Study design: The criterion and construct validities of pain drawing, quantified by a simple total body area score of pain extent (area raw extent assessment score), were analyzed prospectively on consecutive patients (n = 103), drawn from a predefined blue collar worker population, all sick listed for 6 weeks as a result of low back pain.
Objectives: To evaluate the validity of pain drawing as a screening tool in the secondary prevention of subacute low back pain.
Summary of background data: Pain drawings have been used clinically for more than 40 years as a complement to a patient's verbal pain descriptions. The main objectives have been to differentiate functional pain from organic pain and to identify meaningful features in spatial-anatomic pain distribution. The ability of the pain drawing to delineate concurrent psychopathology correctly has been questioned. There is no consensus on which scoring method should be used.
Methods: The area raw extent assessment score was analyzed concurrently against the penalty point system and predictively against return to work and absenteeism over a period of 2 years. Content and construct validity assessed the relative influence of medical, psychologic, and subjective disability as well as psychosocial factors.
Results: Criterion validation of the area raw extent assessment score showed significant correlations, both concurrently against the penalty point score (r = 0.86, P < 0.001, with explained variance R2 = 0.75, P < 0.001) and predictively against occupational handicap (r = 0.48, P < 0.001). In construct validation, the highest explained variance was shown for medical (R2 = 0.46, P < 0.001) and psychologic factors (R2 = 0.46, P < 0.001) and psychologic factors (R2 = 0.34, P < 0.001) and for subjective disability (R2 = 0.32, P < 0.001). Variance in the area raw extent assessment score also was explained by psychosocial factors (R2 = 0.19, P < 0.01).
Conclusions: Pain drawing quantification of the extent of pain shows high criterion and construct validity for the area raw extent assessment score. Content validity could be shown for significant clinical aspects of the disability experience--assets preferred for a screening tool in secondary prevention.