Exploring the relationship between chronic pain and cortisol levels in subjects with osteoarthritis: results from a systematic review of the literature

Management of pudendal neuralgia with electrical stimulation. A systematic review

INTRODUCTION AND OBJECTIVE

Pudendal neuralgia is a severely intense, painful, neuropathic condition, involving the dermatome of the pudendal nerve (S2, S3, S4). The diagnosis is complex and usually takes many years to be made. Techniques that use electrical current have been shown to decrease pain and improve quality of life in patients with this condition. The aim of this review was to analyze the existing literature on the effects of electrical current in the treatment of patients with pudendal neuralgia.

MATERIAL AND METHODS

A literature search was carried out in PubMed, Cinahl, Medline, Cochrane Library, ENFISPO, PEDro, Scopus and Web of Science databases, using the search terms "Electric Stimulation Therapy", "pudendal neuralgia" and "pudendal nerve entrapment".

RESULTS

The most frequently repeated intervention is pulsed radiofrequency. Other techniques used are transcutaneous electrical nerve stimulation, pulsed electromagnetic field therapy and neuromodulation. All studies show significant improvement in pain, analgesic intake, depression-anxiety or quality of life.

CONCLUSIONS

The application of electrical current seems to be effective in the management of pudendal neuralgia. The scientific evidence is scarce, of poor methodological quality, and its use is based on the efficacy demonstrated in other indications of chronic pain.

Balneotherapy and cortisol levels: an updated systematic review and meta-analysis

The main objective of this review is to examine the impact of balneotherapy on serum and salivary cortisol concentrations. A systematic search was conducted in PubMed, Scopus, Web of Science, PEDro, and Google Scholar. The databases were screened from inception up until April 2024. After screening the scientific literature, 845 articles were retrieved and 17 studies, involving a total of 765 participants, were eventually included in the review. Among them, four were randomized controlled trials, five were non-randomized studies, and eight were pre-post studies with no control group. The evidence gathered in this review indicates a significant short-term reduction in cortisol levels in healthy individuals undergoing balneotherapy, particularly those experiencing high levels of stress. Conversely, in patients with rheumatic conditions (especially if elderly), increases in cortisol levels induced by balneotherapy can act as beneficial hormetic stress, reducing inflammatory mediators and improving pain and functional quality of life. The meta-analysis shows an overall trend of reduction in stress hormone levels, more pronounced in the intervention group undergoing mud-balneotherapy compared to the control group, a finding that, however, does not reach statistical significance (g=-0.11 [95% CI: -0.30; 0.08]; p > 0.05). Current scientific evidence demonstrates that balneotherapy has a positive impact on the regulation of cortisol levels. The regulation of the hypothalamic-pituitary-adrenal axis and the beneficial effects observed on health parameters and quality of life allow mud-balneotherapy to be classified as eustressful stimuli useful in preventing stress-related pathologies in healthy individuals and in alleviating symptoms in patients with chronic conditions. Future research on the topic is advised.

A qualitative analysis of the impact of canine hypoadrenocorticism on the quality of life of owners

BACKGROUND

Canine hypoadrenocorticism is a rare chronic disease, which demands intense dog-owner interaction, as its treatment requires to be individualised. The aim of this study was a qualitative analysis of the challenges owners face when dealing with the disease, especially regarding its management and how this affects quality of life. By promoting an online discussion between owners, we transcribed and summarised their experiential knowledge in dealing with the disease.

METHODS

Owners were recruited for the online seminars via social media. After a theoretical introduction, participants were free to share experiences and ask questions. The recorded events were retrospectively analysed.

RESULTS

Twenty-four owners of 22 Addisonian dogs took part in four events. Owners felt most "traumatised" when experiencing their dog's acute adrenal crisis. The initial adjustment phase and distinguishing the non-specific symptoms of hypoadrenocorticism from those of other diseases were also challenging. Overall, owners were well informed on the disease and committed to its long-term adjustment.

CONCLUSIONS

Adrenal crisis and the initial adjustment phase may be more burdening to owners than expected. Understanding what their clients' concerns are, can help veterinarians provide better care and reduce the negative impacts of canine hypoadrenocorticism. Promoting peer to peer support, as well as providing a framework for participative communication might also help.

Autonomic responses to aerobic and resistance exercise in patients with chronic musculoskeletal pain: A systematic review

BACKGROUND

It is unknown whether patients with chronic musculoskeletal pain (CMP) show autonomic dysregulation after exercise, and the interventional effects of exercise on the autonomic dysregulation have not been elucidated. The objectives of this study were to reveal acute autonomic responses after aerobic and resistance exercises and the interventional effects of both exercises on autonomic dysregulation in patients with CMP.

METHODS

A systematic search using nine electronic databases was performed based on three key search terms: "chronic musculoskeletal pain," "autonomic nervous system," and "exercise." Data were extracted from measurements of the autonomic nervous system and pain.

RESULTS

We found a total of 1170 articles; 17 were finally included, incorporating 12 observational and five interventional studies. Although a comparator has not been specified, healthy controls were compared to patients with CMP in observational studies. Three of five interventional studies were pre-post study with healthy controls as a comparator or no controls. The other two interventional studies were randomized controlled trial with a different treatment e.g., stretching. There were four good, 10 fair, and three poor-quality articles. The total number of participants was 617, of which 551 were female. There was high heterogeneity among the five disease conditions and nine outcome measures. Following one-time exposure to aerobic and resistance exercises, abnormal autonomic responses (sympathetic activation and parasympathetic withdrawal), which were absent in healthy controls, were observed in patients with CMP. The effects of aerobic and resistance exercise as long-term interventions were unclear since we identified both positive effects and no change in the autonomic activities in patients with CMP.

CONCLUSIONS

This study indicates dysfunctional autonomic responses following one-time exposure to exercise and inconsistent interventional effects in the autonomic activities in patients with CMP. Appropriate therapeutic dose is necessary for studying the management of autonomic regulation and pain after exercise.

Functional and Neural Correlates Associated with Conditioned Pain Modulation in Patients with Chronic Knee Osteoarthritis Pain: A Cross-Sectional Study

Background: In this study, we aimed to assess the factors that predict a dysfunctional conditioned pain modulation (CPM) in chronic knee OA. Methods: This is a cross-sectional analysis of patients with chronic knee OA from a prospective cohort study in Brazil (n = 85). We performed linear and logistic multivariate regression models using the purposeful selection approach to test the relationship between the CPM in both knees (average) as a dependent variable and demographics, clinical, and neurophysiological as independent variables. Results: A significant negative association between WOMAC pain scores and CPM (β: -0.13) was found. This association was modified by the subjects' race, being stronger in the non-white subjects. In our logistic regression models, pain intensity indexed with the WOMAC pain scale remained a significant association with dichotomized CPM. Furthermore, a significant CPM association with balance, indexed with the Berg Balance score, was evidenced (β: 0.04). Neurophysiological variables showed a significant negative relationship with CPM, such as the relative power of delta oscillations in the frontal area (β: -3.11) and central area (β: -3.23). There was no significant relationship between CPM and the following domains: cognitive, emotion, sleep, opioid receptor polymorphisms, and intrinsic variables of OA disease. There was no association of CPM with TMS-indexed inhibitory markers. Conclusions: These results may indicate that less function of the pain descending inhibitory system in patients with OA is correlated with higher activity-related pain (WOMAC), less balance, and cortical plasticity especially with increased low-frequency (delta) brain oscillations. These associations seem modified by race.

Synovial tissue metabolomics analysis of the therapeutic effects of stir-fried Xanthii Fructus on rheumatoid arthritis in rats

Rheumatoid arthritis (RA) is a rheumatic disease that easily causes synovial hyperplasia and joint damage. Comprehensive metabolomic profiling of synovial tissue can reveal local pathological changes during RA and identify metabolites as candidate biomarkers. Detecting metabolites in synovial tissue can more directly reflect the pathological state and disease activity associated with it. stir-fried Xanthii Fructus has demonstrated efficacy in treating RA, but its pharmacodynamic property and mechanism of action are unclear. In this study, the molecular composition of the extract of stir-fried Xanthium Fructus was determined through HPLC. The major components that exert anti-inflammatory and analgesic effects were speculated to be phenolic acids. Next, the effect of stir-fried Xanthii Fructus extracts in RA treatment was comprehensively evaluated using rat body weight, foot volume, inflammatory factors, and histopathological sections of the ankle joint as evaluation indicators. The results showed that the extract of stir-fried Xanthii Fructus could significantly reduce the inflammatory response and improve the degree of joint swelling and the imbalance between pro-inflammatory and anti-inflammatory in adjuvant arthritis rats. Finally, non-targeted metabolomics based on UPLC-Q-TOF/MS and multivariate statistical analysis were used to explore the changes of endogenous metabolites in synovium tissues and to search for potential biomarkers and related metabolic pathways in stir-fried Xanthii Fructus extract-treated AA rats. The results showed that stir-fried Xanthii Fructus mainly treated RA by regulating energy metabolism, hormone metabolism, amino acid metabolism and oxidative stress response in adjuvant arthritis rats. This study provides a theoretical basis for the mechanism of action of stir-fried Xanthii Fructus extract in treating RA.

Hypertension contributes to exacerbated osteoarthritis pathophysiology in rats in a sex-dependent manner

BACKGROUND

Hypertension is a common comorbidity of osteoarthritis (OA) with known autonomic dysregulation; thus, the autonomic nervous system may provide a shared underlying mechanism. The objective of this study was to examine the role of the autonomic nervous system in a preclinical model of OA and hypertension.

METHODS

Experiments were conducted in spontaneously hypertensive rats and a normotensive control strain, including male and female rats. OA was surgically induced via medial meniscus transection with skin incision used as a sham control (n = 7-8/strain/sex/surgery). Tactile sensitivity, anxiety-related behavior, and serum corticosterone were measured at baseline then bi-weekly across 8 weeks. At weeks 9-10, cardiovascular responses to a chemical vagal nerve agonist were determined to indirectly evaluate vagus nerve function. The joint structure was assessed via grading of histological sections.

RESULTS

In males, OA resulted in thinner cartilage in both hypertensive (OA vs. non-OA p < 0.001) and normotensive (OA vs. non-OA p < 0.001). Only females with comorbid hypertension and OA displayed thinner cartilage (p = 0.013). Male hypertensive OA animals had increased calcified subchondral bone compared to normotensive OA animals (p = 0.043) while female hypertensive OA animals had increased calcified subchondral bone compared to hypertensive sham animals (p < 0.001). All MCLT+MMT groups developed low-grade synovitis; interestingly, hypertensive OA females had higher synovitis scores than normotensive OA females (p = 0.046). Additionally, hypertension led to larger drops in blood pressure with vagal activation in both OA (hypertensive vs. normotensive p = 0.018) and sham (hypertensive vs. normotensive p < 0.001) male animals. In females, this trend held true only in OA animals (normotensive vs. hypertensive p = 0.005).

CONCLUSION

These data provide preliminary evidence that hypertension influences OA progression and encourages further study into the autonomic nervous system as a possible mechanism.

Chronic Pain and Psychiatric Conditions

Introduction

Chronic pain is a common condition with high socioeconomic and public health burden. A wide range of psychiatric conditions are often comorbid with chronic pain and chronic pain conditions, negatively impacting successful treatment of either condition. The psychiatric condition receiving most attention in the past with regard to chronic pain comorbidity has been major depressive disorder, despite the fact that many other psychiatric conditions also demonstrate epidemiological and genetic overlap with chronic pain. Further understanding potential mechanisms involved in psychiatric and chronic pain comorbidity could lead to new treatment strategies both for each type of disorder in isolation and in scenarios of comorbidity.

Methods

This article provides an overview of relationships between DSM-5 psychiatric diagnoses and chronic pain, with particular focus on PTSD, ADHD, and BPD, disorders which are less commonly studied in conjunction with chronic pain. We also discuss potential mechanisms that may drive comorbidity, and present new findings on the genetic overlap of chronic pain and ADHD, and chronic pain and BPD using linkage disequilibrium score regression analyses.

Results

Almost all psychiatric conditions listed in the DSM-5 are associated with increased rates of chronic pain. ADHD and BPD are significantly genetically correlated with chronic pain. Psychiatric conditions aside from major depression are often under-researched with respect to their relationship with chronic pain.

Conclusion

Further understanding relationships between psychiatric conditions other than major depression (such as ADHD, BPD, and PTSD as exemplified here) and chronic pain can positively impact understanding of these disorders, and treatment of both psychiatric conditions and chronic pain.

Neuromodulation as a Potential Disease-Modifying Therapy for Osteoarthritis

PURPOSE OF REVIEW

The following review discusses the therapeutic potential of targeting the autonomic nervous system (ANS) for osteoarthritis (OA) treatment and encourages the field to consider the candidacy of bioelectronic medicine as a novel OA treatment strategy.

RECENT FINDINGS

The study of OA pathogenesis has focused on changes occurring at the joint level. As such, treatments for OA have been aimed at the local joint environment, intending to resolve local inflammation and decrease pain. However, OA pathogenesis has shown to be more than joint wear and tear. Specifically, OA-related peripheral and central sensitization can prompt neuroplastic changes in the nervous system beyond the articular joint. These neuroplastic changes may alter physiologic systems, like the neuroimmune axis. In this way, OA and related comorbidities may share roots in the form of altered neuroimmune communication and autonomic dysfunction. ANS modulation may be able to modify OA pathogenesis or reduce the impact of OA comorbidities. Moreover, blocking chronic nociceptive drive from the joint may help to prevent maladaptive nervous system plasticity in OA.

NURSE: Five Micropractices to Reduce Stress

The Coronavirus pandemic affected patients' health and heightened stress among the frontline caregivers, especially radiology nurses. Although there is literature on the effects of stress on nurses, there is a gap on interventions to mitigate the impact of stress. There are evidence-based mindful interventions to maintain balance in stressful situations and reduce perceived stress in sports, neuroscience, and positive psychology. Studies show that even brief periods of self-care reduce stress and cortisol levels. Nurses work long hours and have personal, family, and community responsibilities. Nurses may not have the luxury of extra time to devote to self-care. Therefore, this essay summarizes what stress does to the body; the tangible and intangible costs associated with unmanaged stress among nurses. Five self-care micropractices requiring no additional time called NURSE are offered. When practiced consistently, these micropractices can enhance nurses' well-being, leading to the retention of nursing talent and improved patient care.

An unexpected connection: A narrative review of the associations between Gut Microbiome and Musculoskeletal Pain

PURPOSE

Multiple diverse factors contribute to musculoskeletal pain, a major cause of physical dysfunction and health-related costs worldwide. Rapidly growing evidence demonstrates that the gut microbiome has overarching influences on human health and the body's homeostasis and resilience to internal and external perturbations. This broad role of the gut microbiome is potentially relevant and connected to musculoskeletal pain, though the literature on the topic is limited. Thus, the literature on the topic of musculoskeletal pain and gut microbiome was explored.

METHODS

This narrative review explores the vast array of reported metabolites associated with inflammation and immune-metabolic response, which are known contributors to musculoskeletal pain. Moreover, it covers known modifiable (e.g., diet, lifestyle choices, exposure to prescription drugs, pollutants, and chemicals) and non-modifiable factors (e.g., gut architecture, genetics, age, birth history, and early feeding patterns) that are known to contribute to changes to the gut microbiome. Particular attention is devoted to modifiable factors, as the ultimate goal of researching this topic is to implement gut microbiome health interventions into clinical practice.

RESULTS

Overall, numerous associations exist in the literature that could converge on the gut microbiome's pivotal role in musculoskeletal health. Particularly, a variety of metabolites that are either directly produced or indirectly modulated by the gut microbiome have been highlighted.

CONCLUSION

The review highlights noticeable connections between the gut and musculoskeletal health, thus warranting future research to focus on the gut microbiome's role in musculoskeletal conditions.

Immune-inflammatory and hypothalamic-pituitary-adrenal axis biomarkers are altered in patients with non-specific low back pain: A systematic review

This systematic review aimed to investigate immune-inflammatory and hypothalamic-pituitary-adrenal (HPA) axis biomarkers in individuals with non-specific low back pain (NSLBP) compared to healthy control. The search was performed in five databases until 4 November 2021. Two reviewers independently conducted screenings, data extraction, risk of bias, and methodological quality assessment of 14 unique studies. All studies reported the source of the fluid analyzed: nine studies used serum, two used plasma, one used serum and plasma, and two studies used salivary cortisol. We found preliminary and limited evidence (only one study for each biomarker) of increased levels in growth differentiation factor 15 (GDF-15), interleukin-23 (IL-23), transforming growth factor–beta (TGF-β), and soluble tumor necrosis factor receptor 1 (sTNF-R1) in NSLBP. Inconsistent and limited evidence was identified for interleukin-10 (IL-10). Although C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor–alpha (TNF-α) levels appear to increase in NSLBP, only one study per each biomarker reported statistically significant differences. Interleukin-1 beta (IL-1β), interleukin-17 (IL-17), interferon gamma (IFN-γ), and high-sensitivity CRP (hsCRP) showed no significant differences. Regarding cortisol, one study showed a significant increase and another a significant decrease. More robust evidence between GDF-15, IL-23, TGF-β, and sTNF-R1 with NSLBP is needed. Moreover, contrary to the findings reported in previous studies, when comparing results exclusively with healthy control, insufficient robust evidence for IL-6, TNF-α, and CRP was found in NSLBP. In addition, cortisol response (HPA-related biomarker) showed a dysregulated functioning in NSLBP, with incongruent evidence regarding its directionality. Therefore, our effort is to find adjusted evidence to conclude which immune-inflammatory and HPA axis biomarkers are altered in NSLBP and how much their levels are affected.

Autonomic Nervous System Dysregulation and Osteoarthritis Pain: Mechanisms, Measurement, and Future Outlook

PURPOSE OF REVIEW

The autonomic nervous system is an important regulator of stress responses and exhibits functional changes in chronic pain states. This review discusses potential overlap among autonomic dysregulation, osteoarthritis (OA) progression, and chronic pain. From this foundation, we then discuss preclinical to clinical research opportunities to close gaps in our knowledge of autonomic dysregulation and OA. Finally, we consider the potential to generate new therapies for OA pain via modulation of the autonomic nervous system.

RECENT FINDINGS

Recent reviews provide a framework for the autonomic nervous system in OA progression; however, research is still limited on the topic. In other chronic pain states, functional overlaps between the central autonomic network and pain processing centers in the brain suggest relationships between concomitant dysregulation of the two systems. Non-pharmacological therapeutics, such as vagus nerve stimulation, mindfulness-based meditation, and exercise, have shown promise in alleviating painful symptoms of joint diseases, and these interventions may be partially mediated through the autonomic nervous system. The autonomic nervous system appears to be dysregulated in OA progression, and further research on rebalancing autonomic function may lead to novel therapeutic strategies for treating OA pain.

Analysis of the Active Measurement Systems of the Thoracic Range of Movements of the Spine: A Systematic Review and a Meta-Analysis

(1) Objective: to analyze current active noninvasive measurement systems of the thoracic range of movements of the spine. (2) Methods: A systematic review and meta-analysis were performed that included observational or clinical trial studies published in English or Spanish, whose subjects were healthy human males or females ≥18 years of age with reported measurements of thoracic range of motion measured with an active system in either flexion, extension, lateral bending, or axial rotation. All studies that passed the screening had a low risk of bias and good methodological results, according to the PEDro and MINORS scales. The mean values and 95% confidence interval of the reported measures were calculated for different types of device groups. To calculate the differences between the type of device measures, studies were pooled for different types of device groups using Review Manager software. (3) Results: 48 studies were included in the review; all had scores higher than 7.5 over 10 on the PEDro and MINORs methodological rating scales, collecting a total of 2365 healthy subjects, 1053 males and 1312 females; they were 39.24 ± 20.64 years old and had 24.44 ± 3.81 kg/m2 body mass indexes on average. We summarized and analyzed a total of 11,892 measurements: 1298 of flexoextension, 1394 of flexion, 1021 of extension, 491 of side-to-side lateral flexion, 637 of right lateral flexion, 607 of left lateral flexion, 2170 of side-to-side rotation, 2152 of right rotation and 2122 of left rotation. (4) Conclusions: All collected and analyzed measurements of physiological movements of the dorsal spine had very disparate results from each other, the cause of the reason for such analysis is that the measurement protocols of the different types of measurement tools used in these measurements are different and cause measurement biases. To solve this, it is proposed to establish a standardized measurement protocol for all tools.

Effects of photobiomodulation and deep water running in patients with chronic non-specific low back pain: a randomized controlled trial

Photobiomodulation therapy (PBM) is often used to treat musculoskeletal disorders such as chronic non-specific low back pain (NSCLBP) as it can have positive effects on biomarkers-creatine kinase (CK) and serum cortisol levels-related to stress caused by physical exercise, such as deep water running (DWR) or by pain. The aim of this study was to evaluate the effects of the combination of PBM and aquatic exercise (DWR) on the intensity of pain, disability, 6-min walk test adapted (6WTA), and on cortisol and creatine kinase (CK) levels in a population with NSCLBP. The participants were allocated into three groups: TG_PBM (Photobiomodulation and Training Group), TG_PLA (Placebo Photobiomodulation and Training Group), and the G_PBM (Photobiomodulation Group). Information regarding anthropometric data, blood pressure, and heart rate were collected, and the questionnaires were applied: IPAQ-Short Form, Oswestry Disability Index, and the Visual Analog Scale for Pain. The submaximal exercise test (6WTA) was performed. Blood was collected for analysis of cortisol and CK levels. The training sessions were performed twice a week, for 4 weeks. In the intragroup comparisons, there were statistically significant changes in the TG_PBM and G_PBM groups in the outcomes pain intensity, disability (reductions in both groups), and in cortisol (increased in the TG_PBM and reduced in the G_PBM); in the TG_PLA group, there was a statistically significant reduction only in the outcome of pain intensity. In the intergroup comparison, in the comparison between TG_PBM and TG_PLA, there was a statistically significant difference in the level of cortisol, as well as in the comparison between TG_PBM and G_PBM, in which there was a statistically significant difference for this same outcome (cortisol) and for the 6WTA outcome. The effects of the combination of PBM and aquatic exercise have positive effects on reducing pain intensity, disability, and cortisol levels, but its effects on other variables (6WTA and CK) are too small to be considered significant. Trial registration number: NCT03465228-April 3, 2019; retrospectively registered (ClinicalTrials.gov).

Depression in Osteoarthritis: Current Understanding

Depression, one of the most common comorbidities with osteoarthritis (OA), affects patient prognosis and quality of life. It also increases the overall burden of disease. This subgroup of patients has not been effectively managed in clinical settings. The study aimed to direct physicians' attention to the co-occurrence of depression and OA. Therefore, this review summarizes the relevant literature published over the past 10 years. The focus is on the prevalence of and risk factors for depression in OA, the effects of depression on OA development and treatment response, comorbidity mechanisms, screening, and non-pharmacological treatment. The research on the etiology of depression has been driven largely by epidemiological studies. Recent studies have shown that high levels of pain, poor levels of function, high numbers of OA sites, and slow gait might be associated with depression. However, the pathophysiology of OA and depression comorbidities remains unclear. In addition to immune inflammation and structural changes in the brain, which have been documented in brain imaging studies, psychosocial factors may also play a role. The evidence indicates that depression can be treated with early intervention; however, adjustments may need to be made for individuals with comorbid depression in OA. It is recommended that health care providers pay more attention to depressive symptoms in patients with OA. Clinicians should develop and implement an individualized and comprehensive treatment plan for patients based on a mental health assessment and in teams with other professionals to optimize treatment outcomes.

Functional and structural neuroplastic changes related to sensitization proxies in patients with Osteoarthritis: a systematic review

OBJECTIVE

Several reports in literature have identified sensitization as a possible basis for the enhanced pain reactions associated with Osteoarthritis (OA). The aim of this current systematic review is to summarize functional and structural brain changes associated with surrogate sensitization parameters assessed in patients with OA-related pain.

DESIGN

Systematic review.

SUBJECTS

Patients with OA related pain.

METHODS

A literature search was conducted systematically in MEDLINE, CINAHL, EMBASE databases for human studies up to December 2019. Articles were included if they assessed brain imaging and senzitisation parameters (quantitative sensory testing and questionnaires) in adults with OA related pain. Methodological quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) score.

RESULTS

Five studies reporting on 138 patients were included in this review. The MINORS scale yielded mean scores of 8.5/16 and 12.3/24, for the cohort and case-control studies respectively. Four low-quality studies suggest a greater pain matrix activation associated with clinical measures of sensitization in patients with OA, while another study underlined the presence of structural changes (reduced gray matter volume) in the cortical areas involved in the nociceptive processing possible also related to sensitization.

CONCLUSION

This review shows conflicting evidence for structural and functional neuroplastic brain changes related to sensitization proxies in patients with OA.

Individual variation in diurnal cortisol in patients with knee osteoarthritis: Clinical correlates

BACKGROUND

The cortisol awakening response (CAR) is a core biomarker of hypothalamic-pituitary-adrenal (HPA) axis regulation. To date, however, studies of HPA-axis function among patients with chronic pain are scarce and show equivocal results. The objectives of this study were to investigate the association between CAR and pain-related outcomes and to investigate potential sex differences in patients with knee osteoarthritis (KOA).

METHODS

In this cross-sectional study, KOA patients (N = 96) completed self-report questionnaires assessing pain and psychosocial factors and underwent Quantitative Sensory Testing (QST) to assess pressure pain threshold (PPT). Additionally, salivary cortisol samples (N = 60) were collected to assess HPA-axis function at 6 time points (awakening, 15- and 30-minute post-awakening, 4 PM, 9 PM and bedtime). The CAR was calculated by examining increases in salivary cortisol from awakening to 30 min post awakening and the total post-awakening cortisol concentration by calculating the lower areas under the curve of cortisol with respect to ground (AUC_G).

RESULTS

Patients with a relatively blunted CAR had significantly higher anxiety levels and lower PPT than patients with relatively normal CAR. Similarly, patients with a relatively reduced AUC_G had significantly higher pain interference and anxiety levels compared to patients with relatively normal AUC_G. PPT was positively correlated with CAR and AUC_G and negatively correlated with pain severity and anxiety_. Men with KOA had significantly lower anxiety, higher PPT and higher CAR and AUC_G than women with KOA. Mediation analysis results revealed a significant indirect effect of PPT on the relationship between sex and AUC_G. CONCLUSIONS: The findings of this study suggest that neuroendocrine factors such as CAR and AUC_G may contribute to individual differences in pain-related outcomes in patients with KOA. Additionally, our results show sex differences in the magnitude of morning HPA activation and pain-related outcomes. Finally, our findings are suggestive of a sex-dependent relationship between post-awakening cortisol concentrations and pain perception. Future research should examine these associations across various pain populations.

Predicting the Physical and Mental Health Status of Individuals With Chronic Musculoskeletal Pain From a Biopsychosocial Perspective: A Multivariate Approach

OBJECTIVES

Chronic pain is theoretically conceptualized from a biopsychosocial perspective. However, research into chronic pain still tends to focus on isolated, biological, psychological, or social variables. Simultaneous examination of these variables in the prediction of outcomes is important because communalities between predictors exist. Examination of unique contributions might help guide research and interventions in a more effective way.

METHODS

The participants were 114 individuals with chronic pain (mean age=58.81, SD=11.85; 58.8% women and 41.2% men) who responded to demographics (age and sex), pain characteristics (duration and sensory qualities), psychological (catastrophizing and perceived injustice), and social (marital adjustment) measures. Multivariate analyses were conducted to investigate their unique contributions to pain-related health variables pain severity, pain interference, disability, anxiety, and depressive symptoms.

RESULTS

Bivariate analyses evidenced significant associations between pain sensory qualities, catastrophizing, perceived injustice, and all health variables. In multivariate analyses, pain sensory qualities were associated with pain severity (β=0.10; 95% confidence interval [CI]=0.05, 0.14; t=4.28, P<0.001), while perceived injustice was associated with pain interference (β=0.08; 95% CI=0.03, 0.12; t=3.59, P<0.001), disability (β=0.25; 95% CI=0.08, 0.42; t=2.92, P=0.004), anxiety (β=0.18; 95% CI=0.08, 0.27; t=3.65, P<0.001), and depressive symptoms (β=0.14; 95% CI=0.05, 0.23; t=2.92, P=0.004). Age, sex, pain duration, and marital adjustment were not associated with health variables either in bivariate or in multivariate analyses (all P>0.010).

DISCUSSION

As expected, communalities between biopsychosocial variables exist, which resulted in a reduced number of unique contributions in multivariate analyses. Perceived injustice emerged as a unique contributor to variables, which points to this psychological construct as a potentially important therapeutic target in multidisciplinary treatment of pain.