Discriminative Validity of the Pain Attitudes and Beliefs Scale for Physical Therapists

Background: The Pain Attitudes and Beliefs Scale (PABS) aims to measure clinicians' biomedical and biopsychosocial treatment orientations regarding nonspecific low back pain. Objective: The objective of this study was to assess whether the PABS can differentiate between subgroups of physical therapists hypothesized to differ in treatment orientations. Design: This study was a cross-sectional survey. Methods: Six hundred sixty-two Norwegian physical therapists with a diversity of professional backgrounds completed the PABS. Twenty-four a priori hypotheses on expected differences in PABS scores were formulated. Sufficient discriminative ability was defined as a minimum of 75% confirmed hypotheses. Hypotheses on differences in scores were tested for the biomedical and biopsychosocial subscales separately as well as for combinations of the 2 subscales, representing responders with high biomedical and low biopsychosocial PABS scores and vice versa. Results: Of the 24 hypotheses, only 15 (62.5%) were confirmed. Between-group differences concerning the separate subscales were small, varying from - 0.63 to 1.70 scale points, representing values up to 6.0% of the total subscale ranges. Between-group differences were larger when combined subscales were used, varying from 1.80 to 6.70 points, representing values up to 25.1% of the total subscale ranges. Despite little spread in scores, 24% of respondents demonstrated extreme attitudes. Limitations: The lack of convincing scientific evidence from previous research on differences in attitudes and beliefs between physical therapists was a limitation for the formulation of hypotheses. Conclusions: Discriminative validity of separate subscales of the PABS was not supported. Combining the 2 subscales into global treatment attitudes allowed for better discrimination. Little spread in biomedical and biopsychosocial orientations explains why more than one-third of the hypotheses were not confirmed. Either Norwegian physical therapists are basically similar in their treatment orientation or the PABS is not able to detect any differences between them.