Validation of the PTSD-8 Scale in Chronic Pain Patients.

Objectives: The aim was to validate the short PTSD-8 scale against the Structured Clinical Interview (SCID-1) for post-traumatic stress disorder and to test the latent structure of post-traumatic stress disorder in chronic pain patients. Methods: A total of 51 chronic nonmalignant pain patients exposed to a traumatic event were consecutively recruited from a multidisciplinary pain center. All participants answered a baseline questionnaire followed by the PTSD-8 and the diagnostic interview for PTSD. Finally, the latent structure of PTSD-8 was tested in a large cohort of 419 patients with chronic nonmalignant pain using confirmatory factor analysis (CFA). Results: In total, 33.3% had a diagnosis of PTSD. A good overall accuracy was found validating the PTSD-8 against the diagnostic interview. Convergent validity was indicated as the PTSD-8 correlated strongly with scores of depression and anxiety. The results of the CFA for the PTSD-8 three-factor structure provided excellent fit for the eight post-traumatic stress disorder symptoms. Conclusions: Overall, the results showed that the PTSD-8 is a valid short screening tool to assess possible post-traumatic stress disorder among patients with chronic pain. In addition, the PTSD-8 scale comprises all of the upcoming ICD-11 post-traumatic stress disorder symptoms within its eight items. Thus, the PTSD-8 is likely also to measure the proposed ICD-11 post-traumatic stress disorder.

Pain and executive function: no association between remote exercise-induced hypoalgesia and cognitive inhibition in pain-free participants.

OBJECTIVES: Cognitive inhibition, which denotes the ability to suppress predominant or automatic responses, has been associated with lower pain sensitivity and larger conditioned pain modulation in humans. Studies exploring the association between cognitive inhibition and other pain inhibitory phenomena, like exercise-induced hypoalgesia (EIH), are scarce. The primary aim was to explore the association between cognitive inhibition and EIH at exercising (local) and non-exercising (remote) muscles after isometric exercise. The secondary aim was to explore the association between cognitive inhibition and pressure pain sensitivity. METHODS: Sixty-six pain-free participants (28.3 ± 8.9 years old, 34 women) completed two cognitive inhibition tasks (stop-signal task and Stroop Colour-Word task), a 3-min isometric wall squat exercise, and a quiet rest control condition with pre- and post-assessments of manual pressure pain thresholds at a local (thigh) and a remote site (shoulder). In addition, cuff pressure pain thresholds, pain tolerance and temporal summation of pain were assessed at baseline. RESULTS: No association was found between remote EIH and cognitive inhibition (Stroop interference score: r=0.12, [-0.15; 0.37], p=0.405, BF01=6.70; stop-signal reaction time: r=-0.08, [-0.32; 0.17], p=0.524, BF01=8.32). Unexpectedly, individuals with worse performance on the Stroop task, as indicated by a higher Stroop interference score, showed higher local EIH (r=0.33; [0.10; 0.53], p=0.007, BF01=0.29). No associations were observed between pain sensitivity and any of the cognitive inhibition performance parameters. CONCLUSIONS: The present findings do not support previous evidence on positive associations between exercise-induced hypoalgesia and cognitive inhibition, as well as baseline pain sensitivity and cognitive inhibition.

Patterns of Approach to Activity in 851 Patients With Severe Chronic Pain: Translation and Preliminary Validation of the 9-item Avoidance-Endurance Fast-Screen (AEFS) Into Danish.

OBJECTIVES: The Avoidance-Endurance Fast-Screen (AEFS) is a 9-item self-report questionnaire that classifies patients with back pain into 4 activity-related subgroups, based on the Avoidance-Endurance Model of pain. The objective of this study was to translate the AEFS into Danish and investigate its discriminative abilities in a large, diverse patient sample. MATERIALS AND METHODS: A total of 851 specialist care-seeking patients with severe chronic pain conditions participated in this cross-sectional study. Participants were categorized as showing a "distress-endurance" (DER), "eustress-endurance" (EER), "fear-avoidance" (FAR), or "adaptive" (AR) pattern. Principal component analysis reduced a large number of psychological variables beforehand. Construct and outcome-based validity were explored using multivariate analysis of variance. RESULTS: Of the participants, 33.6% were categorized as DER, 29.4% as EER, 22% as FAR, and 15% as adaptive. Principal component analysis showed the factors activity-related pain behavior, affective distress, and dysfunctional pain thoughts. The AEFS-DK discriminated all 4 subgroups in terms or their pain behavior with EER>DER>AR>FAR. FAR showed less moderate/vigorous activity than DER and EER and more sedentary time than EER. DER and FAR showed higher affective distress, dysfunctional pain thoughts, and poorer outcomes than AR and EER. CONCLUSION: The results indicate good construct validity of the AEFS-DK discriminating the 4 avoidance-endurance model-related subgroups with respect to approach to activity behavior, psychological variables, and reported physical activity. Concerning outcome-based validity, 2 subgroups DER/FAR and AR/EER could be distinguished with inconclusive results for the eustress-endurance subgroup. Future studies are warranted using longitudinal research designs investigating whether AEFS subgroups differ in terms of treatment effects and long-term prognosis.

Impaired exercise-induced hypoalgesia in individuals reporting an increase in low back pain during acute exercise.

OBJECTIVES: Exercise therapy is recommended for low back pain (LBP) although the immediate effects on pain are highly variable. In 96 individuals with LBP this cross-sectional study explored (a) the magnitude of exercise-induced hypoalgesia (EIH) and (b) measures of pain sensitivity and clinical pain manifestations in individuals reporting a clinical relevant increase in back pain during physical activity compared with individuals reporting low or no increase in back pain during physical activity. METHODS: Cuff algometry was performed at baseline on the leg to assess pressure pain threshold (cPPT), tolerance (cPTT) and temporal summation of pain (cTSP). Manual PPTs were assessed on the back and leg before and after a 6-min walk test (6MWT). Back pain was scored on a numerical rating scale (NRS) after each minute of walking. The EIH-effect was estimated as the increase in PPTs after the walk exercise. RESULTS: Twenty-seven individuals reported an increase of ≥2/10 in pain NRS scores during walking and compared with the individuals with <2/10 NRS scores: cPPT and EIH-effects were lower whereas cTSP, pain intensity and disability were increased (p < 0.03). Baseline NRS scores, EIH and pain thresholds were associated with the likelihood of an increase of ≥2/10 in back pain intensity during walking (p < 0.05). CONCLUSIONS: Pain flares in response to physical activity in individuals with LBP seem to be linked with baseline pain sensitivity and pain intensity, and impair the beneficial EIH. Such information may better inform when individuals with LBP will have a beneficial effect of physical activity. SIGNIFICANCE: Pain flares in response to physical activity in individuals with LBP seem to be linked with baseline pain sensitivity and pain intensity, and impair the beneficial exercise-induced hypoalgesia. Such information may better inform when individuals with LBP will have a beneficial effect of physical activity.

The predictive value of quantitative sensory testing: a systematic review on chronic postoperative pain and the analgesic effect of pharmacological therapies in patients with chronic pain.

Studies have suggested that quantitative sensory testing (QST) might hold a predictive value for the development of chronic postoperative pain and the response to pharmacological interventions. This review systematically summarizes the current evidence on the predictive value of QST for chronic postoperative pain and the effect of pharmacological interventions. The main outcome measures were posttreatment pain intensity, pain relief, presence of moderate-to-severe postoperative pain, responders of 30% and 50% pain relief, or validated questionnaires on pain and disability. A systematic search of MEDLINE and EMBASE yielded 25 studies on surgical interventions and 11 on pharmacological interventions. Seventeen surgical and 11 pharmacological studies reported an association between preoperative or pretreatment QST and chronic postoperative pain or analgesic effect. The most commonly assessed QST modalities were pressure stimuli (17 studies), temporal summation of pain (TSP, 14 studies), and conditioned pain modulation (CPM, 16 studies). Of those, the dynamic QST parameters TSP (50%) and CPM (44%) were most frequently associated with chronic postoperative pain and analgesic effects. A large heterogeneity in methods for assessing TSP (n = 4) and CPM (n = 7) was found. Overall, most studies demonstrated low-to-moderate levels of risk of bias in study design, attrition, prognostic factors, outcome, and statistical analyses. This systematic review demonstrates that TSP and CPM show the most consistent predictive values for chronic postoperative pain and analgesic effect, but the heterogeneous methodologies reduce the generalizability and hence call for methodological guidelines.

Pretreatment Exercise-induced Hypoalgesia is Associated With Change in Pain and Function After Standardized Exercise Therapy in Painful Knee Osteoarthritis.

OBJECTIVES: Exercise-induced hypoalgesia (EIH), a measure of descending pain inhibitory control, has been found hyperalgesic in subgroups of painful knee osteoarthritis (KOA) patients. The effect of standardized exercise therapy (ET) on clinical pain intensity in KOA has been demonstrated. However, the prognostic value of EIH in KOA patients completing an ET program has not been investigated. This study investigated the prognostic value of EIH on pain relief following ET in KOA patients. MATERIALS AND METHODS: In 24 painful KOA patients (Numerical Rating Scale, 0 to 10 ≥3), EIH was assessed as change in pressure pain threshold after 2-minute "lateral raises" before and after ET in this observational study. In addition, temporal summation of pain, clinical pain scores (Numerical Rating Scale, Knee injury and Osteoarthritis Outcome Score [KOOS], and PainDETECT Questionnaire) were assessed before and after ET. The KOOS-4 is defined by the KOOS subscale scores for Pain, Symptoms, Activities of Daily Living, and Quality of Life and was used as the primary outcome. RESULTS: Following ET, all clinical pain scores improved (P<0.01) but no changes in pressure pain threshold, temporal summation of pain, or EIH were found (P>0.05). Linear regression models identified pretreatment EIH (ß=0.59, P<0.005) and PainDETECT Questionnaire (ß=0.57, P<0.005) as independent factors for relative change in KOOS-4 after ET (adjusted R=46.8%). DISCUSSION: These preliminary and exploratory results suggest that patients with a high EIH response before a standardized ET program may be associated with a large improvement in pain after treatment. This measure may potentially help clinicians as a prognostic tool for outcome prediction following ET in KOA patients.

Endogenous Modulation of Pain: The Role of Exercise, Stress, and Cognitions in Humans.

BACKGROUND: Pain is a complex and highly subjective phenomenon that can be modulated by several factors. On the basis of results from experimental and clinical studies, the existence of endogenous pain modulatory mechanisms that can increase or diminish the experience of pain is now accepted. METHODS: In this narrative review, the pain modulatory effects of exercise, stress, and cognitions in humans are assessed. RESULTS: Experimental studies on the effect of exercise have revealed that pain-free participants show a hypoalgesic response after exercise. However, in some patients with chronic pain, this response is reduced or even hyperalgesic in nature. These findings will be discussed from a mechanistic point of view. Stress is another modulator of the pain experience. Although acute stress may induce hypoalgesia, ongoing clinical stress has detrimental effects on pain in many patients with chronic pain conditions, which have implications for the understanding, assessment, and treatment of stress in patients with pain. Finally, cognitive strategies play differing roles in pain inhibition. Two intuitive strategies, thought suppression and focused distraction, will be reviewed as regards experimental, acute, and chronic pain. CONCLUSION: On the basis of current knowledge on the role of exercise, stress, and cognitive pain control strategies on the modulation of pain, implications for treatment will be discussed.

Changing the Narrative in Diagnosis and Management of Pain in the Sacroiliac Joint Area.

The sacroiliac joint (SIJ) is often considered to be involved when people present for care with low back pain where SIJ is located. However, determining why the pain has arisen can be challenging, especially in the absence of a specific cause such as pregnancy, disease, or trauma, when the SIJ might be identified as a source of symptoms with the help of manual clinical tests. Nonspecific SIJ-related pain is commonly suggested to be causally associated with movement problems in the SIJ(s)-a diagnosis traditionally derived from manual assessment of movements of the SIJ complex. Management choices often consist of patient education, manual treatment, and exercise. Although some elements of management are consistent with guidelines, this Perspective article argues that the assumptions on which these diagnoses and treatments are based are problematic, particularly if they reinforce unhelpful, pathoanatomical beliefs. This article reviews the evidence regarding the clinical detection and diagnosis of SIJ movement dysfunction. In particular, it questions the continued use of assessing movement dysfunction despite mounting evidence undermining the biological plausibility and subsequent treatment paradigms based on such diagnoses. Clinicians are encouraged to align their assessment methods and explanatory models with contemporary science to reduce the risk of their diagnoses and choice of intervention negatively affecting clinical outcomes.

Brief Psychological Screening Questions Can be Useful for Ruling Out Psychological Conditions in Patients With Chronic Pain.

OBJECTIVES: Psychological symptoms are highly prevalent in chronic pain patients. Timely and accurate identification may enable individualized treatment and improve outcomes. The aims of this study were to (1) investigate the concurrent validity of brief psychological screening questions assessing anxiety, fear of movement, stress, pain catastrophization, and depression in chronic pain patients, and (2) to determine screening question cut-points at which the likely probability of having these psychological states was <10%. MATERIALS AND METHODS: Responses to 1-item or 2-item screening questions within each of these 5 psychological constructs were compared with those of validated full-length questionnaires in 894 patients with diverse chronic pain conditions. RESULTS: Compared with scores from full-length questionnaires, brief screening question scores had correlations between 0.54 and 0.66, and area under the curve between 0.79 and 0.83. At the dichotomized threshold scores that we chose, the posttest probability after a negative test result ranged from 6.5% to 8.6% for all these psychological constructs, except fear of movement. The pretest probability was so high (70%) for fear of movement that no threshold resulted in a posttest probability (negative test result) that was below 10%. DISCUSSION: Use of these screening tests and scoring thresholds would have correctly identified that between 38.5% and 60.5% of the sample were unlikely to have these psychological states (true negatives), with a false-negative rate between 3.4% and 5.3%. This would allow clinicians to focus on whether there are other patient attributes in those patients requiring more thorough investigation using comprehensive validated questionnaires or structured clinical interviews.

Attentional Avoidance is Associated With Increased Pain Sensitivity in Patients With Chronic Posttraumatic Pain and Comorbid Posttraumatic Stress.

OBJECTIVES: Posttraumatic stress disorder (PTSD) is common in chronic posttraumatic pain. Theoretical models suggest that attentional biases (AB) contribute to the development and maintenance of chronic pain and PTSD; however, the influence of AB on clinical and heat pain sensitivity in chronic posttraumatic pain patients is unknown. This study investigated AB for linguistic pain-related stimuli and trauma-related stimuli, and clinical and thermal sensitivity in patients with chronic posttraumatic pain with and without PTSD. MATERIALS AND METHODS: In total, 34 patients with chronic posttraumatic cervical pain performed the visual attentional probe task assessing patterns of selective attentional responding to trauma cues and to pain cues. The task used short (500 ms) and long (1250 ms) stimulus exposure durations to ensure sensitivity to both the orienting and maintenance of attention. Heat pain threshold was assessed at the nonpainful hand. Clinical pain intensity, psychological distress (anxiety, depression, and disability), and PTSD symptomatology were assessed with questionnaires. RESULTS: The Pain/PTSD group (N=14) demonstrated increased clinical and heat pain sensitivity as well as psychological distress compared with the Pain/No-PTSD group (N=20; P<0.05). AB scores were significantly different between groups (P=0.04). Irrespective of stimulus exposure duration, the Pain/PTSD group demonstrated attentional bias away from trauma and pain cues (avoidance), whereas the Pain/No-PTSD group demonstrated attentional bias toward pain cues (vigilance). Attentional avoidance of pain cues was associated with increased pain intensity and heat pain sensitivity (P<0.02). DISCUSSION: These results suggest that attentional avoidance is associated with increased chronic posttraumatic pain. The causal contribution of attentional avoidance to pain outcomes remains unclear.

Exercise does not produce hypoalgesia when performed immediately after a painful stimulus.

BACKGROUND AND AIMS: Exercise-induced hypoalgesia (EIH) and conditioned pain modulation (CPM) are assumed to reflect descending pain inhibition. Potential interactions between EIH and CPM may be important in the therapy of chronic pain, as reduced CPM and increased pain after exercise are frequently observed. This study compared the EIH response after CPM was activated using a cold pressor task with the EIH response after a control condition. METHODS: Thirty-one participants (age: 27.7±9.8; 15 female) completed two sessions: a cold pressor task (CPT) session, i.e. testing EIH with preceding CPM activation induced using a 2 min CPT at approximately 2°C, and a control session, i.e. testing EIH after a control condition (2 min of quiet rest). EIH was induced using a 15 min bicycling exercise at a target heart rate corresponding to 75% VO2 max. Repeated measures ANOVAs on pressure pain thresholds (PPTs) at the hand, back and leg were used to determine the effects of exercise after the cold pressor test and control condition. Furthermore, correlations between CPM and EIH, in the CPT session as well as control session, were calculated at each assessment site. RESULTS: A significant time x condition interaction (F(1, 30)=43.61, p<0.001, partial η2=0.59), with Bonferroni-corrected post-hoc t-tests showed that PPTs increased after exercise in the control session (p<0.001), but not in the CPT session (p=0.125). Furthermore, there was a small positive correlation of EIH in the control session and CPM at the hand (r=0.37, p=0.043). There was a moderate negative correlation of EIH in the CPT session and CPM at the hand (r=-0.50, p=0.004), and smaller negative correlations at the back (r=-0.37, p=0.036) and at the leg (r=-0.35, p=0.054). CONCLUSIONS: Attenuated EIH after the CPM activation in comparison to a control condition suggests that EIH and CPM may share underlying pain inhibitory mechanisms on a systemic level. This assumption is further supported by the finding of small to moderate significant correlations between EIH and CPM at the hand. The attenuated EIH response furthermore suggests that these mechanisms are exhaustible, i.e. that its effects decline after a certain amount of inhibition. IMPLICATIONS: In patients with chronic pain, assessing the current capacity of the descending pain inhibitory system - as indicated by the CPM response - may aid to make better predictions about how patients will respond to exercise with respect to acute pain reduction.

Increased Pain Sensitivity in Accident-related Chronic Pain Patients With Comorbid Posttraumatic Stress.

OBJECTIVES: Posttraumatic stress disorder (PTSD) is prevalent in chronic pain, and associated with increased pain, hyperalgesia, and psychological distress. This study aimed to investigate antinociceptive and pronociceptive pain mechanisms, pain intensity, and psychological distress (depression, anxiety, pain catastrophizing, and fear of movement) in patients with accident-related chronic spinal pain with (N=44) and without (N=64) comorbid PTSD characteristics. MATERIALS AND METHODS: Cuff algometry was performed on lower legs to assess pressure pain threshold (cPPT), tolerance (cPTT), temporal summation of pain (increase in pain scores to 10 repeated stimulations), and conditioning pain modulation (increase in cPPT during cuff pain conditioning on the contralateral leg). Warmth detection threshold and heat pain threshold at the hand were also assessed. Clinical pain intensity (numerical rating scale), psychological distress, and PTSD symptomatology (ICD-11) were assessed with questionnaires. Mediation analyses were performed to investigate possible psychological mediators in the associations between PTSD and pain (intensity and mechanisms). RESULTS: Patients with PTSD demonstrated increased pain intensity, and psychological distress as well as reduced warmth detection threshold and cPTT compared with patients without PTSD (P<0.05). No significant differences in cPPT, heat pain threshold, temporal summation of pain, and conditioning pain modulation were found. The association between PTSD and pain intensity was mediated by pain catastrophizing, and fear of movement mediated the association with cPTT. DISCUSSION: The association between PTSD and pain intensity is in accordance with the mutual-maintenance and fear-avoidance models. Future studies should investigate changes in pain intensity and mechanisms after treatment targeting comorbid PTSD in chronic pain patients.

Are preoperative experimental pain assessments correlated with clinical pain outcomes after surgery? A systematic review.

BACKGROUND: Pain after surgery is not uncommon with 30% of patients reporting moderate to severe postoperative pain. Early identification of patients prone to postoperative pain may be a step forward towards individualized pain medicine providing a basis for improved clinical management through treatment strategies targeting relevant pain mechanisms in each patient. Assessment of pain processing by quantitative sensory testing (QST) prior to surgery has been proposed as a method to identify patients at risk for postoperative pain, although results have been conflicting. Since the last systematic review, several studies investigating the association between postoperative pain and more dynamic measures of pain processing like temporal summation of pain and conditioned pain modulation have been conducted. OBJECTIVES: According to the PRISMA guidelines, the aim of this systematic review was to evaluate whether assessment of experimental pain processing including measures of central pain mechanisms prior to surgery was associated with pain intensity after surgery. METHODS: Systematic database searches in PubMed and EMBASE with the following search components: QST, association, and postoperative pain, for studies that assessed the association between QST and pain after surgery were performed. Two authors independently reviewed all titles and abstracts to assess their relevance for inclusion. Studies were included if (1) QST was performed prior to surgery, (2) pain was assessed after surgery, and (3) the association between QST and pain after surgery was investigated. Forty-four unique studies were identified, with 30 studies on 2738 subjects meeting inclusion criteria. The methodological quality of the include studies was assessed and data extraction included study population, type of surgery, QST variables, clinical pain outcome measure and main result. RESULTS: Most studies showed moderate to high risk of bias. Type of surgery investigated include 7 studies on total knee replacement, 5 studies on caesarean section, 4 studies on thoracic surgery, 2 studies on herniotomy, 2 studies on hysterectomy/myomectomy, 1 study on tubal ligation, 1 study on gynecologic laparoscopy, 1 study on arthroscopic knee surgery, 1 study on shoulder surgery, 1 study on disc herniation surgery, 1 study on cholecystectomy, 1 study on percutaneous nephrolithotomy, 1 study on molar surgery, 1 study on abdominal surgery, and 1 study on total knee replacement and total hip replacement. The majority of the preoperative QST variables showed no consistent association with pain intensity after surgery. Thermal heat pain above the pain threshold and temporal summation of pressure pain were the QST variables, which showed the most consistent association with acute or chronic pain after surgery. CONCLUSIONS: QST before surgery does not consistently predict pain after surgery. High quality studies investigating the presence of different QST variables in combination or along with other pain-related psychosocial factors are warranted to confirm the clinical relevance of QST prior to surgery. IMPLICATIONS: Although preoperative QST does not show consistent results, future studies in this area should include assessment of central pain mechanisms like temporal summation of pressure pain, conditioned pain modulation, and responses to pain above the pain threshold since these variables show promising associations to pain after surgery.

Preoperative Hypoalgesia After Cold Pressor Test and Aerobic Exercise is Associated With Pain Relief 6 Months After Total Knee Replacement.

OBJECTIVES: Chronic pain after total knee replacement (TKR) is not uncommon. Preoperative impaired conditioning pain modulation (CPM) has been used to predict chronic postoperative pain. Interestingly, exercises reduce pain sensitivity in patients with knee osteoarthritis (KOA). This pilot study investigated the association between exercise-induced hypoalgesia (EIH) and CPM on post-TKR pain relief. METHODS: Before and 6 months post-TKR, 14 patients with chronic KOA performed the cold pressor test on the nonaffected leg and 2 exercise conditions (bicycling and isometric knee extension), randomized and counterbalanced. Before and during the cold pressor test and after exercises test stimuli were applied to extract the pain sensitivity difference: computer-controlled cuff inflation on the affected lower leg until the participants detected the cuff pain threshold (cPPT) and subsequently the cuff pain tolerance (cPTT) and manual pressure pain thresholds (PPTs) at the legs, arm, and shoulder. Clinical pain intensity (numerical rating scale [NRS]) and psychological distress (questionnaires) were assessed. RESULTS: Clinical pain intensity, psychological distress, cPPT, and PPT at the affected leg improved post-TKR compared with pre-TKR (P<0.05). Preoperatively, the CPM and bicycling EIH assessed by the increase in cPTT correlated with reduction in NRS pain scores post-TKR (P<0.05). Improved CPM and EIH responses after TKR were significantly correlated with reduction in NRS pain scores post-TKR (P<0.05). DISCUSSION: In KOA patients, hypoalgesia after cold pressor stimulation and aerobic exercise assessed preoperatively by cuff algometry was associated with pain relief 6 months after TKR. EIH as a novel preoperative screening tool should be further investigated in larger studies.

Does size really matter? A multisite study assessing the latent structure of the proposed ICD-11 and DSM-5 diagnostic criteria for PTSD.

Background: Researchers and clinicians within the field of trauma have to choose between different diagnostic descriptions of posttraumatic stress disorder (PTSD) in the DSM-5 and the proposed ICD-11. Several studies support different competing models of the PTSD structure according to both diagnostic systems; however, findings show that the choice of diagnostic systems can affect the estimated prevalence rates. Objectives: The present study aimed to investigate the potential impact of using a large (i.e. the DSM-5) compared to a small (i.e. the ICD-11) diagnostic description of PTSD. In other words, does the size of PTSD really matter? Methods: The aim was investigated by examining differences in diagnostic rates between the two diagnostic systems and independently examining the model fit of the competing DSM-5 and ICD-11 models of PTSD across three trauma samples: university students (N = 4213), chronic pain patients (N = 573), and military personnel (N = 118). Results: Diagnostic rates of PTSD were significantly lower according to the proposed ICD-11 criteria in the university sample, but no significant differences were found for chronic pain patients and military personnel. The proposed ICD-11 three-factor model provided the best fit of the tested ICD-11 models across all samples, whereas the DSM-5 seven-factor Hybrid model provided the best fit in the university and pain samples, and the DSM-5 six-factor Anhedonia model provided the best fit in the military sample of the tested DSM-5 models. Conclusions: The advantages and disadvantages of using a broad or narrow set of symptoms for PTSD can be debated, however, this study demonstrated that choice of diagnostic system may influence the estimated PTSD rates both qualitatively and quantitatively. In the current described diagnostic criteria only the ICD-11 model can reflect the configuration of symptoms satisfactorily. Thus, size does matter when assessing PTSD.

Planteamiento: Los investigadores y clínicos del campo del trauma pronto decidirán entre dos descripciones diagnósticas diferentes del trastorno de estrés postraumático (TEPT) en el DSM-5 y la propuesta CIE-11. Varios estudios apoyan diferentes modelos en competencia sobre la estructura del TEPT en función de ambos sistemas de diagnóstico; sin embargo, los resultados demuestran que la elección de los sistemas de diagnóstico puede afectar las tasas de prevalencia estimadas. Objetivos: y métodos. El presente estudio tenía como objetivo investigar el impacto potencial de usar una descripción del TEPT amplia (es decir, el DSM-5) en comparación con una pequeña (es decir, la CIE-11). En otras palabras, ¿el tamaño del TEPT importa realmente? El objetivo se investigó mediante el examen de las diferencias en las frecuencias de diagnóstico entre los dos sistemas de diagnóstico y examinando de forma independiente cómo se ajustaban los modelos en competencia para el TEPT del DSM-5 y la CIE-11 en tres muestras de trauma: estudiantes universitarios (N = 4213), pacientes con dolor crónico (N = 573) y personal militar (N = 118). Resultados: Las tasas diagnósticas del TEPT fueron significativamente más bajas según los criterios de la propuesta CIE-11 en la muestra universitaria, pero no se encontraron diferencias significativas para los pacientes con dolor crónico y el personal militar. El modelo de tres factores propuesto por la CIE-11 proporcionó el mejor ajuste de los modelos de la CIE-11 que fueron probados en todas las muestras. En cambio, el modelo híbrido de siete factores del DSM-5 proporcionó el mejor ajuste en las muestras universitaria y del dolor, y el modelo de Anhedonia de seis factores del DSM-5 en la muestra militar de los modelos probados del DSM-5. Conclusiones: Se pueden debatir las ventajas y desventajas de utilizar un conjunto amplio o reducido de síntomas para el TEPT; sin embargo, este estudio demostró que la elección del sistema de diagnóstico puede influir en las tasas estimadas del TEPT, tanto cualitativa como cuantitativamente. Al mismo tiempo, parece que, dados los criterios diagnósticos descritos actualmente, solo el modelo de la CIE-11 puede reflejar satisfactoriamente la configuración de los síntomas. Por lo tanto, el tamaño importa cuando se evalúa el TEPT.

Pain modulatory phenotypes differentiate subgroups with different clinical and experimental pain sensitivity.

Pain biomarkers are warranted for individualized pain management. Based on different pain modulatory phenotypes, the objectives of this study were to explore the existence of subgroups within patients with nonmalignant chronic pain and to investigate differences in clinical pain and pain hypersensitivity between subgroups. Cuff algometry was performed on lower legs in 400 patients with chronic pain to assess pressure pain threshold, pressure pain tolerance, temporal summation of pain (TSP: increase in pain scores to 10 repeated stimulations), and conditioned pain modulation (CPM: increase in cuff pressure pain threshold during cuff pain conditioning on the contralateral leg). Heat detection and heat pain thresholds at clinical painful and nonpainful body areas were assessed. Based on TSP and CPM, 4 distinct groups were formed: group 1 (n = 85) had impaired CPM and facilitated TSP; group 2 (n = 148) had impaired CPM and normal TSP; group 3 (n = 45) had normal CPM and facilitated TSP; and group 4 (n = 122) had normal CPM and normal TSP. Group 1 showed more pain regions than the other 3 groups (P < 0.001), indicating that impaired CPM and facilitated TSP play an important role in widespread pain. Groups 1 and 2 compared with group 4 had lower heat pain threshold at nonpainful areas and lower cuff pressure pain tolerance (P < 0.02), indicating that CPM plays a role for widespread hyperalgesia. Moreover, group 1 demonstrated higher clinical pain scores than group 4 (P < 0.05). Although not different between subgroups, patients were profiled on demographics, disability, pain catastrophizing, and fear of movement. Future research should investigate interventions tailored towards these subgroups.

Hypoalgesia After Exercise and the Cold Pressor Test is Reduced in Chronic Musculoskeletal Pain Patients With High Pain Sensitivity.

OBJECTIVES: In chronic pain patients, impaired conditioned pain modulation (CPM) and exercise-induced hypoalgesia (EIH) have been reported. No studies have compared CPM and EIH in chronic musculoskeletal pain patients with high pain sensitivity (HPS) and low pain sensitivity (LPS). MATERIALS AND METHODS: On 2 days, manual pressure pain thresholds (PPTs) were recorded at the legs, arm, and shoulder in 61 chronic pain patients and they performed the cold pressor test, 2 exercise conditions (bicycling and isometric contraction), and a control condition in a randomized and counterbalanced order. PPTs, pain tolerance, pain tolerance limit, and temporal summation of pain were assessed with cuff algometry before and after the tests. On the basis of a median split of the average PPTs for women and men, respectively, low (LPS; N=30) and high (HPS; N=31) pain-sensitivity groups were created. RESULTS: At baseline, cuff PPT and pain tolerance were decreased and temporal summation of pain was increased in the HPS group (P<0.02). Cuff PPT increased and pain tolerance limit decreased after the cold pressor test and exercises in LPS (P<0.001). Temporal summation of pain was increased after bicycling in HPS (P<0.005). Pain tolerance increased after the cold pressor test and exercise in both groups (P<0.001). DISCUSSION: CPM and EIH were partly impaired in chronic pain patients with high versus less pain sensitivity, suggesting that the CPM and EIH responses depend on the degree of pain sensitivity. This has clinical implications as clinicians should evaluate pain sensitivity when considering treatment options utilizing the descending modulatory pain control.

Prognostic factors for disability and sick leave in patients with subacute non-malignant pain: a systematic review of cohort studies.

OBJECTIVE: This systematic review aims to identify generic prognostic factors for disability and sick leave in subacute pain patients. SETTING: General practice and other primary care facilities. PARTICIPANTS: Adults (>18 years) with a subacute (≤ 3-month) non-malignant pain condition. Eligibility criteria were cohort studies investigating the prediction of disability or long-term sick leave in adults with a subacute pain condition in a primary care setting. 19 studies were included, referring to a total of 6266 patients suffering from pain in the head, neck, back and shoulders. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was long-term disability (>3 months) due to a pain condition. The secondary outcome was sick leave, defined as 'absence from work' or 'return-to-work'. RESULTS: PubMed, EMBASE, CINAHL and PEDro databases were searched from 16 January 2003 to 16 January 2014. The quality of evidence was presented according to the GRADE WG recommendations. Several factors were found to be associated with disability at follow-up for at least two different pain symptoms. However, owing to insufficient studies, no generic risk factors for sick leave were identified. CONCLUSIONS: Multiple site pain, high pain severity, older age, baseline disability and longer pain duration were identified as potential prognostic factors for disability across pain sites. There was limited evidence that anxiety and depression were associated with disability in patients with subacute pain, indicating that these factors may not play as large a role as expected in developing disability due to a pain condition. Quality of evidence was moderate, low or very low, implying that confidence in the results is limited. Large prospective prognostic factor studies are needed with sufficient study populations and transparent reporting of all factors examined. TRIAL REGISTRATION NUMBER: CRD42014008914.