The decision about whether a case of documented COVID-19 illness is accepted as occupationally acquired and thus work compensable is made by insurers, or if contested, by judges or administrative bureaus. Causation for COVID-19 may be difficult to show because of the lack of accurate information and difficulty in meeting some of the criteria established by Bradford Hill. Nevertheless, physicians will be asked for medical records and documentation of illness. This article provides preliminary guidance to assist physicians in responding to insurers or workers compensation agencies' requests for information on the medial aspects of COVID-19.
Physicians may be asked whether a coronavirus 2019 (COVID-19) infection was work-related or meets jurisdictional requirements for coverage under workers' compensation. The current pandemic of COVID-19 cases includes cases identified in emergency medical technicians, nurses, physicians, and others with occupational exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Many of these health care professionals have filed workers' compensation claims. Much is still unknown at this time about the epidemiology, transmission, contagiousness, pathophysiology, and residual permanent organ damage associated with a COVID-19 infection, whether the patient has any recognized initial symptoms, or symptoms that might have required medical treatment. The information in this article should be considered preliminary and might change as the scientific knowledge surrounding COVID-19 evolves. If COVID-19 causes an aggravation of an underlying condition that causes additional permanent organ damage, in many jurisdictions the damage must be more likely than not (>50%) due to the occupational exposure; however, causation may be difficult to show because of the lack of accurate information and difficulty in meeting some of the criteria established by Bradford Hill. Two assessment examples are provided in the article to highlight some examples of known facts and formation of a medical opinion that is supported by reasonable explanations. This article will discuss how physicians can respond to requests for a causation opinion from workers' compensation insurers, or from administrative agencies.
The decision on whether a case is accepted for workers' compensation benefits is the responsibility of an insurance adjuster based on proper review of pertinent medical information. For certain conditions, including COVID-19, presumptions may apply in which it is assumed that a condition is related to an individual's occupation.
It is helpful to provide the decision makers the following information:
Documentation of the employee's description of workplace exposure(s) to known COVID-19 cases
Documentation of known sources of exposure at home or outside the workplace
Current epidemiologic literature on the incidence and prevalence of COVID-19 in specific occupations or the employee's specific work-place
It is the role of the medical practitioner to accurately and completely document the medical information necessary for all parties to make an informed decision.
Should COVID-19 cause an aggravation of an underlying condition that causes permanent organ damage, that damage must be more likely than not (>50%) due to the occupational exposure. It is the job of the physician to document the medical information based on the information available or that can be obtained. Some of the references in the article on rating COVID-19 cases for permanent impairment (in this issue) may be useful to send to the insurer's adjuster about known consequences of COVID-19. If a condition has not been reported in medical studies to accompany an infection or be a complication of COVID-19, then that condition would not be medically supported as caused by COVID-19, even in those who test positive for the virus. For example, currently there are no reports of permanent worsening of neck or low-back disorders from COVID-19, so a claim for low-back pain or exacerbation of a previous low-back disorder due to having had a positive test for COVID-19 would not be medically supportable. However, that decision would be case-specific and dependent on the individual facts.
Causation may be difficult, and in this circumstance harder, because of the lack of accurate information concerning meeting some of the criteria established by Bradford Hill, as illustrated in Box 1. Accurate information concerning COVID-19 infections is not yet known for the criteria of consistency, specificity, and temporality. Because of the nature of transmission from asymptomatic individuals, these three criteria have not been supported by accurate data at present.
In 1965, the English statistician Sir Austin Bradford Hill proposed a set of nine criteria to provide epidemiologic evidence of a causal relationship between a presumed cause and an observed effect. (For example, he demonstrated the connection between cigarette smoking and lung cancer.) The list of the criteria1 is as follows:
Strength (effect size): A small association does not mean that there is not a causal effect, though the larger the association, the more likely that it is causal.
Consistency (reproducibility): Consistent findings observed by different persons in different places with different samples strengthens the likelihood of an effect.
Specificity: Causation is likely if there is a very specific population at a specific site and disease with no other likely explanation. The more specific an association between a factor and an effect is, the bigger the probability of a causal relationship.
Temporality: The effect has to occur after the cause (and if there is an expected delay between the cause and expected effect, then the effect must occur after that delay).
Biological gradient (dose-response relationship): Greater exposure should generally lead to greater incidence of the effect. However, in some cases, the mere presence of the factor can trigger the effect. In other cases, an inverse proportion is observed: greater exposure leads to lower incidence.
Plausibility: A plausible mechanism between cause and effect is helpful (but Hill noted that knowledge of the mechanism is limited by current knowledge).
Coherence: Coherence between epidemiological and laboratory findings increases the likelihood of an effect. However, Hill noted that “... lack of such [laboratory] evidence cannot nullify the epidemiological effect on associations.”
Experiment: “Occasionally, it is possible to appeal to experimental evidence.”
Analogy: The use of analogies or similarities between the observed association and any other associations.
Some authors also consider reversibility: If the cause is deleted, then the effect should disappear as well.
Figure 1 is a checklist of the basic information to obtain. A “yes” or “no” answer to any of these questions does not necessarily make a final opinion. For example, even a negative reverse transcription polymerase chain reaction (RT-PCR) test does not automatically make the causation opinion negative.2-4 Each case must be taken in its entirety.
Opinions must be given with consideration of the following:
A description of the diagnosis(es), both in medical and lay terms.
A complete and detailed description of the reported exposure(s), from the information provided, including the mechanism, time, place, number, duration, or frequency of exposure(s).
If there were symptoms, pre-existing conditions, comorbidities, or prior or concurrent events unrelated to employment, these might be important contributing factors. If those factors existed without a present or ongoing need for treatment except for (“but for”) the work exposure, an appropriate medical opinion might be that the work exposure is more than 50% responsible for the need for treatment.
Whether the need for treatment was an aggravation, a permanent and documented deleterious change of function, or advancement of an underlying condition. For example, even though the injured worker tested positive for COVID-19, the need for treatment was due to complications of pre-existing chronic obstructive lung disease (COPD). Decide then whether this aggravation was (or was not) the cause of the need for medical treatment and was (or was not) medically caused by the exposure at work.
When all this information is taken together, is it more likely than not, to a reasonable degree of medical certainty, that this described exposure or series of exposures was the cause of the need for treatment, death, or disablement (time away from work or limited work capacity)?
Accurately recording the known facts and then forming a medical opinion must be supported by a reasonable explanation of the process of correlation supported by citing the available facts. We offer the following examples of assessments:
A 45-year-old nursing technician at a nursing home worked a normal 12-hour shifts 4 days a week from March 1, 2020, through March 23, 2020, when she developed a fever of 101.5° F with profound fatigue. She did not go to work and reported her illness to her supervisor. She was tested by the county health department and was notified that she was positive for the coronavirus. She was seen and treated by her family physician with supportive antibiotics and additional inhalers for her pre-existing asthma. Her fever subsided but returned 5 days later for 3 days, necessitating an additional period of convalescence. She provided records from her family physician confirming the extra length of leave. She states no one living in her home had suggestive symptoms of COVID-19, and no one was tested for the virus. Her nursing home had greater than 10 cases of COVID-19, including two of the patients she regularly cared for during March. After recovery she felt she was back to baseline, and there were no changes in her medications or spirometry from her pre-illness status. With clear and repetitive exposure to COVID-19 patients at work, and with no known exposure outside the workplace, most physicians would feel this was a work-related case.
A 25-year-old healthy grocery store clerk worked extra shifts from March 15, 2020, and April 21, 2020, because several co-workers chose not to come to work out of fear of the coronavirus. Despite being asymptomatic, he was able to get a viral RT-PCR test at a drive-through testing center on April 21, 2020. It was reported as negative and he returned to work the following day. On April 27, 2020, he reported a fever, shortness of breath, and the loss of sense of smell and taste. When tested again on April 28, 2020, he was negative. He was told to stay home for 2 weeks by his supervisor. No one else in his household was sick. When his shortness of breath worsened, he was seen in the emergency room (ER) and discharged with an inhaler and precautions. He was not tested for the coronavirus in the ER. His fever and lung symptoms subsided, and he reported back to work on May 11, 2020. He states that the loss of smell and taste have not returned as of June 25, 2020. With no proof he was ill with COVID-19, and with just occupational exposure to the general public (not to proven COVID-19 cases), most physicians would not feel this case had reached the “>50% threshold” for causation. The reported loss of the sense of smell is a subjective symptom that has not been confirmed by the University of Pennsylvania smell identification test (UPSIT) or the Burghart Sniffin' Sticks test. Loss of the sense of smell occurs in several known upper respiratory tract infections (URTIs) but recovers with time in 32% to 66% of cases.5
Physicians will be asked to make complex determinations regarding the work-relatedness of the employee's condition in COVID-19 claims. The more thorough the medical analysis, the more likely a claims adjuster and, ultimately, a judge is to accept the physician's opinion.
This article is modified and reprinted with permission from Robert B. Snyder, MD, and James B. Talmage, MD, authors of the same article in AdMIRable Review, Journal of the Tennessee Medical Impairment Rating Registry, Summer 2020.