Clinicians often ask people with chronic pain about their perceived benefit from interventions designed to improve their pain. The aim of this study is to identify factors that contribute to underestimating or overestimating perceived changes in daily pain intensity over a month of daily assessments. We examined data from individuals with chronic pain who provided at least 28 daily assessments using a pain app as secondary analyses. Participants provided baseline demographic information and completed questionnaires assessing pain, activity interference, mood, pain disability, and catastrophizing. Using the pain app, they entered daily ratings of pain (0 = none, 10 = worst pain possible) and impressions of perceived day-to-day change (0 = better, 5 = same, and 10 = worse). Two hundred fifty-two (N = 252) subjects with chronic pain met the inclusion criteria of completing at least 28 daily assessments. Those who underestimated their improvement tended to have higher pain intensity at baseline (P < .001), reported greater activity interference and disability (P < .001), and were prone to greater catastrophizing and anxiety and depression (P < .01). People who were more accurate in assessing their improvement engaged less with the app with fewer 2-way messages compared with those who either underestimated or overestimated their improvement and who had more 2-way messaging (P < .05). This longitudinal study suggests that those who report greater levels of catastrophizing and anxiety and depression are more likely to underestimate any improvements in their pain over time but seem to engage more with a pain app. Future research will help in our understanding of what magnitude of perceived change in pain ratings is clinically meaningful. PERSPECTIVE: Those who report greater levels of pain, disability, anxiety, depression, and catastrophizing are most prone to underestimate improvements of their pain over time.

Chronic pain is exacerbated by maladaptive cognition such as pain catastrophizing (PC). Biomarkers of PC mechanisms may aid precision medicine for chronic pain. Here, we investigate EEG biomarkers using mass univariate and multivariate (machine learning) approaches. We test theoretical notions that PC results from a combination of augmented aversive-value encoding (\"magnification\") and persistent expectations of pain (\"rumination\"). Healthy individuals with high or low levels of PC underwent an experimental pain model involving nociceptive laser stimuli preceded by cues predicting forthcoming pain intensity. Analysis of EEG acquired during the cue and laser stimulation provided event-related potentials (ERPs) identifying spatially and temporally-extended neural representations associated with pain catastrophizing. Specifically, differential neural responses to cues predicting high vs. low intensity pain (i.e. aversive value encoding) were larger in the high PC group, largely originating from mid-cingulate and superior parietal cortex. Multivariate spatiotemporal EEG patterns evoked from cues with high aversive value selectively and significantly differentiated the high PC from low PC group (64.6% classification accuracy). Regression analyses revealed that neural patterns classifying groups could be partially predicted (R2 = 28%) from those neural patterns classifying the aversive value of cues. In contrast, behavioural and EEG analyses did not provide evidence that PC modifies more persistent effects of prior expectation on pain perception and nociceptive responses. These findings support the hypothesis of magnification of aversive value encoding but not persistent expression of expectation in pain catastrophizers. Multivariate patterns of aversive value encoding provide promising biomarkers of maladaptive cognitive responses to chronic pain that have future potential for psychological treatment development and clinical stratification.

BACKGROUND: Pain catastrophizing has been suggested as a prospective risk factor for poor postoperative pain outcomes in total joint arthroplasty (TJA). However, results from the previous studies have been mixed and have not controlled for postoperative opiate analgesic intake. This study investigates pain catastrophizing and postoperative pain intensity in TJA patients, adjusting for analgesic intake. We hypothesized that \"pain catastrophizers\" would exhibit higher pain scores and increased analgesic requirements postoperatively.
METHODS: In this prospective cohort study, patients were defined as catastrophizers (PCS > 30), or non-catastrophizers (PCS ≤ 30). The primary outcome was the visual analog scale (VAS) pain score at 3-month follow-up. Secondary outcomes included length of stay (LOS) for the index hospitalization, total daily opiate analgesic intake, and VAS pain scores on postoperative days 0, 1, 2, and 3 through discharge. Multivariable regression was used to control for total daily morphine equivalent dose consumed during the stay in addition to other clinical and demographic factors.
RESULTS: There were 87 patients in the \"non-catastrophizing\" and 36 in the \"catastrophizing\" groups. There was no clinically significant difference in VAS pain scores between groups at 3-month follow-up. Patients with a length of stay (LOS) ≥ 3 postoperative days differed in VAS pain scores (\"non-catastrophizers\" = 5.08 vs. \"catastrophizers\" = 7.13; p = 0.002) and were 2.4 times more likely to be catastrophizers than non-catastrophizers (p = 0.042). There were no differences in the remaining secondary outcomes.
CONCLUSIONS: The pain catastrophizing scale is a poor predictor of postoperative pain at 3-month follow-up. However, it may be a risk factor for increased LOS.

Human animals have evolved with the primary missions of survival and reproduction and these natural drives may impact behavior whether humans are aware of them or not. The author offers evidence in support of the idea that injury and resulting acute or chronic pain may trigger the unconscious human primate brain to believe there is a threat to survival. This perceived threat may be exacerbated or mitigated by the pain manager, both of which may impact health outcomes in a negative or positive way, respectively. The commentary argues the patient-health care provider relationship is of paramount importance for those with chronic pain and illness and should be nurtured for the best possible outcomes.