Predictive validity of a brief scale to assess subjective prognosis of work capacity (SPE Scale) in a cohort of LVA insured patients with severe back pain or functional complaints relating to internal medicine

Abstract

Vocational (dis-)ability is a central concept in social medicine. Beside from medical factors psychological and system factors play a crucial role in determining vocational disability. The development of instruments assessing the prognosis of gainful employment is an important task in rehabilitation research. A short scale measuring the subjective prognosis of gainful employment (SPE-scale) was administered to 481 blue collar workers suffering from severe back pain or else functional syndromes. Employment status two or three years following the assessment is known. 11% of the subjects have applied for early retirement; 5% actually have retired. There are statistically significant relations of SPE-scores and subjects employment status. Effect sizes of the SPE-scores equal or even outrank those of other instruments assessing vocational (dis-)ability. The positive predictive power of the scale is low, though. The SPE scale can be recommended for further use in (rehabilitation) research. The employment of the instrument for medical appraisal has to be viewed with more caution. The percentage of subjects at risk for early retirement is largely overestimated in case of a positive test. Instruments like the SPE-scale can assist but never replace the medical appraisal.