Course Of Psoriatic Arthritis Research Articles

Interleukin levels and depressive symptoms in psoriatic arthritis patients: insights from a case-control study on socio-demographic factors and disease perception.

In the course of psoriatic arthritis (PsA), depression occurs much more often than in the general population. Depression can be considered a poor prognostic factor. The aim of the study was to assess the relationships between the occurrence of depression and the levels of proinflammatory cytokines in patients with PsA. The study included 86 (47F/39M) patients with PsA. Only patients with high disease activity (DAPSA > 28) were enrolled in the study. The severity of depressive symptoms was assessed using the Beck Depression Inventory II (BDI-II) for all patients. Additionally, sociodemographic data were collected. All patients were also assessed for the levels of interleukins (IL): IL-1, IL-6, IL-17A, IL-23, and tumor necrosis factor alpha (TNF-α) using the enzyme-linked immunosorbent assay (ELISA) test. In the study group, depression (BDI-II ≥ 14) was diagnosed in 45 patients (52%). Patients with coexisting depression reported higher levels of pain and disease activity on the visual analogue scale compared to patients without depression (8.5 vs. 7.7, p < 0.001 and 9.3 vs. 8.4, p < 0.001, respectively). The mean levels of proinflammatory cytokines [pg/ml], IL-1 and IL-6, were also higher in the group of patients with depression (46.4 vs. 4.7, p < 0.001 and 10.5 vs. 4.9, p < 0.001, respectively). The coexistence of depression in the course of Psoriatic Arthritis (PsA) is associated with higher levels of IL-1 and IL-6. Depression has a negative impact on the perception of the underlying disease and is linked to reduced social and occupational activity.

PSORIATIC ARTHRITIS: PROBLEMS AND SOLUTIONS (CASE REPORT)

The purpose of this study is to evaluate the effectiveness of therapy for psoriatic arthritis with tumor necrosis factor inhibitor α–Adalimumab. Material and methods. Retrospective and prospective analyses of psoriatic arthritis course were performed in a patient along with a comprehensive examination before and after administering therapy with a tumor necrosis factor inhibitor α-Adalimumab. The diagnosis of the patient was made on the basis of psoriatic arthritis classification criteria, the assessment of psoriatic rashes was performed according to PASI index. The laboratory study included complete blood cell count and biochemical blood tests. The patient underwent X-ray examinations of the joints and magnetic resonance imaging of the lumbosacral spine in the STIR mode. Study results. The patient's first manifestations of psoriasis were detected at the age of 12 years. At the age of 22, the patient had pain in the lower back of VAS 2-3 points, as well as enthesites in the area of the lateral epicondyle of humerus, wings of the iliac bones, trochanter major, the upper edge of the patella and tibial tuberosity, the PASI index was 17.3 points. In order to relieve pain, the patient took non-steroidal anti-inflammatory drugs. Against the background of therapy with non-steroidal anti-inflammatory drugs, the intensity of pain in the lower back decreased, but enthesites persisted. At the age of 35, the patient was diagnosed with psoriatic arthritis, activity III, stage II, dactylitis, enthesites, PASI index 38.5 points; right-sided active sacroiliitis, ASDAS ESR index activity was 3.92 points, joint functional insufficiency of the 2nd degree. Methotrexate therapy was prescribed. There was no positive dynamics against the background of treatment, in connection with this, therapy with genetically engineered biological drugs was initiated. We observed positive dynamics in the clinical course of psoriatic arthritis when Adalimumab was included in the treatment: after the 2nd week of treatment, the articular syndrome subsided, joint pain decreased when evaluated on a scale of 2-3 points, the number of psoriatic plaques on the trunk and limbs decreased as well, the index of psoriatic rashes was 5.3 points. After 8 weeks from the start of therapy with Adalimumab, regression of pathological skin rashes was noted, the index of psoriatic rashes was 0 points. Conclusions. Therapy with Adalimumab in the patient resulted in regression of psoriatic manifestations on the skin, suppression of psoriatic arthritis activity. The study showed the clinical effectiveness of a genetically engineered biological drug – Adalimumab in achieving persistent clinical remission of psoriatic arthritis.

Molecular Background and Clinical Implications of Glucose Disorders in Patients with Psoriatic Arthritis.

Psoriatic arthritis (PsA) is an inflammatory musculoskeletal disease characterized by joint and entheses involvement. This condition is often associated with an increased prevalence of obesity, encompassing more than one-third of all patients. Given the presence of metabolic disorders, it becomes crucial to enhance clinical oversight of metabolic parameters. An early diagnosis of glucose irregularities in PsA allows for the assessment of an effective treatment strategy. The approach proves valuable in preventing the development of insulin resistance (IR) or diabetes mellitus type 2 (DMt2). Similar pathways characterize the pathomechanism of PsA and DMt2, offering an innovative perspective on treatment management. The cytokines and adipokines synthesized in the course of PsA significantly impact the development process of IR and DMt2 in different mechanisms of action. Conversely, glucose disorders influence the activity of PsA and therapy outcomes. Given the chronic inflammatory background shared by PsA, obesity, and DMt2, it is evident that inadequate management of any of the mentioned conditions can exacerbate the others. Thus, when PsA coincides with DMt2, a comprehensive multidimensional approach is necessary. This includes an effective immunosuppressive regimen complemented by appropriate anti-diabetic and insulin therapies. Moreover, often overlooked recommendations concerning overall well-being and lifestyle adjustments hold significance. This manuscript explores the connections and the relationship between the molecular background of PsA and glucose disorders. It provides a detailed exposition of specific therapeutic approaches for both conditions.

The MAP2K2 Gene as Potential Diagnostic Marker in Monitoring Adalimumab Therapy of Psoriatic Arthritis.

MAP kinases are some of the cascades that are specialized in the cell's response to external stimuli. Their impaired functioning can be observed during the course of psoriatic arthritis. Currently, the best-known class of biological drugs is the inhibitors of the proinflammatory cytokine TNF-α, including adalimumab. The aim of this study was to assess changes in the expression of MAP kinase genes in patients with psoriatic arthritis treated with adalimumab, as well as to determine which of the analyzed transcripts could be used as a diagnostic or therapeutic target. An analysis was performed on the total RNA extracted from PBMCs of patients with psoriatic arthritis before and after three months of adalimumab therapy as well as from a control group. Changes in the expression of the mitogen-activated protein kinase genes were assessed using the HG-U133A 2.0 oligonucleotide microarray method, while the obtained results were validated using the real-time RT-qPCR method. Using the oligonucleotide microarray method, 14 genes coded for proteins from the MAPK group were identified with at least a two-fold change of expression in the control group and during adalimumab therapy. Validation of the results confirmed a statistically significant decrease in the transcriptional activity of the MAP2K2 gene in the group of patients three months after the administration of adalimumab relative to the control group. Adalimumab therapy alters the expression of MAPK-coding genes. The assessment of the number of MAP2K2 mRNA molecules can potentially be used in diagnostic analyses or in monitoring adalimumab therapy.

Retraction of the article “The clinical features and course of psoriatic arthritis in children”

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Minimal disease activity (MDA) in patients with recent-onset psoriatic arthritis: predictive model based on machine learning

BackgroundVery few data are available on predictors of minimal disease activity (MDA) in patients with recent-onset psoriatic arthritis (PsA). Such data are crucial, since the therapeutic measures used to change the adverse course of PsA are more likely to succeed if we intervene early. In the present study, we used predictive models based on machine learning to detect variables associated with achieving MDA in patients with recent-onset PsA.MethodsWe performed a multicenter observational prospective study (2-year follow-up, regular annual visits). The study population comprised patients aged ≥18 years who fulfilled the CASPAR criteria and less than 2 years since the onset of symptoms. The dataset contained data for the independent variables from the baseline visit and from follow-up visit number 1. These were matched with the outcome measures from follow-up visits 1 and 2, respectively. We trained a random forest–type machine learning algorithm to analyze the association between the outcome measure and the variables selected in the bivariate analysis. In order to understand how the model uses the variables to make its predictions, we applied the SHAP technique. We used a confusion matrix to visualize the performance of the model.ResultsThe sample comprised 158 patients. 55.5% and 58.3% of the patients had MDA at the first and second follow-up visit, respectively. In our model, the variables with the greatest predictive ability were global pain, impact of the disease (PsAID), patient global assessment of disease, and physical function (HAQ-Disability Index). The percentage of hits in the confusion matrix was 85.94%.ConclusionsA key objective in the management of PsA should be control of pain, which is not always associated with inflammatory burden, and the establishment of measures to better control the various domains of PsA.

AB0858 Clinical characteristics of patients with spondyloarthritis with COVID-19 in anamnesis in the Republic of Tatarstan

BackgroundThe management of patients with spondyloarthritis (SpA) during the period of the novel coronavirus infection (NCI) pandemic is a significant problem due to insufficient evidence base.ObjectivesTo study the features of the course NCI and its influence on the course of SpA.MethodsFrom March 2020 to January 2022, 55 patients with SpA who underwent NCI (with a confirmed result of SarsCoV2 PCR and / or using X-ray computed tomography (CT) of the lungs): ankylosing spondylitis (AS) 37 people, with psoriatic arthritis (PsA) 18 people. Of these 32 (58.2%) were men, 23 (41.8%) - women, the average age of patients was 49 [37.5; 57.5] years. The duration of SpA at the time of NCI was 11 [7; 16] years. SpA activity before NCI was low in 15 (34.8%) patients, moderate in 25 (58.1%), and high in 3 (6.9%) patients. The results of clinical and laboratory examinations were evaluated during the NCI and after 1, 3, 6 months.ResultsSymptoms of NCI in patients with SpA were comparable in frequency and severity to the course of infection in the population. 47.3% had a mild course of NCI, and 52.7% of those observed had a moderate course, which is comparable with the general population data. Lung involvement was detected in 29 (52.7%) patients. The outcome of COVID-19 in all patients is recovery. Analysis of the course of SpA showed an increase in activity 1 and 3 months after NCI: BASDAI from baseline to COVID-19 4.3±1.57 to 4.9±1.7 points after 3 months, similar to ASDAS_CRP from 2.6±1, 2 to 3.7±0.2, BASFI from 3.0±1.9 to 3.8±1.8. A positive correlation was found between the severity of NCI and the BASFI index after 3 months (0.870). Analysis of the course of PsA showed an increase in activity 1 and 3 months after NCI: DAS28 from the baseline 2.78±0.98 to 4.15±1.16 points after 3 months. Of the total number of recoveries, 72.2% of patients showed an increase in activity due to clinical and laboratory parameters.78.1% of patients noted the presence of post-COVID symptoms after NCI, 56.3% had a combination of more than 3 different symptoms. Most often there was an increase/appearance of pain in the joints - in 78.1%: significant - in 61.8%, insignificant - in 16.3% of respondents. Strengthening/appearance of muscle pain and/or headache and/or dysautonomia occurred in 72.7%. This can be assessed as an exacerbation of the underlying disease, or, conversely, the appearance of arthralgia and myalgia could have an impact on the increase in AS and PsA activity indices. The second most frequent were a decrease in the quality of life (QOL) and working capacity in 69.0% of patients: significant in 36.3% of patients, insignificant in 32.7%.The appearance/intensification of shortness of breath and a decrease in exercise tolerance were noted by 60% of the respondents. Among them, 34.5% of patients with moderate severity, 25.4% - with mild NCI. Appearance/intensification of chest pain and/or palpitations was noted by 16.3% of patientsConclusionThe prevalence and course of the NCI in patients with SpA did not differ from that in the population. However, coronavirus infection has led to increased pain and an increase in AS activity, long-term persistence of post-COVID manifestations in the form of musculoskeletal pain and asthenic symptoms in the form of a decrease in the quality of life. At the same time, specific respiratory symptoms occurred in a third of patients and were not associated with the severity of the NCI.Disclosure of InterestsNone declared

Usefulness of Ultrasound Examination in the Assessment of the Nail Apparatus in Psoriasis.

The assessment of psoriatic nail changes in everyday practice is based exclusively on clinical symptoms that do not reflect the entire disease process in the nail apparatus. The use of imaging methods, especially widely available and inexpensive ultrasonography, creates the possibility of additional revealing and assessing grayscale of morphological changes of the ventral nail plate, nail bed, and matrix, as well as the attachment of the finger extensor tendon to the distal phalanx. What is more, it enables the assessment of inflammation severity in the power Doppler technique. A qualitative classification of nail plate morphological changes corresponding to the severity of psoriatic nail changes has been developed so far and attempts are being made to develop a quantitative method to assess not only the presence of changes but also the severity of inflammation. Nail ultrasonography is not commonly performed, although published studies indicate the possible use of this technique in the assessment of psoriatic changes in nail structures. It can be particularly useful in subclinical changes imaging, preceding clinical manifestation of psoriatic nail changes, enthesopathy: subclinical and in the course of psoriatic arthritis, as well as in the assessment of treatment efficacy. This review article aims to summaries the research on ultrasonography of the nail apparatus which has been carried out so far, taking into account its applicability in clinical practice.

COVID-19 in Patients with Psoriatic Arthritis

The COVID-19 pandemic has a negative impact on all aspects of human life and can lead to the exacerbation of chronic diseases. At the same time, it is known that a higher risk of infection and a more severe course of coronavirus infection is found in the elderly, as well as in people with serious comorbidities. Psoriatic arthritis (PsA) is a type of inflammatory arthritis that is often diagnosed in patients with psoriasis. Specific treatment of patients with chronic inflammatory joint disease include nonsteroidal anti-inflammatory drugs, glucocorticosteroids, disease-modifying antirheumatic drugs, new biological agents, including monoclonal antibodies to IL-6, IL-1, TNF-a, target disease modifying drugs. Medications used for PsA treatment can potentially have both negative and positive effects on the course of COVID-19. The objective: to analyze the features of COVID-19 in patients with PsA and to study the comorbid pathology after coronavirus infection. Materials and methods. The study involved 174 people with a verified diagnosis of PsA. Patients were divided into two groups. Group I included 112 (64.4%) persons who had COVID-19, and group II - 62 (35.6%) who had not had coronavirus infection at the time of first examination. Patients in group I significantly differed from group II in age (p &lt;0.001) and duration of PsA (p &lt;0.001), showed a significantly higher degree of psoriatic skin lesions and activity of the underlying disease (p = 0.001) compared to patients from group II. The participants of the study underwent examination characterize the course of the psoriatic disease and skin lesions and risk of cardiovascular disease. Results. To date, there are no clear scientific data that reveal the specific features of COVID-19 infection and the effect of antirheumatic therapy on the development of dangerous complications associated with coronavirus infection in patients with PsA. The analysis of comorbid pathology has found cardiovascular pathology in 67 (59.8%) of patients, including arterial hypertension – in 58 (51.8%) people, metabolic syndrome – in 34 (30.4%), diseases of the digestive system – in 32 (28.6%) and respiratory system – in 24 (21.4%) of persons. Conclusions. Patients with higher activity and duration of the PsA were significantly more likely to get COVID-19 and demonstrated higher total cardiovascular risk for the next 10 years. Further research is needed to study the impact of specific basic rheumatological drugs on the outcomes of COVID-19 and to analyze the broader effects of the pandemic on the course of psoriatic arthritis.

Psoriatic arthritis: prospects for the future.

Psoriatic arthritis (PsA) is a form of chronic inflammatory arthritis associated with psoriasis and a multitude of other symptoms, most commonly arthritis, dactylitis, enthesitis and axial involvement. PsA is significantly heterogeneous, with a highly variable clinical course of PsA. Patients may experience significant or mild skin and joint symptoms, with some patients developing rapidly progressing joint destruction and skin symptoms. Despite the range of symptom severity, PsA is frequently associated with significantly impaired quality of life from joint destruction, as well as chronic pain and a range of comorbidities such as depression and cardiovascular disease. Currently, there are no definitive diagnostic tests for PsA, with diagnosis remaining challenging owing to the heterogeneous presentation and course of the disease. Presently, the CASPAR criteria are often used to aid rheumatologists in distinguishing PsA from other inflammatory arthritides. Treatment options for patients have been expanded over the last two decades with the emerging clinical utility of biological therapies. However, early identification and diagnosis of patients and effective disease control remain unmet medical needs within the PsA community. In addition, predicting response to treatment also remains a challenge to rheumatologists. This review highlights the current hurdles faced by healthcare professionals in the diagnosis and management of PsA patients and provides future action points for consideration by the members of the multidisciplinary team who treat PsA patients.

Stage of morphological changes in psoriatic arthritis.

Background. Chronically progressive course of psoriatic arthritis, not the certainty of pathogenetic units, and accordingly errors in diagnosis and treatment lead to significant negative results and disability of patients. Objective is to improve the results of the diagnosis of PA by examining the morphological features of the disease. Methods. Histomorphological studies performed on tissues removed during surgery on the joints in 32 patients. The material distributed into groups depending on the severity of the clinical manifestations of the disease. Results. At the beginning of the disease and at the exudative-proliferative stage, a pattern of pronounced inflammatory process, mainly exudative, serous-fibrinous character, was noted in the capsule of the joint. The most significant changes occurred in the synovial membrane, where marked proliferation of the integumentary synovial cells, hypertrophy and hyperplasia of the synovial membrane were observed with the formation of a large number of villi and folds. At histological examination in the tissues of the joint with a dystrophic-degenerative stage there was a pronounced exudative-proliferative inflammatory process, with significant degenerative-dystrophic and fibro-sclerotic changes. Conclusion. Histological studies in patients with PA, evidence of the presence of a sharp non-specific, non-peculiar, non-peculiar, non-peculiar, non-peculiar, non-peculiar, non-peculiar, syllabic history changes. Pathological changes in the articular cartilage and subordinate epiphysis bone are manifested by significant degenerative-dystrophic and destructive manifestations.

Клинические особенности псориатического артрита в детском возрасте

Study Objective: to present literature review of clinical parameters and course of psoriatic arthritis (PsA) in children, and results of PsA patients examination in University Clinical Children Hospital of I.M. Sechenov First Moscow State Medical University. Study Design: open prospective study. Materials and Methods. We analysed medical records of 83 children with PsA aged 3 to 17 years who were examined and managed in University Clinical Children Hospital of I.M. Sechenov First Moscow State Medical University in 1989 – 2019. Study Results. Confirmed PsA was diagnosed in 59 (71%) children, suspected PsA — in 24 (29%) children; 44 (53%) children got ill before they were 6.5 years old. In 24 (29%) patients, disease started with skin involvement; in 59 (71%) patients, articular syndrome was the first manifestation of disease. In the group of patients with confirmed psoriasis, the most common was plaque psoriasis: it was diagnosed in 45 (76.3%) out of 59 children; guttate psoriasis was found in 8 (13.5%) children, isolated nail plaque psoriasis — in 3 (5.1%) patients, and palm and foot psoriasis — in 3 (5.1%) children. Psoriasis of the scalp was diagnosed in 23 (39%) subjects. In 8 (13.5%) patients, skin syndrome was associated with mild infiltration and scant desquamation. 18 (21.7%) out of 83 children had skin involvement together with nail bed involvement. Psoriasic onychodystrophy was diagnosed in 19 (23%) children (onycholysis, “oil patches” on fingers and toes); 15 (18.1%) children had “thimble syndrome”. On disease onset, 68.7% of children had oligoarticular, sometimes asymmetric articular syndrome; 18.1% had symmetric rheumatoid-like disease, 13.2% — psoriasic spondylitis. After 5 years of follow-up, articular syndrome transformed: 41.2% of patients had symmetric rheumatoid-like disease, 24.1% — asymmetric oligoarthritis, 24.1% — spondylarthritis with peripheral joint involvement, and 10.8% — arthritis mutilans. Most commonly PsA affected knee, talocrural joints, small hand joints – 41%, 31.3%, 29%, respectively. Conclusion. Clinical manifestations of PsA varied a lot. Our patients did not have a second peak. Almost one third of children had skin changes prior to arthritis development. Onset of disease was associated with asymmetric oligoarthritis prevalence. Later, articular syndrome changed, and symmetric rheumatoid-like disease prevailed. Keywords: children, psoriatic arthritis, psoriasis, juvenile idiopathic arthritis, Vancouver diagnostic criteria.

Lengthening the time intervals between doses of biological agents in psoriatic arthritis patients: A single-center retrospective study.

Anti-tumor necrosis factor (TNF) alpha therapy has changed the course of psoriatic arthritis (PsA), but clinical experience about lengthening of time intervals between drug administrations is still limited. The aims of the study were to evaluate: (1) the long-term efficacy (over a 4-year period) of etanercept/adalimumab in a subset of PsA patients who did not require switches; and (2) the progressive lengthening of time intervals between treatments in patients who achieved minimal disease activity (MDA). PsA outpatients attending the Rheumatology Clinic-University of Padova who took a single anti-TNF agent (etanercept/adalimumab) for a 4-year period were studied. Therapy efficacy was assessed using clinical, biochemical, and disease activity (DA) indexes. The intervals between treatments were empirically and progressively lengthened after MDA was reached and maintained. One hundred and forty-one patients (mean age, 51.22 ± 12.34 years; mean disease duration, 12.1 ± 8.42 years) treated with etanercept/adalimumab (47.5% and 52.5%, respectively) were studied. DA indexes showed a marked, persistent improvement in all the patients throughout 4 years. The interval between injections could be extended in 46.1% of the patients (35% for adalimumab, 58% for etanercept) without provoking relapses. The mean therapy interval at the end of the study period was 3.12 weeks for adalimumab 40 mg (with respect to 2 weeks) and 2.75 weeks for etanercept 25 mg (with respect to 0.5 weeks). The new therapy timetable also led to cost savings. In conclusion, lengthening the time intervals between injections of anti-TNF agents in PsA patients who reach MDA is safe, effective, cost-effective, and facilitates patient compliance.

Influence of psoriasis on circulatory system function assessed in echocardiography.

Psoriasis vulgaris is a chronic disease with a multifactorial pathogenesis. It affects about 2–4 % of the population all over the world. In course of psoriatic arthritis, joints’ damages are observed. In patients with psoriasis vulgaris and psoriatic arthritis, there is increased morbidity and mortality caused by cardiovascular diseases observed. The aim of the study is to analyze the echocardiography of patients with psoriasis vulgaris and psoriatic arthritis on the basis of the literature available in PubMed database. Abnormalities found in echocardiography of patients with psoriasis include valvular defects (40.7 % of the patients), left ventricle diastolic dysfunction (27.8 %), and left ventricle hypertrophy (11.1 %). Left ventricle’s systolic disorders, increased aorta stiffness index and increased pulmonary artery blood pressure were also observed in this group of patients.

Psoriatic arthritis for the dermatologist.

Psoriatic arthritis (PsA) is a chronic, progressive, inflammatory spondyloarthropathy that affects approximately one-third of patients with all types of psoriasis. Dermatologists are in a unique position to recognize early symptoms of PsA, initiate appropriate therapy, and prevent development of further disability. The course of PsA can be modulated by immunosuppressive therapy; patients with moderate-to-severe disease require aggressive management with medications proven to halt disease progression. It is essential for the dermatologist to understand the safety, tolerability, efficacy, cost, and potential to halt disease progression with available medications for this relatively common and potentially disabling disease.

Imaging modalities in psoriatic arthritis

This review presents an overview of the range of imaging modalities used in the diagnostic evaluation of patients with psoriatic arthritis (PsA). Conventional radiography is used to detect structural changes of the joints and tendon attachments. These changes occur late in the course of PsA hence conventional radiography contributes little to the early detection of PsA; however, the detection of periosteal proliferations on radiographs allows a relatively specific diagnosis of PsA. Skeletal scintigraphy and computed tomography are rarely used in PsA. Arthrosonography (ultrasound of the joints) is gaining increasing importance in the early identification of inflammatory soft tissue signs of PsA in the peripheral joints. Sonography enables early detection of synovitis and tenosynovitis as well as superficial erosions and also inflammatory processes of the tendon attachments. Magnetic resonance imaging (MRI) is indispensable for identifying possible involvement of the axial skeleton. Moreover, it allows good visualization of periostitis and arthritis. High resolution microcomputed tomography is an interesting novel diagnostic tool which allows highly sensitive evaluation of the bone structure and can detect very tiny bone lesions where typical signs of PsA are omega-shaped erosions and small corona-like spikes. Another interesting new diagnostic technique is fluorescence optical imaging (FOI) with the Xiralite system which is highly sensitive for detecting inflammatory processes of the hands.

Inflammatory Musculoskeletal Disease: Identification and Assessment

Diagnosis of psoriatic arthritis (PsA) is complex because not all patients with psoriasis and musculoskeletal symptoms of pain, stiffness, and dysfunction have PsA. Instead, they may have other inflammatory conditions such as rheumatoid arthritis, gout, or septic arthritis, or noninflammatory conditions such as osteoarthritis, recurrent tendonitis, mechanical back pain, or a myriad other musculoskeletal conditions. To acquire skill in diagnosing and monitoring the disease course of PsA, a clinician must recognize that there are multiple clinical domains that may be affected, including peripheral joints, entheseal insertion sites, dactylitis, and the spine. They must also appreciate the clinical features (history and physical examination) that are characteristic of immunologic inflammation and know how to utilize and interpret laboratory and imaging studies. Rheumatologists are expected to be skilled in these assessments. It is also helpful for dermatologists, primary care physicians, and other clinicians who work with psoriasis patients to have a working knowledge of assessments in PsA in order to identify and triage the patient for optimal management. Features that assist identification and assessment of PsA are reviewed in this article.

Bias in 2-part mixed models for longitudinal semicontinuous data

Semicontinuous data in the form of a mixture of zeros and continuously distributed positive values frequently arise in biomedical research. Two-part mixed models with correlated random effects are an attractive approach to characterize the complex structure of longitudinal semicontinuous data. In practice, however, an independence assumption about random effects in these models may often be made for convenience and computational feasibility. In this article, we show that bias can be induced for regression coefficients when random effects are truly correlated but misspecified as independent in a 2-part mixed model. Paralleling work on bias under nonignorable missingness within a shared parameter model, we derive and investigate the asymptotic bias in selected settings for misspecified 2-part mixed models. The performance of these models in practice is further evaluated using Monte Carlo simulations. Additionally, the potential bias is investigated when artificial zeros, due to left censoring from some detection or measuring limit, are incorporated. To illustrate, we fit different 2-part mixed models to the data from the University of Toronto Psoriatic Arthritis Clinic, the aim being to examine whether there are differential effects of disease activity and damage on physical functioning as measured by the health assessment questionnaire scores over the course of psoriatic arthritis. Some practical issues on variance component estimation revealed through this data analysis are considered.

Autoantikörperdiagnostik

In the field of dermatology, autoantibody diagnostics are relevant in bullous autoimmune and connective tissue diseases and in certain forms of systemic vasculopathy and psoriatic arthritis. Autoantibody diagnosis of bullous autoimmune skin diseases is an area of dermatology, while serodiagnosis of the other diseases is also performed in rheumatology or in large laboratory centers. Antibody diagnosis of bullous skin diseases is more targeted, as the localization, molecular structures, and function of the relevant epidermal or dermal autoantigens are now known to a large extent, and there are sound experimental indications of the pathogenetic role of these autoantibodies. In practical terms, it is important that some of these antibodies are not only used for the initial diagnosis but also to evaluate the course of the disease and the success of treatment. The autoantibody profile in patients with connective tissue disease may also be disease specific, whereas the pathogenetic significance of these autoantibodies, which are usually directed against nuclear and cytoplasmic components or membrane receptors, is still largely unknown. Autoantibody diagnosis is also important in practice in certain vascular diseases. The future will show whether the determination of antibodies against cyclic citrullinated peptides will become more important in diagnosing and following the course of psoriatic arthritis in practice.

A longitudinal study of the effect of disease activity and clinical damage on physical function over the course of psoriatic arthritis: Does the effect change over time?

To investigate whether there are differential effects of disease activity and damage on physical functioning as measured by the Health Assessment Questionnaire (HAQ) over the course of psoriatic arthritis (PsA). Between June 1993 and March 2005, 382 patients attending the University of Toronto PsA clinic had completed > or =2 HAQs on an annual basis. At the time of each HAQ assessment, clinical and laboratory measures of disease activity and damage were recorded. Generalized linear mixed-effects models were used to investigate the longitudinal relationship between disease activity, damage, and the HAQ score. To avoid floor effects that would arise in a single mixed-effects model, we adopted a 2-part model. The number of actively inflamed joints (measure of disease activity) and the number of clinically deformed joints (measure of damage) were positively and significantly related to the HAQ score. Furthermore, interaction terms for illness duration with the number of actively inflamed joints were statistically significant, with or without inclusion of the erythrocyte sedimentation rate and morning stiffness in the model (P = 0.029 and P < 0.001, respectively). The positive effects of actively inflamed joints on the level of the HAQ score decreased over increasing duration of PsA. There was less evidence to suggest that the positive effect of joint damage on the HAQ score increased over time. Our results support the view that the influence of disease activity on HAQ scores declines with increased disease duration. We could not demonstrate strong evidence that the effect of clinical damage increases over the course of illness.