Pain-related Sleep Disturbance Research Articles

Sleep disturbances are associated with pain intensity and pain-related functional interference in patients experiencing orofacial pain.

Sleep and pain have a reciprocal relationship, interacting with psychosocial aspects including depression, anxiety, somatization and significant stressful events. The aim of this study was to assess patients with oro-facial pain (OFP) and related sleep disturbances and determine the strongest psychosocial correlates. A cross-sectional study of anonymized data of consecutive patients with OFP {January 2019 and February 2020} were analysed. Diagnostic and Axis-II data were integrated to assess the relationship between sleep disturbances, measured using Chronic Pain Sleep Inventory, and demographic factors, clinical comorbidities, recent stressful events, pain severity and pain- and psychological-related function. Five out of six patients with OFP were presented with pain-related sleep disturbances. Sleep problems were enhanced in patients with primary oro-facial headache compared with other OFP conditions. However, once the level of pain intensity and interference was accounted for, primary headache, was not a significant correlate of pain-related sleep disturbances. Multivariate analysis revealed (average) pain severity and pain interference were both significantly associated with sleep problems. There were also significant independent associations of sleep problems with somatization levels and reported experience of recent stressful events. Identifying sleep problems as a part of OFP management may be beneficial and could result in better management outcomes.

Three-Month Follow-Up Results of a Double-Blind, Randomized Placebo-Controlled Trial of 8-Week Self-Administered At-Home Behavioral Skills-Based Virtual Reality (VR) for Chronic Low Back Pain

Prior work established post-treatment efficacy for an 8-week home-based therapeutic virtual reality (VR) program in a double-blind, parallel arm, randomized placebo-controlled study. Participants were randomized 1:1 to 1 of 2 56-day VR programs: 1) a therapeutic immersive pain relief skills VR program; or 2) a Sham VR program within an identical commercial VR headset. Immediate post-treatment results demonstrated clinically meaningful and superior reduction for therapeutic VR compared to Sham VR for average pain intensity, indices of pain-related interference (activity, mood, stress but not sleep), physical function, and sleep disturbance. The objective of the current report was to quantify treatment effects to post-treatment month 3 and describe durability of effects. Intention-to-treat analyses revealed sustained benefits for both groups and superiority for therapeutic VR for pain intensity and multiple indices of pain-related interference (activity, stress, and newly for sleep; effect sizes ranged from drm = .56–.88) and physical function from pre-treatment to post-treatment month 3. The between-group difference for sleep disturbance was non-significant and pain-interference with mood did not survive multiplicity correction at 3 months. For most primary and secondary outcomes, treatment effects for therapeutic VR showed durability, and maintained superiority to Sham VR in the 3-month post-treatment period. PerspectiveWe present 3-month follow-up results for 8-week self-administered therapeutic virtual reality (VR) compared to Sham VR in adults with chronic low back pain. Across multiple pain indices, therapeutic VR had clinically meaningful benefits, and superiority over Sham VR. Home-based, behavioral skills VR yielded enduring analgesic benefits; longer follow-up is needed.

Serum Levels of TNF-α Are Increased in Patients with Rotator Cuff Tear and Sleep Disturbance.

The purpose of this study was to determine serum levels of sleep-related cytokines in patients with rotator cuff tear (RCT) who were experiencing pain-related sleep disturbance. Peripheral blood samples before surgery were collected from 63 study participants and divided into three groups: RCT with sleep disturbance group; SD group (n = 21), RCT with normal sleep group; NS group (n = 21), and patients with chronic shoulder instability; control group (n = 21). Serum concentration levels of interleukin-1α (IL-1α), IL-1β, IL-2, IL-6, IL-8, IL-10, and tumor necrosis factor-α (TNF-α) were measured via ELISA. The associations between serum levels of sleep-related cytokines and clinical scores and the Pittsburgh Sleep Quality Index (PSQI) were analyzed. Serum concentration levels of TNF-α were significantly higher in the SD group compared with those of the NS and control groups (p = < 0.001 and 0.05). Serum levels of IL-8 and IL-10 were significantly higher in the SD group compared with those of control group (p = 0.01 and = 0.05), but did not differ significantly from that of the NS group. There were no associations between serum levels of sleep-related cytokines and all clinical scores. The current findings suggest that TNF-α may be associated with sleep disturbance in patients with RCT.

Effects of core stabilization exercise and cognitive behavioural therapy in the management of patients with non-specific chronic low back pain

Purpose: Non-specific chronic low back pain (NSCLBP) is a multifaceted type of low back pain affecting the biology, social and psychological aspect of an individual. Although it seems clear that core stabilization and cognitive behavioural therapy administered individually had been shown to be effective in patients with non-specific chronic low back pain, but the comparative efficacy of both interventions has not been satisfactorily studied. This study compared the effects of cognitive behavioural therapy and core stabilization exercise on pain-related disability, psychological status and sleep disturbance in patients with NSCLBP.

Effects of neck stabilization and isometric neck exercises on non-specific chronic neck pain: A pilot study

Purpose: This study evaluated and compared the efficacy of neck stabilization and isometric neck exercises on pain-related disability sleep disturbance, psychological status and cardiopulmonary parameters in patients with non-specific chronic neck pain.

‘Desire for more analgesic treatment’: pain and patient-reported outcome after paediatric tonsillectomy and appendectomy

BackgroundInsufficiently treated pain after paediatric appendectomy and tonsillectomy is frequent. We aimed to identify variables associated with poor patient-reported outcomes. MethodsThis analysis derives from the European PAIN OUT infant registry providing information on perioperative pharmacological data and patient-reported outcomes 24 h after surgery. Variables associated with the endpoint ‘desire for more pain treatment’ were evaluated by elastic net regularisation (odds ratio [95% confidence interval]). ResultsData from children undergoing appendectomy (n=472) and tonsillectomy (n=466) between 2015 and 2019 were analysed. Some 24.8% (appendectomy) and 20.2% (tonsillectomy) wished they had received more pain treatment in the 24 h after surgery. They reported higher composite pain scores (5.2 [4.8–5.5] vs 3.6 [3.5–3.8]), more pain-related interference, and more adverse events than children not desiring more pain treatment, and they received more opioids after surgery (morphine equivalents (81 [60–102] vs 50 [43–56] μg kg−1). Regression analysis revealed that pain-related sleep disturbance (appendectomy odds ratio: 2.8 [1.7–4.6], tonsillectomy 3.7 [2.1–6.5]; P<0.001) and higher pain intensities (1.5-fold increase) increased the probability of desiring more pain treatment. There was an inverse association between the number of different classes of non-opioids administered preventively, and the desire for more analgesics postoperatively. Children not receiving any non-opioid analgesics before the end of a tonsillectomy had a 3.5-fold (2.1–6.5-fold) increase in the probability of desiring more pain treatment, compared with children receiving at least two classes of different non-opioid analgesics. ConclusionsPreventive administration of at least two classes of non-opioid analgesics is a simple strategy and may improve patient-reported outcomes.

EFFECTS OF NECK STABILIZATION AND ISOMETRIC NECK EXERCISES ON NON-SPECIFIC CHRONIC NECK PAIN: A PILOT STUDY

Objectives: To evaluate the efficacy of neck stabilization and isometric neck exercises on pain-related disability, sleep disturbance, psychological status and cardiopulmonary parameters in patients with non-specific chronic neck pain (NSCNP). Methodology: This study was done within a period of May-October, 2019. 14 patients with NSCNP were involved in this research. The patients were enrolled into the research from two post secondary health facilities in Lagos state and distributed into groups A, B and C with the aid of random numbers generated by the computer: Group A received Neck stabilization exercises only, Group B received Neck stabilization and isometric neck exercises, Group C received Isometric neck exercises only. Subjects were evaluated for pain-related disability, sleep disturbance, psychological status (anxiety and depression), systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), rate pressure product (RPP), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR) and perceived exertion rate (RPE) before intervention and end of 4th week. Results: This research showed that neck stabilization combined with isometric exercise improved pain-related disability (p=0.04), anxiety (p=0.04) and depression (p=0.04) after 4 weeks intervention. Some pulmonary parameters, FVC (p=0.05, p=0.02), FEV1 (p=0.02, p=0.01) improved significantly post intervention in both neck stabilization exercise alone and neck stabilization combined with isometric neck exercise groups. While PEFR (p=0.02, p=0.01) improved significantly in both neck stabilization combined with isometric neck exercises and isometric neck exercise group alone post intervention. Conclusion: This study draws the conclusion that neck stabilization exercise only and neck stabilization combined with isometric exercise will better improve pain-related disability, anxiety, depression, sleep disturbance and some selected pulmonary parameters (FVC, FEV1, PEFR) in patients with NSCNP. Keywords: Exercise, chronic neck pain, pilot, study

Cognitive behavioural therapy and core stabilization exercise on pain-related disability and psychological status in patients with non-specific chronic low back pain

Introduction. Exercises have been shown to relieve symptoms in non-specific chronic low back pain (NSCLBP) patients. Aim. This study compared the effects of cognitive behavioural therapy (CBT) and core stabilization exercises (CSE) on pain-related disability, psychological status and sleep disturbance in patients with NSCLBP. Material and methods. This randomized controlled trial involved a total of thirty-seven (37) participants. They were randomly allotted into three groups [CBT (11), CSE (14) and control (12)]. The intervention was done once per week for duration of 60 minutes for the CBT group, 30 minutes for CSE group and 10 minutes for the control group twice per week for 8 consecutive weeks. Assessment of outcome was done at baseline, 4 weeks and 8 weeks. Data were analyzed using statistical package for social science version 25 at alpha level of less than 0.05. Results. The results of this study showed that there was significant improvement in the level of pain-related disability (p= 0.001), level of anxiety (p =0.001), depression (p = 0.01, p = 0.001, p =0.001) and sleep disturbance (p = 0.001) in all the groups (CBT, CSE, control) post treatment. Conclusion. CBT and CSE are both effective in the treatment of pain-related disability, sleep disturbance, and psychological status of NSCLBP patients.

Comorbid fibromyalgia in migraine patients: clinical significance and impact on daily life

ABSTRACTObjective: Herein, we aimed to investigate the impact of FM in migraine patients and the specific features and discriminations of this group of migraineurs with FM according to patients without FM.Methods: 102 consecutive migraine patients among 18–50 years old who accepted to involve in the study were included. All patients were asked to complete the following self-report questionnaires for the assessment of pain-related disability, migraine-related disability, anxiety, depression, sleep disturbance and quality of life. All statistical analyses were performed using the SPSS statistics 20 program.Results: 92% of the patients were diagnosed with episodic migraine, whereas 8% of them was diagnosed with chronic migraine (CM). Comorbid FM which was detected to present in 30.3% of the patients. FM was more frequent in CM patients and in migraine patients with aura. The analyses comparing FM (+) and FM (-) migraineurs revealed that headache frequency, migraine disease duration, headache impact test, MIDAS scores were significantly higher in FM (+) migraineurs. Furthermore, the vitality and role-emotional domains of the SF-36 resulted in worse scores in the group of FM (+) migraineurs.Conclusion: The results of our study may suggest the presence of FM as a clinical sign of a more severe migraine. However, the long-term prospective studies including these group of patients are needed to understand the prognostic impact and importance of the comorbid FM in migraine.Abbreviations: FM: Fibromyalgia; MIDAS: Migraine Disability Assessment

The effect of stabilization exercise on pain-related disability, sleep disturbance, and psychological status of patients with non-specific chronic low back pain.

BackgroundSleep disturbance and depression are becoming more recognized as important symptoms among individuals with chronic low back pain. This study evaluated the effect of stabilization exercise on pain-related disability, sleep disturbance and the psychological status of patients with non-specific chronic low back pain (NSCLBP).MethodsA total of 26 patients (M/F = 17/9) with NSCLBP with a mean age of 50.0 ± 15.5 took part in this study. Participants were recruited from selected hospitals in Lagos state. Ethical approval was sought and obtained from the health research and ethics committee of Lagos University Teaching Hospital Idi-araba, Lagos, Nigeria. Participants performed stabilization exercise for eight weeks consecutively and were assessed for pain-related disability, anxiety, depression, and sleep disturbance using the pain-disability index, hospital anxiety and depression scale, and the insomnia severity index at baseline, the 4th week, and the 8th week, post-intervention.ResultsThe participants studied recorded significant reduction in pain-related disability (P = 0.001). There was also improvement in the sleep quality (P = 0.001), depression level (P = 0.001), and anxiety level (P = 0.001), post intervention.ConclusionsThis study revealed that stabilization exercise is very useful in the management of sleep disturbance, pain-related disability, depression, and anxiety in NSCLBP patients.

Predictive Modeling of Response to Pregabalin for the Treatment of Neuropathic Pain Using 6-Week Observational Data: A Spectrum of Modern Analytics Applications

PurposeThis post hoc analysis used 11 predictive models of data from a large observational study in Germany to evaluate potential predictors of achieving at least 50% pain reduction by week 6 after treatment initiation (50% pain response) with pregabalin (150–600 mg/d) in patients with neuropathic pain (NeP). MethodsThe potential predictors evaluated included baseline demographic and clinical characteristics, such as patient-reported pain severity (0 [no pain] to 10 [worst possible pain]) and pain-related sleep disturbance scores (0 [sleep not impaired] to 10 [severely impaired sleep]) that were collected during clinic visits (baseline and weeks 1, 3, and 6). Baseline characteristics were also evaluated combined with pain change at week 1 or weeks 1 and 3 as potential predictors of end-of-treatment 50% pain response. The 11 predictive models were linear, nonlinear, and tree based, and all predictors in the training dataset were ranked according to their variable importance and normalized to 100%. FindingsThe training dataset comprised 9187 patients, and the testing dataset had 6114 patients. To adjust for the high imbalance in the responder distribution (75% of patients were 50% responders), which can skew the parameter tuning process, the training set was balanced into sets of 1000 responders and 1000 nonresponders. The predictive modeling approaches that were used produced consistent results. Baseline characteristics alone had fair predictive value (accuracy range, 0.61–0.72; κ range, 0.17–0.30). Baseline predictors combined with pain change at week 1 had moderate predictive value (accuracy, 0.73–0.81; κ range, 0.37–0.49). Baseline predictors with pain change at weeks 1 and 3 had substantial predictive value (accuracy, 0.83–0.89; κ range, 0.54–0.71). When variable importance across the models was estimated, the best predictor of 50% responder status was pain change at week 3 (average importance 100.0%), followed by pain change at week 1 (48.1%), baseline pain score (14.1%), baseline depression (13.9%), and using pregabalin as a monotherapy (11.7%). ImplicationsThe finding that pain changes by week 1 or weeks 1 and 3 are the best predictors of pregabalin response at 6 weeks suggests that adhering to a pregabalin medication regimen is important for an optimal end-of-treatment outcome. Regarding baseline predictors alone, considerable published evidence supports the importance of high baseline pain score and presence of depression as factors that can affect treatment response. Future research would be required to elucidate why using pregabalin as a monotherapy also had more than a 10% variable importance as a potential predictor.

The Impact of Fibromyalgia on Disability, Anxiety, Depression, Sleep Disturbance, and Quality of Life in Patients with Migraine

The aim of the present study was to assess the impact of fibromyalgia (FM) comorbidity on disability, anxiety, depression, sleep disturbance, and quality of life in patients with migraine. Eighty-six consecutive migraine patients (age, 35.4±10.3 years; 69 women and 17 men) were enrolled in the study. The headache characteristics of the patients were recorded. FM was diagnosed based on the 1990 American College of Rheumatology classification criteria for the diagnosis of FM. All patients were asked to complete selfreport questionnaires, including the Fibromyalgia Impact Questionnaire (FIQ), Headache Impact Test (HIT-6), Migraine Disability Assessment Questionnaire (MIDAS), Pittsburgh Sleep Quality Index (PSQI), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and the 36- Item Short Form Survey (SF-36) to assess their pain-related disability, migraine-related disability, depression, anxiety, sleep disturbance, and quality of life. Of the migraine patients, 28 (32.6%) met the criteria for FM. Migraine patients with FM showed significantly increased migraine frequency and BDI, BAI, and PSQI scores and decreased quality of life scores for all eight domains of the SF-36 compared to patients with migraine alone, whereas the mean HIT-6 and MIDAS values did not differ between the groups. FIQ score showed statistically significant positive correlations with BDI, BAI, PSQI, and MIDAS scores and with headache frequency (p<0.001, r=0.657; p<0.001, r=0.730; p<0.001, r=0.754; p=0.005, r=0.300; p=0.008, r=0.286, respectively); FIQ score showed negative correlations with scores for all domains of the SF-36. In multivariate linear regression analysis, BDI, BAI, and PSQI scores independently predicted FIQ score. Our study results demonstrate the significant impact of FM comorbidity on anxiety, depression, sleep disturbance, and quality of life in this population. FM evaluation and treatment should be considered in the routine care of patients with migraine to globally improve the patient's quality of life.

Pain-related Sleep Disturbance: A Prospective Study With Repeated Measures.

Pain has been found to be associated with poor sleep quality, awakenings, and shorter sleep time. There is a need to understand the relationship of pain and sleep over time to adequately manage the pain disorder and its consequences. The objectives of this study were to establish the prevalence of sleep disturbance in patients with acute or persistent low back pain (LBP), to investigate the correlation between pain and sleep disturbance and to explore the influence of pain on sleep disturbance. Data from a prospective observational study of 233 patients with acute and persistent LBP were used. Twenty-six weekly pain reports and monthly (weeks 2, 6, 10, 14, 18, 22, and 26) sleep reports were collected with text messages. The prevalence of sleep disturbance, the correlation of pain and sleep disturbance, and the risk of reporting disturbed sleep after experiencing LBP were calculated. Sleep disturbance was reported by 67% of the sample. Among patients with acute and persistent LBP, the prevalence was 55% and 76%, respectively. Measures of pain and sleep disturbance were significantly correlated. Compared with being pain free, the risk of reporting sleep disturbance after experiencing pain the previous week was significantly increased (relative risk=2.1 to 5.8), and a dose-response between the number of days with pain and the risk of sleep disturbance was found. This study used repeated measures of both pain and sleep disturbance. The results were in line with previous research, confirming that sleep disturbance was found in the majority of patients with LBP. Pain and sleep measures were significantly correlated, and there was an increased risk of reporting sleep disturbance after experiencing LBP.

Initial evaluation of nighttime restlessness in a naturally occurring canine model of osteoarthritis pain.

Chronic pain due to osteoarthritis (OA) can lead to significant disruption of sleep and increased restlessness. Our objective was to assess whether naturally occurring canine OA is associated with nighttime restlessness and so has potential as a model of OA-associated sleep disturbance. The study was designed as a two-part prospective masked, placebo-controlled study using client-owned dogs (Part A n = 60; Part B n = 19). Inclusion criteria consisted of OA-associated joint pain and mobility impairment. The primary outcome measure for both parts was nighttime accelerometry. In Part B, quality of sleep was assessed using a clinical metrology instrument (Sleep and Night Time Restlessness Evaluation Score, SNoRE). Part A included dogs receiving two weeks of non-steroidal anti-inflammatory drug (NSAID) preceded with two weeks of no treatment. Part B was a crossover study, with NSAID/placebo administered for two weeks followed by a washout period of one week and another two weeks of NSAID/placebo. Repeated measures analysis of variance was used to assess differences between baseline and treatment. There were no significant changes in accelerometry-measured nighttime activity as a result of NSAID administration. SNoRE measures indicated significant improvements in aspects of the quality of nighttime sleep that did not involve obvious movement. These results reflect the few similar studies in human OA patients. Although accelerometry does not appear to be useful, this model has potential to model the human pain-related nighttime sleep disturbance, and other outcome measures should be explored in this model.

Microdiscectomy for the treatment of lumbar disc herniation: an evaluation of reoperations and long-term outcomes.

Design Retrospective case series. Objective The objective of this study was to assess the reoperation rate after microdiscectomy for the treatment of lumbar disc herniation (LDH) in patients with ≥ 5-year follow-up and identify demographic, perioperative, and outcome-related differences between patients with and without a reoperation. Methods The medical records, operative reports, and office notes of patients who had undergone microdiscectomy at a single institution between March 1994 and December 2007 were reviewed and long-term follow-up was assessed via a telephone questionnaire. Results Forty patients (M:24, F:16) with an average age at surgery of 39.9 ± 12.5 years (range: 18–80) underwent microdiscectomy at the levels L5–S1 (n = 28, 70%), L4-L5 (n = 9, 22.5%), L3–L4 (n = 2, 5.0%), and L1–L2 (n = 1, 2.5%). After an average of 40.4 ± 40.1 months (range: 1–128), 25% of patients (10/40) required further spine surgery related to the initial microdiscectomy. At an average postoperative follow-up of 11.1 ± 4.0 years (range: 5–19), additional symptoms apart from back and leg pain were reported more frequently by patients who underwent a reoperation (p = 0.005). Patient satisfaction was significantly higher in patients who did not undergo a reoperation (p = 0.041). For the Oswestry disability index, pain intensity (p = 0.036), and pain-related sleep disturbances (p = 0.006) were reported to be more severe in the reoperation group. Conclusions Microdiscectomy for the treatment of LDH results in a favorable long-term outcome in the majority of cases. The reoperation rate was higher in our series than reported in previous investigations with shorter follow-up. Although there were no statistically significant pre-/perioperative differences between patients with and without reoperation, our findings suggest a difference in self-reported long-term outcome measures.

Pharmacological management of central post-stroke pain: a practical guide.

Pain is one of the most troublesome sequelae of stroke. Some of this post-stroke pain is caused by the brain lesion itself; this is called central post-stroke pain (CPSP). Although the prevalence of CPSP is low (1-8%), persistent, often treatment-resistant, painful sensations are a major problem for stroke patients. The pathogenesis of CPSP remains unknown, but suggested underlying causes include hyperexcitation in the damaged sensory pathways, damage to the central inhibitory pathways, or a combination of the two. For pharmacological treatment, amitriptyline, an adrenergic antidepressant, is currently the first-line drug for CPSP. However, its effect is frequently incomplete and a high dose is commonly not tolerated in stroke patients. Lamotrigine, an antiepileptic, was also found to be effective in a controlled trial and can be used as an alternative or additive therapy. GABAergic drugs with potential calcium channel-blocking effects, such as gabapentin or pregabalin, have recently emerged as a potentially useful therapy. These drugs are effective in various neuropathic pain syndromes, but their effect on CPSP remains to be proven. Pregabalin may improve pain-related anxiety and sleep disturbances. Fluvoxamine and mexiletine may be used adjunctively in some patients. Non-pharmacological treatments such as motor cortex stimulation or deep brain stimulation are used in some centers, but are not proven to be effective. Further well designed clinical trials as well as basic research should be performed to improve our understanding of the pathophysiology of CPSP and to develop better treatment strategies.

Latent variables may be useful in pain’s assessment

BackgroundUnobserved “latent” variables have the potential to minimize “measurement error” inherent to any single clinical assessment or categorical diagnosis.ObjectivesTo demonstrate the potential utility of latent variable constructs in pain’s assessment.DesignWe created two latent variables representing depressive symptom-related pain (Pd) and its residual, “somatic” pain (Ps), from survey questions.SettingThe Hispanic Established Population for Epidemiological Studies in the Elderly (H-EPESE) project, a longitudinal population-based cohort study.ParticipantsCommunity dwelling elderly Mexican-Americans in five Southwestern U.S. states. The data were collected in the 7th HEPESE wave in 2010 (N = 1,078).MeasurementsSelf-reported pain, Center for Epidemiological Studies Depression Scale (CES-D) scores, bedside cognitive performance measures, and informant-rated measures of basic and instrumental Activities of Daily Living.ResultsThe model showed excellent fit [χ2 = 20.37, DF = 12; p = 0.06; Comparative fit index (CFI) = 0.998; Root mean statistical error assessment (RMSEA) = 0.025]. Ps was most strongly indicated by self-reported pain-related physician visits (r = 0.48, p ≤0.001). Pd was most strongly indicated by self-reported pain-related sleep disturbances (r = 0.65, p <0.001). Both Pd and Ps were significantly independently associated with chronic pain (> one month), regional pain and pain summed across selected regions. Pd alone was significantly independently associated with self-rated health, life satisfaction, self-reported falls, Life-space, nursing home placement, the use of opiates, and a variety of sleep related disturbances. Ps was associated with the use of NSAIDS. Neither construct was associated with declaration of a resuscitation preference, mode of resuscitation preference declaration, or with opting for a “Do Not Resuscitate” (DNR) order.ConclusionThis analysis illustrates the potential of latent variables to parse observed data into “unbiased” constructs with unique predictive profiles. The latent constructs, by definition, are devoid of measurement error that affects any subset of their indicators. Future studies could use such phenotypes as outcome measures in clinical pain management trials or associate them with potential biomarkers using powerful parametric statistical methods.

A double-blinded randomized evaluation of alfentanil and morphine vs fentanyl: analgesia and sleep trial (DREAMFAST)

Patients using fentanyl patient-controlled analgesia (PCA), the standard first-line choice in our hospitals, commonly complain of postoperative sleep disruption due to pain. The aim of this study was to determine whether the PCA combination of alfentanil and morphine, which provides longer analgesia without compromising onset speed, would improve postoperative pain-related sleep interference. Two hundred and twelve adults undergoing major surgery where PCA was the planned principal postoperative analgesic modality were randomized to either the combination of alfentanil and morphine (Group AM) or fentanyl (Group F). The primary outcome was pain-related awakenings during the second postoperative night as measured by the study questionnaire, based on the St Mary's Hospital Sleep Questionnaire. Analgesic efficacy, other sleep measures, and opioid-related side-effects were also assessed. There was no difference in pain-related sleep disturbance between the groups, with 41% of Group AM and 53% of Group F waking due to pain (P=0.10). Group AM had better rest and dynamic analgesia in the first 24 h with fewer requiring rescue ketamine infusion during the 2 day study period (2 vs 14%, P=0.001). Those in Group AM experienced less nausea and vomiting in the second 24 h (18 vs 35%, P=0.028) but more pruritus (40 vs 23%, P=0.013). Despite better early postoperative analgesia, pain-related sleep interference was not improved by the PCA combination of alfentanil and morphine. AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY: Ref: ACTRN12608000118303.

The Pain and Sleep Questionnaire three-item index (PSQ-3): a reliable and valid measure of the impact of pain on sleep in chronic nonmalignant pain of various etiologies.

Sleep disturbance is among the more common complaints reported by chronic pain patients. Because pain-related sleep disturbance may serve as a marker for the assessment of responses to treatment for chronic pain, inclusion of a measure designed to assess the impact of pain on sleep in clinical trial protocols is important, if not necessary. Measures typically used for this purpose lack scales specifically designed for the assessment of the impact of pain on sleep or are based on a single item. Single-item scales lack reliability and, therefore, validity. To investigate the psychometric properties of the five-item Pain and Sleep Questionnaire (PSQ) Index, which is embedded in the eight-item inventory, by applying an accepted methodology using retrospective analyses in controlled clinical trials in which the measure had been administered among patients with chronic nonmalignant pain. Data were pooled from nine independent, single-site, double-blind, randomized placebo-controlled clinical trials conducted over a period of approximately 10 years, the majority of which were cross-over designs. A cross-validation approach was adopted with exploratory and confirmatory factor analyses conducted to evaluate the underlying structure and dimensionality of the measure. Internal consistency reliability was evaluated using Cronbach's alpha coefficient. Mean score differences were used to assess the ability of the index to detect important treatment changes. Correlation coefficients were calculated between index scores and scores from other health-related outcome measures to evaluate the criterion validity of the index. Finally, predictive validity was assessed using multiple regression analyses. Pooling the data resulted in a sample of 605 patients (65.5% female; mean age 55.7 years). Findings suggested a revised three-item PSQ Index (PSQ-3). The PSQ-3 demonstrated high internal consistency across samples (ranging from 0.82 to 0.93) and was sensitive to detecting meaningful treatment effects within different chronic pain categories. Moderate to strong correlations (r>0.40) between the PSQ-3 and other health-related outcome measures provided preliminary evidence for criterion-related validity. Results of multiple regression analyses demonstrated that the PSQ-3 accounted for between 29% and 40% of the variance in scores from other health-related outcome measures. Results support the scoring of a revised three-item index for the assessment of the impact of pain on sleep. The revised index demonstrated acceptable levels of internal consistency and preliminary support for the structural, criterion-related and predictive validity of the index was achieved.

Chronic pain management issues in the primary care setting and the utility of long-acting opioids

Importance of the field: Chronic/persistent pain – a highly prevalent condition that places a substantial burden on patients in terms of personal suffering, reduced productivity and health care costs – remains inadequately treated in many patients. The purpose of this review is to provide an overview and evaluate the burden and undertreatment of chronic/persistent pain, considerations for choosing an analgesic and the utility of long-acting opioids.Areas covered in this review: A PubMed search was conducted to identify randomized, placebo-controlled trials evaluating the efficacy and safety of long-acting opioids in chronic pain conditions. The following search terms were used: long-acting opioids, extended-release opioids, controlled-release opioids, sustained-release opioids, and transdermal opioids. The search was limited to randomized, controlled trials published within the last 10 years (1998 – 2008). Studies meeting the following criteria were excluded from review: those focused on a neuropathic pain condition or specific patient subpopulations (e.g., opioid-experienced patients); those conducted outside the USA; and those evaluating a long-acting opioid that is not on the US market at present.What the reader will gain: The reader will first develop a better understanding of the individual and societal ramifications of undertreated chronic pain. Then, a critical review of safety and efficacy data from well-controlled randomized studies will help readers understand the choices and variables that should be considered when selecting appropriate treatments for patients with chronic pain.Take home message: Successful management of chronic/persistent pain should be individually tailored to each patient, taking into account his or her pain intensity and duration, disease state, tolerance of adverse events and risk of medication abuse or diversion. The literature supports the efficacy and safety of a number of long-acting opioids for the treatment of moderate to severe chronic pain, demonstrating sustained improvements in pain intensity and pain-related sleep disturbances with these agents.