Canadian Journal of Pain-Revue Canadienne de la Douleur最新文献

Objective: This study explored the heterogeneity of Canadian Armed Forces veterans living with chronic pain to inform service needs planning and research using cluster analysis. Design: We used a national cross-sectional Statistics Canada population survey. Participants: Participants included 2754 Canadian Armed Forces (CAF) Regular Force veterans released from service between 1998 and 2015 and surveyed in 2016. Methods: We used cluster analysis of veterans with chronic pain based on pain severity, mental health, and activity limitation characteristics. We compared clusters for sociodemographic, health, and service utilization characteristics. Results: Of 2754 veterans, 1126 (41%) reported chronic pain. Veterans in cluster I (47%) rarely had severe pain (2%) or severe mental health problems (8%), and none had severe activity limitations. Veterans in cluster II (26%) more often than veterans in cluster I but less often than veterans in cluster III endorsed severe pain (27%) and severe mental health problems (22%) and were most likely to report severe activity limitation (91%). Veterans in cluster III (27%) were most likely to report severe pain (36%) and severe mental health problems (96%), and a majority reported severe activity limitations (72%). There was evidence of considerable heterogeneity among individuals in terms of socioeconomic characteristics, pain characteristics, mental and physical health status, activity limitations, social integration, and service utilization indicators. Conclusions: About half of Canadian veterans living with chronic pain infrequently endorse severe pain or serious mental health issues without severe activity limitations. The other half had more complex characteristics. The heterogeneity of CAF veterans with chronic pain emphasizes the need for support systems that can address variability of needs.

Background: The opioid overdose epidemic has led health care providers to increased vigilance for opioid-related risks in the treatment of chronic non-cancer pain (CNCP). Media have conveyed stigmatizing representations of opioid analgesics. Aims: This study aimed to understand how the opioid overdose epidemic has impacted health care experiences among people living with CNCP in two Canadian provinces (British Columbia, Quebec). Methods: This qualitative study proceeded through 22 semi-structured interviews conducted in 2019. Participants were recruited from a cross-sectional survey examining the effects of the opioid overdose epidemic on individuals with CNCP. We collected in-depth narratives that we analyzed using a thematic framework. The sample included 12 women and 10 men aged 20 to 70 years, with 11 from each province. Results: Several participants described increased difficulty in accessing medical services for pain since the onset of the opioid overdose epidemic. They reported that some physicians urged them to taper opioids regardless of their pain severity and functional limitations. Some participants reported facing discrimination and care denials as they were labeled "drug-seeking," especially in hospital. Depending on their educational resources, they were unequally able to counter providers' stigmatizing behaviors. However, participants described empathetic relationships with providers with whom they had a long-term relationship. Some participants drew distinctions between themselves and the stigmatized status of "addict" in ways that reinforced stigma toward people who are dependent on opioids. Conclusions: Health policies and provider education programs aimed at reducing opioid-related stigma are needed to counter detrimental consequences of the opioid overdose epidemic for people living with CNCP.

Background: Chronic low back pain (CLBP) is a major cause of disability globally. Stratified care has been proposed as a means to improve prognosis and treatment but is generally based on limited aspects of pain, including biopsychosocial drivers. Aims: Following Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) recommendations, the present study explored pain phenotypes with a sample of workers with CLBP, a population for which no pain phenotypes have been derived to date. Methods: A cross-sectional design was used with a sample of 154 workers with CLBP attending a rehabilitation clinic, recruited in person and from social media. Latent class analysis was used to identify subgroups of patients with different pain profiles based on ten pain indicators (pain variability, pain intensity, pain quality, somatization, sleep quality, depression, fatigue, pain catastrophizing, neuropathic pain, and central sensitization). Results: The majority of the sample (85%) were recruited through social media. Both the two-class and three-class solutions were found to be satisfactory in distinguishing phenotypes of workers with CLBP. Three variables proved particularly important in distinguishing between the pain phenotypes-pain quality, fatigue, and central sensitization-with higher scores on these indicators associated with pain phenotypes with higher pain burden. Increased chronic pain self-efficacy, work-related support, and perceived work abilities were protective risk factors for being in a higher pain burden class. Conclusions: The present study is the first to explore IMMPACT recommendations for pain phenotyping with workers with CLBP. Future prospective research will be needed to validate the proposed pain phenotypes.

Background: The prevalence of inadequate treatments for chronic pain has necessitated the search for biological factors that influence the transition to chronicity. Methods: Antecubital blood was drawn from those who experienced acute, noncatastrophic musculoskeletal trauma. Follow-up occurred at 1, 3, 6, and 12 months with the primary outcome being Brief Pain Inventory (BPI) Functional Interference scores. Eight markers were chosen for latent profile analysis: brain-derived neurotrophic factor (BDNF); transforming growth factor-beta 1 (TGF-β1); C-reactive protein (CRP); tumor necrosis factor-alpha (TNF-α); interleukins (ILs) 1-beta, 6, and 10; and the stress hormone cortisol. Results: Mean age of the 106 participants was 44.6 years and 58.5% were female. The final model indicated a three-class solution that could be adequately described by three of the eight markers: class 1 = low concentration of all markers (33.9% of the sample), class 2 = average concentration of all markers (47.7%), and class 3 = high concentration of BDNF and TGF-β1 (18.3%). BPI Pain Interference scores captured at both inception and 6-month follow-up were compared across the three groups. Mean scores were significantly higher in class 3 for the BPI Interference subscale at inception (27.0 [SD 16.4] vs. 35.8 [SD 17.3], P = 0.05) and at 6-month follow-up (2.2 [SD 4.8] vs. 7.3 [SD 10.7], P = 0.03) compared to those of the other two classes. Conclusions: Although recovered populations are not significantly different in BDNF and TGF-β1 levels, those who experience persisting disability are more likely to have moderate to high levels in serum.

Background: Little is known about how the specialized treatment journey is perceived by youth with pain-related disability and their parents. Aims: Describe and compare the treatment effects and outcomes as perceived by youth and their parents enrolled in intensive interdisciplinary pain treatment (IIPT) or multimodal treatment (MMT). Methods: Eleven IIPT youth and five parents and three MMT youth and five parents were recruited. All were asked to complete a treatment journey timeline, followed by separately conducted semistructured interviews. Transcribed interviews were analyzed using reflective thematic analysis. Results: The main themes spanned the treatment trajectory. All participants described similar initial struggles (Theme 1). Positive and negative treatment effects associated with acquisitions and disruptions (Theme 2), and outcomes post-discharge related to supports and realities (Theme 3) emerged. Knowledge, skills, and support acquisition during treatment and feeling empowered and confident to self-manage postdischarge were identified as IIPT benefits. However, the change effort and life disruptions required and the difficulty transitioning to real life postprogram were acknowledged as detrimental IIPT impacts. Continuing with life as usual and maintaining supports in daily contexts (e.g., school personnel, friends) were reported MMT benefits. However, the challenges of managing pain, treatment adherence within the competing demands of daily realities, and the lack of support to integrate strategies were emphasized as detrimental MMT impacts. Conclusions: Detailed impacts of two specialized multidisciplinary pain rehabilitation interventions on the lives of youth with pain-related disability and their parents are described. The treatments benefits and previously unexplored detrimental effects are unveiled.

Background: The magnitude and duration of conditioned pain modulation (CPM) likely depends on the nature and intensity of the conditioning stimulus (CS). Aims: The aim of this study was to measure the effect of CS intensity on the duration of CPM hypoalgesia. Methods: In this single-blind, nonrandomized, repeated measures study, we assessed CPM hypoalgesia in 20 healthy participants following cold pressor tests (CPT) at 7°C and 12°C. The test stimulus, a 60-s heat stimulation, was administered before the CPT and immediately after, and again at 5-min intervals until participants' pain scores returned to pre-CS levels. Two hypoalgesia thresholds were used to establish return to pre-CS level: within -10/100 of baseline and within -20/100 of baseline. Results: CPM hypoalgesia, when defined as a reduction in pain levels >10/100, did not last longer following the more intense 7°C CPT compared to the 12°C CPT (32 min vs. 20 min, respectively; P = 0.06); similar results were obtained when CPM hypoalgesia was defined as a reduction in pain levels of >20/100 (16 min following the 7°C CPT vs. 9 min following the 12°C CPT; P = 0.33). The duration of CPM hypoalgesia was significantly longer when the 10/100 threshold was used compared to the 20/100 threshold, regardless of CPT temperature (P = 0.008 for the 12°C CPT; P < 0.001 for the 7°C CPT). Conclusions: The more intense CS did not induce CPM hypoalgesia of longer duration compared to the less intense CS. The choice of threshold for what constitutes CPM hypoalgesia did have a significant effect on the results.