the troubling case of the construction worker who has long standing non-industrial diabetes who steps on a nail at work and eventually has a below knee amputation due to poor circulation from the diabetic condition. Is the below knee amputation (a 28% WPI rating by the way) directly caused by the industrial injury or is there apportionment to the diabetes? There is no consensus between the WCAB panels or the trial judges how to evaluate apportionment in this type of case.

There is absolutely no published WCAB en banc decision or any appellate court decision that defines what is meant by permanent disability that is “directly caused by the industrial injury.” Direct causation of permanent disability has never been defined in the context of apportionment under SB 899, nor is it defined in the Escobedo and Gatten cases. So can a risk factor become causative of a permanent disability? Probably. The physicians at the CSIMS annual summer convention made it abundantly clear that they would like some guidance from the courts to properly and reasonably assess apportionment using their skills as scientists and not as speculators. We all look forward to a case that defines “directly caused.” So take some Advil or Tylenol for that headache and remember, there is no 3% impairment for it because you failed to prove your headache is permanent.

© 2010 Robert G. Rassp, All rights reserved. Reprinted with permission.