Causation Standards and Medical Experts
At the 2016 National Workers’ Compensation & Disability Conference, Stuart Colburn from Downs Stanford P.C and Jacob Lazarovic, M.D., from Broadspire explained causation standards that can assist in defending soft tissue claims.
Causation standards vary significantly by jurisdiction. The exact same argument in two different states can result in two different results based on how judges in that state interprete the information.
An important element of any causation argument is evidence-based medical guidelines. It is important to focus on these industry-accepted standards, which can be applied regardless of the jurisdiction.
NIOSH standards for determining causation:
- Is the disease present?
- What is epidemiology behind condition?
- Evidence of exposure
- Other relevant factors.
- Validity of evidence
- Evaluation and conclusions.
Bradford-Hill Criteria – Outlines a number things to consider in determining causation:
- Strength – To what degree is the exposure associated with the outcome?
- Consistency – Has the association been seen repeatedly across a variety of patients and situations?
- Specificity – Is the observed exposure limited to the exposures and outcomes?
- Temporality – Does the exposure always proceed the outcome?
- Biologic Gradient – Is there a dose-response relationship between the exposure and the outcome?
- Plausibility – Is there a physiological basis for the observed association?
- Cohearance – Does the cause-and-effect association seriously conflict with generally known facts about the natural history and biology of the disease?
- Experiment – Is the frequency of the associated events affected by efforts to decrease the exposure?
- Analogy – Does an exposure with a similar action cause the outcome?
Other key concepts:
- Aggravation – Workplace factors permanently worsen pre-existing conditions. There is significant variation among states on whether this can be a compensable workers’ compensation injury.
- Exacerbation – Workplace factors temporarily worsen a pre-existing condition.
- Apportionment – Allocation of causation among multiple factors.
It is very important to use the appropriate medical expert for the case. If you are constantly using the same expert, this will undermine your credibility and the credibility of that physician. A good medical expert will not only be well qualified, but they must be able to write a good report that clearly explains their opinions. Make sure you have looked into the expert’s background to ensure there are no recent investigations against them, which could come up during depositions. Pick experts that are believable, not those that tell you what you want to hear.
When you are getting a peer review or IME it is important to consider your audience. Is it the treating doctor, a state doctor, the injured worker or their attorney, or just a judge.
The American Medical Association has published AMA Guides to Evaluation of Disease and Injury Causation. This is a resource used by physicians to determine medical causation for a wide variety of orthopedic injuries. It considers both occupational and non-occupational exposures.
Diagnostic Imaging
Interpreting diagnostic images is not a black and white thing. Multiple radiologists can look at the same images and come up with different conclusions. A study done in this area showed that multiple radiologists disagreed with each other 30% of the time. Even more striking, when they viewed the same image at different times, they disagreed with their initial diagnosis 25% of the time. It is very important that you obtain a radiology peer review to look at the actual images to see if they agree with the interpretation of the report. You cannot assume the interpretation is accurate.
In a study done by the Spine Journal, they sent the same set of MRI images to ten diffrent facilities. The average error rate in interpreting the results was 12.5% and the average miss rate was 43.6%. The training and experience of the radiologist is the most-important factor in obtaining an accurate MRI interpretation. This is a very specialized field right now.