Differences between pain belief tests: Comparing the pain and impairment relationship scale to the pain beliefs and perceptions inventory

Over recent years, there has been an increase in the number of tests which measure the pain beliefs of chronic low back pain (LBP) patients. However, it has not been determined if these different pain belief tests measure separate beliefs or if they are only assessing varied expressions of the same construct. This study examined whether the Pain and Impairment Relationship Scale (PAIRS) and the Pain Beliefs and Perception Inventory (PBPI) were assessing distinct beliefs that LBP patients have about their condition. A total of 177 LBP patients were consecutively admitted to a 4-week multidisciplinary pain treatment center. The PAIRS and the PBPI were compared to pre- and post-treatment measures of mood, pain level, perceived disability and patient demographics. Correlational, multiple regression, and factor analytic techniques were used to explore the data. The results indicated that the PAIRS and the Time scale of the PBPI had an identical pattern of correlation with the other variables. Multiple regression analysis revealed that the PBPI-Time scale accounted for a significant proportion for the pre- and post-measures of pain level, and the PAIRS significantly accounted for the pre- and post-measures of behavioral inhibition. A factor analysis was used to hypothesize about the constructs underlying the PAIRS and the PBPI. The PAIRS clustered with measures of perceived disability, the PBPI - Time scale was with measures of pain level, and the PBPI - Mystery scale with measures of mood. It appeared that the PAIRS and the PBPI were assessing separate pain beliefs, but there was some overlap in the area of emotionality.