Pain behavior in industrial subacute low back pain. Part I. Reliability: concurrent and predictive validity of pain behavior assessments.

The reproducibility of overt pain behavior ratings was shown to be reliable between independent observers. In the clinical evaluation of 103 blue collar workers with subacute low back pain (LBP), concurrent validity was high between Behavioural Signs (Waddell et al. 1980) and UAB Pain Behavior Rating scale (Richards et al. 1982). Correlations with pain rated on visual analogue scales (Scott and Huskisson 1976) were generally lower. Behavioural Signs correlated separately with covert pain behavior (general convictions concerning back strength and general health). It seems that subacute LBP patients do not behave as a homogenous group since pain behaviors predicted occupational handicap (absenteeism) in a non-linear fashion. Return to work was best predicted by UAB and covert pain behavior, absenteeism up to 2 years by covert pain behavior. The findings emphasize the potential social implications of overt pain behaviors and the importance of covert pain behavior in maintaining the sick role. The conclusion is that, in secondary prevention, where the main targets are to interfere with somatic deconditioning and sick-role development, a more diversified primary approach may be possible, based on supplementary use of relatively easy observational tests and quick self-reports.