Pre-existing conditions are all medical conditions that an injured worker has had prior to sustaining a
work-related injury. Pre-existing conditions are not uncommon; however, as a general rule, they are not
addressed as part of a workers’ compensation claim until relatedness and medical necessity considerations
are addressed. With both of these issues, parties to the claim (i.e., injured workers, employers and their
authorized representatives) and, particularly, medical providers, must submit documentation describing
relatedness and necessity. Furthermore, it is important to remember that these issues are not mutually
exclusive; therefore, they must always be considered together.
In terms of relatedness, a work-related injury or disease may aggravate a pre-existing condition. When this
happens, it is possible for a pre-existing condition to become an allowed condition in the claim because the
injury or diseases may not have been sustained had it not been for the injured worker’s employment.
(This relationship is commonly referred to as the “but for” rule.) For example, an employee with pre-existing
back problems aggravates this condition while lifting heavy boxes at work. Had the injured worker not been
lifting the boxes, it is possible that the injury would not have arisen from the individual’s employment.
With respect to medical necessity, pre-existing conditions sometimes affect the outcome of the injured worker’s
allowed conditions or medical care. When this occurs, these pre-existing conditions are frequently referred to
as co-morbidity conditions. Payment can be allowed for the treatment of co-morbidity conditions for as long as
the allowed conditions or medical care are affected; however, the conditions are not included in the workers’
compensation claim. For example, an injured worker has pre-existing diabetes which is impacting healing times
post-surgery. Treatment of the diabetes is authorized and the associated costs reimbursed. The diabetes, though,
will not be included as an allowed condition in the claim because it is not work-related. Additionally, when
supported by medical documentation, the authorizations and reimbursements for the diabetes treatment will be