Do patient characteristics affect the predictive validity of Functional Capacity Evaluations?

Abstract

Purpose: The aim of this study was to identify patient-related characteristics that affect the predictive validity of the FCE assessment ELA.

Methods: A prospective multicenter study was conducted on 303 patients with musculoskeletal disorders (MSD) recruited from eleven rehabilitation centers. The ELA-based estimation of the participants' ability to cope with physical work demands was considered valid if RTW was paired with a positive ELA outcome (≥ moderate) as well as if non-RTW was accompanied by a negative ELA outcome (rather or very poor). In the remaining cases, the ELA result was judged as non-valid. To reduce the risk of false conclusions, the rating was performed inversely in participants that (1) reported severe limitations regarding their productivity at work, (2) attributed RTW to a change in job resp. a reduction of their physical work demands and in those that (3) attributed non-RTW to non-physical reintegration barriers only. Using questionnaires, 28 patient-related characteristics were collected. Logistic regression models were calculated to identify characteristics that affected the predictive validity of ELA.

Results: ELA was considered valid in 208 of 303 (69%) participants. A moderate and strong pain-related disability at work were associated with a 0.15-fold (95% confidence interval (95% CI) 0.05-0.46), respectively, 0.19-fold (95% CI 0.05-0.72) chance for a valid outcome. In addition, a negative influence was found in participants that reported psychosocial distress (odds ratio (OR) 0.35; 95% CI 0.15-0.82), a native language different from the national language (OR 0.16; 95% CI 0.05-0.56) as well as in those that expected to return to work, but not within one month (OR 0.17; 95% CI 0.06-0.46). Further variables-including age, employment status, fear-avoidance beliefs and the level of physical work demands-did not affect the predictive validity of ELA.

Conclusions: The results suggest that the predictive validity of ELA is primarily limited by patients that report a moderate or strong pain-related disability at work, psychosocial distress as well as the expectation to return to work, but not within one month. Furthermore, a negative influence can be assumed for language barriers.

Keywords: FCE; Physical work capacity; Rehabilitation; Return to work; Work assessment.