Predictors of autonomic neuropathy in rheumatoid arthritis

Corneal nerve loss and increased Langerhans cells are associated with disease severity in patients with rheumatoid arthritis

BACKGROUND/OBJECTIVES

Rheumatoid arthritis (RA) is a multisystem autoimmune disorder characterized by articular and extra-articular manifestations. Neuropathy is a poorly studied manifestation of RA. The aim of this study was to utilize the rapid non-invasive ophthalmic imaging technique of corneal confocal microscopy to identify whether there is evidence of small nerve fibre injury and immune cell activation in patients with RA.

SUBJECTS/METHODS

Fifty consecutive patients with RA and 35 healthy control participants were enrolled in this single-centre, cross-sectional study conducted at a university hospital. Disease activity was assessed with the 28-Joint Disease Activity Score and erythrocyte sedimentation rate (DAS28-ESR). Central corneal sensitivity was measured with a Cochet-Bonnet contact corneal esthesiometer. A laser scanning in vivo corneal confocal microscope was used to quantify corneal nerve fibre density (CNFD), nerve branch density (CNBD), nerve fibre length (CNFL), and Langerhans cell (LC) density.

RESULTS

Corneal sensitivity (P = 0.01), CNFD (P = 0.02), CNBD (P < 0.001), and CNFL (P < 0.001) were lower, and mature (P = 0.001) and immature LC densities (P = 0.011) were higher in patients with RA compared to control subjects. CNFD (P = 0.016) and CNFL (P = 0.028) were significantly lower in patients with moderate to high (DAS28-ESR > 3.2) compared to mild (DAS28-ESR ≤ 3.2) disease activity. Furthermore, the DAS28-ESR score correlated with CNFD (r = -0.425; P = 0.002), CNBD (ρ = -0.362; P = 0.010), CNFL (r = -0.464; P = 0.001), total LC density (ρ = 0.362; P = 0.010) and immature LC density (ρ = 0.343; P = 0.015).

CONCLUSIONS

This study demonstrates reduced corneal sensitivity, corneal nerve fibre loss and increased LCs which were associated with the severity of disease activity in patients with RA.

Association between Gastroparesis and Rheumatoid Arthritis: A US Population-Based Study

OBJECTIVES

Patients with rheumatoid arthritis (RA) have a high prevalence of nausea, vomiting, postprandial fullness, and abdominal pain; these are symptoms that are similar to those in gastroparesis (GP). The aim of this study was to assess the association between GP and RA and the determinants of GP.

METHODS

We identified patients with RA and patients with GP from the 2012-2014 National Inpatient Sample database. The t test and the χ² test were used for continuous and categorical variables, respectively. We determined the association between RA and GP and independent predictors of GP by multivariate analysis.

RESULTS

Of 1,514,960 patients with RA, there were 1070 hospitalizations in which a primary diagnosis of GP was identified. The GP odds ratio in RA was found to be 1.36 and the 95% confidence interval was 1.24 to 1.49 (P < 0.0001). The variables increasing the odds of GP were age intervals of 18 to 35 years, 36 to 50 years, and 51 to 65 years; being female, White, or Black; a median household income in the 26th to 50th and the 51st to 75th percentiles; having diabetes mellitus; and having RA.

CONCLUSIONS

An increased likelihood of 36% of GP among patients with RA was determined. White and Black patients younger than age 65 showed a greater risk of developing GP.

The value of electrochemical skin conductance measurement by Sudoscan® for assessing autonomic dysfunction in peripheral neuropathies beyond diabetes

The diagnosis and follow-up of peripheral neuropathies involving small-diameter nerve fibers require specific examinations beyond conventional nerve conduction studies which only concern large-diameter nerve fibers. Among these tests, some are dedicated to the investigation of cutaneous innervation by the autonomic nervous system, mainly by unmyelinated sympathetic C fibers. To this end, various laboratory tests have been proposed, but the measurement of electrochemical skin conductance (ESC) by Sudoscan® is increasingly becoming the most widely used technique, because it allows a quick and simple assessment of the sudomotor function of the limb extremities. This technique is based on the principles of reverse iontophoresis and chronoamperometry and since its introduction in 2010, has been the source of nearly 200 publications. In the clinical field, most of these publications concern the evaluation of diabetic polyneuropathy, for which the value of Sudoscan® no longer needs to be demonstrated. However, there is also evidence for a role for Sudoscan® in the testing of the autonomic nervous system in various peripheral neuropathies of other origins or diseases primarily affecting the central nervous system. In this article, a comprehensive review of the literature on the clinical value of Sudoscan® outside of diabetes is presented, detailing ESC changes in neuropathies associated with various clinical conditions, such as hereditary amyloidosis or other genetic pathologies, chemotherapy neurotoxicity, dysimmune or infectious disorders, fibromyalgia, parkinsonism or other neurodegenerative diseases.

The Utility of COMPASS-31 Questionnaire to Predict Autonomic Dysfunction in Patients With Cervical/Upper Thoracic Compressive Myelopathy

BACKGROUND

Patients with cervical/upper thoracic compressive myelopathy may have autonomic dysfunction. The composite autonomic severity score (CASS) is the gold standard test to detect autonomic dysfunction, and the self-rated composite autonomic system scale (COMPASS-31) questionnaire is a screening tool to diagnose autonomic dysfunction. This study compared the COMPASS-31 and modified CASS scores for the detection of autonomic dysfunction in patients with compressive myelopathy.

METHODS

Patients with cervical/upper thoracic compressive myelopathy scheduled for decompressive surgery completed a COMPASS-31 questionnaire and underwent autonomic function tests to calculate the modified CASS score before surgery.

RESULTS

Forty-two patients were included in the study; 19 (45.2%) had mild autonomic dysfunction, 5 (11.9%) had moderate autonomic dysfunction, and 18 (42.9%) had severe autonomic dysfunction. Median (interquartile range) of modified CASS and COMPASS-31 scores were 19 (6.33) and 3 (2.5), respectively. There was a positive correlation between modified CASS and COMPASS-31 scores ( r =0.43; P =0.004). Receiver operating characteristic curve analysis confirmed that COMPASS-31 had fair accuracy for prediction of moderate to severe autonomic dysfunction (area under the curve, 0.74; 95% confidence interval, 0.64-0.82; P =0.009). A cut-off of 30 for total COMPASS-31 score had a sensitivity of 52.2% and specificity of 89.5% to detect moderate to severe autonomic dysfunction, with positive and negative predictive values of 85.7% and 60.7%, respectively.

CONCLUSION

Patients with cervical/upper thoracic compressive myelopathy had varying degrees of autonomic dysfunction based on the modified CASS. There was a positive correlation between the modified CASS and COMPASS-31 questionnaire. A COMPASS-31 score of >30 30 could be utilized to predict moderate to severe autonomic dysfunction in patients with compressive myelopathy.

High-resolution ultrasound of peripheral neuropathies in rheumatological patients: An overview of clinical applications and imaging findings

Peripheral neuropathies are surprisingly common and can be associated with a number of conditions, including rheumatological diseases. Whether the co-existence of peripheral neuropathies with rheumatological disorders is coincidental or related to a common pathogenic mechanism, these disabling conditions can affect the outcome of rheumatological patients and should be targeted with specific treatment. The clinical presentation of peripheral neuropathy can be multifaceted and difficult to recognize in polysymptomatic patients. However, physicians adopting state-of-art diagnostic strategies, including nerve imaging, may improve the detection rate and management of neuropathies. In particular, a diagnostic approach relying exclusively on clinical history and nerve conduction studies may not be sufficient to disclose the etiology of the nerve damage and its anatomical location and thus requires integration with morphological studies. High-Resolution Ultrasound (HRUS) is increasingly adopted to support the diagnosis and follow-up of both joint disorders in rheumatology and peripheral neuropathies of different etiologies. In this review, the different types of nerve disorders associated with the most common syndromes of rheumatological interest are discussed, focusing on the distinctive sonographic features.

Investigating the Dose-Response Relationship between Deep Breathing and Heart Rate Variability in Healthy Participants and Across-Days Reliability in Patients with Rheumatoid Arthritis and Systemic Lupus Erythematosus

Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) are associated with autonomic dysfunction, potentially through reduced vagus nerve tone. Vagus nerve stimulation has been proposed as an anti-inflammatory treatment, and it can be performed through deep breathing (DB) exercises. In this study, the dose-response relationship between DB exercises and heart rate variability (HRV) was investigated in healthy participants and reliability across days in patients with RA and SLE. On three separate days, 41 healthy participants performed DB for: 5, 15, or 30 min. On two separate days, 52 RA or SLE patients performed DB with the dose associated with the highest HRV increase in healthy participants. The HRV was estimated from ECG-recordings recorded prior and post the DB exercises. Increases in dose led to larger HRV-responses. Thirty minutes led to the largest HRV-response. In the RA and SLE patients, this dose increased the HRV-parameters consistently across the two days, indicating reliability. DB increases HRV in healthy participants and RA or SLE patients, which indicates stimulation of the vagus nerve. Of the tested durations, 30 min of DB was the optimal period of stimulation. A potential anti-inflammatory effect of DB exercises should be investigated in future studies.

Clinical Manifestations, Pathogenesis, Diagnosis and Treatment of Peripheral Neuropathies in Connective Tissue Diseases: More Diverse and Frequent in Different Subtypes than Expected

Purpose of review: To discuss and summarize recent findings in peripheral neuropathy (PN) related to connective tissue diseases (CTD) including its prevalence, clinical manifestations, pathogenesis, diagnosis and treatment. Recent findings: Although PN is a common complication in CTD and has been well studied, recent research has shown that PN is more diverse and frequent in different subtypes of CTD than was expected. The incidence of PN in Sjögren’s syndrome and rheumatoid arthritis (RA) varies according to different disease subtypes, and the pathogenesis of neuropathic pain in different subtypes of eosinophilic granulomatosis with polyangiitis (EGPA) may also differ. Neurogenic inflammation, autoantibody-mediated changes, ischemia of the vascular wall and metabolic mechanisms have been shown to contribute to the pathogenesis of PN in CTD. Moreover, allergic inflammation has been recently identified as a possible new mechanism producing peripheral neuropathic pain associated with MPO-ANCA negative EGPA patients. Glucocorticoids are routinely used to relieve pain caused by PN. However, these steroids may cause hyperalgesia, exacerbate neuropathic pain, and activate the early phase of pain induction and produce hyperalgesia. Recently, neuroactive steroids, such as progesterone, tetrahydroprogesterone and testosterone, have been shown to exert protective effects for several PN symptoms, and in particular neuropathic pain. Neuroactive steroids will be an interesting topic for future research into PN in CTD. Summary: It is essential for the diagnosis and treatment of PN in CTD to be updated. Timely diagnosis, appropriate treatments, and multidisciplinary care are essential to minimize morbidity and decrease the risk of permanent neurologic deficits. Further studies are needed to guide diagnosis and treatment.

CNS-Spleen Axis - a Close Interplay in Mediating Inflammatory Responses in Burn Patients and a Key to Novel Burn Therapeutics

Severe burn-induced inflammation and subsequent hypermetabolic response can lead to profound infection and sepsis, resulting in multiple organ failure and high mortality risk in patients. This represents an extremely challenging issue for clinicians as sepsis is the leading cause of mortality in burn patients. Since hyperinflammation and immune dysfunction are a result of an immune imbalance, restoring these conditions seem to have promising benefits for burn patients. A key network that modulates the immune balance is the central nervous system (CNS)-spleen axis, which coordinates multiple signaling pathways, including sympathetic and parasympathetic pathways. Modulating inflammation is a key strategy that researchers use to understand neuroimmunomodulation in other hyperinflammatory disease models and modulating the CNS-spleen axis has led to improved clinical outcomes in patients. As the immune balance is paramount for recovery in burn-induced sepsis and patients with hyperinflammatory conditions, it appears that severe burn injuries substantially alter this CNS-spleen axis. Therefore, it is essential to address and discuss the potential therapeutic techniques that target the CNS-spleen axis that aim to restore homeostasis in burn patients. To understand this in detail, we have conducted a systematic review to explore the role of the CNS-spleen axis and its impact on immunomodulation concerning the burn-induced hypermetabolic response and associated sepsis complications. Furthermore, this thorough review explores the role of the spleen, CNS-spleen axis in the ebb and flow phases following a severe burn, how this axis induces metabolic factors and immune dysfunction, and therapeutic techniques and chemical interventions that restore the immune balance via neuroimmunomodulation.

The Link Between Autonomic Nervous System and Rheumatoid Arthritis: From Bench to Bedside

Neuronal stimulation is an emerging field of research focused on the management and treatment of various diseases through the reestablishment of physiological homeostasis. Electrical vagus nerve stimulation has recently been proposed as a revolutionary therapeutic option for rheumatoid arthritis (RA) in combination with or even as a replacement for conventional and biological drugs. In the past few years, disruption of the autonomic system has been linked to RA onset and activity. Novel research on the link between the autonomic nervous system and the immune system (immune-autonomics) has paved the way for the development of innovative RA management strategies. Clinical evidence supports this approach. Cardiovascular involvement, in terms of reduced baroreflex sensitivity and heart rate variability-derived indices, and mood disorders, common comorbidities in patients with RA, have been linked to autonomic nervous system dysfunction, which in turn is influenced by increased levels of circulating pro-inflammatory cytokines. This narrative review provides an overview of the autonomic nervous system and RA connection, discussing most of the common cardiac and mental health-related RA comorbidities and their potential relationships to systemic and joint inflammation.

Correlation between sarcopenia and nailfold microcirculation, serum 25-hydroxycholecalciferol (vitamin D3) and IL-17 levels in female patients with rheumatoid arthritis

AIMS

To investigate the correlation between sarcopenia and nailfold microcirculation and serum 25-hydroxycholecalciferol [25 (OH) D3] (instead of 25-hydroxyvitamin D) and IL-17 levels in female rheumatoid arthritis (RA) patients.

METHODS

130 female rheumatoid arthritis (RA) patients and 80 healthy controls were tested. Nailfold capillaroscopic scores (NFCS) were measured. Bioimpedance analysis (BIA) was used to measure skeletal muscle mass. Enzyme-linked immunosorbant assay (ELISA) was used to detect the levels of IL-17, IL-6 and TNF-α. Serum 25 (OH) D3 concentration was determined by photochemical immunoassay. The correlation was analyzed by Pearson's correlation, and the influencing factors were analyzed by binary logistic regression.

RESULTS

(1) Compared with the control group, NFCS and serum IL-17 levels were higher in the RA group, while the serum 25 (OH) D3 and skeletal mass index (SMI) were lower. (2) Pearson correlation analysis found: SMI was positively correlated with 25 (OH) D3 (r=0.515, P<0.001), SMI was negatively correlated with IL-17 (r=-0.468, P<0.001), SMI was negatively correlated with NFS (r = -0.229, P=0.009); (3) Logistic regression analysis: serum 25 (OH) D3 was a protective factor for sarcopenia (OR=0.392, P=0.016); IL-17, C-reactive protein, and NFS were risk factors for sarcopenia (OR=1.516, P=0.049; OR=1.469, P=0.045; OR=3.497, P=0.002).

CONCLUSION

Secondary sarcopenia in RA is common and is closely related to microcirculation abnormalities. Increased NFCS is a risk factor for sarcopenia. Decreased serum 25 (OH) D3 levels and increased IL-17 are also risk factors for sarcopenia, but the mechanisms involved in sarcopenia and microcirculation abnormalities need further investigation.

Ganglionic Acetylcholine Receptor Antibodies and Autonomic Dysfunction in Autoimmune Rheumatic Diseases

Autonomic neuropathy has been reported in autoimmune rheumatic diseases (ARD) including Sjögren’s syndrome, systemic sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. However, the pathophysiological mechanism underlying autonomic dysfunction remains unknown to researchers. On the other hand, autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder, which causes dysautonomia that is mediated by autoantibodies against ganglionic acetylcholine receptors (gAChRs). The purpose of this review was to describe the characteristics of autonomic disturbance through previous case reports and the functional tests used in these studies and address the importance of anti-gAChR antibodies. We have established luciferase immunoprecipitation systems to detect antibodies against gAChR in the past and determined the prevalence of gAChR antibodies in various autoimmune diseases including AAG and rheumatic diseases. Autonomic dysfunction, which affects lower parasympathetic and higher sympathetic activity, is usually observed in ARD. The anti-gAChR antibodies may play a crucial role in autonomic dysfunction observed in ARD. Further studies are necessary to determine whether anti-gAChR antibody levels are correlated with the severity of autonomic dysfunction in ARD.

Efficacy of wIRA in the treatment of sacroiliitis in male patients with ankylosing spondylitis and its effect on serum VEGF levels

Background

This study aimed to assess the efficacy of water-filtered infrared A (wIRA) in sacroiliitis in male patients with ankylosing spondylitis (AS) and the effect of wIRA therapy on serum vascular endothelial growth factor (VEGF).

Methods

One hundred twenty male AS patients with active sacroiliitis were randomly divided into wIRA group and control group. wIRA treatment was performed twice daily for 5 consecutive days with 24-h interval before switching the treatment (crossover design). Bath ankylosing spondylitis disease activity index (BASDAI) scores, pain visual analogue scale (VAS), and morning stiffness VAS were recorded prior to and after each treatment period. Additionally, C-reactive protein (CRP), serum VEGF, and resistance index (RI) of sacroiliac joints detected by ultrasonography were recorded at baseline and after the first and second treatment period, respectively. The efficacy was examined by using repeated measures analysis of variance (ANOVA).

Results

BASDAI, pain VAS, and morning stiffness VAS scores decreased significantly (P < 0.001) after wIRA treatment and no-wIRA treatment (control group), and the difference between the two groups was significant (P < 0.001). CRP declined and RI increased during the wIRA treatment as compared with the no-wIRA treatment (P < 0.001). The increase in RI was associated with improvement of pain VAS scores (P = 0.018), while serum VEGF was unaffected by the treatment.

Conclusions

wIRA treatment achieved symptom and pain relief for AS patients with active sacroiliitis. wIRA treatment also improved RI revealed by ultrasonography, and this effect was associated with improved pain VAS scores.

Heart rate variability testing: could it change spending for rheumatoid arthritis patients in the United States? An exploratory economic analysis

BACKGROUND

Autonomic nervous system (ANS) testing with heart rate variability (HRV) has been shown in early research to predict 52-week outcomes in rheumatoid arthritis (RA). HRV testing could be combined with putative ANS biologic pathways to improve treatment response for RA patients. This study explored potential costs and health outcomes of introducing HRV testing into RA treatment, without and with ANS optimization.

METHODS

A decision tree exploratory economic model compared HRV testing to standard care in moderate-to-severe biologic-eligible patients over a 10-year time horizon. HRV data was derived from an observational study of RA patients (n = 33). Patients were stratified into treatment groups based on HRV test scores indicating "low probability of response" and "moderate to high probability of response". This study explored adding ANS optimization based on HRV score followed by clinically-appropriate treatment. Costs and quality-adjusted life-years (QALYs) for the US population were estimated.

RESULTS

HRV testing in biologic-eligible patients decreased non-effective biologic use, reducing US healthcare costs by $34.6 billion over 10 years with QALYs unchanged. When combined with ANS optimization in biologic-eligible patients, HRV testing could increase costs by $3.6 billion over 10 years but save over 350,000 QALYs. Among all RA patients, HRV testing with ANS optimization could save over $8 billion and over 100,000 QALYs over 10 years, depending on the positive predictive value (PPV) of the HRV test.

CONCLUSIONS

The potential economic impact of introducing HRV testing and ANS optimization into RA treatment appears substantial and cost-effective based on the exploratory analysis. Additional rigorous studies are warranted in larger patient samples to better inform decision-making.

Sudomotor function testing by electrochemical skin conductance: does it really measure sudomotor function?

OBJECTIVE

Electrochemical skin conductance (ESC) is a non-invasive test of sweat function developed as a potential marker of small fiber neuropathy. Here we systematically review the evolution of this device and the data obtained from studies of ESC across different diseases.

METHODS

Electronic databases, including MEDLINE, and Google Scholar were searched through to February 2018. The search strategy included the following terms: "electrochemical skin conductance," "EZSCAN," and "Sudoscan." The data values provided by each paper were extracted, where available, and input into tabular and figure data for direct comparison.

RESULTS

Thirty-seven studies were included this systematic review. ESC did not change by age or gender, and there was significant variability in ESC values between diseases, some of which exceeded control values. Longitudinal studies of disease demonstrated changes in ESC that were not biologically plausible. Of the 37 studies assessed, 25 received support from the device manufacturer. The extracted data did not agree with other published normative values. Prior studies do not support claims that ESC is a measure of small fiber sensory function or autonomic function.

CONCLUSIONS

Although many papers report significant differences in ESC values between disease and control subjects, the compiled data assessed in this review raises questions about the technique. Many of the published results violate biologic plausibility. A single funding source with a vested interest in the study outcomes has supported most of the studies. Normative values are inconsistent across publications, and large combined data sets do not support a high sensitivity and specificity. Finally, there is insufficient evidence supporting the claim that Sudoscan tests sudomotor or sensory nerve fiber function.

Sympathetic Nerve Hyperactivity in the Spleen: Causal for Nonpathogenic-Driven Chronic Immune-Mediated Inflammatory Diseases (IMIDs)?

Immune-Mediated Inflammatory Diseases (IMIDs) is a descriptive term coined for an eclectic group of diseases or conditions that share common inflammatory pathways, and for which there is no definitive etiology. IMIDs affect the elderly most severely, with many older individuals having two or more IMIDs. These diseases include, but are not limited to, type-1 diabetes, obesity, hypertension, chronic pulmonary disease, coronary heart disease, inflammatory bowel disease, and autoimmunity, such as rheumatoid arthritis (RA), Sjőgren's syndrome, systemic lupus erythematosus, psoriasis, psoriatic arthritis, and multiple sclerosis. These diseases are ostensibly unrelated mechanistically, but increase in frequency with age and share chronic systemic inflammation, implicating major roles for the spleen. Chronic systemic and regional inflammation underlies the disease manifestations of IMIDs. Regional inflammation and immune dysfunction promotes targeted end organ tissue damage, whereas systemic inflammation increases morbidity and mortality by affecting multiple organ systems. Chronic inflammation and skewed dysregulated cell-mediated immune responses drive many of these age-related medical disorders. IMIDs are commonly autoimmune-mediated or suspected to be autoimmune diseases. Another shared feature is dysregulation of the autonomic nervous system and hypothalamic pituitary adrenal (HPA) axis. Here, we focus on dysautonomia. In many IMIDs, dysautonomia manifests as an imbalance in activity/reactivity of the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS). These major autonomic pathways are essential for allostasis of the immune system, and regulating inflammatory processes and innate and adaptive immunity. Pathology in ANS is a hallmark and causal feature of all IMIDs. Chronic systemic inflammation comorbid with stress pathway dysregulation implicate neural-immune cross-talk in the etiology and pathophysiology of IMIDs. Using a rodent model of inflammatory arthritis as an IMID model, we report disease-specific maladaptive changes in β₂-adrenergic receptor (AR) signaling from protein kinase A (PKA) to mitogen activated protein kinase (MAPK) pathways in the spleen. Beta₂-AR signal "shutdown" in the spleen and switching from PKA to G-coupled protein receptor kinase (GRK) pathways in lymph node cells drives inflammation and disease advancement. Based on these findings and the existing literature in other IMIDs, we present and discuss relevant literature that support the hypothesis that unresolvable immune stimulation from chronic inflammation leads to a maladaptive disease-inducing and perpetuating sympathetic response in an attempt to maintain allostasis. Since the role of sympathetic dysfunction in IMIDs is best studied in RA and rodent models of RA, this IMID is the primary one used to evaluate data relevant to our hypothesis. Here, we review the relevant literature and discuss sympathetic dysfunction as a significant contributor to the pathophysiology of IMIDs, and then discuss a novel target for treatment. Based on our findings in inflammatory arthritis and our understanding of common inflammatory process that are used by the immune system across all IMIDs, novel strategies to restore SNS homeostasis are expected to provide safe, cost-effective approaches to treat IMIDs, lower comorbidities, and increase longevity.

Evidence of reduced parasympathetic autonomic regulation in inflammatory joint disease: A meta-analyses study

BACKGROUND

Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are inflammatory joint disorders (IJD) with increased risk of cardiovascular disease (CVD). Autonomic dysfunction (AD) is a risk factor for CVD, and parasympathetic AD is linked to key features of IJD such as inflammation, physical inactivity and pain. Heart-rate variability (HRV) is a marker of cardiac AD. The study objective was to compare parasympathetic cardiac AD, measured by HRV, between patients with IJD and healthy controls, using meta-analysis methodology, and to examine the impact of inflammation, physical inactivity and pain on HRV in IJD.

METHODS

Medline, Embase and Amed were searched. Inclusion criteria were adult case-control studies published in English or a Scandinavian language, presenting HRV data in IJD. Two measures of HRV and 3 from the Ewing protocol were selected: square root of mean squared difference of successive R-R intervals (RMSSD), high frequency (HF), Ewing protocol; standing (E-S), breathing (E-B) and Valsalva (E-V). Patients with RA, SpA and healthy controls were compared separately using random-effects meta-analyses of standardized mean differences (SMD).

RESULTS

In all, 35 papers were eligible for inclusion. For RMSSD the pooled SMD (95% CI) RA vs. controls was -0.90 (-1.35 to -0.44), for SpA vs. controls; -0.34 (-0.73 to 0.06). For HF pooled SMD RA vs. controls was -0.78 (-0.99 to -0.57), for SpA vs. controls; -0.04 (-0.22 to 0.13). All Ewing parameters were significantly lower in cases, except for E-V which was comparable between cases and controls in patients with RA.

CONCLUSION

Patients with IJD have cardiac parasympathetic AD which is related to inflammation.

Neurological Complications of Rheumatic Disease

Rheumatic disease represents a broad spectrum of systemic conditions manifested by multisystem involvement and mediated by autoimmunity and inflammation. Their neurological complications may occur at any point in the disease process and are diagnostically challenging. For years central nervous system (CNS) was considered as a system uniquely protected from effects of the immune system because of the blood-brain barrier. Indeed, under physiological conditions immune access to CNS is tightly regulated. Over the past decade, new scientific discoveries highlighted pathways by which immune and neurological systems interact, including a variety of mechanisms controlling permeability of blood-brain barrier, and specific roles that CD4⁺ and CD8⁺ T-lymphocytes play in initiation of specific adaptive immune response to neural specific antigens. This leads to release of proinflammatory cytokines (interleukin 1, interleukin 6, and tumor necrosis factor alpha). In addition, B-cells involved in CNS inflammation produce antibodies against membrane bound and soluble antigens. This article describes specific neurological manifestations of the most common autoimmune rheumatic disorders.