European Journal of Pain最新文献

Background: Fibromyalgia (FM) is a chronic pain syndrome in which central sensitization has been suggested. Several patients also present with small fibre pathology. Neurofilament light chain (NfL) is a biomarker of axonal injury, but its role in FM remains unclear. We evaluated serum NfL in FM patients and tested possible correlations between NfL levels, clinical features, dysfunction at the central level assessed with a cognitive battery, and small fibre pathology assessed with skin biopsy.

Methods: We conducted an observational case-control study including 70 FM patients and 55 healthy controls. Serum NfL was measured using the LUMIPULSE G600II platform. Clinical assessment included pain (WPI), disability (FIQ), sleep (MOS Sleep Scale), and neuropsychological testing (MoCA and an executive function battery). Forty patients underwent skin biopsy with intraepidermal nerve fibre density (IENFD) quantification. Group comparisons were performed with non-parametric tests and correlations using Spearman coefficients.

Results: FM patients showed higher NfL levels compared to controls, independent of age. In both groups, NfL correlated positively with age (ρ = 0.25, p = 0.005). Among FM patients, NfL values did not differ between those with normal skin biopsy and those with proximal or combined proximal-distal denervation, and NfL did not correlate with IENFD. NfL was unrelated to disease duration, pain scores, sleep duration, or cognitive performance. The only clinical correlation observed was an association with disability (FIQ; ρ = 0.29, p = 0.02).

Conclusions: Serum NfL is elevated in FM but not linked to small fibre pathology or cognitive impairment. Instead, it may reflect neuronal changes related to disease burden.

Significance: These findings support the concept of FM as a neurogenic disorder and suggest serum NfL as a potential biomarker of neuronal stress in chronic pain, although it is not specific for peripheral nerve damage or cognitive dysfunction.

Background: Chronic pain frequently co-occurs with multiple somatic comorbidities. However, little is known about how these conditions naturally cluster in patients with high-impact chronic pain. This study aimed to describe somatic comorbidities and identify clusters of co-occurring diseases in patients with high-impact chronic pain referred to specialised interdisciplinary treatment and to examine associations between these clusters and patient-reported physical health, mental health and pain distribution.

Methods: A cross-sectional study was conducted with 10,256 chronic pain patients referred to specialised interdisciplinary pain treatment using data from the Danish PainData registry. Somatic comorbidities were self-reported from a list of 16 diseases and conditions. Exploratory factor analysis with tetrachoric correlations identified clusters of comorbidities. Physical and mental health were evaluated using the PROMIS-10 Global Health questionnaire and pain distribution was assessed by a 71-area pain drawing. Statistical analyses, including ANOVA and Kruskal-Wallis tests, evaluated differences in patient-reported outcomes between disease clusters.

Results: Patients reported a median of three somatic comorbidities, with migraine (56%), herniated disc/spinal disorders (53%) and osteoarthritis (42%) being most prevalent. Factor analysis revealed six disease clusters, including systemic illness, cardiovascular disease, musculoskeletal disorders, metabolic-vascular conditions, allergy-respiratory issues and neurosensory disturbances. Distinct clusters of co-occurring diseases and conditions were associated with poorer physical health and more widespread pain.

Conclusions: Somatic comorbidities were highly prevalent in this large chronic pain cohort, with six disease clusters associated with varying levels of physical health and pain distribution. These findings highlight the need for stratified approaches in pain care, informed by somatic disease clustering.

Significance statement: This study identifies distinct clusters of somatic comorbidities among patients with high-impact chronic pain and links them to health outcomes. Understanding these clusters may help clinicians tailor more precise, stratified pain interventions and offers basic scientists insight into potential underlying mechanisms connecting chronic pain with systemic disease patterns.

Background: A growing body of research reports positive consequences of acute pain, including emotional self-regulation. Pain as a pleasurable experience has also been regarded in the context of sadomasochistic (SM) interest, albeit quantitative empirical evidence is scarce. Recently, an elevated prevalence of chronic pain (CP) has been reported in SM practitioners; however, in absence of a control group. To contribute to research in the field, we strove to see whether we could replicate the finding and further aimed to identify psychological predictors of SM.

Method: A total of 617 participants (N = 242 with SM sexual preference) completed an online questionnaire battery comprising psychometric instruments for the measurement of pain attitudes, sensation seeking and pain sensitivity. An age- and sex-matched sample was created to control for their respective influence.

Results: CP prevalence in the SM subsample was 47.2%, which we found to be significantly increased compared to the prevalence in the non-SM subsample (29.4%). Neither sex nor age seemed to explain the relationship. There were no interaction effects of SM × CP on pain attitudes. A hierarchical logistic regression model explained around 42% of the variance in SM, with CP, sensation seeking, and viewing pain as a challenge as significant predictors.

Conclusions: We replicated an increased CP prevalence in SM and ruled out previous sampling biases. We further extended evidence on factors predicting SM sexual preference. Large-scale, representative and prospective studies are needed to corroborate the idea of SM as a coping strategy used by some CP patients.

Significance statement: We demonstrated a significantly elevated chronic pain prevalence of around 47% in individuals with sadomasochistic sexual preference, ruling out previously discussed sampling biases. Possibly, sadomasochistic practise is used as a coping strategy by some chronic pain patients. We further presented a model of pain-related and psychological variables explaining around 42% of variance in sadomasochistic sexual preference in general. The results are discussed in terms of their potential to inform pain management strategies.

Background: Continuity of care is a core element of high-quality primary care and may prevent inappropriate opioid use. However, evidence on its association with opioid initiation among opioid-naïve adults with non-cancer pain remains scarce.

Methods: We conducted a population-based cohort study using South Korea's national claims data (2015-2022). The study included 392,988 adults aged ≥ 20 years diagnosed in 2016 with musculoskeletal and connective tissue disorders who received outpatient primary care without prior opioid exposure. Continuity of care was measured using the Bice-Boxerman Continuity of Care Index (COCI) and categorised as high (≥ 0.90), medium (0.48-< 0.90), or low (< 0.48). The primary outcomes were the incidence of new opioid prescriptions and a composite indicator of potentially inappropriate opioid prescribing, defined by five criteria.

Results: Among 392,988 participants, 52,670 (13.4%) initiated opioid therapy. Compared with the high-continuity group, the medium- and low-continuity groups had 1.27-fold (95% CI, 1.25-1.28) and 1.43-fold (95% CI, 1.41-1.45) higher risks of opioid initiation, respectively. High continuity was associated with a median delay of 303 days in opioid initiation. Potentially inappropriate prescribing occurred in 12.1% of opioid users, with higher risks in the medium- (adjusted hazard ratio [aHR] = 1.26; 95% CI, 1.23-1.28) and low-continuity groups (aHR = 1.41; 95% CI, 1.39-1.44).

Conclusions: Higher continuity of primary care was associated with delayed opioid initiation and reduced inappropriate opioid prescribing among adults with non-cancer pain. Strengthening continuity-focused interventions may help mitigate opioid-related harms and promote safer pain management.

Significance statement: Relational continuity in primary care plays a key role in shaping opioid prescribing patterns among adults with non-cancer pain. Using nationwide data, our findings suggest that stronger continuity is associated with more cautious opioid use, including delayed initiation and a lower likelihood of inappropriate prescribing. These results highlight the importance of fostering ongoing, trust-based relationships between patients and primary care providers as a strategy to reduce unnecessary opioid exposure and promote safer, patient-centered pain management. Strengthening continuity in primary care may therefore have meaningful implications for both clinical practice and health policy.

Background: Shoulder-hand syndrome (SHS) is a neurological disorder characterised by pain, loss of function, and trophic changes in the shoulder and hand of the affected limb. SHS shares a number of features with Complex Regional Pain Syndrome (CRPS). Historically, several terms have been used interchangeably with SHS, obfuscating clinical presentation. This review aimed to characterise the presentation of SHS to provide a full clinical picture for clinicians and researchers. Furthermore, we aimed to examine whether symptoms differ between triggered and idiopathic SHS, as indicated in previous research.

Methods: A systematic search of three databases (PubMed, Web of Science and Google Scholar) and bibliographies was performed. Articles published from 1940 to 2025 describing symptoms of shoulder-hand syndrome in any context were screened for eligibility. Papers were excluded if they used alternative terms in place of 'shoulder-hand syndrome', such as reflex sympathetic dystrophy.

Results: 16,843 articles were identified, with 33 meeting the inclusion criteria. The clinical presentation of SHS was similar across included studies, with some variations observed between post-hemiplegic (PH) and post-myocardial infarction (PM) SHS patients. The predominant symptoms were pain in the shoulder, accompanied by pain and swelling of the hand. PH patients exhibited more trophic symptoms (e.g., nail growth changes, skin thickening), while PM patients demonstrated joint contractures and stiffness.

Conclusions: This review provides a detailed description of the symptoms of shoulder-hand syndrome, including both triggered and idiopathic cases. We hypothesize that SHS might be a sub-type of CRPS; however, more research is required to validate this categorization.

Significance statement: This review provides a detailed description of the symptoms of shoulder-hand syndrome. This information may be useful for clinicians and researchers examining cases of SHS and possibly contrast this with CRPS. A concerted effort to phenotype these patients, including the influence of inciting events, using modern techniques such as quantitative sensory testing would be useful. We propose that SHS may be a sub-type of CRPS and if confirmed should be classified accordingly, however more research is needed.

Objective: High blood pressure (BP) often co-occurs with osteoarthritis (OA) and may influence pain sensitivity, potentially contributing to pain-pathology discordance. We hypothesized that higher BP would associate with reduced pain sensitivity and greater OA severity in adults with chronic knee pain.

Methods: A cross-sectional analysis of 213 community-dwelling adults (44-78 years) with chronic knee pain was conducted. Hypertension was defined by diagnosis or antihypertensive use; others were normotensive. Systolic, diastolic, pulse (PP), and mean arterial (MAP) BP were measured. Quantitative sensory testing assessed pressure/thermal pain sensitivity, temporal summation (TS), and conditioned pain modulation (CPM). Radiographic knee OA (rKOA) was graded using the Kellgren-Lawrence scale. Models adjusted for race, age, BMI, site, and diabetes.

Results: Blood pressure-pain associations were moderated by sex and hypertensive status, observed only in normotensive individuals. Among normotensive males, each 10 mmHg increase in BP was associated with reduced pressure pain sensitivity (β [95% CI]: systolic -0.21 [-0.42, -0.002]; diastolic -0.36 [-0.68, -0.05]; MAP -0.31 [-0.59, -0.03]; all p < 0.05) but greater odds of late-stage rKOA (AOR [95% CI]: systolic 1.70 [1.07, 2.70]; MAP 2.10 [1.10, 4.01]). Among normotensive females, temporal summation of mechanical pain increased with higher BP (β [95% CI]: systolic 0.14 [0.01, 0.27], p = 0.027; PP 0.20 [0.02, 0.38], p = 0.026). No significant associations were observed for heat/cold pain sensitivity, TS of heat pain, or CPM.

Discussion: Elevated BP was associated with hypoalgesia and more severe rKOA severity in normotensive males. In normotensive females, elevated BP showed greater pain facilitation but not rKOA severity. Together, these sex-specific findings suggest BP as a vascular factor contributing to pain-pathology mismatch in OA.

Significance statement: Associations between arterial blood pressure and pain in older adults with knee pain were found to be sex- and hypertension-dependent, primarily evident in normotensive individuals. Elevated blood pressure was associated with reduced mechanical pain sensitivity but greater radiographic OA in normotensive males; normotensive females showed enhanced pain facilitation without increased OA severity. These findings support arterial pressure as a shared vascular factor in pain-pathology mismatch and highlight the importance of incorporating cardiovascular markers into chronic pain phenotyping and interpretation.

Background: The Graded Chronic Pain Scale-Revised (GCPS-R) enables a standardised measure of chronic pain severity. Only sparse data are available on the prevalence of chronic pain stages assessed by the GCPS-R and the predictors of high-impact chronic pain (HICP) in the general European population.

Methods: A cross-sectional cohort study surveyed 2498 people ≥ 16 years living in Germany in 2025. Self-reported measures were obtained for demographic variables, chronic pain stages and disease load (Patient Health Questionnaire 4 and chronic illness). Potential predictors of HICP (age, gender, education, net income, probable depressive and anxiety disorder, chronic illness) compared to no and mild-impact and to bothersome chronic pain were assessed by adjusted univariate and multivariate logistic regression analyses.

Results: Response rate was 37.9%. The prevalence of chronic pain present most or every day prior to 3 months was 11.4 (95% CI, 7.7% to 15.1%) of which 1.1% (-2.9% to 5.0%) with mild impact chronic pain; 3.3% (-0.6% to 7.2%) with bothersome impact chronic pain; and 7.1% (3.3% to 10.9%) with HICP. HICP compared to no and mild chronic pain was predicted in multivariate-adjusted analysis by age, lower educational level, lower income, probable anxiety and/or depressive disorder and chronic illness. Multivariate-adjusted analysis did not show significant associations of HICP with the selected variables when compared to bothersome pain.

Conclusions: Biological, psychological and social factors are associated with HICP. Targeted pain services for populations at highest risk for HICP need to be developed.

Significance statement: The prevalence of bothersome and high-impact chronic pain rather than prevalence rates of any chronic pain might provide evidence in support of pain specialist care. Identifying risk factors of high-impact chronic pain in specific populations could lead to an improved understanding of the risk factors, causes and consequences of chronic pain. European public health policies could be influenced by gathering data on high-impact chronic pain in other European countries.