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Background and aims Elite athletes reportedly have superior pain tolerances, but it is unclear if results extend to conditioned pain modulation (CPM). The aim of our study was to synthesize existing literature in order to determine whether CPM is increased in elite athletes compared to healthy controls. Methods A systematic review and random-effects meta-analysis was conducted. Cochrane Central Register of Controlled Trials, SPORTDiscus, PsycINFO, CINAHL, Web of Science, and PubMed were searched for English-language studies that examined CPM in adult elite athlete populations. Results Seven studies were identified; all were of poor to fair methodological quality. There was no overall difference in CPM between elite athletes and controls (Hedges g = 0.37, CI 95 −0.03−0.76; p  = 0.07). There was heterogeneity between studies, including one that reported significantly less CPM in elite athletes compared to controls. An exploratory meta-regression indicated that a greater number of hours trained per week was associated with higher CPM. Conclusions The overall number and quality of studies was low. Despite nominally favoring higher CPM in elite athletes, aggregate results indicate no significant difference compared to healthy controls. A possible factor explaining the high degree of variability between studies is the number of hours elite athletes spent training. Implications Based on available evidence, athletes do not have remarkable endogenous pain modulation compared to controls. High quality experimental studies are needed to address the effect of hours trained per week on CPM in athletes.

Background and aims The placebo response has been identified as one factor responsible for the lack of therapeutic trials with positive outcomes in neuropathic pain. Reviews have suggested that certain neuropathic pain conditions, including HIV-associated sensory neuropathy (HIV-SN), exhibit a greater placebo response than other neuropathic aetiologies. If true, such a finding could substantially affect clinical trial design and therapeutic developments for these conditions. This study aimed to identify any difference in placebo response between trials of systemic pharmacological intervention in HIV-SN and a comparable neuropathic condition, diabetic polyneuropathy (DPN) and to identify factors influencing the placebo response. Methods A systematic review search to identify randomised, double-blind studies of systemic pharmacological interventions for painful HIV-SN and DPN published between January 1966 and June 2019 was performed. A meta-analysis of the magnitude of placebo response and the proportion of placebo responders was conducted and compared between the two disease conditions. A meta-regression was used to assess for any study and participant characteristics that were associated with the placebo response. Only studies meeting a methodological quality threshold were included. Results Seventy-five trials were identified. There was no statistically significant difference in the proportion of placebo responders (HIV-SN = 0.35; versus DPN = 0.27, p  = 0.129). The difference observed in the magnitude of the placebo response [pain reduction of 1.68 (1.47–1.88) DPN; 2.38 (1.87–2.98) in HIV-SN] was based on only 2 trials of HIV-SN and 35 of DPN. Potential factors influencing the placebo response such as psychological measures, were reported inconsistently. Conclusions We found no statistically significant difference in the placebo response rate between painful HIV-SN and DPN. Too few studies were available that reported the necessary information to clarify potential differences in the magnitude of placebo response or to elucidate parameters that could be contributing such differences. Implications The placebo response is one factor that may contribute to a lack of positive trials in neuropathic pain; some etiologies may display larger responses than others. This meta-analysis found no significant difference in placebo response between trials of HIV-associated sensory neuropathy and painful diabetic polyneuropathy, although limited data were available.

Background and aims The randomized controlled trial (RCT) is currently facing several challenges, one of these being that the placebo response appears to be increasing in RCTs, thereby making it difficult to demonstrate an effect of potentially new treatments over placebo. This problem has primarily been approached by predicting the magnitude of the placebo response via stable factors, such as demographic variables, and/or by developing complex designs aimed at reducing the placebo response in the hope that it will improve the test of the active treatment. Yet, the success of this approach has so far been limited. Methods A new approach toward improving the RCT is put forward based on placebo and nocebo mechanism studies, i.e. studies that investigate the mechanisms underlying placebo analgesia and nocebo hyperalgesia. In a series of meta-analyses the magnitude of placebo and nocebo effects were determined. Experimental studies across nociplastic and neuropathic pain conditions and across pharmacological and acupuncture treatments investigated psychological and neurobiological mechanisms underlying these effects. The obtained results were used to make approximations of expectations to see if that could predict the placebo response in RCTs and function as a new way of tapping into the placebo component of treatment effects. Results The magnitude of placebo and nocebo effects is large and highly variable. Placebo effects exist across chronic pain conditions with varying degrees of known etiology as well as across pharmacological and non-pharmacological treatments. Patients’ perception of the treatment, the verbal suggestions given for pain relief, and the patients’ expectations toward pain relief contribute to the magnitude of the placebo effect and to pain relief following placebo interventions. Also, unintentional unblinding and patients’ perception of a treatment markedly influence the treatment outcome. By making approximations of expectations toward treatment effects it was possible to predict the magnitude of the placebo response in RCTs. Conclusions and implications The new approach of tapping into or directly asking patients about their perception and expectations toward a treatment, along with the account of the natural history of pain, has the potential to improve the information that can be obtained from RCTs. Thus, by interfacing insights from placebo and nocebo mechanism studies, it may be possible to enhance the information that can be obtained from RCTs and to account for a large part of the variability in the placebo component of the overall treatment effect. This approach has the potential to improve the scientific evaluation of treatments, as well as to illustrate how the effect of treatments can be optimized in clinical practice, which is the crux of evidence-based medicine.

Introduction There is limited evidence for effect of interventional treatment, and pragmatic studies are needed to assess these interventions within a clinical setting. The aim of this study was to describe patients referred to an interventional pain clinic and investigate responses after spinal intervention in general and for radiofrequency ablation (RFA) and transforaminal epidural corticosteroid administration (TECA), specifically. Methods This is a prospective, non-controlled study of patients with chronic spinal pain. The procedures were performed in accordance with the Spine Intervention Society recommendations. Outcome data after a median of 4.5 months are presented, and for those treated with RFA also after 6 and 12 months. Results Among 815 patients, 190 patients underwent diagnostic blocks only and 625 interventional treatment, of these 94 RFA and 246 TECA. Of the whole sample 70% reported pain reduction, for 49% ≥ 50%, while 9% were pain free ( p  < 0.001). Highest pain intensity decreased from 7.1 to 5.4 [95% Confidence Interval of the Difference (95%-CI): 1.4–1.9] ( p  < 0.001), while Euroqual – visual analogue scale for general health (EQ-VAS) improved from 48 to 58 (95%-CI: 7.6–11.9) ( p  < 0.001), and Euroqual-5 Dimensions-5 Levels Index for health related quality of life (EQ-5D-5L Index) from 0.489 to 0.628 (95%-CI: 0.123–0.157) ( p  < 0.001). The proportions, not taking analgesics, increased from 16% to 30%, and proportion taking strong opioids decreased from 14% to 9% ( p  < 0.001). We found no significant change in proportion receiving physiotherapy/other treatment nor occupational status. No complications were reported. Among patients treated with RFA, 77% reported pain reduction, for 56% ≥ 50%, while 9% were pain free ( p  < 0.001). Highest pain intensity decreased from 6.9 to 4.6 (95%-CI: 1.6–3.0) ( p  < 0.001), while EQ-VAS improved from 47 to 57 (95%-CI: 4.8–13.6 ( p  < 0.001), and EQ-5D-5L Index from 0.489 to 0.643 (95%-CI: 0.117–0.191) ( p  < 0.001). The proportion not taking analgesics, increased from 7% to 23% and proportion taking strong opioids decreased from 16% to 10%. Among patients who responded at 6- and 12-month follow up, the proportions reporting pain reduction, EQ-VAS, and EQ-5D-5L Index remained significantly improved from baseline, and the change in proportions taking analgesic and opioids achieved statistical significance. We found no significant change in proportion receiving physiotherapy/other treatment nor occupational status. Among patients treated with TECA, 58% reported pain reduction, for 36% ≥ 50%, while 5% were pain free ( p  < 0.001). Highest pain intensity decreased from 7.2 to 6.2 (95%-CI 0.5–1.4) ( p  < 0.001), while EQ-VAS improved from 46 to 52 (95%-CI: 2.0–3.6) ( p  < 0.001), and EQ-5D-5L Index from 0.456 to 0.571 (95%-CI: 0.077–0.138) ( p  < 0.001). The proportions, not taking analgesics, increased from 17% to 27% and proportion taking strong opioids decreased from 15% to 10%, but the changes did not reach statistical significance. We found no significant changes in the proportion who recieved physiotherapy/other treatment nor occupational status. Conclusion The study demonstrates substantial short-term responses after spinal intervention and long-lasting improvement for a subsample of the RFA treated patients. We observed larger proportions reporting pain reduction among those treated with cervical RFA. Implementation Quality assessment should be implemented in interventional pain clinics to improve treatment quality.

Background and aims The Core Outcome Measures Index (COMI) is a short, self-reported questionnaire for assessing important outcomes in patients with low back pain (LBP). The present study was conducted to explore the responsiveness and longitudinal validity of the Persian COMI (COMI-P) in patients with non-specific chronic LBP. Methods In this prospective cohort study of patients with non-specific chronic LBP receiving physiotherapy, patients completed a booklet containing the COMI-P, Persian Functional Rating Index (FRI-P), and a visual analogue scale (VAS) for pain before and after the end of ten-sessions of physiotherapy. Patients also completed a global rating of change scale (GRCS) at the end of the physiotherapy. Responsiveness was examined by means of internal responsiveness methods [ t -test, standard effect size (SES); standardized response mean (SRM), and Guyatt responsiveness index (GRI)] and external responsiveness methods [correlation with external criteria and receiver operating characteristics (ROC) curve]. Results Fifty patients with a mean age of 50.62 ± 13.8 years participated. The paired t -test showed significant changes in COMI-P scores ( p  < 0.001). The effect sizes for COMI-P were large (range 0.96–1.23). The score changes for the COMI-P revealed significant correlations with FRI-P (r = 0.67, p  < 0.001), the VAS (r = 0.65, p  < 0.001), and the GRCS (r = 0.34, p  = 0.02). The COMI-P change scores showed excellent correlation with the dichotomized smallest detectable change (SDC) criterion (r = 0.83, p  < 0.001). The ROC area under the curve for the COMI-P based on the dichotomized SDC criterion was perfect. The minimal clinically important change was estimated 2.15 points (sensitivity 94% and specificity 100%). Conclusions The COMI-P appears to have responsiveness and longitudinal validity in detecting changes after physiotherapy for non-specific chronic LBP. An improvement of 2.15 points in COMI-P total score is required to be interpreted as minimally clinically important change in individual patients.

Background and aims Psoriasis is a common chronic skin condition, causing skin lesions with thickened and scaling skin, as well as erythema and inflammation that may involve painful sores, cracks, and pustules. Previously psoriasis was regarded as a painless skin condition. However, over the past decade studies show that skin pain is a frequently reported and bothersome symptom in patients with psoriasis. There is however a lack of rich narratives describing the experience of skin pain in these patients. The aims of this qualitative study were therefore to explore in depth how patients experience psoriasis-related skin pain, and how they deal with it. Methods Thirteen patients with psoriasis were recruited from a dermatology ward and outpatient clinic. One of the investigators (TML) performed individual, semi-structured interviews at an undisturbed room in the hospital. Interviews were thematically analyzed using the method of Systematic Text Condensation as described by Malterud (2012). Results Three main themes were identified from the interviews. First, the skin pain experience was complex. Patients used a variety of adjectives and metaphors to describe their pain, and their skin was sensitive to stimuli of every-day activities. Itch was a common cosymptom, and could both mask pain but also cause severe pain due to excessive scratching and damage to the skin. Second, skin pain had a negative impact on patients’ life. Skin pain reduced their physical activity level, impaired their sleep, and made them irritable, depressed, unconcentrated on tasks, as well as withdrawn from other people and social activities. Third, patients dealt with their skin pain in various ways. Although some took action to relieve the pain and distract themselves from pain, most of the patients applied maladaptive and passive coping strategies such as put up with it, avoid painful activities, become fearful or trivialize their pain. Conclusions The experience of psoriasis related skin pain is complex. The pain has a major negative impact on patients’ life in terms of physical, emotional, cognitive, and social functions. Patients use a variety of adaptive but most frequently maladaptive coping strategies in order to deal with their skin pain. Implications This study provides new and in-depth knowledge on psoriasis related skin pain. This information is valuable for further work on pain assessment tools and pain management recommendations customized for skin pain experienced by patients with psoriasis.

Background and aims A sizable body of research has elucidated the significant role of psychological reactions to trauma on pain coping and outcomes. In order to best inform intervention development and clinical care for patients with both trauma and pain at the tertiary care level, greater clarity is needed regarding the magnitude of these effects and the specific pathways through which they may or may not function at the time of first presentation to such a treatment setting. To achieve this, the current study examined the cross-sectional relationships between traumatic etiology of pain, psychological distress (anger, depressive symptoms, and PTSD symptoms), and pain outcomes (pain catastrophizing, physical function, disability status). Methods Using a structural path modeling approach, analyses were conducted using a large sample of individuals with chronic pain ( n  = 637) seeking new medical evaluation at a tertiary pain management center, using the Collaborative Health Outcomes Information Registry (CHOIR). We hypothesized that the relationships between traumatic etiology of pain and poorer pain outcomes would be mediated by higher levels of psychological distress. Results Our analyses revealed modest relationships between self-reported traumatic etiology of pain and pain catastrophizing, physical function, and disability status. In comparison, there were stronger relationships between indices of psychological distress and pain catastrophizing, but a weaker pattern of associations between psychological distress and physical function and disability measures. Conclusions To the relatively small extent that self-reported traumatic etiology of pain correlates with pain-related outcomes, these relationships appear to be due primarily to the presence of psychiatric symptoms and manifest most notably in the context of psychological responses to pain (i.e. catastrophizing about pain). Implications Findings from this study highlight the need for early intervention for patients with traumatic onset of pain and for clinicians at tertiary pain centers to include more detailed assessments of psychological distress and trauma as a component of comprehensive chronic pain treatment.

Background and aims A multimodal rehabilitation programme (MMRP) is an evidence-based treatment of chronic pain conditions. The complexity involved in chronic pain needs to be identified and evaluated in order to adapt the rehabilitation to patients’ needs. The aim was to investigate the multivariate relationships between self-reported variables in patients with chronic pain before taking part in MMRP in primary care, with a special focus on gender and degree of sick leave. Methods Prior to MMRP, 397 patients (339 women and 58 men) filled in a questionnaire about pain, healthcare aspects, health-related quality of life, anxiety and depression, coping, physical function, and work-related variables e.g. sick leave. Data were analysed by principal component analysis (PCA) and partial least square analysis. Results The PCA identified four components that explained 47% of the variation in the investigated data set. The first component showed the largest variation and was primarily explained by anxiety and depression, quality of life, acceptance (activity engagement), and pain-related disability. Gender differences were only seen in one component with the pain variables having the highest loadings. Degree of sick leave was not well explained by the variables in the questionnaire. Conclusions The questionnaire filled out by the patients prior to participation in MMRP in primary care identified much of the complexity of chronic pain conditions but there is room for improvement, e.g. regarding explanation of work-related factors. In the multivariate analysis, gender did not fall out as an important factor for how most patients answered the questions. Implications There are not many studies that describe patients who undergo MMRP in primary care since previously such patients were treated mostly in specialist care. More knowledge is needed about these patients in order to improve rehabilitation plans and interventions. The results suggest that the questionnaire identifies the complexity among chronic pain patients in primary care. The identified components could improve assessment before MMRP and contribute to better tailored programmes.

Background and aims Four out of 10 referrals to tertiary care pain centres in Norway are not granted pain centre treatment, confirming earlier research on that this group of patients struggle to access the highest standard of care. Still, no study investigating how people with chronic pain experience rejections from pain centres was found. The aim of the study was therefore to investigate how people with chronic pain experience receiving a rejection from tertiary care pain centres after being referred by their general practitioners (GPs). Methods This was a qualitative study with semi-structured individual interviews with 12 persons, seven men and five women, rejected from the four different pain centres in Norway. The data were analysed thematically using systematic text condensation. Results The pain centre rejection created strong reactions, partly because the rejection was perceived as a refusal from the health care system as a whole. This was especially so because the pain centre was regarded as the last remaining treatment option, and given the rejection, they were now declined help by the experts in the field. Even though some informants had received an explanation for why they had not been granted pain centre treatment, a prominent experience was that the informants found it difficult to understand why their referral had been rejected given the severity of their pain. The incomprehensibility of the rejection together with a feeling of lack of future treatment options, increased the hopelessness and frustration of their situation and made it challenging to move on and search for help elsewhere. Conclusions The experiences with the pain centre rejections indicate that the rejection can have grave consequences for each individual in the following months. An improved system for how to handle expectations towards referrals, including prepare for the possibility of rejection and how to follow up a rejection, seems warranted. Implications Because a pain centre rejection most likely is received by persons in a vulnerable position, there should be available health care services to help them understand the rejections. And furthermore, help them to move from disappointment and hopelessness, towards an experience of empowerment and reorientation, by for instance planning further actions and interventions, and thereby, acknowledge their need for help.

Background and aims Few studies have reported the long-term impact of chronic pain on health care utilization. The primary aim of this study was to investigate if chronic musculoskeletal pain was associated with health care utilization in the general population in a 21-year follow-up of a longitudinal cohort. The secondary aim was to identify and describe factors that characterize different long-term trajectories of health care utilization. Methods A prospective cohort design with a baseline sample of 2,425 subjects (aged 20–74). Data were collected by self-reported questionnaires, and three time points (1995, 2007, and 2016) were included in the present 21-year follow up study. Data on health care utilization were dichotomized at each time point to either high or low health care utilization. High utilization was defined as >5 consultations with at least one health care provider, or ≥1 consultation with at least 3 different health care providers during the last 12 months. Low health care utilization was defined as ≤5 consultations with one health care provider and <3 consultations with different health care providers. The associations between baseline variables and health care utilization in 2016 were analyzed by multiple logistic regression. Five different trajectories for health care utilization were identified by visual analysis, whereof four of clinical relevance were included in the analyses. Results Baseline predictors for high health care utilization at the 21-year follow-up in 2016 were chronic widespread pain (OR: 3.2, CI: 1.9–5.1), chronic regional pain (OR:1.8, CI: 1.2–2.6), female gender (OR: 2.0, CI: 1.4–3.0), and high age (OR: 1.6, CI:0.9–2.9). A stable high health care utilization trajectory group was characterized by high levels of health care utilization, and a high prevalence of chronic pain at baseline and female gender (n = 23). A stable low health care utilization trajectory group (n = 744) was characterized by low health care utilization, and low prevalence of chronic pain at baseline. The two remaining trajectories were: increasing trajectory group (n = 108), characterized by increasing health care utilization, chronic pain at baseline and female gender, and decreasing trajectory group (n = 107) characterized by decreasing health care utilization despite a stable high prevalence of chronic pain over time. Conclusions The results suggest that chronic pain is related to long-term health care utilization in the general population. Stable high health care utilization was identified among a group characterized by female gender and a report of chronic widespread pain. Implications This cohort study revealed that chronic widespread pain predicted high health care utilization over a 21-year follow-up period. The results indicate the importance of early identification of musculoskeletal pain to improve the management of pain in the long run.

Background and aims Psychological resilience refers to successful adaptation or a positive outcome in the context of significant life adversity, such as chronic pain. On the other hand, anxiety closely associates with pain. The aim of this study was to explore how anxiety and psychological resilience together associate with persistent and experimental pain. Methods In a cross-sectional design, we studied 160 patients who had previously been treated for breast cancer and who now reported at least moderate pain (NRS ≥ 4) in any area of the body. Psychological resilience was measured on the Resilience Scale-14, anxiety on the Hospital Anxiety and Depression Scale, and intensity and interference of persistent pain by means of the Brief Pain Inventory. The cold pressor test was conducted to assess sensitivity to experimental cold pain. Results The results showed that resilience associated with pain interference in persistent pain, and that anxiety moderated this effect. Higher psychological resilience was associated with lower pain interference and this association was stronger in patients with low anxiety than among patients with high anxiety. These effects were visible with regard to persistent pain but not in experimental cold pain. Conclusions These results indicate that chronic pain and experimental pain as well as pain severity and pain interference are psychologically different phenomena. Psychological resilience protects against pain interference but effectively only in patients with low anxiety. It is necessary also to consider protective factors in addition to vulnerability factors in cases of persistent pain. Implications Resilience has been considered a potential target for intervention in chronic pain. However, high levels of anxiety might diminish the protective effect of psychological resilience in clinical settings. Therefore, it is important to treat anxiety in addition to resilience enhancing interventions. Patients with low psychological distress might be more suitable for resilience enhancing interventions than patients with high anxiety.

Background and aims Patients usually receive a prescription for morphine or another opioid at discharge after surgery. Several studies have shown that many patients do not step down but develop persistent opioid use following surgery. The purpose of this study was to gain insight of patients’ experiences with opioid tapering after surgery and to propose recommendations for clinicians to assist patients in opioid tapering. Methods Using a qualitative study design, 15 adult patients who took opioids before surgery and still had a daily consumption of opioids 6 months following spine surgery were interviewed. Results Analyses of the transcripts identified three major themes and eight subthemes. The major themes were as follows: (1) The patients’ experienced that their whole life revolved around pain and opioids and felt stigmatized and suspected of being drug addicts by their social circle and health care professionals (2) Barriers for opioid tapering were increased pain, opioid dependency and fear of withdrawal symptoms (3) Motivational factors for opioid tapering were fear of dependency, the prospect of a better health, patient involvement in opioid tapering and a trusting relationship between patient and clinician. Conclusions The results of this study highlight that opioid tapering is challenging and may be influenced by many different factors. Some patients find opioid tapering particularly difficult and therefore need additional assistance in order to taper off successfully. Implications For opioid tapering to succeed, it is highly important to establish a trustful relationship with the patients, to take each patient’s personal circumstances into account and to address fears of increased pain and withdrawal symptoms. Clinicians should also focus on patient involvement in opioid tapering and consider to offer a follow-up after discharge to patients at risk for prolonged opioid use.

Background and aims Although several studies have been conducted, knowledge about chronic pain and dyspareunia after childbirth is still limited. The aim of this study was to explore the prevalence of chronic pain 8 months after childbirth in a cohort of Swedish women. The characteristics of chronic pain, such as, pain intensity, localization and frequency as well as pain interference with daily activities were examined. An additional aim was to describe the prevalence and intensity of dyspareunia. Methods Data were obtained through two self-administered questionnaires and the patient record system, Obstetrix. The first questionnaire was distributed on the maternity ward, 24–36 h after labour, to Swedish-speaking women who had given birth to a living child (n = 1,507). The second questionnaire was sent by post 8 months after childbirth. We collected data about demographic and social characteristics, pain presence and its onset, as well as pain intensity, frequency, bodily localization and pain interference with activities of women’s daily life. Results In total, 1,171 (77.7%) responded to both questionnaires and were included in the analysis. Eight months after giving birth, totally 16.7% (195/1,171) of the women reported chronic pain related to childbirth. Of these, 9.1% (106/1,171) of women reported chronic pain with onset during pregnancy, 4.5% (53/1,171) experienced chronic pain with onset following labour and 3.1% (36/1,171) of women had both chronic pain with onset during pregnancy and chronic pain with onset following labour (each participant could only appear in one of the groups). Women reported a lower prevalence of chronic pain after vaginal delivery than caesarean section (61/916, 6.7% vs. 28/255, 11%, p  = 0.021, OR 1.73, 95% CI 1.1–2.8). Moreover, 19.2% (211/1,098) of women experienced dyspareunia. There was no difference regarding prevalence of dyspareunia and the mode of delivery. Of those women who had a vaginal delivery, 19.5% (167/858) experienced pain during intercourse and the corresponding number for women after caesarean section was 18.3% (44/240) ( p  = 0.694, OR 0.929, CI 0.6–1.3). Approximately 80% of women with chronic pain, and 60% of women that experienced dyspareunia, rated their worst pain as moderate or severe (NRS 4–10). The corresponding number regarding average chronic pain was between 50 and 70%. More than 35% of the women with chronic pain scored pain interference with daily activities as ≥4 on a 0–10 NRS. Conclusions In our study, chronic pain 8 months after childbirth was reported by one in six women and one in five of the women experienced dyspareunia. The intensity of both chronic pain and dyspareunia was reported as moderate to severe in a significant proportion of women and chronic pain interfered considerably with daily activities. Implications There is a need to raise awareness among healthcare providers of this clinical problem as well as to revise and upgrade education regarding pain after childbirth to prevent potential long-term health problems, women’s suffering and increased need for health care. The development of strategies for prevention, follow-up and treatment of pain is warranted. More research, including women’s experiences of pain as well as intervention studies, are also needed.

Background and aims Recognition of the biopsychosocial aspects of pain is important for a true understanding of the burden of pain and the necessity of pain management. Biopsychosocial aspects of pain may differ between countries and cultures. Market research methods can be well suited and effective for assessing patient perspectives of pain and biopsychosocial differences. We conducted and combined 3 cross-sectional, international surveys to document the impact of pain on physical and emotional aspects of life, as well as quality of life (QOL). Methods Online panelists from 24 countries took part in our surveys in 2014, 2016, and 2017. Fourteen countries (Australia, Brazil, Canada, China, Germany, Italy, Japan, Poland, Russia, United Kingdom, United States, Mexico, Sweden, Saudi Arabia) contributed data in all 3 surveys and comprise the analysis population. A Global Pain Index (GPI) was constructed using 8 questions in 3 categories: Physical (frequency, duration, intensity of pain), Emotional (anxiety, impact on self-esteem, happiness), and Impact on QOL and ability to enjoy life. Each item was scored as the percentage of respondents meeting a prespecified threshold indicative of a substantial pain impact. Scores for the items within each category were averaged to obtain a category score, category scores were averaged to obtain a total score for each survey, and total scores from each survey were averaged to obtain a final combined score. Scores were assessed for the overall population, by individual countries, by age and gender, and by self-identified pain-treatment status (treat immediately, wait, never treat). Results Of the 50,952 adult respondents, 28,861 (56.6%) had ever experienced musculoskeletal pain; 50% of those with pain had pain with a multifaceted impact based on the GPI (Physical: 51%; Emotional: 40%; QOL Impact: 59%). Russia (57%) and Poland (56%) had the highest scores; Mexico (46%), Germany (47%), and Japan (47%) had the lowest. GPI score was higher in women (52%) than men (48%), and initially increased with age through age 54 (18‒24 years: 45%; 25‒34 years: 52%; 35‒44 years: 53%; 45‒54 years: 54%), after which it decreased again (55‒64 years: 51%; ≥65 years: 45%). A majority (65%) of respondents wait to treat their pain, whereas 21% treat their pain immediately and 14% never treat pain. The most common reason for waiting (asked in survey 3 only) was to avoid taking medication. Conclusions In this combined analysis of 3 international surveys using a novel biopsychosocial pain assessment tool, pain had a substantial impact on ~50% of respondents’ lives, spanning physical (51%), emotional (40%), and QOL effects (59%). Despite the substantial impact, a majority of patients tried to avoid treating their pain. Implications Clinicians should take a biopsychosocial approach to pain by asking patients not only about the presence and severity of pain, but the extent to which it affects various aspects of their lives and daily functioning. Patients may also need education about the efficacy and safety of available treatments for self-management of pain. The GPI may be a useful new tool for future studies of the biopsychosocial effects of pain in large populations.

Background and aims A considerable research-literature focuses on pain during labor and associations with postpartum persistent pain and depression, with findings pointing in various directions. The aim of this study was to examine the role of labor pain and overall birth experience in the development of pain and depression 8 weeks after delivery. Methods The study sample was drawn from the Akershus Birth Cohort. Data from multiple sources were used, including the hospital’s birth record (n = 4,391), questionnaire data from gestational week 17 of pregnancy (n = 3,752), 8 weeks postpartum (n = 2,217), and two questions about pain and birth experience asked within 48 h after delivery (n = 1,221). The Edinburgh Postnatal Depression Scale was used to measure postpartum depression, a single question was used to measure persistent pain 8 weeks postpartum, while pain and birth experience were measured by numeric rating scales. A history of pre-pregnant depression and chronic pain were measured through self-report questions in gestational week 17. A total of 645 women had complete data from all sources. We applied multiple imputation techniques to handle missing responses on the two questions about pain and birth experience. Results The results showed that neither labor pain nor birth experience were associated with persistent pain 8 weeks postpartum, whereas pain before pregnancy (OR 3.70; 95% CI 2.71–5.04) and a history of depression (OR 2.31; 95% CI 1.85–2.88) were statistically significant predictors of persistent pain. A negative birth experience was significantly (OR 1.16; 95% CI 1.04–1.29) associated with postpartum depression, whereas labor pain intensity was not. A history of depression (OR 3.95; 95% CI 2.92–5.34) and pre-pregnancy pain (OR 2.03; 95% CI 1.37–3.01) were important predictors of postpartum depression 8 weeks after delivery. Conclusions and implications Whilst the relationship between labor pain intensity and postpartum pain and depression remain unclear, our results do imply the need to screen for previous depression and chronic pain conditions in pregnant women, as well as consider preventive measures in those who screen positive.

Background and aims Restless legs syndrome is a sensorimotor disorder associated with mental health conditions notably depression. Restless legs symptoms and depression are commonly associated with pain. The study investigated the influence of restless legs symptoms on musculoskeletal pain in patients with depression or with increased depressive symptoms. Methods A cross-sectional study of primary care patients in the Central Finland Hospital District. The prevalence of restless legs symptoms was studied in patients with depressive symptoms (n = 695) and controls without a psychiatric diagnosis (n = 410) by using a structured questionnaire. The depressive symptoms were evaluated with the Beck Depression Inventory and the psychiatric diagnosis was confirmed by means of a diagnostic interview (MINI). The prevalence and intensity of musculoskeletal pain was captured with form-based questions. A single-question screen for restless legs symptoms was applied. Results There was a significant difference in the prevalence of continuous widespread musculoskeletal pain between the three study groups: the controls 4.6% (95% CI: 2.8–7.1), the patients with symptoms of depression without a diagnosis 16.0% (11.7–21.1), and the patients with diagnosed depression 22.1% (18.3–23.3) ( p  = 0.006 after being adjusted for age, sex, smoking, use of alcohol, education years, body mass index, use of antidepressants, and physical activity, after multiple corrections, all groups were significantly different from each other). Compared with those not having restless legs symptoms, subjects with restless legs symptoms had more often continuous widespread musculoskeletal pain in the control subjects ( p  = 0.001; 2.3% vs. 10.5%) and in the patients with depressive symptoms without a depression diagnosis ( p  = 0.024; 9.1 vs. 18.7%) but not in those with diagnosed depression ( p  = 0.98; 19.5 vs. 19.4%). The restless legs symptoms were associated with the intensity of pain in all groups ( p  < 0.001). Conclusions Restless legs symptoms were related to continuous widespread musculoskeletal pain in subjects without depressive symptoms and in patients with depressive symptoms without a depression diagnosis. Pain intensity was higher in the subjects with restless legs symptoms regardless of depressive symtoms or depression. Implications Clinical management of pain in patients with restless legs symptoms should include an increased focus on the prevention and treatment of either conditions.

Background and aims Previous research on pain and cognition has largely focused on non-social cognitive outcomes (e.g. attention, problem solving). This study examines the relationship between pain and stereotyping, which constitutes a fundamental dimension of social cognition. Drawing on dual process theories of cognition, it was hypothesized that higher levels of pain would increase stereotyped judgments based on ethnicity and age. The hypothesis was tested in conjunction with experimentally induced pain (Study 1) and clinical pain (Study 2). Methods In Study 1, experimental pain was induced with the cold pressor method on a between-subjects basis. Participants ( n  = 151) completed a judgment task that assessed to what extent they relied on stereotypes (ethnic and age) when estimating other people’s cognitive performance. In Study 2, 109 participants with clinical, musculoskeletal pain completed the same stereotype judgment task. Correlations between stereotyped judgments and various pain qualities (intensity, interference with daily activities, duration, and persistence) were performed. Results In Study 1, pain induced participants did not form significantly more stereotyped judgments compared to pain-free participants. However, higher reported pain intensity was associated with more ethnically stereotyped judgments. In Study 2, there were no significant correlations between different aspects of clinical pain and stereotyped judgments. Conclusions The results provide weak support for the hypothesis that pain increases stereotyped judgments. This was the case for both experimentally induced pain and clinical pain. The present study is the first to investigate the link between pain and stereotyping, suggesting that stereotypical judgments may be a social cognitive outcome that is relatively unaffected by pain. Implications The results have practical implications for the clinic, for example, where chronic pain patients may not have greater difficulties interacting with health care professionals that are members of a stereotyped social group (e.g. ethnic).

Background and aims Evidence for analgesic effects of oral alcohol consumption on heat pain has recently been documented in a placebo-controlled, randomized and double-blind design. We aimed at further investigating these effects and now set the focus on pain threshold and the ratings of supra-threshold pain to cover most of the pain range. Moreover, we now firstly evaluated sex differences in these effects. Methods We investigated 41 healthy participants (22 females) in a randomized, double-blind and placebo-controlled design and targeted two different moderate breath-alcohol levels of 0.06% and 0.08%. Before and after an alcoholic or placebo drink, contact heat was applied at the forearm. Subjects evaluated pain threshold (method of adjustment) and rated pain intensity and pain unpleasantness of supra-threshold stimuli (intensity: threshold +3 °C; duration: 5 s). Results Analgesic effects taking the form of increased pain thresholds were found after both alcohol doses, surprisingly with more pronounced effects for the lower dose. While the high alcohol dose exerted small analgesic effects on pain intensity ratings (i.e. decrease), slightly increased ratings of pain intensity and pain unpleasantness after the low alcohol dose rather suggest pain enhancement. Alcohol did not affect intensity vs. unpleasantness ratings differentially. We found no evidence for sex differences in any of these effects. Conclusions Overall, acute alcohol effects on pain were subtle. Our findings suggest that while low alcohol doses already exert analgesic effects on pain threshold, stronger doses are required for pain reduction on supra-threshold pain levels. Furthermore, sex differences could not be detected within our experimental paradigm but should be further explored in future research. Implications Analgesic effects of sub-toxic alcohol doses – as normally occurring during social drinking – might be weak; however, susceptibility to pain relieving effects of alcohol might be a risk factor for the use of alcohol as self-medication in acute pain states.

Background and aims Psychological traits such as pain catastrophizing may play a role in the development of chronic pelvic pain (CPP). Pain catastrophizing is the tendency to amplify negative cognitive and emotional pain processes. The Pain Catastrophizing Scale (PCS) assesses elements of pain catastrophizing divided into three subgroups of factors (rumination, helplessness and magnification). Previous studies have shown associations between CPP and increased pain sensitivity, widespread generalized hyperalgesia, and decreased pain thresholds, but the relation between pain catastrophizing and specific pain thresholds has not yet been widely examined in this patient group. The aims of this study were (a) to determine if catastrophizing is increased in women with CPP compared with pain-free women, (b) to assess the importance of pain catastrophizing, psychological distress variables, and subjective pain sensitivity for pain thresholds of heat, cold and pressure in these two groups, and (c) to determine whether psychological variables or pain thresholds best contribute to the differentiation between CPP and controls. Methods Thirty-seven women with chronic pelvic pain who underwent diagnostic laparoscopy on the suspicion of endometriosis participated along with 55 healthy and pain-free controls. All underwent quantitative sensory testing on six locations on the body to determine heat (HPT), cold (CPT) and pressure (PPT) pain thresholds. The PCS, the Pain Sensitivity Questionnaire (PSQ), the Hospital Anxiety Depression Scale, (HADS) demographics and clinical data were collected prospectively. Principal component analysis and orthogonal partial least square regressions were used to assess the associations between PCS scores and pain thresholds. Results The women with CPP scored significantly higher on PCS than the healthy controls. PCS-helplessness, PCS-rumination and HADS-depression were significantly associated with pain thresholds for the whole group. In the CPP group, PCS-rumination, body mass index and PSQ were significant regressors for HPT and CPT. The PCS and the HADS subscales were strongly intercorrelated in women with CPP and were stronger regressors of group membership than the three pain thresholds. In the group of healthy control women, no relationships were found to be significant. The psychological variables were somewhat stronger significant regressors than pain thresholds (also significant) for group membership. Conclusions Women with CPP have significantly higher pain catastrophizing scores than women without CPP. The pain catastrophizing rumination factor is significantly associated with pain thresholds of heat and cold in CPP women. PCS and HADS are strongly intercorrelated and PSQ correlates positively with these variables. It seems that the psychological variables are important for group differentiation. Implications The results clearly indicate the need for a multimodal assessment (bio-psycho-social) of CPP patients including psychological symptoms such as catastrophizing, anxiety and depression. The registration of semi-objective pain thresholds captures both specific pain sensitivity information (mechanical pressure, cold or heat) and the degree of wide spread pain hypersensitivity. There is a need for future larger studies investigating whether certain profiles in the clinical presentations (including pain thresholds and psychological variables) are associated with outcomes after different types of interventions.