Psychometric examination of short forms from the University of Washington pain-related self-efficacy and concerns about pain item banks in patients with low back pain

The Moderating Effects of Cognitive Processes on Pain-related Outcomes

Although evidence supports the importance of pain-related thoughts (ie, cognitive content, or what people think) as predictors of pain and pain-related function, evidence regarding the role of cognitive processes (ie, how people think about pain, eg, by accepting pain, not making judgments about pain, or being absorbed by the pain experience) in adjustment to chronic pain is in its early stages. Using baseline data from a clinical trial of individuals with chronic low back pain (N = 327), the study aimed to increase knowledge regarding the associations between cognitive processes, pain intensity, pain interference, and depression. The results indicate that a number of cognitive processes are significantly related to pain intensity when controlling for catastrophizing, although the pattern of associations found was opposite to those anticipated. One cognitive process (pain absorption) was found to be significantly associated with pain interference, and 9 of 10 cognitive processes were significantly associated with depression when controlling for catastrophizing. In each case, the processes thought to be adaptive were negatively associated with pain interference and depression, and processes thought to be maladaptive evidenced the opposite pattern. The findings are consistent with-but do not prove, given the cross-sectional nature of the data-the possibility that cognitive processes play an important role in adjustment to chronic pain. The potential role these variables play in depression was particularly noteworthy. Longitudinal and experimental studies to evaluate the causal nature of the associations identified are warranted. PERSPECTIVE: The study findings highlight the potential importance of cognitive process variables (ie, how people think) in adjustment to chronic pain. Research to evaluate cognitive processes as potential mechanism variables in pain treatment is warranted.

Responsiveness of the UW Concerns About Pain Scale and UW Pain-Related Self-Efficacy Scale in Individuals With Chronic Low Back Pain

OBJECTIVES

The aim was to examine the responsiveness, presence of floor or ceiling effects, and minimal clinically important differences (MCIDs) for 2 new measures of pain-related catastrophizing and self-efficacy in individuals with chronic low back pain.

METHODS

A total of 183 individuals with chronic low back pain recruited from physical therapy clinics in Thailand completed the Thai versions of the 6-item University of Washington Concerns About Pain scale (T-UW-CAP6) and 6-item University of Washington Pain-Related Self-Efficacy scale (T-UW-PRSE6) at baseline and at 4 weeks follow-up. Perceived change in low back symptom was assessed at 4 weeks using a 7-point measure of Global Perceived Effect (GPE). Responsiveness of the T-UW-CAP6 and the T-UW-PRSE6 scale scores were evaluated by computing the effect sizes and standardized response means for change over time, and examining these as a function of the GPE ratings. Floor and ceiling effects were examined by evaluating the score distributions. Scale core MCIDs were estimated by computing a half a SD and SE of measurement statistics for each scale.

RESULTS

Responsiveness of the scales to pain treatment was supported by differences found in the mean change scores as a function of the treatment response categories. No significant floor or ceiling effects were found for either measure. Changes of 4.38 and 3.68 appeared to be the smallest change score perceived as clinical meaningful for the T-UW-CAP6 and T-UW-PRSE 6 scale scores, respectively.

DISCUSSION

The T-UW-CAP6 and T-UW-PRSE6 demonstrated good ability to detect perceived changes over time in patients with chronic low back pain. The MCIDs values provide a benchmark for assessing individual improvement in this clinical context.