On December 10th, 2018 the First Appellate District Court of Appeals issued its ruling in City of Petaluma v. W.C.A.B. (Lindh). The court in this case has greatly clarified the issue of apportionment under Labor Code §4663. The ruling states that pre-existing conditions which are asymptomatic and had not yet manifested any disability should be a basis for apportionment where they contribute in any part to an applicant’s disability.

The claimant in the case was a law enforcement officer who sustained an injury to his left eye. The injury occurred after a canine training session in which the applicant received several blows to his head. Approximately a month later he suddenly lost all vision in his left eye. Initial doctors reporting indicated that there was no industrial connection. The QME in the case opined that the applicant suffered the loss of vision (the disability) in his left eye in part due to the blows he received to the head. However, the QME also indicated that another reason for the loss of vision to his left eye was an underlying non-industrial vascular condition which had not yet resulted in any loss of vision prior to the industrial injury.

The QME in the case stated that the applicant could have gone his entire life without losing vision as a result of the vascular condition alone. Alternatively the underlying non-industrial condition could have caused lost vision due to those conditions alone without the industrial blows to the head. In discussing apportionment, the QME stated that 85% of the claimant’s permanent disability was due to his pre-existing underlying vascular condition, and 15% to the industrial injury (the blows to the head).

The Workers’ Compensation Judge in the matter ruled the QME opinion on apportionment was not substantial evidence and thus apportioned 100% of the disability to the industrial injury. This was upheld by the WCAB on reconsideration. The case then went to the First Appellate District Court of Appeals. They overturned the WCAB opinion, and found the QME’s opinion regarding apportionment was substantial evidence and permissible under Labor Code § 4663.

There is additional discussion in Lindh which involved whether the QME fully understood the difference between causation o f injury and causation of disability. While the trial Judge and WCAB felt the QME conflated the two, the Appellate Court was convinced the QME understood the distinction and had analyzed both, although in this case the analysis was the same. A great deal of the Appellate Court’s decision discusses the history of apportionment since the 2004 amendments under SB899. There is a thorough discussion of cases including Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604 (Escobedo), E.L. Yeager Construction v. Workers’ Comp. Appeals Bd. (2006) 145 Cal.App.4th 922 (E.L. Yeager), Acme Steel v. Workers’ Comp. Appeals Bd. (2013) 218 Cal.App.4th 1137 (Acme Steel), and City of Jackson v. Workers’ Comp. Appeals Bd. (2017) 11 Cal.App.5th 109 (Jackson).

The Court in Lindh makes it clear that apportionment is required where an underlying condition contributes to an applicant’s disability. The Court distinguishes the claimant’s underlying vascular condition from a mere risk factor. Under cases such as Escobedo apportionment based on risk factors alone is not permitted. However, in the case of Lindh, the underlying condition is not a mere risk factor but a medical condition which could have, on its own, led to a loss of vision, and in the QME’s opinion contributed to the loss of vision which was the disability in this case.

Some of the commentary on the Lindh opinion seems to indicate that risk factors are now a basis for apportionment. This author disagrees as the Court in Lindh repeatedly emphasized that there was an underlying, asymptomatic condition which of the QME found contributed to the disability. In their opinion, the Court repeatedly add italics to the phrase “underlying condition” for emphasis, and discuss why apportionment to those conditions is appropriate. They also specifically point to the fact that the QME identified the underlying condition as an asymptomatic condition and not a mere risk factor for the ultimate disability. Although the QME did use the phrasing that the underlying condition put the patient at a “higher risk” of suffering the disability, it did not change the fact that the claimant had an underlying condition. It still does not appear that the mere existence of a risk factor, such as obesity, diabetes, or even genetics, would be a basis for apportionment on its own. It must still be shown that the risk factor is an underlying condition which contributed to the disability or had the potential to contribute to the disability.

The crucial paragraph in this case may be found on page 18 where it states:

“Under the current law, the salient question is whether the disability resulted from both nonindustrial and industrial causes, and if so, apportionment is required. [Citations omitted] Whether or not an asymptomatic preexisting condition that contributed to the disability would, alone, have inevitably become manifest and resulted in disability, is immaterial.”

The Court in Lindh also states the underlying condition need not be degenerative in nature. Although many of the prior cases discussing apportionment such as E.L. Yeager, Acme Steel and Jackson all involved degenerative conditions, that element is not required to apportion to the underlying condition. It is only required that the underlying condition contributed in some way to the disability.

Lindh makes it clear that apportionment is required in cases where there is an asymptomatic underlying condition which contributes to the applicant’s disability. However, it remains the defendant’s burden of proof to show that, with reasonable medical probability, the underlying condition contributed to the disability. Therefore it is necessary to have any medical-legal evaluator fully explain that a pre-existing condition contributed to an applicant’s disability.