Restorative sleep predicts the resolution of chronic widespread pain: results from the EPIFUND study

A noradrenergic pathway for the induction of pain by sleep loss

An epidemic of sleep loss currently affects modern societies worldwide and is implicated in numerous physiological disorders, including pain sensitization, although few studies have explored the brain pathways affected by active sleep deprivation (ASD; e.g., due to recreation). Here, we describe a neural circuit responsible for pain sensitization in mice treated with 9-h non-stress ASD. Using a combination of advanced neuroscience methods, we found that ASD stimulates noradrenergic inputs from locus coeruleus (LCNA) to glutamatergic neurons of the hindlimb primary somatosensory cortex (S1HLGlu). Moreover, artificial inhibition of this LCNA→S1HLGlu pathway alleviates ASD-induced pain sensitization in mice, while chemogenetic activation of this pathway recapitulates the pain sensitization observed following ASD. Our study thus implicates activation of the LCNA→S1HLGlu pathway in ASD-induced pain sensitization, expanding our fundamental understanding of the multisystem interplay involved in pain processing.

A Narrative Review of the Reciprocal Relationship Between Sleep Deprivation and Chronic Pain: The Role of Oxidative Stress

Sleep is crucial for human health, insufficient sleep or poor sleep quality may negatively affect sleep function and lead to a state of sleep deprivation. Sleep deprivation can result in various health problems, including chronic pain. The intricate relationship between sleep and pain is complex and intertwined, with daytime pain affecting sleep quality and poor sleep increasing pain intensity. The article first describes the influence of sleep on the onset and development of pain, and then explores the impact of daytime pain intensity on nighttime sleep quality and subsequent pain thresholds. However, the primary emphasis is placed on the pivotal role of oxidative stress in this bidirectional relationship. Although the exact mechanisms underlying sleep and chronic pain are unclear, this review focuses on the role of oxidative stress. Numerous studies on sleep deprivation have demonstrated that it can lead to varying degrees of increased pain sensitivity, while chronic pain leads to sleep deprivation and further exacerbates pain. Further research on the role of oxidative stress in the mechanism of sleep deprivation-induced pain sensitization seems reasonable. This article comprehensively reviews the current research on the interrelationship between sleep deprivation, pain and the crucial role of oxidative stress.

Change in number of pain sites - which factors are important? A 12-year prospective cohort study

BACKGROUND

Pain in multiple body sites is common and often persistent. The purpose of this prospective study was to examine the change in the number of pain sites (NPS) over time and to evaluate to which extent clinical, demographic, lifestyle and health-related factors predict a change in NPS.

METHODS

This was a population-based longitudinal cohort study of adults (n = 2,357). Data on pain, demographic, lifestyle, and health-related variables were collected by questionnaires in 2008 and 2020 and register data from 2006 to 2017. Data was analysed with linear regression.

RESULTS

We found a mean decrease in NPS over the 12-year follow-up period (-0.36 (95% CI; -0.44; -0.27) and 56% of this sample reported no change or only one pain site increase/decrease over 12 years. While participants reporting pain for less than 3 months at baseline had almost no change in NPS (-0.04 (95% CI; -0.18; 0.10)), participants with pain for longer than 3 months decreased by -0.51 (95% CI; -0.62; -0.41). Age at baseline (20-49 years), pain intensity, and obesity (BMI ≥ 30) were associated with an increase in NPS over the follow-up period.

CONCLUSIONS

NPS is relatively stable over time. We found a small mean decrease in NPS over 12 years varying between participants with pain for longer than 3 months and pain for less than 3 months respectively. The results also indicate that pain intensity, age, and obesity could be relevant factors to consider when predicting change in NPS.

Sex and Sleep Disruption as Contributing Factors in Alzheimer's Disease

Alzheimer's disease (AD) affects more women than men, with women throughout the menopausal transition potentially being the most under researched and at-risk group. Sleep disruptions, which are an established risk factor for AD, increase in prevalence with normal aging and are exacerbated in women during menopause. Sex differences showing more disrupted sleep patterns and increased AD pathology in women and female animal models have been established in literature, with much emphasis placed on loss of circulating gonadal hormones with age. Interestingly, increases in gonadotropins such as follicle stimulating hormone are emerging to be a major contributor to AD pathogenesis and may also play a role in sleep disruption, perhaps in combination with other lesser studied hormones. Several sleep influencing regions of the brain appear to be affected early in AD progression and some may exhibit sexual dimorphisms that may contribute to increased sleep disruptions in women with age. Additionally, some of the most common sleep disorders, as well as multiple health conditions that impair sleep quality, are more prevalent and more severe in women. These conditions are often comorbid with AD and have bi-directional relationships that contribute synergistically to cognitive decline and neuropathology. The association during aging of increased sleep disruption and sleep disorders, dramatic hormonal changes during and after menopause, and increased AD pathology may be interacting and contributing factors that lead to the increased number of women living with AD.

Modifiable physical and behavioural factors associated with widespread pain in older adults with radiographic evidence of knee osteoarthritis

OBJECTIVE

To identify modifiable physical and behavioural factors associated with widespread pain (WSP) in older adults with radiographic evidence of knee osteoarthritis (OA).

METHODS

Cross-sectional initial visit data of participants with radiographic knee OA (Kellgren-Lawrence grade of ≥2) from the Osteoarthritis Initiative Study were analysed. WSP was defined as pain on both sides of the body, above and below the waist, and in the axial skeleton. Time (hrs/d) spent participating in sitting and moderate-strenuous physical activities were calculated from the Physical Activity Scale for the Elderly questionnaire. Physical function was quantified using gait speed and the chair stand test. Restless sleep was assessed using an item on the CES-D Scale. Logistic regression models were constructed to examine the strength of the associations between primary exposures and WSP in unadjusted and adjusted analyses.

RESULTS

Among the 2637 participants (mean age 62.6 years, 58.6% female), 16.8% met the criteria for WSP. All primary measures of interest were related to WSP in unadjusted analyses. In adjusted multivariable analysis, slow gait speed (adjusted odds ratio [aOR] 1.43; 95% CI 1.01, 2.02), lower chair stand rate (aOR 0.98; 95% CI 0.97-0.99), and restless sleep (aOR 1.61; 95% CI 1.25-2.08) maintained significant associations with WSP.

CONCLUSION

Poor sleep behaviours and low physical function capacity are associated with WSP in adults with radiographic knee OA. These findings highlight the importance of assessing sleep, physical function, and pain distribution in this population. Interventions to improve physical function and sleep behaviours should be investigated as potential strategies to mitigate WSP.

The Role of Cortisol in Chronic Stress, Neurodegenerative Diseases, and Psychological Disorders

Cortisol, a critical glucocorticoid hormone produced by the adrenal glands, plays a pivotal role in various physiological processes. Its release is finely orchestrated by the suprachiasmatic nucleus, governing the circadian rhythm and activating the intricate hypothalamic-pituitary-adrenal (HPA) axis, a vital neuroendocrine system responsible for stress response and maintaining homeostasis. Disruptions in cortisol regulation due to chronic stress, disease, and aging have profound implications for multiple bodily systems. Animal models have been instrumental in elucidating these complex cortisol dynamics during stress, shedding light on the interplay between physiological, neuroendocrine, and immune factors in the stress response. These models have also revealed the impact of various stressors, including social hierarchies, highlighting the role of social factors in cortisol regulation. Moreover, chronic stress is closely linked to the progression of neurodegenerative diseases, like Alzheimer's and Parkinson's, driven by excessive cortisol production and HPA axis dysregulation, along with neuroinflammation in the central nervous system. The relationship between cortisol dysregulation and major depressive disorder is complex, characterized by HPA axis hyperactivity and chronic inflammation. Lastly, chronic pain is associated with abnormal cortisol patterns that heighten pain sensitivity and susceptibility. Understanding these multifaceted mechanisms and their effects is essential, as they offer insights into potential interventions to mitigate the detrimental consequences of chronic stress and cortisol dysregulation in these conditions.

Evaluation of sleep health documentation and sleep-related intervention by physiatrists treating musculoskeletal disorders: A retrospective investigation

BACKGROUND

Sleep health is linked to pain, function, and global health. Unfortunately, sleep health may not be consistently addressed as a part of musculoskeletal care.

OBJECTIVE

To describe the frequency of sleep health documentation and intervention by musculoskeletal physiatrists. Additionally, patient-reported outcome measures were compared between patients with and without sleep impairment. We hypothesized that sleep health is documented and addressed in less than half of initial patient encounters and that patients with a sleep impairment have worse patient-reported outcomes scores compared to those without sleep impairment.

DESIGN

Retrospective study.

SETTING

Tertiary orthopedic hospital.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Frequency of provider documentation of sleep health, frequency and characteristics of sleep health intervention provided, and Patient-Reported Outcome Measurement Information System (PROMIS)-10 mental health and physical health scores.

RESULTS

Initial visits for a musculoskeletal condition of 39,452 patients from January 1, 2020 to October 1, 2022 were included. Documentation of sleep health was found in 33.0% (13,002/39,452) of patients. Of those with sleep health documentation, 59.2% (7697/13,002) were classified as having a sleep impairment. Only 19.0% of patients were provided with sleep-related education or other intervention. Patients with a sleep impairment had worse PROMIS-10 mental health and physical health scores (p < .001), as compared to those without a sleep impairment.

CONCLUSIONS

Patients with sleep impairment had worse mental and physical health scores than those without sleep impairment, and only 19.0% received sleep health intervention. These data suggest that sleep impairment is common in patients presenting for evaluation of a musculoskeletal condition, and advanced provider education and tools to help patients improve their sleep health are needed.

Sleep characteristics and pain in middle-aged and older adults: Sex-specific impact of physical and sitting activity

OBJECTIVES

The relationship between poor sleep health and worse pain is established. Physical activity has been successful in reducing chronic pain and improving sleep in aging adults. Despite known sex differences (more women than men experiencing chronic pain and insomnia), sex-specific patterns of interactive associations between physical activity, sleep, and pain remain unexplored. This study tested whether physical and sitting activity moderated associations between sleep characteristics and pain intensity, and whether sex further moderated these relationships.

METHODS

Participants aged 50+ (N = 170, Mage = 64.34, 72 women) completed an online survey measuring pre-sleep arousal (Pre-sleep Arousal Scale), sleep (Pittsburgh Sleep Quality Index), past month average pain intensity, and physical activity (International Physical Activity Questionnaire). Multiple regressions evaluated whether minutes of physical activity (total, vigorous, moderate, walking) or sitting activity, pre-sleep arousal, sleep, sex, or their interaction was associated with pain. Analyses controlled for education, difficulty walking, body mass index, total medical conditions, pain medication, and depressive/anxiety symptoms.

RESULTS

In women, vigorous activity interacted with total pre-sleep arousal and somatic pre-sleep arousal in its association with pain. Higher total arousal and somatic arousal were associated with worse pain intensity only for women who reported highest levels of vigorous activity. No such associations were observed for men or for other physical or sitting activity levels.

CONCLUSIONS

Vigorous physical activity may exacerbate the association between more pre-sleep arousal and worse pain in middle-aged and older women. Research should explore potential sex-specific mechanisms (e.g., inflammatory cytokines, arousal neural networks) underlying these results.

The bidirectional association between chronic musculoskeletal pain and sleep-related problems: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis synthesizes the evidence on prospective bidirectional associations between sleep-related problems (SRP) and chronic musculoskeletal pain (CMP).

METHODS

A literature search for cohort studies available in the PubMed, Scopus, Web of Science, PsycINFO and Cochrane Library databases as of 19 July 2022 was performed. Pooled odds ratios and effect sizes were calculated through random effects meta-analysis. Subgroup and meta-regression analyses were performed to explore differences by follow-up time, proportion of each sex and mean age. The Meta-analysis Of Observational Studies in Epidemiology guidelines were strictly followed.

RESULTS

Twenty studies with a total of 208 190 adults (aged 34.4-71.7 years) were included, with 17 of them being used in the meta-analysis. Individuals with SRP at baseline had a 1.79-fold higher incidence (odds ratio [OR] = 1.79; 95% CI: 1.55, 2.08; I2 = 84.7%; P < 0.001) and a 2.04-fold higher persistence (OR = 2.04; 95% CI: 1.42, 2.94; I2 = 88.5%; P < 0.005) of CMP than those without SRP. In the subgroup analysis of the association between SRP and CMP, the longer the follow-up time of the studies, the higher the heterogeneity between them. In the corresponding meta-regression, no significant effect was observed for follow-up time, sex proportion or age. Individuals with CMP at baseline had a 2.02-fold higher incidence of SRP (OR = 2.02; 95% CI: 1.62, 2.53; I2 = 90.0%; P < 0.001) than those without CMP.

CONCLUSION

This study provides robust evidence concerning the longitudinal association between SRP and incidence-persistence of CMP in adults. In addition, the available prospective studies support the existence of a bidirectional relationship between CMP and SRP.

PROSPERO REGISTRATION NUMBER

CRD42020212360.

A randomized, placebo-controlled, double-blinded mechanistic clinical trial using endotoxin to evaluate the relationship between insomnia, inflammation, and affective disturbance on pain in older adults: A protocol for the sleep and Healthy Aging Research for pain (SHARE-P) study

Chronic pain is prevalent in older adults. Treatment, especially with opioids, is often ineffective and poses considerable negative consequences in this population. To improve treatment, it is important to understand why older adults are at a heightened risk for developing chronic pain. Insomnia is a major modifiable risk factor for chronic pain that is ubiquitous among older adults. Insomnia can also lead to heightened systemic inflammation and affective disturbance, both of which may further exacerbate pain conditions in older adults. Endotoxin exposure can be used as an experimental model of systemic inflammation and affective disturbance. The current study aims to understand how insomnia status and endotoxin-induced changes in inflammation and affect (increased negative affect and decreased positive affect) may interact to impact pain facilitatory and inhibitory processes in older adults. Longitudinal data will also assess how pain processing, affective, and inflammatory responses to endotoxin may predict the development of pain and/or depressive symptoms. The current study is a randomized, double-blinded, placebo-controlled, mechanistic clinical trial in men and women, with and without insomnia, aged 50 years and older. Participants were randomized to either 0.8ng/kg endotoxin injection or saline placebo injection. Daily diaries were used to collect variables related to sleep, mood, and pain at two-week intervals during baseline and 3-, 6-, 9-, and 12-months post-injection. Primary outcomes during the experimental phase include conditioned pain modulation, temporal summation, and affective pain modulation ∼5.5 hours after injection. Primary outcomes for longitudinal assessments are self-reported pain intensity and depressive symptoms. The current study uses endotoxin as an experimental model for pain. In doing so, it aims to extend the current literature by: (1) including older adults, (2) investigating insomnia as a potential risk factor for chronic pain, (3) evaluating the role of endotoxin-induced affective disturbances on pain sensitivity, and (4) assessing sex differences in endotoxin-induced hyperalgesia.

Clinicaltrialsgov

NCT03256760.

Trial sponsor

NIH R01AG057750-01.

Including a Three-Party Meeting Using the Demand and Ability Protocol in an Interdisciplinary Pain Rehabilitation Programme for a Successful Return to Work Process

The Demand and Ability Protocol (DAP) is used in three-party meetings involving an employee, an employer, and a representative from the rehabilitation team. The aim of this study is to investigate the inclusion of an intervention using the DAP in an interdisciplinary pain rehabilitation programme (IPRP) compared to usual care. This non-randomised controlled trial included patients assigned to an IPRP in Sweden. The intervention group received a DAP intervention targeting their work situation in addition to the usual care provided by the IPRP. The control group received IPRP only. Outcome measures were collected from the Swedish Quality Registry for Pain Rehabilitation. Results demonstrated improvements in both groups regarding self-reported anxiety, depression and EQ5D. Sleep was improved in the intervention group but not in the control group. No statistical differences in outcomes were observed between the groups. In conclusion, adding the DAP intervention to IPRP seemed to have the potential to improve sleep among the patients, which may indicate an overall improvement regarding health outcomes from a longer perspective. The results were less clear, however, regarding the work-related outcomes of sickness absence and workability.

The Influence of Sleep Disturbance on Chronic Pain

PURPOSE OF REVIEW

The purpose of this review is to present an overview of common sleep disturbance pathologies and their impact on chronic pain, while examining various factors that are implicit in the relationship between sleep disturbance and chronic pain, including neurobiochemistry, anatomy, and systemic mediators, and reviewing recent and landmark literature.

RECENT FINDINGS

Earlier literature reviews and studies have introduced the bidirectional relationship between sleep disturbance and chronic pain; that is, impaired sleep may worsen chronic pain, and chronic pain causes sleep disturbance. However, more recent reviews and studies seem to show a more associative, rather than causative relationship. There have been recent studies that attempt to determine mechanisms that link sleep disturbance and chronic pain; the results of these studies were more varied, ultimately concluding that there may be a separate, yet-to-be discovered mechanism that shows the causative relationship between sleep disturbance and pain. There are several neurotransmitters that are involved in the mediation of chronic pain and sleep disturbance as separate entities, and some studies have shown that there may be mechanisms that govern both chronic pain and sleep disturbance as a single unit. Other neuroendocrine substances also serve to mediate chronic pain and sleep disturbance. All these substances are found to be associated with various sleep disorders and are also associated with chronic pain symptoms as well. Inflammation plays a role in chronic pain and sleep disturbance, with an increase in inflammatory substances and mediators associated with an increase or worsening in chronic pain symptoms and sleep disorders. The HPA axis plays a role in chronic pain and sleep disorders, influencing pain and sleep pathways through stress response, inflammation, and maintenance of homeostasis. There are several variables that influence both chronic pain and sleep disturbance, and more research into these variables may further our understanding into the complex pathways governing the influence of sleep disturbance on pain, and ultimately to improve treatment for this issue.

Sleep Problems Mediate the Relationship Between Psychosocial Stress and Pain Facilitation in Native Americans: A Structural Equation Modeling Analysis from the Oklahoma Study of Native American Pain Risk

BACKGROUND

Native Americans (NAs) are more likely to experience chronic pain than non-Hispanic Whites (NHWs); however, the proximate causes predisposing NAs to chronic pain remain elusive. Likely due to centuries of adversity, discrimination, and marginalization, NAs report greater psychological stress than NHWs, which may place them at risk for sleep problems, a well-established risk factor for chronic pain onset.

PURPOSE

This study examined the effects of psychological stress and sleep problems on subjective and physiological measures of pain processing in NAs and NHWs.

METHODS

Structural equation modeling was used to determine whether ethnicity (NA or NHW) was associated with psychological stress or sleep problems and whether these variables were related to conditioned pain modulation of pain perception (CPM-pain) and the nociceptive flexion reflex (CPM-NFR), temporal summation of pain (TS-pain) and NFR (TS-NFR), and pain tolerance in a sample of 302 (153 NAs) pain-free participants.

RESULTS

NAs experienced more psychological stress (Estimate = 0.027, p = .009) and sleep problems (Estimate = 1.375, p = .015) than NHWs. When controlling for age, sex, physical activity, BMI, and general health, NA ethnicity was no longer related to greater sleep problems. Psychological stress was also related to sleep problems (Estimate = 30.173, p = <.001) and psychological stress promoted sleep problems in NAs (indirect effect = 0.802, p = .014). In turn, sleep problems were associated with greater TS-pain (Estimate = 0.714, p = .004), but not other pain measures.

CONCLUSIONS

Sleep problems may contribute to chronic pain risk by facilitating pain perception without affecting facilitation of spinal neurons or endogenous inhibition of nociceptive processes. Since psychological stress promoted pain facilitation via enhanced sleep problems, efforts to reduce psychological stress and sleep problems among NAs may improve health outcomes.

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.

Stress, non-restorative sleep, and physical inactivity as risk factors for chronic pain in young adults: A cohort study

Background

Chronic pain is a common condition which causes patients much suffering and is very costly to society. Factors known to be associated with chronic pain include female gender, acute pain, depression, and anxiety. This study investigated whether stress, sleep disturbance, and physical inactivity were risk factors for developing chronic pain among young adults, and whether there were any interactions between these.

Methods

This retrospective longitudinal study was based on an existing database from a cohort study on IT use and health, called Health 24 Years. A questionnaire was sent to students aged 19–24 in Sweden for five consecutive years, containing questions on pain, stress, sleep, physical activity, technology use, health, and more. In logistic regressions, stress, sleep, and physical activity at baseline were potential predictors of chronic pain one and four years later. In addition, a new variable including all possible interactions between potential predictors was created to test for effect modification between risk factors.

Results

At the one-year follow-up, stress, non-restorative sleep, and physical inactivity showed odds ratios of 1.6 (95% CI: 1.0–2.4), 1.5 (95% CI: 1.0–2.3), and 1.8 (95% CI: 1.1–3.0) respectively after adjusting for confounders, the reference being non-stressed, having restorative sleep and being active. At the four-year follow-up, stress showed an adjusted odds ratio of 1.9 (95% CI: 1.3–2.9), while non-restorative sleep and physical inactivity were statistically insignificant. At the one-year follow-up, the interaction between risk factors were significant. The most clear example of this effect modification was to be inactive and not have -restorative sleep, compared to individuals who were active and had restorative sleep, showing an adjusted odds ratio of 6.9 (95% CI: 2.5–19.2) for developing chronic pain one year after baseline. This in comparison of odds ratios for only inactive respectively only non-restorative sleep being 1.7 (95% CI: 0.6–5.3) respectively 1.6 (95% CI: 0.7–3.5).

Conclusions

Stress, non-restorative sleep, and physical inactivity were risk factors for developing chronic pain one year after baseline, and stress were also a risk factor four years after baseline. These findings suggest that non-restorative sleep and inactivity are risk factors in the short term while stress is a risk factor in both the short and the long term. In addition to the independent effects of non-restorative sleep and inactivity, their combination seems to further increase the odds of chronic pain.

Cross-Cultural Adaptation, Reliability, and Psychophysical Validation of the Pain and Sleep Questionnaire Three-Item Index in Finnish

Reciprocal relationships between chronic musculoskeletal pain and various sleep disturbances are well established. The Pain and Sleep Questionnaire three-item index (PSQ-3) is a concise, valid, and reliable patient-reported outcome measure (PROM) that directly evaluates how sleep is affected by chronic low back pain (CLBP). Translation and cross-cultural validation of The Pain and Sleep Questionnaire three-item index Finnish version (PSQ-3-FI) were conducted according to established guidelines. The validation sample was 229 subjects, including 42 pain-free controls and 187 subjects with chronic musculoskeletal pain. Our aims were to evaluate internal consistency, test-retest reliability, measurement error, structural validity, convergent validity, and discriminative validity and, furthermore, to study the relationships between dizziness, postural control on a force plate, and objective sleep quality metrics and total PSQ-3-FI score. The PSQ-3-FI demonstrated good internal consistency, excellent test-retest reliability, and small measurement error. Confirmatory factor analysis confirmed acceptable fit indices to a one-factor model. Convergent validity indicated fair to good correlation with pain history and well-established pain-related PROMs. The PSQ-3-FI total score successfully distinguished between the groups with no pain, single-site pain, and multisite pain. A higher prevalence of dizziness, more impaired postural control, and a general trend towards poorer sleep quality were observed among subjects with higher PSQ-3-FI scores. Postural control instability was more evident in eyes-open tests. The Finnish PSQ-3 translation was successfully cross-culturally adapted and validated. The PSQ-3-FI appears to be a valid and reliable PROM for the Finnish-speaking CLBP population. More widespread implementation of PSQ-3 would lead to better understanding of the direct effects of pain on sleep.

Insomnia Symptoms and Chronic Pain among Patients Participating in a Pain Rehabilitation Program-A Registry Study

Insomnia and chronic pain are prevalent health complaints. Previous research has shown that they are closely associated, but their interaction and causality are not completely understood. Further research is needed to uncover the extent to which a treatment strategy focusing on one of the conditions affects the other. This study aimed to map the prevalence of insomnia symptoms among patients in interdisciplinary pain rehabilitation program (IPRP) and investigate associations between the degree of insomnia at baseline and the treatment outcome regarding pain intensity, physical function, social function, mental well-being, anxiety, and depression. Of the 8515 patients with chronic pain, aged 15–81 who were registered in the Swedish Quality Registry for Pain Rehabilitation during 2016–2019 and participated in IPRP, 7261 had follow-up data after treatment. Logistic regression analysis was used to investigate associations. The prevalence of clinical insomnia, according to Insomnia Severity Index (ISI), among chronic pain patients in IPRP was 66%, and insomnia symptoms were associated with both country of birth and educational level. After IPRP, the prevalence of clinical insomnia decreased to 47%. There were statistically significant associations between the degree of insomnia symptoms before IPRP and physical function (p < 0.001), social function (p = 0.004) and mental well-being (p < 0.001). A higher degree of insomnia symptoms at baseline was associated with improvement after IPRP. In conclusion, IPRP seem to have beneficial effects on insomnia symptoms in chronic pain patients. Nevertheless, almost half of the patients still suffer from clinical insomnia after IPRP. The possible effect of systematic screening and treatment of insomnia for improving the effect of IPRP on pain is an important area for future research.

Morning and evening salivary cortisol levels in patients with chronic widespread pain and those at high risk

BACKGROUND

Hypothalamic-Pituitary-Adrenal (HPA) axis dysregulation has been implicated in chronic widespread pain (CWP); the hallmark of fibromyalgia (FM). This is the first study to compare HPA axis changes in individuals with CWP and those at high risk of symptom development.

METHODS

We sought to determine differences in morning and evening salivary cortisol levels in FM (n = 19), those at-risk (n = 20) and pain-free controls (n = 17). Risk factors included non-CWP pain, somatic symptoms, illness behaviour and sleep disturbance. We conducted the study in the absence of centrally acting medication, to address limitations of previous research.

RESULTS

Repeated measures ANOVA revealed significant main effects of group (p = 0.003), and time of day (p = 0.002), with no significant interaction. Cortisol levels were higher in FM (p = 0.027) and at-risk (p = 0.003) groups, compared to controls, but there was no significant difference between FM and at-risk groups. The main effect of group remained significant with sleep problems (p = 0.021) and life events (p = 0.007), but was not significant with anxiety (p = 0.076) or depression (p = 0.098) scores as covariates. With sleep problems as a covariate, cortisol levels remained significantly higher only in the at-risk group (p = 0.017).

CONCLUSIONS

This study indicates elevated salivary cortisol in FM and those at high risk, and identifies anxiety, depression and sleep problems as potential contributing factors. The results shed light on the dynamic relationship between stress, mood and sleep disorders and the brain's resilience to pain.

SIGNIFICANCE

This study examines neurobiological changes in chronic widespread pain and high risk individuals. One strength of the study is the absence of centrally acting medication. We found high salivary cortisol common to Fibromyalgia and those at risk and identified contributing factors. Our results offer insight into the early mechanistic changes underlying Fibromyalgia development and open up possibilities for early diagnosis and prevention.

Sleep disturbance predicts future health status after stroke

STUDY OBJECTIVES

We evaluated factors associated with the presence of sleep disturbance in patients with stroke and whether sleep disturbance predicted change in other patient-reported domains of health over time.

METHODS

Observational cohort study of 2,190 patients with stroke seen in a cerebrovascular clinic February 17, 2015 to July 5, 2017 who completed patient-reported outcome measures (PROMs) at ≥ 1 visit, including the Patient Health Questionnaire-9 depression screen, Quality of Life in Neurological Disorders (NeuroQoL) cognitive function and Patient-Reported Outcomes Information Measurement System (PROMIS) sleep disturbance, fatigue, anxiety, social role satisfaction, physical function, and pain interference. Separate multivariable models were constructed with PROMIS sleep disturbance as the dependent variable. Covariates included clinical and demographic variables, the Patient Health Questionnaire-9 depression screen scored on the PROMIS metric, and 1 of the 6 other PROMs. Among the 476 patients with ≥ 2 visits, linear regression models were constructed to determine the association of baseline sleep disturbance with follow-up PROMs after adjustment for the corresponding baseline PROMIS/NeuroQol scores, depression score, and clinical variables.

RESULTS

Younger age and all PROM scores were associated with sleep disturbance; depression had the greatest association among PROMs (beta estimate 0.53, 95% confidence interval, 0.49, 0.57), physical function had the least (-0.06, 95% confidence interval, -0.11, -0.01). Baseline PROMIS sleep disturbance score was associated with worse adjusted follow-up scores for depression, fatigue, social role satisfaction, and physical function.

CONCLUSIONS

Younger age and all 8 PROMs were associated with sleep disturbance in patients with stroke. The degree of sleep disturbance predicted future patient-reported outcomes for multiple domains of health. Further study is warranted to determine if interventions shown to improve sleep symptoms will also improve other outcomes.

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.

Resolution of fibromyalgia by controlling obstructive sleep apnea with a mandibular advancement device

Fibromyalgia (FM) is a chronic, often disabling disorder characterized by multisite pain along with sleep problems and fatigue. Pain and sleep exhibit a reciprocal relationship. When FM and obstructive sleep apnea/hypopnea (OSA) co-exist, treatment options include continuous positive airway pressure or mandibular advancement device. We present a patient experiencing fibromyalgia and OSA whose symptoms vanished wearing a Mandibular Advancement Device (MAD) during sleep. To our knowledge, this is the first documented case of FM symptom resolution by MAD treatment.

Sleep Disturbance and Its Association with Pain Severity and Multisite Pain: A Prospective 10.7-Year Study

INTRODUCTION

Sleep disturbance is often comorbid with chronic pain disorders, with emerging evidence suggesting a stronger effect of sleep disturbance on pain than vice versa; however, few studies have evaluated the long-term associations between sleep disturbance and pain. This study was to examine the associations of sleep disturbance with knee pain severity, number of painful sites (NPS) and persistent pain in a 10.7-year cohort study.

METHODS

A total of 1099 community-dwelling older adults (age mean ± SD, 63 ± 7.5 years; 51% female) were recruited and followed up at 2.6, 5.1 and 10.7 years later. Data on demographics, body mass index, physical activity and comorbidities were collected. At each time point, sleep disturbance, knee pain severity and NPS were assessed by using questionnaires. Multisite pain (MSP) was defined as NPS ≥ 2. Persistent knee pain or MSP was defined as having knee pain or MSP at all time points, respectively. Multivariable mixed-effects models and log-binomial regression were applied.

RESULTS

In multivariable analyses, sleep disturbance was associated with greater knee pain severity (β 0.91/unit, 95% CI 0.70-1.11) and more NPS [(relative risk (RR) 1.10/unit, 95% CI 1.07-1.14] in a dose-response manner. Persistent sleep disturbance was associated with persistent knee pain (RR 1.90, 1.26-2.87) and MSP (RR 1.29, 1.07-1.56). Persistent knee pain and MSP were also associated with persistent sleep disturbance (knee pain: RR = 1.99; MSP: RR = 2.71, both P < 0.05).

CONCLUSIONS

Sleep disturbance was independently associated with greater pain severity and NPS in a dose-response manner. A reciprocal relationship between persistent sleep disturbance and persistent pain suggests treating either problem could help the other.

Therapeutic Effect of Mirogabalin on Peripheral Neuropathic Pain due to Lumbar Spine Disease

Study Design

Retrospective study.

Purpose

This study aims to evaluate the effectiveness of mirogabalin in treatment of peripheral neuropathic pain due to lumbar spine disease.

Overview of Literature

Mirogabalin is a novel selective ligand for the α2δ subunit of voltage-gated Ca channels.

Methods

Between April and December 2019, we used mirogabalin to treat 60 consecutive patients (mean age, 67.6 years) with leg symptoms due to lumbar disease. The treatment outcome after 8 weeks of mirogabalin therapy was evaluated by comparing the preand post-administration Numerical Rating Scale (NRS) for leg symptoms and sleep disturbance, the NRS and Roland–Morris Disability Questionnaire for low back pain (LBP), and the quality of life (QOL) score (based on EuroQol five-dimension five-level scale).

Results

Mirogabalin treatment was stopped at less than eight weeks in eight patients. The remaining 52 patients for evaluation were divided as group 1 (17 patients who presented with leg symptoms that lasted for less than 3 months) and group 2 (35 patients with leg symptoms that lasted longer than 3 months). The leg symptoms and LBP in both groups significantly improved at 4 and 8 weeks of treatment, and sleep disturbance and QOL were improved at 8 weeks as well. Compared to group 2, the pretreatment leg symptoms and QOL were significantly worse in group 1, and their improvement after 8 weeks of mirogabalin treatment was significantly better (p<0.05). Of the 60 original patients, 17 suffered adverse effects, which were mild in 16 patients and required treatment cessation due to excessive weight gain in one patient.

Conclusions

We have validated the effect of mirogabalin on neuropathic pain due to lumbar spine disease, which has effectively addressed the associated leg symptoms, LBP, and sleep disturbance.

(Neuro)Inflammatory Component May Be a Common Factor in Chronic Widespread Pain and Restless Legs Syndrome

Purpose of Review

Recent studies have linked fibromyalgia (nociplastic pain) and depression to neuroinflammation. Restless legs syndrome (RLS) is highly prevalent in CWP (chronic widespread pain) and FMS (fibromyalgia syndrome) as well as in depression. This review focuses on evidence in the relationship between CWP and RLS and possible common pathophysiological mechanisms.

Recent Findings

CWP is chronic pain spread over various locations of the body and is a cardinal sign of fibromyalgia. Poor sleep quality is a common symptom in fibromyalgia as well as high levels of fatigue, poor cognition, and other associated features which include depression, headache, and abdominal pain. Evidence for a bilateral relationship between pain and sleep deficit is robust. The latest research focus is not only on insomnia symptoms in chronic pain but also on other types of sleep disorders such as RLS which is characterized by complaints of an “urge to move” frequently associated with dysesthesias. These sensations can also have painful characteristics. Thus, there is a possible overlap between these two entities. The high prevalence of RLS (33–54%) in CWP has been shown in several studies. The pathophysiological mechanisms behind CWP and RLS are still not completely known, but there is a rising amount of evidence on proinflammatory and neuroinflammatory processes in CWP. In RLS, there are links to dopaminergic dysfunction and more generally to monoaminergic dysfunctional circuits, BID (brain iron deficiency), altered glutamatergic neurotransmission, and genetic traits. Depression is a common comorbidity as well in CWP as RLS, and proinflammatory mechanisms have also been demonstrated in this condition.

Summary

The association between CWP and RLS is shown to be high and the pathogenesis of both conditions is still not completely understood. Recent research is focusing on proinflammatory and neuroinflammatory processes, not uniquely emerging in fibromyalgia/CWP, but inflammatory features have been found in depression as well as in sleep deficit. Proinflammatory/neuroinflammatory processes may be an underlying, common factor in both CWP and RLS that future research should investigate further.

The impact of chronic widespread pain on health status and long-term health predictors: a general population cohort study

Background

Chronic widespread pain (CWP) has a negative impact on health status, but results have varied regarding gender-related differences and reported health status. The aim was to study the impact of CWP on health status in women and men aged 35–54 years in a sample of the general population. The aim was further to investigate lifestyle-related predictors of better health status in those with CWP in a 12- and 21-year perspective.

Method

A general population cohort study including 975 participants aged 35–54 years, with a 12- and 21-year follow-up. CWP was measured with a pain mannequin, and the questionnaire included questions on lifestyles factors with SF-36 for measurement of health status. Differences in health status were analysed with independent samples t-test and health predictors with logistic regression analysis.

Results

The prevalence of CWP was higher in women at all time points, but health status was reduced in both women and men with CWP (p < 0.001) with no gender differences of clinical relevance. At the 12-year follow-up, a higher proportion of women than men had developed CWP (OR 2.04; CI 1.27–3.26), and at the 21-year follow-up, a higher proportion of men had recovered from CWP (OR 3.79; CI 1.00–14.33). In those reporting CWP at baseline, a better SF-36 health status (Physical Functioning, Vitality or Mental Health) at the 12-year follow-up was predicted by male gender, having personal support, being a former smoker, and having no sleeping problems. In the 21-year follow-up, predictors of better health were male gender, a weekly intake of alcohol, and having no sleeping problems.

Conclusion

Women and men with CWP have the same worsening of health status, but men recover from CWP to a greater extent in the long-term. Being male, having social support, being a former smoker, and having no sleeping problems were associated with better health status in those with CWP.

Chronic Pain and Sleep Disturbances: A Pragmatic Review of Their Relationships, Comorbidities, and Treatments

Objective

The objective of this review is to answer three questions: 1) How are chronic pain severity and pain duration affected in patients with chronic pain and sleep disturbances that occur simultaneously? 2) What are common comorbidities and pain-related symptoms seen in patients with chronic pain and sleep disturbances? and 3) What are potentially effective pharmacological and nonpharmacological treatment options for both conditions?

Methods

Ovid Medline and PubMed were searched. Search terms included sleep wake disorder, chronic pain, fibromyalgia, treatment outcome, psychotherapy, complementary therapies, and therapeutics. Studies that assessed outcomes between individuals with chronic pain and those with concurrent chronic pain and sleep disturbances were included. Randomized controlled clinical trials of treatments for both conditions were included.

Results

Sixteen studies indicated that patients with both chronic pain and sleep disturbances have greater pain severity, longer duration of pain, greater disability, and are less physically active than those without sleep disturbances. Patients with both conditions are more likely to have concurrent depression, catastrophizing, anxiety, and suicidal ideation. Thirty-three randomized controlled trials assessed treatment for both chronic pain and sleep disturbances. Pregabalin was the most frequently studied medication, showing improvement in pain and sleep symptoms. Cognitive behavioral therapy for insomnia showed long-term improvement in sleep for patients with chronic pain.

Conclusions

Individuals with chronic pain and sleep disturbances have greater symptom severity, longer duration of symptoms, more disability, and additional comorbidities. Pharmacological and nonpharmacological treatments may be useful in the treatment of concurrent chronic pain and sleep disturbances, but further study is needed.

Sleep, Experimental Pain and Clinical Pain in Patients with Chronic Musculoskeletal Pain and Healthy Controls

Purpose

Everyday variations in night sleep in healthy pain-free subjects are at most weakly associated with pain, whereas strong alterations (eg, sleep deprivation, insomnia) lead to hyperalgesic pain changes. Since it remains unclear how substantial sleep alterations need to be in order to affect the pain system and lead to a coupling of both functions, the present study aimed at providing sufficient variance for co-variance analyses by examining a sample consisting of both healthy subjects and chronic pain patients.

Methods

A sample of 20 chronic musculoskeletal pain patients and 20 healthy controls was examined. This sample was assumed to show high inter-individual variability in sleep and pain, as pain patients frequently report sleep disturbances, whereas healthy subjects were required to be pain-free and normal sleepers. Sleep of two non-consecutive nights was measured using portable polysomnography and questionnaires. Experimental pain parameters (pressure pain thresholds (PPT), temporal summation of pain (TSP), conditioned pain modulation (CPM)) and situational pain catastrophizing (SCQ) were assessed in laboratory sessions before and after sleep. Pain patients’ clinical pain was assessed via questionnaire.

Results

As expected, both groups differed in several sleep parameters (reduced total sleep time and sleep efficiency, more time awake after sleep onset, lower subjective sleep quality in the patients) and in a few pain parameters (lower PPTs in the patients). In contrast, no differences were found in TSP, CPM, and SCQ. Contrary to our expectations, regression analyses indicated no prediction of overnight pain changes by sleep parameters.

Conclusion

Since sleep parameters were hardly apt to predict overnight pain changes, this leaves the association of both systems mainly unproven when using between-subject variance for verification.

The change of pain classes over time: a latent transition analysis

BACKGROUND

Pain is common in older adults, and associated with increased morbidity and reduced quality of life. Recent research has highlighted different classes of older adults with pain, each with differing impacts on their life. It has not yet been investigated if, and how, such classes change over time and what influences individuals to prospectively transition to a profile of either improved or worsened pain impact.

METHODS

Latent transition analysis (LTA) is a longitudinal model-based approach to identifying underlying subgroups in a population. LTA was used to model the change in pain of people aged 50 and above, from The Irish Longitudinal Study on Ageing, across three waves (n = 5,925). The LTA model was extended to include biopsychosocial covariates to predict transition probabilities between classes over time.

RESULTS

Three latent classes were identified based on three pain indicators (pain presence; pain affects daily life; pain requires medication) and were characterized as "No Pain", "Low-Moderate Impact Pain" and "High Impact Pain". Results indicate that the pain class of many changes over time. However, poor physical or mental health increased the risk of transitioning to a more severe pain class, from Wave 1 to Wave 2 and Wave 2 to Wave 3.

CONCLUSIONS

These findings show the change in pain of older adults over time, with both marked improvement and deterioration being observed. Critically, the predictors of individuals transitioning between classes reflect the breadth of biopsychosocial factors involved in pain.

SIGNIFICANT STATEMENT

This article identified differing classes of pain in older adults, using latent transition analysis. The analysis demonstrated how the pain classes of older adults are broadly consistent over time, however both improvement and deterioration in pain impact were observed. Transitions between classes were associated with several biopsychosocial factors. These results have important implications for the health and quality of life of older adults. Consideration of health, lifestyle and socio-demographic factors may enhance assessment and management of pain in older adults.

The psychological and physiological health effects of fatigue

Background

The issue of employee fatigue is becoming increasingly prominent, particularly in safety-critical industries.

Aims

To produce an in-depth review collating the known psychological and physiological health and work effects of fatigue to guide mitigation strategies in safety-critical industries.

Methods

Literature searches were conducted via scientific databases using appropriate filters and keywords. The available results were collated into a review and commentary.

Results

Decreased sleep duration and chronodisruption have been shown to cause both significant morbidity and mortality. There is a large body of evidence showing strong associations between fatigue, reduced cognition and occupational accidents, as well as increased metabolic and reproductive health sequelae, some forms of cancer and mortality. Additional evidence links fatigue with mental, gastrointestinal, neurological and chronic pain sequelae.

Conclusions

Fatigue risk mitigation strategies should be implemented, not only to reduce these short- and long-term health risks in employees of safety-critical industries, but also to create more efficient, productive and effective workplace personnel with longer and more fulfilling careers. This requires improved acute fatigue mitigation, as well as the prevention of cumulative fatigue build-up and the formation of acute-on-chronic fatigue. The health recommendations for fatigue mitigation outlined in this paper are pertinent to all professions where employees have high rates of both acute and chronic fatigue.

Insomnia Increases Symptom Severity and Health Care Utilization in Patients With Fibromyalgia: A Population-based Study

Supplemental Digital Content is available in the text.

Objective:

This study aimed to determine whether comorbid insomnia is associated with increased use of fibromyalgia-related medications and health resources in fibromyalgia (FM) patients.

Materials and Methods:

We analyzed data retrieved from the Longitudinal Health Insurance Database 2010, which contains claims data of 1 million beneficiaries randomly selected from Taiwan’s National Health Insurance program. Patients treated for FM (n=17,920) on 2 separate visits between 2000 and 2001 were selected and subsequently divided into 2 groups: patients with and without comorbid insomnia (n=5466 and 12,454, respectively). Insomnia was identified through diagnosis on 2 separate visits after the index FM date. FM-related pharmacotherapies and ambulatory care visits were tracked from the index date to the end of 2013.

Results:

Insomnia was associated with increased likelihood of future use of antidepressants (adjusted odds ratio [OR]=3.84, P<0.001), gabapentin (adjusted OR=1.67, P<0.001), pregabalin (adjusted OR=1.79, P=0.046), muscle relaxants (adjusted OR=3.05, P<0.001), and opioids and tramadol (adjusted OR=1.59, P<0.001) among FM patients compared with FM patients without insomnia. In addition, a diagnosis of insomnia was associated with an increased frequency of visits to ambulatory care services for both FM (β=1.79; 95% confidence interval, 1.57-2.02; P<0.001) and other conditions (β=108.51; 95% confidence interval, 103.14-113.89; P<0.001).

Discussion:

This study demonstrates the substantial burden of comorbid insomnia in patients with FM.

Risk factors for development and persistence of chronic widespread pain in spondyloarthritis: a population-based two-year follow-up study

Objective: To study chronic widespread pain (CWP) over time in patients with spondyloarthritis (SpA), and to identify risk factors for development and persistence of CWP.Methods: In this cohort study with baseline and 2.5 year follow-up postal surveys, patients with ankylosing spondylitis (AS) and undifferentiated spondyloarthritis (USpA) (47% women) answered questions regarding pain, and were categorized as no chronic pain (NCP), chronic regional pain (CRP), or CWP. For each risk factor candidate (disease duration, body mass index, smoking, and patient-reported outcome measures), logistic regression analyses with CWP as the main outcome were performed separately, together with a basic model including age, gender, and SpA subgroup.Results: Altogether, 644 patients could be categorized at both time-points, yielding similar prevalence estimates at baseline and follow-up, although 38% transitioned between pain groups. Risk factors (odds ratio; 95% confidence interval) for development of CWP included more pain regions (1.36; 1.20‒1.53), higher pain intensity (1.35; 1.20‒1.52), worse fatigue (1.25; 1.13‒1.38), and worse global health (1.35; 1.19‒1.54). Persistent CWP was reported by 72%. In addition to factors predicting development of CWP, higher age (1.02; 1.00‒1.04), female gender (1.82; 1.06‒3.10), and anxiety (1.07; 1.00-1.14) also predicted persistence.Conclusion: The prevalence of CWP remained high over time, but with individual transitions between the pain groups. The development and persistence of CWP were predicted by more pain and worse health, with the addition of female gender and higher age for persistent CWP. Special attention and treatment alternatives for patients with SpA and concomitant CWP are essential in the clinic.

Development of pain in older adults: a latent class analysis of biopsychosocial risk factors

Pain significantly restricts the quality of life and well-being of older adults. With our increasingly ageing population, it is important to examine whether differing classes of biopsychosocial risk factors can predict the development of pain in older adults. Latent class analysis provides a model-based approach to identifying underlying subgroups in a population, based on some measured characteristics. In this study, latent class analysis was used to identify biopsychosocial risk classes in people aged 50 years and older, from The Irish Longitudinal Study on Ageing, who reported not often being troubled by pain at wave 1 and completed the 2-year follow-up at wave 2 (n = 4458). Four classes were identified based on 11 potential risk factors at wave 1. These classes were characterised as "Low Risk," "Physical Health Risk," "Mental Health Risk," and "High Risk." The Low-Risk class accounted for over half the sample (51.2%), whereas the High-Risk class represented 7.8% of the sample. At follow-up (wave 2), 797 (17.9%) participants reported being troubled by pain. Associations between the biopsychosocial risk classes and developing pain were examined using logistic regression, adjusting for sociodemographic variables. The High-Risk class was more likely to develop pain compared with the Low-Risk class (adjusted OR = 3.16, 95% CI = 2.40-4.16). These results add to existing data in other populations supporting the role of a range of biopsychosocial risk factors that increase the risk of developing pain. These findings have important implications for the identification, and potential moderation, of these risk factors.

Effectiveness of an innovative mattress overlay for improving rehabilitation in low back pain: A pilot randomized controlled study

BACKGROUND AND OBJECTIVE

Sleep disorders should be routinely evaluated and treated in low back pain (LBP) patients because they represent an important contributor to pain. However, no study thus far has investigated the potential benefit to LBP management of a device improving the sleep quality. Therefore, aim of this study was to assess the effectiveness of an innovative mattress overlay as add-on treatment to LBP rehabilitation.

METHODS

Thirty eight LBP patients were randomized to standard rehabilitation plus mattress overlay use (cases) or standard rehabilitation only (controls). The intervention duration was 2 months and the following assessments were performed before and after: pain intensity; level of perceived back disability and sleep health; spine mobility; thickness and echo intensity of the lumbar multifidus.

RESULTS

Significant pre-post-intervention improvements were observed in cases for resting and movement pain, perceived back disability, sleep, fingertip-to-floor distance, multifidus thickness (∼ 6% increase) and echo intensity (∼ 13% decrease). On the contrary, all these variables remained constant between the two experimental phases in controls.

CONCLUSIONS

A combination of rehabilitation and mattress overlay use seems an effective approach for improvement of pain, perceived back disability, sleep, spine mobility, and lumbar multifidus size and structure of LBP patients.

Prediction of therapeutic response to pregabalin in subjects with neuropathic pain

OBJECTIVE

To evaluate four models based on potential predictors for achieving a response to pregabalin treatment for neuropathic pain (NeP).

METHODS

In total, 46 pain studies were screened, of which 27 NeP studies met the criteria for inclusion in this analysis. Data were pooled from these 27 placebo-controlled randomized trials to assess if baseline characteristics (including mean pain and pain-related sleep interference [PRSI] scores), early clinical response during weeks 1-3 of treatment (change from baseline in pain and PRSI scores), and presence of treatment-emergent adverse events (AEs) were predictive of therapeutic response. Therapeutic response was defined as a ≥30% reduction from baseline in either pain and/or PRSI scores at week 5 with supplemental analyses to predict pain outcomes at weeks 8 and 12. Predictors of Patient Global Impression of Change (PGIC) were also evaluated. Four models were assessed: Random Forest, Logistic Regression, Naïve Bayes, and Partial Least Squares.

RESULTS

The number of pregabalin-treated subjects in the training/test datasets, respectively, were 2818/1407 (30% pain analysis), 2812/1405 (30% sleep analysis), and 2693/1345 (PGIC analysis). All four models demonstrated consistent results, and the most important predictors of treatment outcomes at week 5 and pain outcomes at weeks 8 and 12 were the reduction in pain score and sleep score in the first 1-3 weeks. The presence or absence of the most common AEs in the first 1-3 weeks was not correlated with any treatment outcome.

CONCLUSIONS

Subjects with an early response to pregabalin are more likely to experience an end-of-treatment response.

Sleep problems and fatigue as predictors for the onset of chronic widespread pain over a 5- and 18-year perspective

BACKGROUND

Previous research suggests that sleep problems may be an important predictor for chronic widespread pain (CWP). With this study we investigated both sleep problems and fatigue as predictors for the onset of CWP over a 5-year and an 18-year perspective in a population free from CWP at baseline.

METHODS

To get a more stable classification of CWP, we used a wash-out period, including only individuals who had not reported CWP at baseline (1998) and three years prior baseline (1995). In all, data from 1249 individuals entered the analyses for the 5-year follow-up and 791 entered for the 18-year follow-up. Difficulties initiating sleep, maintaining sleep, early morning awakening, non-restorative sleep and fatigue were investigated as predictors separately and simultaneously in binary logistic regression analyses.

RESULTS

The results showed that problems with initiating sleep, maintaining sleep, early awakening and non-restorative sleep predicted the onset of CWP over a 5-year (OR 1.85 to OR 2.27) and 18-year (OR 1.54 to OR 2.25) perspective irrespective of mental health (assessed by SF-36) at baseline. Also fatigue predicted the onset of CWP over the two-time perspectives (OR 3.70 and OR 2.36 respectively) when adjusting for mental health. Overall the effect of the sleep problems and fatigue on new onset CWP (over a 5-year perspective) was somewhat attenuated when adjusting for pain at baseline but remained significant for problems with early awakening, non-restorative sleep and fatigue. Problems with maintaining sleep predicted CWP 18 years later irrespective of mental health and number of pain regions (OR 1.72). Reporting simultaneous problems with all four aspects of sleep was associated with the onset of CWP over a five-year and 18-yearperspective, irrespective of age, gender, socio economy, mental health and pain at baseline. Sleep problems and fatigue predicted the onset of CWP five years later irrespective of each other.

CONCLUSION

Sleep problems and fatigue were both important predictors for the onset of CWP over a five-year perspective. Sleep problems was a stronger predictor in a longer time-perspective. The results highlight the importance of the assessment of sleep quality and fatigue in the clinic.

Pain and sleep : A bidirectional relationship

Disturbed sleep and persistent pain are common in old people. Persistent pain has a well proven impact on sleep but the relationship between both phenomena is bidirectional since disturbed sleep affects pain perception by lowering the pain threshold. An optimal disease management takes both phenomena into account.

Sleep, Sleep Disorders, and Circadian Health following Mild Traumatic Brain Injury in Adults: Review and Research Agenda

A rapidly expanding scientific literature supports the frequent co-occurrence of sleep and circadian disturbances following mild traumatic brain injury (mTBI). Although many questions remain unanswered, the preponderance of evidence suggests that sleep and circadian disorders can result from mTBI. Among those with mTBI, sleep disturbances and clinical sleep and circadian disorders contribute to the morbidity and long-term sequelae across domains of functional outcomes and quality of life. Specifically, along with deterioration of neurocognitive performance, insufficient and disturbed sleep can precede, exacerbate, or perpetuate many of the other common sequelae of mTBI, including depression, post-traumatic stress disorder, and chronic pain. Further, sleep and mTBI share neurophysiologic and neuroanatomic mechanisms that likely bear directly on success of rehabilitation following mTBI. For these reasons, focus on disturbed sleep as a modifiable treatment target has high likelihood of improving outcomes in mTBI. Here, we review relevant literature and present a research agenda to 1) advance understanding of the reciprocal relationships between sleep and circadian factors and mTBI sequelae and 2) advance rapidly the development of sleep-related treatments in this population.

Efficacy of Mirogabalin (DS-5565) on Patient-Reported Pain and Sleep Interference in Patients with Diabetic Neuropathic Pain: Secondary Outcomes of a Phase II Proof-of-Concept Study

Objective

To evaluate the effects of mirogabalin on patient-reported pain and sleep interference in diabetic peripheral neuropathic pain (DPNP).

Subjects

Adults (≥18 years) with type 1 or 2 diabetes, glycosylated hemoglobin of 10% or less at screening, and DPNP for six months or more were eligible for participation.

Methods

Subjects (N = 452) were randomly assigned (2:1:1:1:1:1:1) to receive placebo, dose-ranging mirogabalin (5, 10, 15, 20, 30 mg/day), or pregabalin (300 mg/day) for five weeks. Secondary efficacy end points studied here included patient global impression of change (PGIC), modified brief pain inventory (BPI), and average daily sleep interference score (ADSIS). Correlation plots were generated to examine the relationship between ADSIS and average daily pain score (ADPS).

Results

At week 5, significant reductions in ADSIS were observed in the mirogabalin 15, 20, and 30 mg/day groups, compared with placebo (P < 0.05). Baseline ADSIS and ADPS were strongly correlated (R2 = 0.4407), as were mean changes from baseline in ADSIS and ADPS at week 5 (R2 = 0.6694). The mirogabalin 30 mg/day group showed significant improvement compared with placebo in four of six BPI subscales at end point; the mirogabalin 15 mg/day group showed significant improvement in three of six BPI subscales (P < 0.05). At end of treatment, the percentage of subject with PGIC status of "much improved or better" was greater in all mirogabalin dose groups than in the placebo group (P < 0.05). A low incidence of treatment-related adverse events was reported for mirogabalin.

Conclusions

Results support the effectiveness of mirogabalin in improving patient-reported pain and sleep interference in DPNP.

Effects of sleep changes on pain-related health outcomes in the general population: A systematic review of longitudinal studies with exploratory meta-analysis

Emerging longitudinal research has highlighted poor sleep as a risk factor of a range of adverse health outcomes, including disabling pain conditions. In establishing the causal role of sleep in pain, it remains to be clarified whether sleep deterioration over time is a driver of pain and whether sleep improvement can mitigate pain-related outcomes. A systematic literature search was performed using PubMed MEDLINE, Ovid EMBASE, and Proquest PsycINFO, to identify 16 longitudinal studies involving 61,000 participants. The studies evaluated the effect of sleep changes (simulating sleep deterioration, sleep stability, and sleep improvement) on subsequent pain-related outcomes in the general population. A decline in sleep quality and sleep quantity was associated with a two- to three-fold increase in risk of developing a pain condition, small elevations in levels of inflammatory markers, and a decline in self-reported physical health status. An exploratory meta-analysis further revealed that deterioration in sleep was associated with worse self-reported physical functioning (medium effect size), whilst improvement in sleep was associated with better physical functioning (small effect size). The review consolidates evidence that changes in sleep are prospectively associated with pain-related outcomes and highlights the need for further longitudinal investigations on the long-term impact of sleep improvements.

Impaired sleep predicts onset of low back pain and burnout symptoms: evidence from a three-wave study

In a three-wave questionnaire study of 405 working participants, who were initially free of low back pain (LBP) and emotional exhaustion, sleep problems were evaluated as a potential risk factor for the development of LBP and burnout up to three years later. Prospective risk paths were compared between the sexes and between two age-groups (18 to 45 years and older than 45 years). A longitudinal structural equation model showed a good fit with empirical data (RMSEA = .04, SRMR = .06, CFI = .97). Prospective risk paths between the latent constructs showed sleep problems to significantly predict self-reported LBP (β = .15, p = .011) and burnout (β = .24, p < .001) two years later. Sleep problems also predicted the occurrence of burnout three years later (β = .18, p = .002). Sleep-related risk of burnout after two years was greater in older than younger participants (β_older = .42 vs. β_younger = .13, p < .001). Sleep problems seem to precede LBP and burnout in working individuals. Health promotion initiatives should use sleep quality as an important early risk indicator, and interventions should focus on promoting better quality sleep, in an attempt to reduce the incidence of LBP and burnout.

Insomnia with Musculoskeletal Pain in Postmenopause: Associations with Symptoms, Mood, and Quality of Life

Objectives

To investigate the relationship between insomnia (INS) combined with chronic musculoskeletal pain (MSP) in postmenopausal women and its characteristics regarding MSP, menopausal and mood symptoms, sleep and quality of life (QOL).

Methods

A cross-sectional control study in 4 groups of postmenopausal women: control (n = 15), MSP (n = 15), INS (n =15) and INS + MSP (n = 17). Sixty-two participants completed questionnaires and had blood collected, and 43 underwent polysomnography.

Results

INS was associated with increased anxiety (P = 0.04) and sleep fragmentation (P = 0.02); worse MSP severity (P = 0.00), MSP interference with daily function (P = 0.00), higher pain intensity at midday (P = 0.02) and menopausal symptoms (P = 0.00); and reduced QOL (P = 0.00). MSP was associated with increased anxiety (P = 0.02) and menopausal symptoms (P = 0.00), and reduced QOL (P = 0.05). In the whole sample, depression symptoms were higher but no statistical differences were found between groups (P = 0.47). Worse QOL was associated with both higher depressive symptoms (P = 0.01) and worse pain interference (P = 0.02)

Conclusions

INS + MSP was related to higher menopausal and anxiety symptoms, more sleep fragmentation and complaints of MSP severity and interference, more pain sites and worse QOL. The presence of INS was associated to more MSP. Sleep management is essential in women who have developed chronic MSP.

Insomnia Really Hurts: Effect of a Bad Night's Sleep on Pain Increases With Insomnia Severity

Insomnia and chronic pain are highly prevalent conditions and are often comorbid. Somatic complaints other than pain are also often observed in insomnia. Poor sleep and pain are known to mutually reinforce each other. However, it is unknown whether the habitual severity of insomnia modulates the acute effect of a particularly bad night's sleep on the next day's pain severity, and whether it modulates the acute effect of pain on the following night's sleep quality. Using data from 3,508 volunteers (2,684 female, mean age 50.09 y), we addressed these questions in addition to the associations between the habitual severity of insomnia, somatic complaints, and pain. Results indicated that people suffering from more severe habitual insomnia showed stronger mutual acute within-day reactivity of pain and poor sleep quality. The same increased reactivity was found in people with more severe habitual pain. Interestingly, the acute within-day mutual reactivity of pain and sleep quality showed consistent asymmetry. Pain worsened more after a particularly bad night's sleep than it improved after a particularly good night's sleep. Likewise, sleep worsened more after a day with more-than-usual pain than it improved after a day with less-than-usual pain. Future interventions may profit from addressing this asymmetric mutual reactivity especially in people with severe comorbid insomnia and chronic pain.

Perceived sleep deficit is a strong predictor of RLS in multisite pain - A population based study in middle aged females

BACKGROUND

Chronic pain conditions as well as Restless Legs Syndrome (RLS) are known to be associated with subjectively and objectively disturbed sleep. RLS has been recently described as highly prevalent in multisite pain and the role of sleep as a modifying factor in this RLS phenotype is unknown. This study aimed to investigate if perceived sleep deficit and other sleep related parameters predict RLS in subjects with multisite pain.

CURRENT KNOWLEDGE/STUDY RATIONALE

We have recently demonstrated a strong association between Restless Legs Syndrome (RLS) and number of pain locations. In the current analysis we hypothesized that impaired sleep predicts RLS in subjects with multisite pain.

METHOD

Questionnaire-based data from 2727 randomly selected women aged 18-64 years were used to analyze RLS symptoms, self-reported sleep quality, and the degree of daytime sleepiness (Epworth Sleepiness Scale (ESS)) in relation to type, degree and localization of body pain. Potential confounders including anthropometrics, pain localization, co-morbidities, and medication were adjusted for in the Generalized Linear Models (GLM).

RESULTS

Perceived sleep deficit ≥90min (OR 2.4 (1.5-3.8), p<0.001) and frequent nocturnal awakenings (OR 2.3 (1.4-3.6), p<0.001) were the strongest sleep related predictors for RLS in subjects with multisite pain. Additional factors include prolonged sleep latency (≥30min, OR 1.8 (1.1-2.8), p=0.01) and daytime symptoms like elevated daytime sleepiness (ESS score ≥9, OR 1.8 (1.2-2.7), p=0.005). Accordingly, RLS diagnosis was associated with impaired sleep quality (TST (Total Sleep Time) -8.2min, sleep latency +8.0min, and number of awakenings from sleep +0.4, p<0.01). ESS score increased with RLS diagnosis (+0.74, p<0.01) and number of pain locations (0.5, 1.7, and 1.8 for 1, 3, and 5 pain areas, p<0.001). In addition, confounders like pain severity, the history of psychiatric disease, and current smoking were associated with impaired sleep quality in this group of females.

CONCLUSIONS

Perceived sleep deficit and sleep fragmentation are the strongest sleep related predictors of RLS in multisite pain. Potential implication of our results are that clinical management programmes of RLS in subjects with multisite pain need to consider both sleep quality and sleep quantity for individually tailored treatment regimes.

STUDY IMPACT

RLS, pain, and sleep disorders are highly interrelated. Our study strongly suggests that clinical management of RLS in patients with multisite pain needs to consider sleep quality as an independent risk factor.