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

Deciphering the temporal link between pain and sleep in a heterogeneous chronic pain patient sample: a multilevel daily process study

OBJECTIVES

Because insomnia is a common comorbidity of chronic pain, scientific and clinical interest in the relationship of pain and sleep has surged in recent years. Although experimental studies suggest a sleep-interfering property of pain and a pain-enhancing effect of sleep deprivation/fragmentation, the temporal association between pain and sleep as experienced by patients is less understood. The current study was conducted to examine the influence of presleep pain on subsequent sleep and sleep on pain reports the next day, taking into consideration other related psychophysiologic variables such as mood and arousal.

DESIGN

A daily process study, involving participants to monitor their pain, sleep, mood, and presleep arousal for 1 wk. Multilevel modeling was used to analyze the data.

SETTING

In the patients' natural living and sleeping environment.

PATIENTS

One hundred nineteen patients (73.9% female, mean age = 46 years) with chronic pain and concomitant insomnia.

MEASUREMENT

An electronic diary was used to record patients' self-reported sleep quality/efficiency and ratings of pain, mood, and arousal at different times of the day; actigraphy was also used to provide estimates of sleep efficiency.

RESULTS

Results indicated that presleep pain was not a reliable predictor of subsequent sleep. Instead, sleep was better predicted by presleep cognitive arousal. Although sleep quality was a consistent predictor of pain the next day, the pain-relieving effect of sleep was only evident during the first half of the day.

CONCLUSIONS

These findings challenge the often-assumed reciprocal relationship between pain and sleep and call for a diversification in thinking of the daily interaction of these 2 processes.

Sodium oxybate therapy provides multidimensional improvement in fibromyalgia: results of an international phase 3 trial

BACKGROUND

Fibromyalgia is characterised by chronic musculoskeletal pain and multiple symptoms including fatigue, multidimensional function impairment, sleep disturbance and tenderness. Along with pain and fatigue, non-restorative sleep is a core symptom of fibromyalgia. Sodium oxybate (SXB) is thought to reduce non-restorative sleep abnormalities. This study evaluated effects of SXB on fibromyalgia-related pain and other symptoms.

METHODS

573 patients with fibromyalgia according to 1990 American College of Rheumatology criteria were enrolled at 108 centres in eight countries. Subjects were randomly assigned to placebo, SXB 4.5 g/night or SXB 6 g/night. The primary efficacy endpoint was the proportion of subjects with ≥30% reduction in pain visual analogue scale from baseline to treatment end. Other efficacy assessments included function, sleep quality, effect of sleep on function, fatigue, tenderness, health-related quality of life and subject's impression of change in overall wellbeing.

RESULTS

Significant improvements in pain, sleep and other symptoms associated with fibromyalgia were seen in SXB treated subjects compared with placebo. The proportion of subjects with ≥30% pain reduction was 42.0% for SXB4.5 g/night (p=0.002) and 51.4% for SXB6 g/night (p<0.001) versus 26.8% for placebo. Quality of sleep (Jenkins sleep scale) improved by 20% for SXB4.5 g/night (p≤0.001) and 25% for SXB6 g/night (p≤0.001) versus 0.5% for placebo. Adverse events with an incidence ≥5% and twice placebo were nausea, dizziness, vomiting, insomnia, anxiety, somnolence, fatigue, muscle spasms and peripheral oedema.

CONCLUSION

These results, combined with findings from previous phase 2 and 3 studies, provide supportive evidence that SXB therapy affords important benefits across multiple symptoms in subjects with fibromyalgia.

The role of the work context in multiple wellness outcomes for hospital patient care workers

OBJECTIVE

To examine the relationships among low back pain (LBP), inadequate physical activity, and sleep deficiency among patient care workers, and of these outcomes to work context.

METHODS

A cross-sectional survey of patient care workers (N = 1572, response rate = 79%).

RESULTS

A total of 53% reported LBP, 46%, inadequate physical activity, and 59%, sleep deficiency. Inadequate physical activity and sleep deficiency were associated (P = 0.02), but LBP was not significantly related to either. Increased risk of LBP was significantly related to job demands, harassment at work, decreased supervisor support, and job title. Inadequate physical activity was significantly associated with low decision latitude. Sleep deficiency was significantly related to low supervisor support, harassment at work, low ergonomic practices, people-oriented culture, and job title.

CONCLUSIONS

These findings point to shared pathways in the work environment that jointly influence multiple health and well-being outcomes.

Sleep and fatigue and the relationship to pain, disease activity and quality of life in juvenile idiopathic arthritis and juvenile dermatomyositis

OBJECTIVES

To determine and compare the prevalence of disturbed sleep in JIA and JDM and the relationship of sleep disturbance to pain, function, disease activity and medications.

METHODS

One hundred fifty-five patients (115 JIA, 40 JDM) were randomly sampled and were mailed questionnaires. Sleep disturbance was assessed by the sleep self-report (SSR) and the children's sleep habits questionnaire (CSHQ). Fatigue, pain and function were assessed by the paediatric quality of life inventory (PedsQL) and disease activity by visual analogue scales (VASs). Joint counts were self-reported.

RESULTS

Eighty-one per cent responded, of whom 44% reported disturbed sleep (CSHQ > 41); there were no differences between disease groups. Poor reported sleep (SSR) was highly correlated with PedsQL fatigue (r = 0.56, P < 0.0001). Fatigue was highly negatively correlated with quality of life (r = -0.77, P < 0.0001). The worst pain intensity in the last week was correlated to sleep disturbance (r = 0.32, P = 0.0005). Fatigue was associated with prednisone and DMARD use.

CONCLUSIONS

Sleep disturbance and fatigue are prevalent among children with different rheumatic diseases. Sleep disturbance and fatigue are strongly associated with increased pain and decreased quality of life. Strategies aimed at improving sleep and reducing fatigue should be studied as possible ways of improving quality of life for children with rheumatic illness.

Sleep disturbances in adults with arthritis: prevalence, mediators, and subgroups at greatest risk. Data from the 2007 National Health Interview Survey

OBJECTIVE

To examine the prevalence of sleep disturbances in adults with arthritis in a nationally representative sample, mediators of sleep difficulties, and subgroups of individuals with arthritis at greatest risk.

METHODS

Using data on US adults ages≥18 years participating in the 2007 National Health Interview Survey, we computed the prevalence of 3 measures of sleep disturbance (insomnia, excessive daytime sleepiness, and sleep duration<6 hours) among persons with arthritis. We used logistic regression analysis to examine if the association of arthritis and sleep disturbances was independent of sociodemographic characteristics and comorbidities, and to identify potential mediators. We used classification trees to identify subgroups at higher risk.

RESULTS

The adjusted prevalence of insomnia was higher among adults with arthritis than those without arthritis (23.1% versus 16.4%; P<0.0001), but was similar to those with other chronic diseases. Adults with arthritis were more likely than those without arthritis to report insomnia (unadjusted odds ratio 2.92, 95% confidence interval 2.68-3.17), but adjustment for sociodemographic characteristics and comorbidities attenuated this association. Joint pain and limitation due to pain mediated the association between arthritis and insomnia. Among adults with arthritis, those with depression and anxiety were at highest risk for sleep disturbance. Results for excessive daytime sleepiness and sleep duration<6 hours were similar.

CONCLUSION

Sleep disturbance affects up to 10.2 million US adults with arthritis, and is mediated by joint pain and limitation due to pain. Among individuals with arthritis, those with depression and anxiety are at greatest risk.

Sleep disturbances as a predictor of cause-specific work disability and delayed return to work

STUDY OBJECTIVE

To examine sleep disturbances as a predictor of cause-specific work disability and delayed return to work.

DESIGN

Prospective observational cohort study linking survey data on sleep disturbances with records of work disability (> or = 90 days sickness absence, disability pension, or death) obtained from national registers.

SETTING

Public sector employees in finland.

PARTICIPANTS

56,732 participants (mean age 44.4 years, 80% female), who were at work and free of work disability at the study inception.

MEASUREMENTS AND RESULTS

During a mean follow-up of 3.3 years, incident diagnosis-specific work disability was observed in 4,028 (7%) employees. Of those, 2,347 (60%) returned to work. Sleep disturbances 5-7 nights per week predicted work disability due to mental disorders (hazard ratio [HR] 1.6, 95% confidence interval [CI] 1.3-1.9) and diseases of the circulatory system (HR = 1.6, 95% CI 1.2-2.1), musculoskeletal system (HR = 1.6, 95% CI 1.4-1.8) and nervous system (HR = 1.5, 95% CI 1.0-2.2), and injuries and poisonings (HR = 1.6, 95% CI 1.2-2.1) after controlling for baseline age, sex, socioeconomic status, night/shift work, health behaviors (e.g., smoking, exercise), diagnosed somatic diseases, use of pain killers, depression, and anxiety. In addition, sleep disturbances prior to disability were associated with higher likelihood of not returning to work after work disability from musculoskeletal diseases (HR = 1.2, 95% CI 1.1-1.7) and, in men, after work disability due to mental disorders (HR = 4.4, 95% CI 1.7-11.1).

CONCLUSIONS

Sleep disturbances are associated with increased risk for subsequent disabling mental disorders and various physical illnesses. They also predict the outcome of work disability due to musculoskeletal disorders.

Naturalistic changes in insomnia symptoms and pain in temporomandibular joint disorder: a cross-lagged panel analysis

An increasing number of prospective studies suggest a bi-directional association between the pain and sleep quality. Few of these investigations have controlled for synchronous correlations, an important source of extraneous variance in lagged associations, which may have confounded conclusions of prior investigations. Despite high rates of insomnia in temporomandibular joint disorders (TMD), no studies have examined temporal associations between naturalistic fluctuations in insomnia and pain in TMD. We conducted cross-lagged panel analysis to examine reciprocal temporal associations between 1-month changes in insomnia symptom severity and self-reported pain over 3 months among 53 TMD patients. This rigorous analytic strategy represents a comprehensive method to explore possible reciprocal temporal associations between insomnia and pain that controls for both auto- and synchronous correlations. Analyses revealed that initial-month increases in insomnia were associated with next-month increases in average daily pain, but not vice versa. The direction of the effect was such that initial-month increases in insomnia symptom severity were associated with next-month increases in average daily pain. These data suggest that naturally occurring fluctuations in insomnia symptom severity are prospectively associated with fluctuations in daily pain experience for persons with TMD. Potential mechanisms by which insomnia might influence pain in TMD and therapeutic implications of these findings are discussed.

Pathophysiology of fibromyalgia

This article reviews the biologic, genetic, and environmental factors that may contribute to the pathophysiology of fibromyalgia. As an affective spectrum disorder, fibromyalgia may share these causal factors with a number of related and co-occurring pain conditions, such as irritable bowel syndrome or temporomandibular disorder. There is strong evidence that cardinal pain symptoms of fibromyalgia may be due to alterations in central processing of sensory input, along with aberrations in the endogenous inhibition of pain. Genetic research has shown familial aggregation of fibromyalgia and other related disorders such as major depressive disorder. Exposure to physical or psychosocial stressors, as well as abnormal biologic responses in the autonomic nervous system and neuroendocrine responses, may also contribute to dysfunctional pain processing. As fibromyalgia research continues to progress, it is expected that the pathophysiology of this disorder will be further elucidated, leading to more rational and targeted strategies for the treatment of patients with this condition.