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

The Impact of Diagnosed Chronic Sleep Disorders on Outcomes Following Total Knee Arthroplasty

BACKGROUND

Up to 20% of patients undergoing total knee arthroplasty (TKA) remain dissatisfied with their outcome, leading to the identification of risk factors for poor outcomes. The purpose of this study was to analyze the effect of chronic sleep disorders on patient-reported outcomes after primary TKA.

METHODS

A retrospective review of patients undergoing primary TKA was conducted using a prospectively collected database of patients from a single institution between 2018 and 2022. The cohort was split based on the presence of documented chronic sleep disorders, identified preoperatively from the electronic medical record using current procedural terminology codes. The sample was further restricted to include all patients who have sleep disorders (SDs), as well as a 3:1 propensity-matched (on age, sex, body mass index, and American Society of Anesthesiologists class) cohort of patients who had no documented SDs (NSDs) prior to surgery. The final sample included 172 patients (SD: 43; NSD: 129). Repeated-measures linear mixed model analysis was used to analyze the progression of Knee Injury and Osteoarthritis Outcome Score (KOOS) through time between groups.

RESULTS

Those who had SDs had a lower preoperative mean total KOOS score (40.2) than the NSD group (44.1); however, this was not significantly different (P = .108). At 1 year postoperatively, those who had an SD had a significantly higher mean total KOOS score (87.2) than the NSD group (80.4), P = .005. When comparing total KOOS scores by group, over each time period, the SD group showed a better progression when compared to the NSD group, P = .001.

CONCLUSIONS

Compared to patients who did not have documented chronic sleep disorders, patients who had a prior history of chronic sleep disorders reported significantly greater improvements in most KOOS domains in the 12-month period following TKA.

Impact of Pain on Activities of Daily Living in Older Adults: A Cross-Sectional Analysis of Korean Longitudinal Study of Aging (KLoSA)

Pain, particularly musculoskeletal (MSK) and multi-site pain, significantly impacts activities of daily living (ADL) in the elderly, leading to a decline in overall quality of life (QoL). This study, comprising 7490 participants, (mean age: 69 ± 10; females: 57%) from the sixth wave of the Korean Longitudinal Study of Aging (KLoSA), aimed to assess the association between self-reported pain and ADL impairment among the elderly population. Notably, 62% of participants reported experiencing pain, with back pain being the most prevalent (36%) and stomachache the least (0.39%). A majority (61%) of individuals reported MSK-related pain. Additionally, 20% reported pain at one site and 0.03% experienced pain at 12 sites. ADL impairment was observed in 376 (5.0%) participants. Compared to those without pain, participants reporting moderate and severe pain had higher odds of ADL impairment [2.31 (95% CI, 1.66-3.21) and 2.98 (95% CI, 1.95-4.53), respectively]. Pain experienced in the shoulder, arm, wrist, back, hip, leg, and ankle had a significant association with ADL impairment, with ORs ranging from 2.66 (95% CI, 1.80-3.93; hip pain) to 1.36 (95% CI 1.07-1.72; back pain). Furthermore, multi-site pain was associated with higher ADL impairment [1-6 sites: OR: 1.49 (95% CI, 1.11-2.01); 7-12 sites: OR: 7.16 (95% CI, 3.60-14.26)]. These findings underscore the importance of addressing MSK and multi-site pain through targeted interventions, potentially enhancing ADL and contributing to an improved QoL among the elderly population.

A common neuronal ensemble in nucleus accumbens regulates pain-like behaviour and sleep

A comorbidity of chronic pain is sleep disturbance. Here, we identify a dual-functional ensemble that regulates both pain-like behaviour induced by chronic constrictive injury or complete Freund's adjuvant, and sleep wakefulness, in the nucleus accumbens (NAc) in mice. Specifically, a select population of NAc neurons exhibits increased activity either upon nociceptive stimulation or during wakefulness. Experimental activation of the ensemble neurons exacerbates pain-like (nociceptive) responses and reduces NREM sleep, while inactivation of these neurons produces the opposite effects. Furthermore, NAc ensemble primarily consists of D1 neurons and projects divergently to the ventral tegmental area (VTA) and preoptic area (POA). Silencing an ensemble innervating VTA neurons selectively increases nociceptive responses without affecting sleep, whereas inhibiting ensemble-innervating POA neurons decreases NREM sleep without affecting nociception. These results suggest a common NAc ensemble that encodes chronic pain and controls sleep, and achieves the modality specificity through its divergent downstream circuit targets.

The interplay between symptoms of insomnia and pain in people with osteoarthritis: A narrative review of the current evidence

Osteoarthritis (OA) is a leading cause of disability worldwide and clinical pain is the major symptom of OA. This clinical OA-related pain is firmly associated with symptoms of insomnia, which are reported in up to 81% of people with OA. Since understanding the association between both symptoms is critical for their appropriate management, this narrative review synthesizes the existing evidence in people with OA on i) the mechanisms underlying the association between insomnia symptoms and clinical OA-related pain, and ii) the effectiveness of conservative non-pharmacological treatments on insomnia symptoms and clinical OA-related pain. The evidence available identifies depressive symptoms, pain catastrophizing and pain self-efficacy as mechanisms partially explaining the cross-sectional association between insomnia symptoms and pain in people with OA. Furthermore, in comparison to treatments without a specific insomnia intervention, the ones including an insomnia intervention appear more effective for improving insomnia symptoms, but not for reducing clinical OA-related pain. However, at a within-person level, treatment-related positive effects on insomnia symptoms are associated with a long-term pain reduction. Future longitudinal prospective studies offering fundamental insights into neurobiological and psychosocial mechanisms explaining the association between insomnia symptoms and clinical OA-related pain will enable the development of effective treatments targeting both symptoms.

Association between chronic pain and risk of incident dementia: findings from a prospective cohort

BACKGROUND

Chronic musculoskeletal pain has been linked to dementia; however, chronic pain typically occurs in multiple sites; therefore, this study was to investigate whether greater number of chronic pain sites is associated with a higher risk of dementia and its subtypes.

METHODS

Participants (N = 356,383) in the UK Biobank who were dementia-free at baseline were included. Pain in the hip, knee, back, and neck/shoulder or 'all over the body' and its duration were assessed. Participants were categorised into six groups: no chronic pain; chronic pain in 1, 2, 3, and 4 sites, and 'all over the body'. All-cause dementia and its subtypes were ascertained using hospital inpatient and death registry records. Cox regression was used to investigate the associations between the number of chronic pain sites and the incidence of all-cause dementia and its subtypes.

RESULTS

Over a median follow-up of 13 years, 4959 participants developed dementia. After adjustment for sociodemographic, lifestyle, comorbidities, pain medications, psychological problems, and sleep factors, greater number of chronic pain sites was associated with an increased risk of incident all-cause dementia (hazard ratio [HR] = 1.08 per 1 site increase, 95% CI 1.05-1.11) and Alzheimer's disease (AD) (HR = 1.09 per 1-site increase, 95% CI 1.04-1.13) in a dose-response manner but not vascular and frontotemporal dementia. No significant association was found between the number of chronic pain sites and the risk of incident all-cause dementia among a subsample that underwent a fluid intelligence test.

CONCLUSIONS

Greater number of chronic pain sites was associated with an increased risk of incident all-cause dementia and AD, suggesting that chronic pain in multiple sites may contribute to individuals' dementia risk and is an underestimated risk factor for dementia.

Fall Risk in Elderly with Insomnia in Western Romania-A Retrospective Cross-Sectional Study

Background and Objectives: Falls are frequent among the elderly, imply large social and economic costs, and have serious outcomes. The purpose of this study was to investigate the links between insomnia, comorbidities, multisite pain, physical activity, and fall risk in the elderly. Materials and Methods: This retrospective cross-sectional study included persons recruited from nursing homes for the elderly in Timisoara. We separated the participants into two groups by the absence (group I) or presence of fractures (group II) starting with the age of 65 years. Participants were asked how they feel about their sleep using one item on a 4-point scale from the Assessment of Quality of Life questionnaire. The risk of fall was evaluated using the Falls Risk Assessment Tool. Results: The study enrolled 140 patients with a mean age of 78.4 ± 2.4 years (range 65-98 years), 55 of them being males (39%). By comparing the two groups, we found that the elderly with a history of fractures had a greater number of comorbidities, a higher risk of fall, and more severe sleep disturbances. When using univariate logistic regression, the occurrence of fractures in the elderly was significantly associated with the number of comorbidities, the risk of fall, and the presence of sleep disturbances (p < 0.0001). The multivariate regression analysis selected four independent parameters significantly linked to fractures, and these were the number of comorbidities (p < 0.03), the risk of fall score (p < 0.006), and the sleep disturbances of type 3 (p < 0.003) and 4 (p = 0.001). Conclusions: A fall-risk score over 14 and a number of comorbidities over 2 were notably associated with the occurrence of fractures. We also found strong positive correlations between the type of sleep disturbance and the risk of fall score, the number of comorbidities, and the number of fractures in the elderly.

The complexities of the sleep-pain relationship in adolescents: A critical review

Chronic pain is a common and disabling condition in adolescents. Disturbed sleep is associated with many detrimental effects in adolescents with acute and chronic pain. While sleep and pain are known to share a reciprocal relationship, the sleep-pain relationship in adolescence warrants further contextualization within normally occurring maturation of several biopsychological processes. Since sleep and pain disorders begin to emerge in early adolescence and are often comorbid, there is a need for a comprehensive picture of their interrelation especially related to temporal relationships and mechanistic drivers. While existing reviews provide a solid foundation for the interaction between disturbed sleep and pain in youth, we will extend this review by highlighting current methodological challenges for both sleep and pain assessments, exploring the recent evidence for directionality in the sleep-pain relationship, reviewing potential mechanisms and factors underlying the relationship, and providing direction for future investigations. We will also highlight the potential role of digital technologies in advancing the understanding of the sleep and pain relationship. Ultimately, we anticipate this information will facilitate further research and inform the management of pain and poor sleep, which will ultimately improve the quality of life in adolescents and reduce the risk of pain persisting into adulthood.

Microglial Responses and Pain Behaviors Are Exacerbated by Chronic Sleep Deprivation in Rats with Chronic Pain Via Neuroinflammatory Pathways

The inflammatory response of central nervous system (CNS) and microglial activation is important in the development of pain behaviors induced by sleep deprivation. We found that chronic sleep deprivation (CSD) aggravated pain behaviors in rats with chronic pain by upregulating expression of Toll-like receptor 4 (TLR4), NOD-like receptor pyrin domain containing 3 (NLRP3), and interleukin 1β (IL-1β), which promoted microglial activation in the brain. We also found that CSD increased numbers of Iba1⁺ and TLR4⁺ cells, as well as neuronal apoptosis. Inhibitors of TLR4 and NLRP3 (TAK-242 and MCC950, respectively) reduced expression levels of inflammatory factor proteins and M1-related factor mRNA, decreased microglial activation, and relieved the hyperalgesia caused by CSD. These results suggest that CSD aggravated pain behavior in rats with chronic pain through the TLR4/NLRP3/IL-1β signaling pathway, which mediates microglial activation and promotes CNS inflammation and neuronal apoptosis.

Relationship Between Opioid Prescriptions and Number of Chronic Pain Conditions in Women With Interstitial Cystitis

OBJECTIVES

The aim of this study was to determine the relationship between opioid prescriptions and number of chronic pain conditions in women with interstitial cystitis (IC).

METHODS

This was a cross-sectional study. Women diagnosed with IC based on International Classification of Diseases, Ninth Revision/Tenth Revision codes over an 11-year period (2010-2020) were identified from electronic medical records. Data on comorbidities and ambulatory opioid prescriptions were also extracted. Univariable and multivariable logistic regressions were used to assess the relationship between opioid prescriptions and the number and type of coexisting chronic pain conditions.

RESULTS

Of the 1,219 women with IC, 207 (17%) had received at least 1 opioid prescription. The proportions of women with opioid prescriptions for no, 1, 2, and 3 or more coexisting chronic pain conditions were 13%, 20%, 28%, and 32%, respectively. On univariable analysis, factors significantly associated with opioid use were higher body mass index ( P < 0.001), depression ( P < 0.001), sleep disorder ( P < 0.001), endometriosis ( P < 0.05), chronic pelvic pain ( P < 0.001), fibromyalgia ( P < 0.05), joint pain ( P < 0.001), and number of coexisting chronic pain diagnoses ( P < 0.001). On multivariable analysis, opioid prescriptions remained significantly associated with the number of coexisting chronic pain diagnoses: 1 diagnosis (adjusted odds ratio [aOR], 1.8; 95% confidence interval [CI], 1.3-2.7), 2 diagnoses (aOR, 2.6; 95% CI, 1.6-4.3), 3 or more diagnoses (aOR, 2.5; 95% CI, 1.1-5.5), diagnosis of chronic pelvic pain (aOR, 2.1; 95% CI, 1.3-3.5), endometriosis (aOR, 2.4; 95% CI, 1.4-4.3), chronic joint pain (aOR, 1.8; 95% CI, 1.1-2.9), and sleep disorders (aOR, 2.4; 95% CI, 1.6-3.6).

CONCLUSION

The likelihood of opioid prescriptions in women with IC increases with the number and type of coexisting chronic pain conditions and sleep disorders.

Lipidomic Profiling Identifies Serum Lipids Associated with Persistent Multisite Musculoskeletal Pain

Lipid mediators have been suggested to have a role in pain sensitivity and response; however, longitudinal data on lipid metabolites and persistent multisite musculoskeletal pain (MSMP) are lacking. This study was to identify lipid metabolic markers for persistent MSMP. Lipidomic profiling of 807 lipid species was performed on serum samples of 536 participants from a cohort study. MSMP was measured by a questionnaire and defined as painful sites ≥4. Persistent MSMP was defined as having MSMP at every visit. Logistic regression was used with adjustment for potential confounders. The Benjamini–Hochberg method was used to control for multiple testing. A total of 530 samples with 807 lipid metabolites passed quality control. Mean age at baseline was 61.54 ± 6.57 years and 50% were females. In total, 112 (21%) of the participants had persistent MSMP. Persistent MSMP was significantly associated with lower levels of monohexosylceramide (HexCer)(d18:1/22:0 and d18:1/24:0), acylcarnitine (AC)(26:0) and lysophosphatidylcholine (LPC)(18:1 [sn1], 18:2 [sn1], 18:2 [sn2], and 15-MHDA[sn1] [104_sn1]) after controlling for multiple testing. After adjustment for age, sex, body mass index, comorbidities, and physical activity, HexCer(d18:1/22:0 and d18:1/24:0) and LPC(15-MHDA [sn1] [104_sn1]) were significantly associated with persistent MSMP [Odds Ratio (OR) ranging from 0.25–0.36]. Two lipid classes—HexCer and LPC—were negatively associated with persistent MSMP after adjustment for covariates (OR = 0.22 and 0.27, respectively). This study identified three novel lipid signatures of persistent MSMP, suggesting that lipid metabolism is involved in the pathogenesis of persistent pain.

Importance of sleep quality in functional abdominal pain disorder in pediatric patients

The incidence of sleep problems is increasing in children, and they are thought to contribute to pain in functional abdominal pain disorder (FAPD). In this study, we aimed to evaluate the pattern of sleep disturbance in children with FAPD and identify the associated factors. We retrospectively analyzed patients aged 12-18 years who were diagnosed with FAPD based on the Rome IV criteria. To assess sleep problems, we used the Korean version of the Pittsburgh Sleep Quality Index (PSQI-K). To evaluate factors associated with sleep disturbances, we used the odds ratios (OR) estimated in logistic regression models. Among the 66 patients evaluated, 57.6% (38/66) had a total PSQI-K score > 5, indicating a significant disturbance in sleep, 52.6% (20/38) had irritable bowel syndrome (IBS), and 47.4% (18/38) had functional abdominal pain-not otherwise specified. The mean PSQI-K score was 7.2 ± 6.0, and longer sleep onset latency was noted (26.33 ± 19.44 min) in all patients than healthy controls. Almost all PSQI-K subscales scores were elevated in patients with IBS. In univariate analysis, abdominal pain score > 7 and IBS were associated with poor sleep quality. In multivariate analysis, only IBS was associated with sleep disturbance. A relatively large proportion of patients with FAPD had sleep problems and these were more common in patients with IBS. Thus, interventions for improving sleep quality should also be considered in patients with FAPD with severe abdominal pain and IBS.

Sleep disturbance and bone mineral density, risk of falls and fracture: Results from a 10.7-year prospective cohort study

Sleep problems are common in the general population and have been linked to bone health, falls risk and fracture. However, longitudinal studies on sleep-bone health outcomes are lacking and no study has investigated whether an increased risk of fracture is attributable to sleep-related low bone mineral density (BMD) and an increased risk of falls. This study was designed to examine the associations of sleep disturbance with bone mineral density (BMD), risk of falls and fractures over 10.7 years. The analyses were performed in a population-based cohort study with 1099 participants (mean age 62.9 years) enrolled at baseline, and 875, 768 and 563 participants traced at a mean follow-up of 2.6, 5.1 and 10.7 years, respectively. At each visit, self-reported sleep disturbance was recorded. BMD (by dual-energy x-ray absorptiometry), falls risk score and fracture were measured at each visit. The short-form Physiological Profile Assessment was used to measure falls risk score expressed as Z-score. Fractures were self-reported. Mixed-effects model and generalized estimating equations were used for the analyses. In multivariable analysis, there was a dose-response relationship between the extent of sleep disturbance and falls risk score with the strongest association in those reporting the worst sleep disturbance (β = 0.15/unit; 95%CI 0.02-0.28). The worst sleep disturbance was associated with an increased risk of any (relative risk [RR] 1.30/unit; 95%CI 1.01-1.67) and vertebral fracture (RR 2.41/unit; 95%CI 1.00-5.80) compared with those reporting no interrupted sleep. Women but not men with sleep disturbance had a higher risk of vertebral fracture (RR: 2.07 to 6.02, P < 0.05). These were independent of covariates, hip BMD and falls risk. There was no statistically significant association between sleep disturbance and BMD at the hip, spine or total body. Sleep disturbance was independently associated with a greater falls risk score and an increased risk of fractures. Further research is needed to confirm and identify underlying mechanisms for these associations.