Pain-related cognitions and emotional distress are not associated with conditioned pain modulation: an explorative analysis of 1142 participants with acute, subacute, and chronic pain.

ABSTRACT: Reduced conditioned pain modulation (CPM) and psychological distress co-occur frequently in many pain conditions. This study explored whether common negative pain cognitions and emotional factors were related to lower CPM in individuals across the spectrum from acute to chronic pain. Previously collected data on the CPM effect, pain-related cognitions (fear of movement, pain catastrophizing), and emotional distress (depression, anxiety) through questionnaires from 1142 individuals with acute, subacute, or chronic pain were used. The presence of negative psychological factors was dichotomized according to cutoff values for questionnaires. Associations between the presence of each negative psychological factor and the amplitude of pain reduction in the CPM paradigm was explored with Generalized Linear Models adjusted for sex, age, body mass index, and pain duration. A secondary analysis explored the cumulative effect of psychological factors on CPM. When dichotomized according to cutoff scores, 20% of participants were classified with anxiety, 19% with depression, 36% with pain catastrophizing, and 48% with fear of movement. The presence of any negative psychological factor or the cumulative sum of negative psychological factors was associated with lower CPM (individual factor: ß between -0.15 and 0.11, P ≥ 0.08; total: ß between -0.27 and -0.12, P ≥ 0.06). Despite the common observation of psychological factors and reduced CPM in musculoskeletal pain, these data challenge the assumption of a linear relationship between these variables across individuals with acute, subacute, and chronic pain. Arguably, there was a nonsignificant tendency for associations in nonexpected directions, which should be studied in a more homogenous population.

The association of probable PTSD at baseline and pain-related outcomes after chronic pain rehabilitation: A comparison of DSM-5 and ICD-11 criteria for PTSD.

BACKGROUND: There is a high prevalence of posttraumatic stress disorder (PTSD) in patients with chronic pain. However, different patients are identified depending on the diagnostic system used. Moreover, it is unclear if the conceptualizations of PTSD are differently associated with outcomes of pain rehabilitation. Hence, the aims of the present study were first to explore the prevalence rates and diagnostic agreement of probable PTSD according to the ICD-11 and the DSM-5 screening tools (International Trauma Questionnaire [ITQ] vs. PTSD Checklist [PCL-5]), and secondly, to explore the associations of probable PTSD determined by ITQ and PCL-5 with psychological distress measures at baseline, and thirdly, the associations with pain and disability after pain rehabilitation adjusting for psychological covariates. METHODS: A consecutive cohort of patients with chronic non-malignant pain (n = 152) referred to a Danish interdisciplinary pain center was assessed at baseline prior to their first visit and at follow-up three days after completed treatment. RESULTS: The estimated probable PTSD baseline prevalence rates were 15.8% (ITQ) and 16.4% (PCL-5). However, the diagnostic agreement between the PCL-5 and the ITQ was only moderate (k = 0.64). Overall, compared to the ITQ probable PTSD according to the PCL-5 correlated more strongly with psychological distress. Only the ITQ was associated with poorer outcomes after rehabilitation, explaining alone 7-8% of the variance in disability and pain intensity adjusted for covariates. CONCLUSIONS: The results underline the importance of taking the conceptualization and assessment of PTSD into consideration when investigating the impact of PTSD on pain rehabilitation. SIGNIFICANCE: There is a high prevalence of probable PTSD in patients with chronic pain. However, different patients with probable PTSD are identified depending on the diagnostic system used. Although similar probable PTSD prevalence rates (about 16%) were found using DSM-5 and ICD-11 PTSD screening tools (PCL-5 and ITQ, respectively), the diagnostic agreement between the systems was only moderate (k = 0.64). At the same time, only probable PTSD estimated according to the ITQ and not the PCL-5 was a significant predictor of disability after pain rehabilitation.