Health-related quality of life and burden of disease in chronic pain measured with the 15D instrument

Holistic Treatment Response: An International Expert Panel Definition and Criteria for a New Paradigm in the Assessment of Clinical Outcomes of Spinal Cord Stimulation

BACKGROUND

Treatment response to spinal cord stimulation (SCS) is focused on the magnitude of effects on pain intensity. However, chronic pain is a multidimensional condition that may affect individuals in different ways and as such it seems reductionist to evaluate treatment response based solely on a unidimensional measure such as pain intensity.

AIM

The aim of this article is to add to a framework started by IMMPACT for assessing the wider health impact of treatment with SCS for people with chronic pain, a "holistic treatment response".

DISCUSSION

Several aspects need consideration in the assessment of a holistic treatment response. SCS device data and how it relates to patient outcomes, is essential to improve the understanding of the different types of SCS, improve patient selection, long-term clinical outcomes, and reproducibility of findings. The outcomes to include in the evaluation of a holistic treatment response need to consider clinical relevance for patients and clinicians. Assessment of the holistic response combines two key concepts of patient assessment: (1) patients level of baseline (pre-treatment) unmet need across a range of health domains; (2) demonstration of patient-relevant improvements in these health domains with treatment. The minimal clinical important difference (MCID) is an established approach to reflect changes after a clinical intervention that are meaningful for the patient and can be used to identify treatment response to each individual domain. A holistic treatment response needs to account for MCIDs in all domains of importance for which the patient presents dysfunctional scores pre-treatment. The number of domains included in a holistic treatment response may vary and should be considered on an individual basis. Physiologic confirmation of therapy delivery and utilisation should be included as part of the evaluation of a holistic treatment response and is essential to advance the field of SCS and increase transparency and reproducibility of the findings.

Altered social decision making in patients with chronic pain

BACKGROUND

Chronic pain affects up to 20% of the population, impairs quality of life and reduces social participation. Previous research reported that pain-related perceived injustice covaries with these negative consequences. The current study probed whether chronic pain patients responded more strongly to disadvantageous social inequity than healthy individuals.

METHODS

We administered the Ultimatum Game, a neuroeconomic social exchange game, where a sum of money is split between two players to a large sample of patients with chronic pain disorder with somatic and psychological factors (n = 102) and healthy controls (n = 101). Anonymised, and in truth experimentally controlled, co-players proposed a split, and our participants either accepted or rejected these offers.

RESULTS

Chronic pain patients were hypersensitive to disadvantageous inequity and punished their co-players for proposed unequal splits more often than healthy controls. Furthermore, this systematic shift in social decision making was independent of patients' performance on tests of executive functions and risk-sensitive (non-social) decision making .

CONCLUSIONS

Our findings indicate that chronic pain is associated with anomalies in social decision making (compared to healthy controls) and hypersensitivity to social inequity that is likely to negatively impact social partaking and thereby the quality of life.

Burden of disease of chronic pain in Ecuador

OBJECTIVES

to estimate the burden of disease related to chronic pain in Ecuador.

METHODS

We used Global Burden of Disease (GBD) methods to estimated disability-adjusted life years (DALYs) related to chronic pain in Ecuador. We focused on chronic pain related to lumbar pain, osteoarthritis, post-herpetic neuralgia, diabetic neuropathy, cancer-related pain, and other musculoskeletal pain. We estimated the prevalent cases by sex and age group using literature data. We only estimated years lived with disability using disability weights obtained from the GBD, with the assumption that no premature death would be related to pain. We used a prevalence-based approach to estimate cases by sex and age group using literature, without discounting or age adjustment. We calculated total DALYs and DALYs/100,000 inhabitants.

RESULTS

Our estimated yielded a total of 3,644,108 patients with chronic pain. They would produce 256,090 DALYs or 1,483 DALYs/100,000 inhabitants attributable to chronic pain. Low back pain, osteoarthritis and cancer-related pain were the drivers of DALY production.

CONCLUSIONS

Chronic pain is an important source of burden of disease. It is comparable to other important causes such as headaches, stroke, diabetes and chronic obstructive pulmonary disease, among others. Low back pain, osteoarthritis and other musculoskeletal pain were the biggest contributors given their high prevalence.

Caregiving for older people living with chronic pain: analysis of the English longitudinal study of ageing and health survey for England

Background

Chronic pain is a disabling condition. Many people with chronic pain seek informal support for everyday activities of daily living (ADL). However, there remains uncertainty on the type of people with chronic pain who access this support, what types of support they need and who provides such support. The purpose of this analysis was to answer these uncertainties.

Methods

Data from the Health Survey for England (HSE) and English Longitudinal Study of Ageing (ELSA) were accessed. People who reported chronic pain (moderate or above for minimum of 12 months) were identified. From these cohorts, we determined if individuals self-reported receiving informal care. Data on caregiver profiles and caregiving activities were reported through descriptive statistics. Logistic regression analyses were performed to compare health status outcomes between people with pain who received and who did not receive informal care.

Results

2178 people with chronic pain from the ELSA cohort and 571 from the HSE cohort were analysed. People who received care were frequently female, older aged with several medical morbidities including musculoskeletal diseases such as arthritis. People with chronic pain received informal care for several diverse tasks. Most frequently these related to instrumental activities of daily living (IADL) such as shopping and housework. They were most frequently provided by partners or their children. Although they reported greater disability and symptoms ( p < 0.001), people who received care did not report differences in health status, loneliness or wellbeing ( p = 0.27; p = 0.46).

Conclusions

Whilst it may be possible to characterise people living in chronic pain who receive informal care, there is some uncertainty on the impact of informal caregiving on their health and wellbeing. Consideration should now be made on how best to support both care recipients and informal caregivers, to ensure their health and quality of life is promoted whilst living with chronic pain.

Eveningness intensifies the association between musculoskeletal pain and health-related quality of life: a Northern Finland Birth Cohort Study 1966

ABSTRACT

People with an evening (E)-type preference (ie, chronotype) experience musculoskeletal (MSK) pain and reduced health-related quality of life (HRQoL) more often than morning (M) types. Musculoskeletal pain is a well-established contributor to reduced HRQoL. This study aimed to evaluate whether eveningness amplifies the association between MSK pain and HRQoL in contrast to morningness. Questionnaire data on MSK pain dimensions (intensity, disability at work, number of pain sites [NPSs], and frequency), chronotype, covariates (sex, sufficiency of sleep duration, mental distress, and presence of coexisting diseases), and HRQoL (measured by 15D) were collected among 46-year-old individuals belonging to the Northern Finland Birth Cohort 1966 (N = 4257). Individuals without any MSK pain were excluded. General linear models were conducted to estimate the associations between chronotypes, MSK pain dimensions, and HRQoL. The interaction terms (chronotype × pain dimension) were tested in the models. There were 13% E-types and 43% M-types in the study sample. Each pain dimension and chronotype were related to HRQoL. In the sex-adjusted chronotype-specific models, the reduction in HRQoL in relation to pain appeared to be stronger among E-types than among M-types in respect to all pain dimensions. After adjustments, this was particularly seen in terms of NPS and pain frequency. Our findings suggest that eveningness intensifies the association between MSK pain and HRQoL, and, thus, they are indicative of E-types being more sensitive than M-types to the consequences of MSK pain. As such, MSK pain treatment and rehabilitation actions to improve HRQoL should be especially targeted at E-types.

Chronic pain in adults with osteogenesis imperfecta and its relationship to appraisal, coping, and quality of life: A cross-sectional study

Chronic pain is a common experience in osteogenesis imperfecta (OI). However, there are few studies on this topic, and none of them emerge from psychology as a discipline. The purpose of this work is to describe the frequency of chronic pain and its characteristics in a large sample of adults with OI, as well as its relationship with clinical, sociodemographic, psychological, and quality of life variables. A cross-sectional study was carried out in a sample of 418 adults with OI who answered a battery of online questionnaires. Sociodemographic and clinical variables, pain parameters, participants' appraisal of pain, coping strategies, interference in daily activities, and health-related quality of life were evaluated. A descriptive and correlational analysis was performed. Up to 83% of the sample reported experiencing pain frequently. Both the frequency and intensity of pain were related to the accumulation of fractures over the years (P < .05), but were independent of other variables like the severity of the pathology or the use of bisphosphonates. Higher threat appraisal of pain was associated with an increase in perceived pain intensity and its interference with daily activities, as well as a decrease in physical and mental health (P < .001). Chronic pain frequent condition in adults with OI, regardless of the severity of the pathology. It interferes with their usual activities and has an impact on their quality of life. The way in which participants appraise their pain also have an influence on its intensity and its consequences. Interventions aimed at training strategies for managing appraisals about pain could potentially improve adaptation to chronic pain.

Sleep problems in pain patients entering tertiary pain care: the role of pain-related anxiety, medication use, self-reported diseases, and sleep disorders

ABSTRACT

Chronic pain and sleep problems frequently co-occur. Pain itself disturbs sleep, but other factors may also contribute to sleep problems in pain patients. This cross-sectional study of 473 patients (69.9% female, mean age 47 years) entering tertiary pain management compared normally sleeping pain patients with those having recurring sleep problems to determine the relationship between pain and sleep. Groups were compared for pain and pain aetiology, pain-related anxiety, childhood adversities, use of sleep and pain medications, self-reported diseases, and sleep disorders. Furthermore, the association of pain-related anxiety (cognitive anxiety, escape/avoidance, fear, and physiological anxiety) with more disturbing sleep problems was investigated in the whole cohort. The main results were that those with sleep problems more often reported multiple health conditions than those sleeping normally (depression 31.6% vs 5.0%; angina pectoris 6.5% vs 0.0%; asthma 19.6% vs 1.7%; low back problems 55.1% vs 23.3%; joint disease other than rheumatoid arthritis 32.3% vs 18.3%). Accumulations of 5 or more childhood adversities were more often present in those with sleep problems. Restless legs symptoms were more common in those with sleep problems than those sleeping normally (33.2% vs 11.7%). Patients having sleep problems reported more use of sleep and pain medications than those sleeping normally. Findings about pain-related anxiety suggest physiological reactions as significant factors for increased sleep disturbances. These factors need to be addressed in the management of the comorbidity of pain and sleep problems, and research to understand mechanisms in these is sorely needed.

Health-related quality of life of Malaysian patients with chronic non-malignant pain and its associated factors: a cross-sectional study

Background

Chronic pain has a major impact on a patient’s quality of life, affecting physical and psychological functioning. It has debilitating consequences on social and economic aspects too. This study aimed to explore the status of health-related quality of life (HRQoL) of Malaysian patients suffering from chronic non-malignant pain.

Methods

Four hospitals offering pain clinic services were involved in this multicentre cross-sectional study conducted between June and September 2020. Adult patients who had been diagnosed with non-malignant chronic pain lasting for at least three months and able to communicate in English or Malay language were recruited in this study. Participants were informed about the study and were made aware that their participation was entirely voluntary. A battery of questionnaires consists of the EuroQol-5 dimensions-5 levels questionnaire (EQ-5D-5L) and the EuroQol visual analogue scale (EQ VAS), the Pain Self-Efficacy questionnaire (PSEQ) and the Pain Catastrophizing Scale (PCS) were self-administered by the patients. Besides, a structured questionnaire was used to collect their socio-demographic information, pain condition, sleep quality and working status. Participants’ usage of pain medications was quantified using the Quantitative Analgesic Questionnaire (QAQ).

Results

A total of 255 patients participated in this study. A median EQ-5D index value of 0.669 (IQR: 0.475, 0.799) and a median EQ VAS score of 60.0 (IQR: 50.0, 80.0) were recorded. Malay ethnicity (Adj. B: 0.77; 95% CI: 0.029, 0.126; p = 0.002) and a higher level of self-efficacy (Adj. B: 0.008; 95% CI: 0.006, 0.011; p < 0.001) were predictors of a better HRQoL, while suffering from pain in the back and lower limb region (Adj. B: -0.089; 95% CI: − 0.142, − 0.036; p = 0.001), the use of a larger amount of pain medications (Adj. B: -0.013; 95% CI: − 0.019, − 0.006; p < 0.001), and a higher degree of pain magnification (Adj. B: -0.015; 95% CI: − 0.023, − 0.008; p < 0.001) were associated with a poorer HRQoL.

Conclusions

These findings suggested that Malay ethnicity and a higher level of self-efficacy were predictors of a better HRQoL in patients with chronic pain, whereas pain-related factors such as higher usage of medication, specific pain site and pain magnification style were predictors of poorer HRQoL.

Health-related quality of life in patients with chronic orofacial pain compared with other chronic pain patients

Background

Health‐related quality of life (HRQoL) of orofacial pain patients is lower than that of the general population and impaired in multiple dimensions. The aim of the present study was to investigate HRQoL of orofacial pain patients in comparison with patients suffering from other chronic pain disorders.

Materials and Methods

One hundred and fifty‐one tertiary care facial pain patients (mean age, 50 years; standard deviation [SD], 15; 119 females), were compared with 312 other non‐cancer chronic pain patients (mean age, 46 years; SD, 13; 204 women), recruited from three multidisciplinary pain clinics in Finland. The groups were compared using the 15D, and pain‐related measures such as pain interference, pain acceptance, anxiety, depression, and sleep. Statistical comparisons between groups were done using t test, χ² test, or analysis of covariance. Multivariate linear regression analysis was used to study whether pain‐related aspects influencing HRQoL are similar between the patient groups.

Results

The 15D score was significantly higher in facial pain patients (0.823; SD, 0.114) indicating better HRQoL in comparison with other chronic pain patients (0.732; SD, 0.107) (p < .001). The 15D profiles of studied populations resembled each other but orofacial pain patients showed significantly higher scores for most individual 15D dimensions. Dimensions regarding discomfort and symptoms and sleep were most affected in both groups. Orofacial pain patients showed less psychosocial disability and better acceptance of their pain. Pain acceptance was a weaker explanatory factor of HRQoL in orofacial pain patients.

Conclusion

Compared to other non‐cancer chronic pain, chronic pain in the orofacial area causes less impairment in HRQoL. Orofacial pain patients showed less psychosocial disability and better pain acceptance.

Efficacy and tolerability in patients with chronic facial pain of two consecutive treatment periods of rTMS applied over the facial motor cortex, using protocols differing in stimulation frequency, duration, and train pattern

OBJECTIVE

We conducted an open-label cross-over study assessing the global effect of two high-frequency protocols of electric-field navigated repetitive transcranial magnetic stimulation (rTMS) targeted to functional facial motor cortex and comparing their efficacy and tolerability in patients with chronic facial pain. Outcome predictors were also assessed.

METHODS

We randomized twenty consecutive patients with chronic facial pain (post-traumatic trigeminal neuropathic pain, n=14; persistent idiopathic facial pain, n=4; secondary trigeminal neuralgia, n=2) to receive two distinct 5-day rTMS interventions (10Hz, 2400 pulses and 20Hz, 3600 pulses) separated by six weeks. The target area was assessed by mapping of lower face representation. The primary endpoint was the change in weekly mean of pain intensity (numeric rating scale, NRS) between the baseline and therapy week (1^st week), and follow-up weeks (2^nd and 3^rd weeks) for each rTMS intervention. Response was defined using a combination scale including the patient's global impression of change and continuance with maintenance treatment.

RESULTS

Overall, pain intensity NRS decreased from 7.4 at baseline to 5.9 ten weeks later, after the second rTMS intervention (p=0.009). The repetition of the treatment had a significant effect (F=4.983, p=0.043) indicating that the NRS scores are lower during the second four weeks period. Eight (40%) patients were responders, 4 (20%) exhibited a modest effect, 4 (20%) displayed no effect, and 4 (20%) experienced worsening of pain. High disability and high pain intensity (>7) predicted a better outcome (p=0.043 and p=0.045). Female gender, shorter duration of pain and low Beck Anxiety Inventory scores showed a trend towards a better outcome (p=0.052, 0.060 and 0.055, respectively).

CONCLUSIONS

High-frequency rTMS targeted to face M1 alleviates treatment resistant chronic facial pain. Repeated treatment improves the analgesic effect. A protocol with higher frequency (above 10Hz), longer session duration (more than 20 minutes) and higher number of pulses (above 2400 pulses/session) did not improve the outcome. The results support early consideration of rTMS.

Worse health‐related quality of life, impaired functioning and psychiatric comorbidities are associated with excess mortality in patients with severe chronic pain

Background

Severe chronic pain that interferes with daily activities is associated with an increased risk of mortality. We assessed the overall mortality of tertiary chronic pain patients in comparison with the general population, with a special aim to analyse the association of health‐related quality of life (HRQoL) and its dimensions with the risk of death.

Methods

In this prospective observational follow‐up study, patients with non‐cancer chronic pain attended an outpatient multidisciplinary pain management (MPM) episode in a tertiary pain clinic in 2004–2012 and were followed until May 2019. Mortality between the patients and the general population was compared with standardized mortality ratios (SMR) in different age groups. Causes of death and comorbidities were compared among the deceased. Association of mortality and HRQoL and its dimensions, measured with the 15D instrument, was studied with Cox proportional hazards model.

Results

During a mean of 10.4‐year follow‐up of 1498 patients, 296 died. The SMR in the youngest age group (18–49 years) was significantly higher than that of the general population: 2.6 for males and 2.9 for females. Even elderly females (60–69 years) had elevated mortality (SMR 2.3). Low baseline HRQoL at the time of MPM, as well as poor ratings in the psychosocial dimensions of HRQoL, was associated with an increased risk of death.

Conclusions

Our results support the role of HRQoL measurement by a validated instrument such as the 15D in capturing both the physical and the psychological symptom burden, and consequently, an elevated risk of death, in patients with chronic pain.

Significance

Severe chronic pain is associated with elevated mortality. In patients in chronic pain under 50 years old, the mortality was 2.5–3 times higher than in the general population. Psychological distress appears to contribute to the increased mortality. Regular follow‐up by health‐related quality of life (HRQoL) measurement could be useful in identifying patients in chronic pain who are in need of intensive symptom management and to prevent early death.

Scientific Knowledge Graph and Trend Analysis of Central Sensitization: A Bibliometric Analysis

Background

Central sensitization refers to a state of hypersensitivity in the central nervous system and is associated with the development and maintenance of chronic pain. Central sensitization plays an essential role in various diseases. Nevertheless, there has been no bibliometric analysis before in this field. The purpose of this study was to provide critical themes and trends in the area of central sensitization, to build a network of knowledge, and to facilitate the future development of relevant basic and clinical research.

Methods

Publications on central sensitization were extracted from the Science Citation Index-Expanded. We used R software to systematically analyze the countries, institutions, authors, journals, references, and keywords of the publications. Besides, conceptual structure, intellectual structure, and social structure were constructed.

Results

A total of 4466 publications were included. Research in the field of central sensitization generally showed a steady upward trend. The three structural networks showed that the United States is the leading country in this field. Arendt-Nielsen L and Woolf CJ were the most productive and influential authors, respectively. “Pain” was the journal with the most studies. Most journals that published and cited articles about central sensitization were academically influential. Cluster analysis revealed that research in central sensitization contains three main conceptual clusters, and the themes of research evolve frequently. Current research focuses on the pathogenesis of central sensitization in neuropathic pain, the role of central sensitization in different diseases, and related clinical double-blind trials.

Conclusion

Central sensitization received widespread attention. The United States led the way in academic activity. In this field, the current situation of cooperation and communication between different countries and institutions is positive. The present research hotspots were the pathogenesis of central sensitization in neuropathic pain, the role of central sensitization in different diseases, and related clinical double-blind trials.

Patient-reported outcomes in coronary artery disease: the relationship between the standard, disease-specific set by the International Consortium for Health Outcomes Measurement (ICHOM) and the generic health-related quality of life instrument 15D

BACKGROUND

Patient-reported outcome (PRO) instruments measure health gains, including changes in health-related quality of life (HRQoL). Previous studies have assessed the reliability and relationship of multiple HRQoL instruments in search of the optimal instrument for feasible measurement of PROs. Although the 15D instrument was shown to have the best sensitivity and construct validity among cardiac patients, it is unknown how well it captures relevant disease-specific information scores compared to instruments included in the International Consortium for Health Outcomes Measurement (ICHOM) standard set. The aim of this study was to investigate whether the disease-specific PRO instruments and a generic HRQoL instrument capture disease related symptoms in coronary artery disease (CAD) patients.

METHODS

Health status and HRQoL were assessed with the instruments included in the ICHOM standard set: Seattle Angina Questionnaire short-form (SAQ-7), Rose Dyspnea Scale (RDS), two-item Patient Health Questionnaire (PHQ-2), and with the 15D HRQoL instrument at baseline and 1 year from the treatment in a university hospital setting. Spearman correlation and explanatory factor analysis were used to assess the relationship of baseline scores and 1-year change in scores of 297 patients.

RESULTS

At baseline, the overall 15D score and SAQ-physical limitation (SAQ-PL), 15D "breathing" and SAQ-PL, as well as "breathing" and RDS showed moderately strong correlations. The factor interpreted to reflect "Breathing-related physical activity", based on high loadings of "breathing", RDS, SAQ-PL, "mobility", "vitality", and "usual activities", explained 19.2% of the total variance. Correlations between 1-year changes in scores were fair. The factor of "Breathing-related physical activity", with significant loading of RDS, SAQ-PL, "breathing, "usual activities", "vitality", "sexual activity", "mobility", and disease-specific quality of life explained 20.5% of the total variance in 1-year change in scores. The correlation of angina frequency measured by SAQ-7 and the 15D instrument was poor.

CONCLUSIONS

The 15D detects dyspnea and depression similarly to RDS and PHQ-2 but not angina similarly to the SAQ-7. This may call for supplementing the 15D instrument with a disease-specific instrument when studying CAD patients.

Acanthoscurria gomesiana spider-derived synthetic mygalin in the dorsal raphe nucleus modulates acute and chronic pain

Mygalin, a diacylspermidine that is naturally found in the hemolymph of the spider Acanthoscurria gomesiana, is of interest for development as a potential analgesic. Previous studies have shown that acylpolyamines modulate glutamatergic receptors with the potential to alter pain pathways. This study aimed to evaluate the effects of mygalin on acute and chronic pain in rodents. For evaluation of acute pain, Wistar rats were subjected to tail-flick and hot-plate nociceptive tests. For the evaluation of chronic neuropathic pain, a partial ligation of the sciatic nerve was performed and, 21 days later, animals were examined in hot-plate, tail-flick, acetone, and von Frey tests. Either Mygalin or vehicle was microinjected in the dorsal raphe nucleus (DRN) before the tests. Another group was pretreated with selective antagonists of glutamate receptors (LY 235959, MK-801, CNQX, and NBQX). Mygalin decreases nociceptive thresholds on both acute and chronic neuropathic pain models in all the tests performed. The lowest dose of mygalin yielded the most effective nociception, showing an increase of 63% of the nociceptive threshold of animals with neuropathic chronic pain. In conclusion, mygalin microinjection in the DRN results in antinociceptive effect in models of neuropathic pain, suggesting that acylpolyamines and their derivatives, such as this diacylspermidine, could be pursued for the treatment of neuropathic pain and development of selective analgesics.

Pain experience in an aging adult population during a 10-year follow-up

OBJECTIVES

This 10-year follow-up study aimed to examine the persistence of SF-36 pain intensity and pain-related interference and to identify baseline factors that may relate to pain experience among community-dwelling aging adults.

METHODS

Questionnaire and clinical data on a total of 1,954 participants (mean age at baseline 63 years) were collected in 2002, 2005, 2008, and 2012. Based on pain reports, four pain intensity, pain interference (PIPI) groups were formed at each time point: PIPI group I: none to mild pain intensity and interference; II: moderate to extreme pain intensity, none to mild pain-related interference; III: None to mild pain intensity, moderate to extreme pain-related interference, IV: Moderate to extreme pain intensity and interference.

RESULTS

Participants with the most pain at baseline improved their pain situation the most during the follow-up. Higher BMI was associated with pain interference, and metabolic syndrome (MetS) and musculoskeletal diseases with both pain intensity and interference (p<0.05, statistically significant interaction between pain intensity and pain interference) at baseline. According to multivariate logistic regression analysis the following baseline characteristics were associated with remaining in PIPI group I throughout the follow-up: presence of musculoskeletal disease (OR 0.22 [95% CI 0.16-0.30]), high BMI (OR 0.93 [95% CI 0.90-0.97]), high household income (OR 1.46 [95% CI 1.07-1.98]), good childhood home environment (OR 1.03 [95% CI 1.00-1.05]).

CONCLUSIONS

Multiple factors may affect pain persistence in late adulthood with varying effect on pain intensity and pain-related interference. Pain situation of even those with most pain may be improved.

Health-related quality of life and pain interference in two patient cohorts with neuropathic pain: breast cancer survivors and HIV patients

OBJECTIVES

Persistent pain is common in HIV patients and breast cancer (BC) survivors. The aim of this study was to compare two patient groups with neuropathic pain (NP) regarding several psychological variables and Health-related Quality of Life. Although, treatment of pain is always planned individually, the knowledge of the differences and similarities between the patient groups may help us to understand more precisely the targets of the interventions for pain.

METHODS

Eighty nine BC and 73 HIV patients with symptoms of neuropathic pain (patients with ≥3/7 in the Douleur Neuropathique four interview part (DN4i)) participated in a cross-sectional study. Patients completed questionnaires about mood (HADS), symptoms of insomnia (ISI), pain catastrophizing (PCS), personality (TIPI), Mental and Physical Health-related Quality of Life (M/PHrQoL, RAND/SF-36), and pain intensity and interference (BPI). Analyses were applied by using t-tests and linear regression to assess associations between the studied factors.

RESULTS

HIV patients reported higher anxiety (p<0.001), depressive symptoms (p<0.001), pain catastrophizing (p<0.001) and pain interference (p<0.001), poorer sleep (p<0.001), and lower HrQoL in all dimensions compared with BC survivors. There were significant differences in personality traits extraversion, emotional stability, and agreeableness between the two patient groups. In HIV patients, pain interference (β=-0.344, p<0.001) and mood (β=-0.580, p<0.001) and in the BC group, mood (β=-0.591, p<0.001), extraversion (β=0.229, p=0.005) and sleep (β=-0.154, p=0.042) associated with MHrQoL. Pain interference (HIV β=-0.645, p<0.001, BC β=-0.491, p<0.001) and age (HIV β=-0.016, p=0.042 and BC β=-0.018, p=0.019) associated with PHrQoL in both groups, and catastrophizing in the BC group (β=-0.303, p<0.001).

CONCLUSIONS

HIV patients and BC survivors with neuropathic pain, measured with DN4i, have significant differences in various health-related variables and Health-related Quality of Life with both patient groups reporting low HrQoL. The differences in low HrQoL may reflect the fundamental differences between these diseases, BC survivors in remission and HIV patients living with a chronic disease that is under control. This study brings information about the diversity of different patient populations with symptoms of neuropathic pain, and how neuropathic pain associates with wide range of health-related factors. Interventions to support better coping with the symptoms of neuropathic pain could be tailored more individually if the background disease is taken into account.

Muscle activity and acute stress in fibromyalgia

Background

Fibromyalgia (FM) patients are likely to differ from healthy controls in muscle activity and in reactivity to experimental stress.

Methods

We compared psychophysiological reactivity to cognitive stress between 51 female FM patients aged 18 to 65 years and 31 age- and sex-matched healthy controls. They underwent a 20-minute protocol consisting of three phases of relaxation and two phases of cognitive stress. We recorded surface electromyography normalized to maximum voluntary muscle contraction (%EMG), the percentage of time with no muscle activity (EMG rest time), and subjective pain and stress intensities. We compared group reactivity using linear modelling and adjusted for psychological and life-style factors.

Results

The FM patients had a significantly higher mean %EMG (2.2 % vs. 1.0 %, p < 0.001), pain intensity (3.6 vs. 0.2, p < 0.001), and perceived stress (3.5 vs. 1.4, p < 0.001) and lower mean EMG rest time (26.7 % vs. 47.2 %, p < 0.001). In the FM patients, compared with controls, the pain intensity increased more during the second stress phase (0.71, p = 0.028), and the %EMG decreased more during the final relaxation phase (-0.29, p = 0.036). Within the FM patients, higher BMI predicted higher %EMG but lower stress. Leisure time physical activity predicted lower %EMG and stress and higher EMG rest time. Higher perceived stress predicted lower EMG rest time, and higher trait anxiety predicted higher pain and stress overall.

Conclusions

Our results suggest that repeated cognitive stress increases pain intensity in FM patients. FM patients also had higher resting muscle activity, but their muscle activity did not increase with pain. Management of stress and anxiety might help control FM flare-ups.

Trial registration

Retrospectively registered on ClinicalTrials.gov (NCT03300635).

What factors are associated with health-related quality of life among patients with chronic musculoskeletal pain? A cross-sectional study in primary health care

BACKGROUND

Chronic musculoskeletal pain (CMP) affects daily life function and is the most prevalent disorder in primary health care. The primary objective was to examine demographic factors and pain characteristics associated with reduced health-related quality of life (HRQoL) among patients in primary care reporting CMP. Our secondary objective was to compare HRQoL in patients with and without CMP.

METHOD

This cross-sectional study was conducted in Trondheim, Norway. Twenty randomly selected GPs, and their listed patients aged 21-58 were invited to participate. Self-reported CMP data was collected using online questionnaires. HRQoL was measured by the 15D questionnaire, total score of 0.9 was used as cut-off for clinical reduced HRQoL.

RESULTS

A total of 969 patients (650 females) were recruited from six GPs' patient lists, mean age 45.6 (SD 10.1). CMP was reported by 517 (53%). Factors significantly associated with reduced HRQoL were gender (OR 2.0, 95% CI 1.2, 3.4), disability pension (OR 26.6, 95% CI 3.1, 228.0), mood (OR 1.3, 95% CI 1.1, 1.6), relations with other people (OR 0.8, 95% CI 0.6, 0.9), sleep (OR 1.2, 95% CI 1.0, 1.3) and enjoyment (OR 1.2, 95% CI 1.0). CMP patients had significantly lower total HRQoL score compared to patients without CMP (Between group difference 0.08, 95% CI 0.07-0.09). Half of the CMP patients reported a HRQoL score < 0.9 compared to 14% in the no CMP group.

CONCLUSIONS

Being female, receiving disability pension, and several psychosocial factors were found highly associated with reduced HRQoL in CMP patients, whereas pain characteristics were not. Patients with CMP reported statistically and clinically significant lower HRQoL than patients without CMP. Due to low response rate the conclusions must be handled with caution.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT02020772).

Machine learning suggests sleep as a core factor in chronic pain

Patients with chronic pain have complex pain profiles and associated problems. Subgroup analysis can help identify key problems. We used a data-based approach to define pain phenotypes and their most relevant associated problems in 320 patients undergoing tertiary pain management. Unsupervised machine learning analysis of parameters "pain intensity," "number of pain areas," "pain duration," "activity pain interference," and "affective pain interference," implemented as emergent self-organizing maps, identified 3 patient phenotype clusters. Supervised analyses, implemented as different types of decision rules, identified "affective pain interference" and the "number of pain areas" as most relevant for cluster assignment. These appeared 698 and 637 times, respectively, in 1000 cross-validation runs among the most relevant characteristics in an item categorization approach in a computed ABC analysis. Cluster assignment was achieved with a median balanced accuracy of 79.9%, a sensitivity of 74.1%, and a specificity of 87.7%. In addition, among 59 demographic, pain etiology, comorbidity, lifestyle, psychological, and treatment-related variables, sleep problems appeared 638 and 439 times among the most important characteristics in 1000 cross-validation runs where patients were assigned to the 2 extreme pain phenotype clusters. Also important were the parameters "fear of pain," "self-rated poor health," and "systolic blood pressure." Decision trees trained with this information assigned patients to the extreme pain phenotype with an accuracy of 67%. Machine learning suggested sleep problems as key factors in the most difficult pain presentations, therefore deserving priority in the treatment of chronic pain.

Analgesic opioid use disorders in patients with chronic non-cancer pain: A holistic approach for tailored management

Chronic pain is a major public health issue that frequently leads to analgesic opioid prescriptions. These prescriptions could cause addiction issues in high-risk patients with associated comorbidities, especially those of a psychiatric, addictive, and social nature. Pain management in dependent patients is complex and is yet to be established. By combining the views of professionals from various specialties, we conducted an integrative review on this scope. This methodology synthesizes knowledge and results of significant practical studies to provide a narrative overview of the literature. The main results consisted in first proposing definitions that could allow shared vocabulary among health professionals regardless of their specialties. Next, a discussion was conducted around the main strategies for managing prescription opioid dependence, as well as pain in the context of opioid dependence and associated comorbidities. As a conclusion, we proposed to define the contours of holistic management by outlining the main guidelines for creating a multidisciplinary care framework for multi-comorbid patients with chronic pathologies.

Interpretation of cluster structures in pain-related phenotype data using explainable artificial intelligence (XAI)

BACKGROUND

In pain research and clinics, it is common practice to subgroup subjects according to shared pain characteristics. This is often achieved by computer-aided clustering. In response to a recent EU recommendation that computer-aided decision making should be transparent, we propose an approach that uses machine learning to provide (1) an understandable interpretation of a cluster structure to (2) enable a transparent decision process about why a person concerned is placed in a particular cluster.

METHODS

Comprehensibility was achieved by transforming the interpretation problem into a classification problem: A sub-symbolic algorithm was used to estimate the importance of each pain measure for cluster assignment, followed by an item categorization technique to select the relevant variables. Subsequently, a symbolic algorithm as explainable artificial intelligence (XAI) provided understandable rules of cluster assignment. The approach was tested using 100-fold cross-validation.

RESULTS

The importance of the variables of the data set (6 pain-related characteristics of 82 healthy subjects) changed with the clustering scenarios. The highest median accuracy was achieved by sub-symbolic classifiers. A generalized post-hoc interpretation of clustering strategies of the model led to a loss of median accuracy. XAI models were able to interpret the cluster structure almost as correctly, but with a slight loss of accuracy.

CONCLUSIONS

Assessing the variables importance in clustering is important for understanding any cluster structure. XAI models are able to provide a human-understandable interpretation of the cluster structure. Model selection must be adapted individually to the clustering problem. The advantage of comprehensibility comes at an expense of accuracy.

Evaluation of Biased and Balanced Salvinorin A Analogs in Preclinical Models of Pain

In the search for safer, non-addictive analgesics, kappa opioid receptor (KOPr) agonists are a potential target, as unlike mu-opioid analgesics, they do not have abuse potential. Salvinorin A (SalA) is a potent and selective KOPr agonist, however, clinical utility is limited by the short duration of action and aversive side effects. Biasing KOPr signaling toward G-protein activation has been highlighted as a key cellular mechanism to reduce the side effects of KOPr agonists. The present study investigated KOPr signaling bias and the acute antinociceptive effects and side effects of two novel analogs of SalA, 16-Bromo SalA and 16-Ethynyl SalA. 16-Bromo SalA showed G-protein signaling bias, whereas 16-Ethynyl SalA displayed balanced signaling properties. In the dose-response tail-withdrawal assay, SalA, 16-Ethynyl SalA and 16-Bromo SalA were more potent than the traditional KOPr agonist U50,488, and 16-Ethynyl SalA was more efficacious. 16-Ethynyl SalA and 16-Bromo SalA both had a longer duration of action in the warm water tail-withdrawal assay, and 16-Ethynyl had greater antinociceptive effect in the hot-plate assay, compared to SalA. In the intraplantar 2% formaldehyde test, 16-Ethynyl SalA and 16-Bromo SalA significantly reduced both nociceptive and inflammatory pain-related behaviors. Moreover, 16-Ethynyl SalA and 16-Bromo SalA had no anxiogenic effects in the marble burying task, and 16-Bromo SalA did not alter behavior in the elevated zero maze. Overall, 16-Ethynyl SalA significantly attenuated acute pain-related behaviors in multiple preclinical models, while the biased KOPr agonist, 16-Bromo SalA, displayed modest antinociceptive effects, and lacked anxiogenic effects.

Composite Score Is a Better Reflection of Patient Response to Chronic Pain Therapy Compared With Pain Intensity Alone

OBJECTIVE

The pain Numeric Rating Scale (NRS) score became standard when pain was introduced as the fifth vital sign in the 1990s. Although plagued with issues, it remains the basis for primary outcome measures in clinical trials for chronic pain therapies. Multidimensional composite scoring that considers all aspects of the chronic pain experience may provide a more meaningful response measure. Herein we propose a multidimensional responder index.

MATERIALS AND METHODS

Data were extracted from an ongoing prospective, multicenter study on DeRidder Burst spinal cord stimulation (B-SCS) for chronic back and/or leg pain (NCT03082261). The analysis cohort consisted of subjects who completed the NRS, Pain Catastrophizing Scale (PCS), EuroQol-5D (EQ-5D), and eight-item Patient-Reported Outcomes Measurement Information System Physical Function preoperatively and at 12 months after implant.

RESULTS

A principal component analysis showed that each of the four measures contributed equally to the variance in the data set, confirming that pain score should not be used alone. Subjects who failed to respond on NRS responded on both PCS and EQ-5D. Eighty-one percent of subjects responded on at least two measures. The responder algorithm yielded an 84% success rate at both 6- and 12-month time points.

CONCLUSIONS

Our study suggests that therapeutic response, similar to the chronic pain experience, is multidimensional. Careful consideration should be made to incorporate composite endpoints in future SCS clinical trials.

Pre-consultation biopsychosocial data from patients admitted for management at pain centers in Norway

Background and aims

A bio-psycho-social approach has been recommended in multidisciplinary pain clinics, and in Norway patients with severe chronic nonmalignant pain (CNMP, defined as pain that has persisted for more than 3 months) might be treated at a regional multidisciplinary pain center. The specific aims of this study were (1) to describe characteristics of a sample of outpatients referred and accepted for treatment/management to three regional multidisciplinary pain centers in Norway, (2) to examine patient differences between the centers and (3) to study associations between symptom scores (insomnia, fatigue, depression, anxiety) and patient characteristics.

Methods

Patients, aged 17 years or older with CNMP admitted to and given a date for first consultation at one of three tertiary, multidisciplinary pain centers: St. Olavs Hospital Trondheim University Hospital (STO), Haukeland University Hospital (HUS) and University Hospital of North Norway (UNN), were included in the study. Data on demographics, physical activity, characteristics of pain, previous traumatic events, social network, Insomnia Severity Index (ISI), Chalder Fatigue Questionnaire (CFQ), Hopkins Symptom Checklist-25 (HSCL-25) and SF-36v2® were retrieved from the local quality registry at each pain center.

Results

Data from 1563 patients [mean age 42 (SD 15) years and 63% females] were available for analyses. Average years with pain were 9.3 (SD 9.1). Primary education as highest level of education was reported by 20%, being actively working/student/military by 32%, and no physical activity by 31%. Further, 48% reported widespread pain, 61% reported being exposed to serious life event(s), and 77% reported having a close friend to talk to. Non-worker status, no physical activity, lack of social network, reports of being exposed to serious life event(s) and widespread pain were all characteristics repeatedly associated with clinically high symptom scores. No significant differences between the centers were found in the proportions of patients reporting fatigue nor mean levels of insomnia symptoms. However, the proportion of patients reporting symptoms of anxiety and depression was a little lower at UNN compared with STO and HUS.

Conclusions

Analyses of registry data from three tertiary multidisciplinary pain centers in Norway support previous findings from other registry studies regarding patient characterized: A large proportion being women, many years of pain, low employment rate, low physical activity rate, and a large proportion reporting previous traumatic event(s). Characteristics such as non-work participation, no physical activity, lack of social network, have been exposed to serious life event(s), and chronic widespread pain were all associated with high clinical score levels of insomnia, fatigue, and mental distress. Health related quality of life was low compared to what has been reported for a general population and a range of other patient groups.

Implications

The findings of this study indicate that physical activity and work participation might be two important factors to address in the rehabilitation of patients with chronic non-malignant pain. Future studies should also explore whether pre consultation self-reported data might give direction to rehabilitation modalities.

The impact of chronic orofacial pain on health-related quality of life

Background and aims

Health-related quality of life (HRQoL) assessments have been widely used in pain medicine as they are able to reflect the subjective and multidimensional nature of chronic pain. Studies have shown a consistent impairment in HRQoL in different chronic pain conditions. However, it is not known whether HRQoL is impaired in chronic orofacial pain (OFP). The generic 15D HRQoL instrument has been shown to fare as well as or better than other generic HRQoL instruments in the study of chronic pain. The aim was to investigate HRQoL in patients with chronic OFP using the generic 15D HRQoL instrument. The validity of the instrument was tested by studying the association of the 15D data with pain interference.

Methods

One hundred fifty-one patients (mean age 50 years, SD 15 years, 119 females) were recruited from three tertiary facial pain clinics. HRQoL data of the participants were contrasted with that of an age- and gender- standardized sample of general population by comparing the mean 15D scores and profiles. The data for the general population came from the National Health 2011 Survey representing Finnish population aged 18 years and older. Pain interference was assessed using Brief Pain Inventory. Based on pain interference distribution the participants were divided into tertiles. Statistical comparison between patient and population HRQoL values were performed using Monte-Carlo-type simulations. Statistical significance for the hypothesis of linearity was evaluated by using generalized linear models.

Results

The mean 15D score of OFP patients (0.824, SD 0.113) was statistically significantly lower than that of the age- and gender-standardized general population (0.929, SD 0.019) (p < 0.001). The difference between the patients and the general population was also clinically important, i.e. over the minimum clinically important difference in the 15D score. All mean 15D dimension values were significantly lower compared with the general population values (p < 0.001 for all dimensions). The largest differences were seen in the dimensions of discomfort and symptoms (0.418, SD 0.222 vs. 0.816, SD 0.027), sleeping (0.693, SD 0.258 vs. 0.838, SD 0.029), and vitality (0.702, SD 0.221 vs. 0.884 SD 0.026). There was a statistically significant linear decrease in the 15D dimension values (p < 0.001) with increasing pain interference. The greatest differences were found on the dimensions of discomfort and symptoms, sleeping and vitality.

Conclusions

HRQoL is significantly impaired in patients with chronic OFP. A decrease in the 15D dimension values with increasing pain interference indicated convergent validity between 15D and pain interference.

Implications

The findings suggest that 15D is an appropriate instrument for use in the assessment of HRQoL in OFP patients. By showing the usefulness of the 15D, the present study may encourage further use of generic HRQoL assessments in the study of chronic OFP, and contribute e.g. to the implementation of HRQoL as one of the core outcome measures in future treatment studies on chronic OFP.

Pain interference type and level guide the assessment process in chronic pain: Categorizing pain patients entering tertiary pain treatment with the Brief Pain Inventory

Chronic pain patients enter treatment with different problem profiles making careful assessment a necessity for more individualized treatment plans. In this cross-sectional study we assigned 320 patients entering tertiary multidisciplinary pain treatment into four categories based on whether they scored low or high on the activity and the affective pain interference dimensions of the Brief Pain Inventory (BPI). To determine whether this categorization system delineates issues that should be assessed further, the categories were compared with ANOVA and MANOVA analyses on three domains: variables affecting physical well-being (body mass index, exercise, substance use), psychological resources (mood), and pain-specific psychological factors (pain anxiety, pain acceptance). The results indicated that subjects who scored low on both interference dimensions compared similarly in weight: mean Body Mass Index (BMI) 27.0 (SD 6.0) kg/m², and exercise: mean of 2.4 (SD 1.7) exercising sessions over 20 minutes per week, to the general population, had no depressive symptoms on average: mean Beck Depression Index II (BDI-II) score 11.7 (SD 7.5), and had the most favorable psychological reactions to pain relative to the other categories: mean total Pain Anxiety Symptoms Scale-20 (PASS-20) score 36.4 (SD 17.9). In contrast, when interference was high on activity, more physical well-being problems were evident e.g. weight: mean BMI 31.0 (SD 7.3) kg/m², diminished exercise: mean of 1.5 (SD 1.6) exercising sessions per week, and avoidance behavior: mean PASS-20 Escape/Avoidance subscale 3.7 (95% CI: 1.7 to 5.8) scores higher in comparison to activity interference remaining low. With high affective interference, more depressive symptoms: mean BDI-II score 17.7 (SD 7.3), and more cognitive pain anxiety: mean PASS-20 Cognitive Anxiety subscale 2.8 (95% CI 0.7 to 4.8) scores higher in comparison to affective interference remaining low, emerged. Having high interference on both dimensions indicated accumulated risks for reduced physical well-being: mean BMI 29.9 (SD 6.1) kg/m², mean of 1.2 (SD 1.7) exercising sessions per week, mood problems: mean BDI-II 20.3 (SD 10.6), and negative psychological reactions to pain: mean total PASS-20 score 53.2 (18.4). The results suggest that low interference on both dimensions may allow assessment with only physician consultations, while high interference on either dimension may call attention to distinct issues to be addressed with the help of a physiotherapist or a psychologist, whereas high interference on both dimensions highlights the need for a full multidisciplinary assessment.

Pain-related factors in older adults

BACKGROUND AND AIMS

Pain is an evident factor affecting the quality of life in all age groups. The objective was to examine the prevalence of self-reported SF-36 bodily pain and pain-related factors in community-dwelling older adults.

METHODS

One thousand four hundred and twenty adults aged 62-86 years self-reported SF-36 bodily pain during the previous month. For the analysis, four pain groups were formed (group I [0-45, moderate to very severe pain intensity and interference], group II [47.5-70], group III [77.5-90], and group IV [100, no pain at all]). Additional questionnaire-provided data regarding education, wealth, life habits, and morbidity, as well as clinical data were considered.

RESULTS

The overall pain prevalence was 78% (SF-36 bodily pain score <100). The prevalence of cohabiting, as well as the years of education and household income were found to decrease with an increasing SF-36 bodily pain score. The prevalence of a BMI of over 30 and of central obesity emerged as the highest in group I. Morbidities were found to be most prevalent in group I.

CONCLUSIONS

A high prevalence of intense and interfering pain was reported. Multiple factors that were found to relate to pain have previously been demonstrated to associate with social exclusion. Increasing attention should be paid to distinguishing these factors in patients with pain, as well as targeted pain assessment and measures to improve the sense of community among older adults.

IMPLICATIONS

There is a lack of large studies that examine a wide scale of pain-related factors in the older adult population. To distinguish subjects with multiple such factors would help medical professionals to target their attention to patients at a high risk of chronic pain.

Quebec Serve and Protect Low Back Pain Study: What About Mental Quality of Life?

Background

As of now, the impact of low back pain (LBP) and its chronic state, chronic low back pain (CLBP), on mental health-related quality of life (HRQOL) has never been investigated among police officers. The present investigation aims at studying this relationship using a biopsychosocial model.

Methods

Between May and October 2014, a Web-based cross-sectional study was conducted among Quebec police officers (Quebec, Canada). Mental HRQOL was measured using the role emotional (RE) and the mental health (MH) domains of the SF-12v2 Health Survey. The impact of CLBP on mental HRQOL (as opposed to acute/subacute LBP or no LBP) was studied with a multivariate linear regression model.

Results

Of the 3,589 police officers who participated in the study, 1,013 (28.4%) reported CLBP. The mean age of respondents was 38.5 ± 8.7 years, and 32.0% were females. The RE (44.1/100) and MH (49.0/100) mean scores of the CLBP group were comparable with the scores found in populations suffering from cancer or heart diseases. Compared to officers without LBP, the presence of CLBP was significantly associated with lower RE (β: -0.068; p = 0.003) and MH (β: -0.062; p = 0.002) scores. These relationships were not found in the acute/subacute LBP group.

Conclusion

Our results underscore how frequent CLBP is among police officers and how burdensome it is. Considering the importance of good physical and mental health for this occupational population, police organizations should be aware of this issue and contribute to the efforts toward CLBP prevention and management in the workplace.

Impact of Chronic Pain on Patients' Quality of Life: A Comparative Mixed-Methods Study

Background:

Chronic pain has become a common problem within primary care and can negatively impact patients’ lives.

Objective:

To assess and explore the impact of chronic pain on patients’ quality of life (QoL) using quantitative and qualitative data, respectively.

Methods:

A convergent parallel mixed-methods design was used. Chronic pain patients were recruited from a community-based pain clinic located in the North of England. Quality of life was assessed using Short-Form 36 version 2. Quality of life data were also extracted from the Third Oxford and Lifestyles Survey and Welsh Health Survey to allow comparison of QoL of chronic pain patients with that of the general population and patients with long-term conditions. Qualitative interviews were conducted face-to-face using a semistructured topic guide. Quantitative data were analyzed using SPSS version 24 and qualitative data were analyzed thematically.

Results:

Seventy-nine patients participated in the quantitative phase. The mean (standard deviation) age was 46.5 (14.5). Lower back (54; 68.3%) followed by lower limb were the most common pain sites. Compared with the general population and patients with long-term conditions, chronic pain patients had significantly lower mean QoL scores across all domains of SF-36 (All P < .05). Six themes emerged from qualitative data: interference with physical functioning, interference with professional life, interference with relationships and family life, interference with social life, interference with sleep, and interference with mood.

Conclusion:

The multidimensional negative impact of chronic pain leads to poorer QoL among patients with chronic pain compared to the general population and patients with other long-term conditions.

Pain chronification: what should a non-pain medicine specialist know?

OBJECTIVE

Pain is one of the most common reasons for an individual to consult their primary care physician, with most chronic pain being treated in the primary care setting. However, many primary care physicians/non-pain medicine specialists lack enough awareness, education and skills to manage pain patients appropriately, and there is currently no clear, common consensus/formal definition of "pain chronification".

METHODS

This article, based on an international Change Pain Chronic Advisory Board meeting which was held in Wiesbaden, Germany, in October 2016, provides primary care physicians/non-pain medicine specialists with a narrative overview of pain chronification, including underlying physiological and psychosocial processes, predictive factors for pain chronification, a brief summary of preventive strategies, and the role of primary care physicians and non-pain medicine specialists in the holistic management of pain chronification.

RESULTS

Based on currently available evidence, we propose the following consensus-based definition of pain chronification which provides a common framework to raise awareness among non-pain medicine specialists: "Pain chronification describes the process of transient pain progressing into persistent pain; pain processing changes as a result of an imbalance between pain amplification and pain inhibition; genetic, environmental and biopsychosocial factors determine the risk, the degree, and time-course of chronification."

CONCLUSIONS

Early intervention plays an important role in preventing pain chronification and, as key influencers in the management of patients with acute pain, it is critical that primary care physicians are equipped with the necessary awareness, education and skills to manage pain patients appropriately.

Validation of EQ-5D and 15D in the assessment of health-related quality of life in chronic pain

Chronic pain has a significant impact on quality of life. Measurement of health-related quality of life (HRQoL) is essential in the assessment of pain management outcomes, but different instruments have produced varying results. We assessed the validity of 2 HRQoL instruments, EuroQol 5 dimensions questionnaire (EQ-5D) and 15-dimensional health-related quality of life measure (15D), in patients with challenging chronic pain. Three hundred ninety-one chronic noncancer pain patients referred to tertiary pain clinics completed EQ-5D, 15D, and a broad set of questionnaires mapping socioeconomic factors, self-rated health, pain intensity and interference, depression, pain acceptance, pain-related anxiety, and sleep. The 2 HRQoL instruments were compared with each other, and head-to-head comparisons were made with self-rated health and the symptom-specific questionnaires. 15D and EQ-5D showed moderate agreement (ρ = 0.66), but there were also considerable differences between the instruments. 15D correlated better with self-rated health than EQ-5D (ρ = -0.62 vs -0.45, P < 0.001). The EQ-5D appeared less sensitive than 15D especially in those patients with chronic pain who had a better health status. The principal component constructed from measures of pain intensity and interference, anxiety, pain acceptance, depression, and sleep had higher standardized beta coefficients with 15D than with EQ-5D (P = 0.038). The principal component explained more variance in the 15D (R = 0.65) than in the EQ-5D (R = 0.43). The study identified differences in the pain-related variables between the EQ-5D and the 15D. In patients with chronic pain, both instruments are valid, but 15D appears somewhat more sensitive than EQ-5D.

Assessment and manifestation of central sensitisation across different chronic pain conditions

Different neuroplastic processes can occur along the nociceptive pathways and may be important in the transition from acute to chronic pain and for diagnosis and development of optimal management strategies. The neuroplastic processes may result in gain (sensitisation) or loss (desensitisation) of function in relation to the incoming nociceptive signals. Such processes play important roles in chronic pain, and although the clinical manifestations differ across condition processes, they share some common mechanistic features. The fundamental understanding and quantitative assessment of particularly some of the central sensitisation mechanisms can be translated from preclinical studies into the clinic. The clinical perspectives are implementation of such novel information into diagnostics, mechanistic phenotyping, prevention, personalised treatment, and drug development. The aims of this paper are to introduce and discuss (1) some common fundamental central pain mechanisms, (2) how they may translate into the clinical signs and symptoms across different chronic pain conditions, (3) how to evaluate gain and loss of function using quantitative pain assessment tools, and (4) the implications for optimising prevention and management of pain. The chronic pain conditions selected for the paper are neuropathic pain in general, musculoskeletal pain (chronic low back pain and osteoarthritic pain in particular), and visceral pain (irritable bowel syndrome in particular). The translational mechanisms addressed are local and widespread sensitisation, central summation, and descending pain modulation.

Significance

Central sensitisation is an important manifestation involved in many different chronic pain conditions. Central sensitisation can be different to assess and evaluate as the manifestations vary from pain condition to pain condition. Understanding central sensitisation may promote better profiling and diagnosis of pain patients and development of new regimes for mechanism based therapy. Some of the mechanisms underlying central sensitisation can be translated from animals to humans providing new options in development of therapies and profiling drugs under development.

Impact of marital status and comorbid disorders on health-related quality of life after cardiac surgery

PURPOSE

To explore associations between HRQL, marital status, and comorbid disorders in men and women following cardiac surgery.

METHOD

A secondary analysis was completed using data from a randomized controlled trial in which 416 individuals (23% women) scheduled for elective coronary artery bypass graft and/or valve surgery were recruited between March 2012 and September 2013. HRQL was assessed using the Health State Descriptive System (15D) preoperatively, then at 2 weeks, and at 3, 6, and 12 months following cardiac surgery. Linear mixed model analyses were performed to explore associations between HRQL, social support, and comorbid disorders.

RESULTS

The overall 15D scores for the total sample improved significantly from 2 weeks to 3 months post surgery, with only a gradual change observed from 3 to 12 months. Thirty percent (n = 92) of the total sample reported a lower 15D total score at 12 months compared to preoperative status, of whom 78% (n = 71) had a negative minimum important differences (MID), indicating a worse HRQL status. When adjusted for age and marital status, women had statistically significant lower 15D total scores compared to men at 3, 6, and 12 months post surgery. Compared to pre-surgery, improvement was demonstrated in 4 out of 15 dimensions of HRQL for women, and in 6 out of 15 dimensions for men at 12 months post surgery. Both men and women associated back/neck problems, depression, and persistent pain intensity with lower HRQL; for women, not living with a partner/spouse was associated with lower HRQL up to 12 months.

CONCLUSION

Women experienced decreased HRQL and a slower first-year recovery following cardiac surgery compared to men. This study demonstrates a need for follow-up and support to help women manage their symptoms and improve their function within the first year after cardiac surgery. This was particularly pronounced for those women living alone.

Reliability and Validity of the Medical Outcomes Study Short Form-12 Version 2 (SF-12v2) in Adults with Non-Cancer Pain

Limited evidence exists on how non-cancer pain (NCP) affects an individual's health-related quality of life (HRQoL). This study aimed to validate the Medical Outcomes Study Short Form-12 Version 2 (SF-12v2), a generic measure of HRQoL, in a NCP cohort using the Medical Expenditure Panel Survey Longitudinal Files. The SF Mental Component Summary (MCS12) and SF Physical Component Summary (PCS12) were tested for reliability (internal consistency and test-retest reliability) and validity (construct: convergent and discriminant; criterion: concurrent and predictive). A total of 15,716 patients with NCP were included in the final analysis. The MCS12 and PCS12 demonstrated high internal consistency (Cronbach's alpha and Mosier's alpha > 0.8), and moderate and high test-retest reliability, respectively (MCS12 intraclass correlation coefficient (ICC): 0.64; PCS12 ICC: 0.73). Both scales were significantly associated with a number of chronic conditions (p < 0.05). The PCS12 was strongly correlated with perceived health (r = 0.52) but weakly correlated with perceived mental health (r = 0.25). The MCS12 was moderately correlated with perceived mental health (r = 0.42) and perceived health (r = 0.33). Increasing PCS12 and MCS12 scores were significantly associated with lower odds of reporting future physical and cognitive limitations (PCS12: OR = 0.90 95%CI: 0.89-0.90, MCS12: OR = 0.94 95%CI: 0.93-0.94). In summary, the SF-12v2 is a reliable and valid measure of HRQoL for patients with NCP.