[General concepts and pathogenesis of the spondyloarthropathies]

The spondyloarthritides are a group of interrelated diseases with a close association with the HLA-B27 antigen that share many common articular and extra-articular features. This paper summarizes the different classification criteria that are currently in use. While the exact pathogenesis of these diseases is not yet clearly elucidated, there are a number of hypotheses relating to HLA-B27, modifications of the microbiome and biomechanical stresses. This in turn leads to upregulation of various proinflammatory cytokines such as TNF-alpha, IL-17, IL-22 and IL-23, which results in further inflammation and osteoproliferation.

Relationship of Psoriatic Arthritis to Other Spondyloarthritides

In the early 1970s, Moll and co-workers formulated the unified concept of spondyloarthritides, a group of conditions sharing similar clinical features. Subsequently, criteria for their classification have been proposed by Amor and coworkers, the European Spondylarthropathy Study Group, and the Assessment in SpondyloArthritis international Society. Opinion, however, is divided between those who believe that the different entities of the complex represent the variable expression of the same disease ("lumpers") and those who think that these should be considered separately but under the same umbrella ("splitters"). Several sets of criteria have been proposed for psoriatic arthritis (PsA), the most recent being the ClASsification for Psoriatic Arthritis (CASPAR) criteria. According to some authors, there are persuasive arguments to support the view of PsA as a distinct entity.

[Undifferentiated spondyloarthropathies]

The article is a review of the various aspects of the undifferentiated spondyloarthropathies. Data on the prevalence denote considerable frequency of undifferentiated spondyloarthropathies in various age groups. Clinical symptoms, evolution and treatment are provided. The special attention is given to a problem of juvenile spondyloarthropathies. Changes of the nomenclature of the spondyloarthropathies are offered, allowing to improve diagnostics and treatment of these diseases.

Classification of the spondyloarthropathies

PURPOSE OF REVIEW

The spondyloarthropathies are a group of conditions which share similar clinical features. Classification criteria permit separation of the conditions, allow better targeting of therapies, better measurement of outcomes, and better prognostic information. Early diagnosis remains problematic, but validated criteria for established disease are now emerging.

RECENT FINDINGS

Histopathology and histochemistry are providing a better understanding of the underlying process of inflammatory arthritis in spondyloarthropathy and other inflammatory arthritides. Early disease, however, continues to challenge current criteria. Sophisticated imaging with magnetic resonance imaging is being increasingly used and is proving useful for early diagnosis as well as helping to understand the pathophysiology of disease. Juvenile idiopathic arthritis continues to provide problems and criteria have recently been modified to allow a greater clinical utility and inclusion of more patients. Poststreptococcal reactive arthritis appears to be a heterogeneous clinical entity, with a group looking more like rheumatic fever and a group with spondyloarthropathy traits. It may be that the association is not streptococcal, but is a throat infection. Currently available criteria for psoriatic arthritis have been evaluated in a large cohort. Four of the criteria performed well with high specificity and sensitivity whereas the other two had moderate specificity and low sensitivity. It was shown that rheumatoid factor positivity does not exclude a diagnosis of psoriatic arthritis--the single most important clinical feature of this condition being the presence of psoriasis.

SUMMARY

The spondyloarthropathy classification criteria continue to be an area of development. This is most apparent in juvenile arthritis and psoriatic arthritis. The latter is currently undergoing intense scrutiny to develop classification criteria and outcome measures.

Primate spondyloarthropathy

Spondyloarthropathy is a common occurrence in Old World primates, with only limited presence in New World monkeys. Clearly distinguished from rheumatoid arthritis, this erosive arthritis afflicts 20% of great apes, baboons, and rhesus macaques and had been increasing in frequency. Habitat-dependent infectious agent diarrhea-induced reactive arthritis is implicated on a background of genetic predisposition. A gorilla-derived therapeutic preventative approach has possible application in human clinical medicine.

Evaluation of the European Spondyloarthropathy Study Group (ESSG) classification criteria in a Chinese population

OBJECTIVE

To evaluate for thefirst time in a Chinese population, the usefulness of the European Spondyloarthropathy Study Group (ESSG) criteria.

METHODS

A total of 193 clinically diagnosed SpA patients were compared to 166 patients with other types of arthritis, using the parameters listed in the ESSG criteria.

RESULTS

The sensitivity and specificity of the ESSG criteria in this Chinese population were high at 85.4% and 96.4% respectively.

CONCLUSION

The use of ESSG criteria for classifying SpA in Chinese will not lead to significant omission of SpA patients or inclusion of patients who do not have SpA.

Seronegative spondyloarthropathies: to lump or split?

The advent of novel biological therapies for the treatment of rheumatic disease has renewed interest in the seronegative spondyloarthropathies (SpAs). International efforts are redefining disease classification and measures of disease activity, outcome, metrology, and imaging. However, opinion is divided between those who propose that the SpA group represents the same disease with variable expression (the "lumpers") and those who consider these to be separate diseases with shared clinical features (the "splitters"). This review presents the evidence for both approaches.

Two major spondylarthropathy phenotypes are distinguished by pattern analysis in multiplex families

OBJECTIVE

To examine whether spondylarthropathy (SpA) disease manifestations would combine in any ordered pattern among patients from SpA multiplex families.

METHODS

SpA patients (n = 540) belonging to 190 multiplex families were thoroughly investigated. Clinical data was collected, systematic pelvic radiographs were taken, and HLA-B27 status was determined. The patterns of SpA manifestations were examined by several methods, including multiple correspondence analysis, nonhierarchical and hierarchical clustering, and discriminant analysis.

RESULTS

The nonhierarchical cluster analysis allowed us to classify patients, independent of disease duration, into 2 major groups of comparable size. Group A contained a majority of the women, whereas group B predominantly consisted of men. The 2 groups were very similar regarding axial symptoms, radiographic sacroiliitis, and uveitis. Group B was characterized by a younger age at onset and a higher frequency of clinical enthesitis, peripheral arthritis, dactylitis, psoriasis, and inflammatory bowel disease than group A. Patients belonging to those groups exhibited some degree of familial aggregation, thereby supporting their intrinsic validity.

CONCLUSION

Pattern analysis of SpA manifestations among familial SpA allowed us to recognize 2 main clusters independent of disease duration. Furthermore, there was a trend toward aggregation by cluster among families, suggesting that they are determined by specific genetic factors. These clusters may indeed correspond to different severity patterns.

[Grading sacroiliitis with emphasis on MRT-imaging]

Cross-sectional imaging techniques play a decisive role in identification, localization, and characterization of alterations in the sacroiliac joint during the early stage of seronegative spondylarthropathy (SpA). Although several studies showed that the diagnostic capabilities of MRI and CT are superior to those of conventional radiography, they have not yet become established and accepted as methods for evaluating the grade of ankylosing spondylitis (AS) in contrast to conventional radiography. The lack of acceptance for MRI and/or CT methods for evaluating and grading changes in the sacroiliac joint makes it difficult to include the results of these procedures in classifying the grade of SpA. Moreover, grading the changes in the sacroilac joint in SpA with a method more sensitive than conventional radiography will be of prime importance in assessing treatment, e.g., the efficacy of new biological therapeutic agents directed against the tumor necrosis factor-alpha (TNF-alpha). An overview of the available grading methods is provided and MRI and CT techniques are presented.

Relationship of psoriatic arthritis with the other spondyloarthropathies

PURPOSE OF REVIEW

The seronegative spondyloarthropathies are a group of disorders sharing common clinical features, the hallmark of which is sacroiliitis. Despite the 40 years since psoriatic arthritis was recognized, controversy still exists about which patients to include within this disease group and the relation of psoriatic arthritis with the other spondyloarthropathies.

RECENT FINDINGS

Early disease can present difficulties because it is inappropriate to use criteria developed on established cases in early arthritis, in which many cases may be initially undifferentiated. The taxonomy of juvenile spondyloarthropathy remains a contentious issue, and further modifications of the Durban criteria have been suggested. The predictive value of the European Spondyloarthropathy Study Group criteria for spondyloarthropathy varies with the prevalence of the disease in the population under consideration, as has been demonstrated in ambulatory practice in France and Spain. It appears that physicians differ in their interpretation of the individual features, particularly of such clinical items as asymmetry and predominantly lower limb involvement. The combination of dactylitis of a toe, heel pain, and oligoarthritis appears to be strongly suggestive of psoriatic arthritis. However, solitary heel pain can be problematic, and ultrasonographic entheseal erosion at the calcaneum has been shown equally in rheumatoid arthritis and psoriatic arthritis. MRI may be more sensitive and quantitatively discriminative in psoriatic arthritis. Spinal involvement in psoriatic arthritis can be asymptomatic, as in classical ankylosing spondylitis. Importantly, psoriatic spondylitis has been observed in the absence of sacroiliitis.

SUMMARY

Clinicians generally agree that psoriatic arthritis constitutes a discreet subset within the spondyloarthropathy group, but the demarcation continues to be the subject of clinical research. The matter is confounded by the lack of agreed classification criteria for psoriatic arthritis; although in both adult and juvenile disease criteria for spondyloarthropathy exist, the place of psoriatic arthritis within this larger group requires further definition.

Evaluation of classification criteria for juvenile-onset spondyloarthropathies

OBJECTIVE

The aim of this study was to investigate the adequacy of the following criteria for the classification of juvenile-onset spondyloarthropathies (JSpA): European Spondyloarthropathy Study Group criteria (ESSGCr) and Amor criteria (ACr) (proposed for adult SpA), Garmisch-Partenkirchen (G-PCr), seronegative enthesopathy and arthropathy syndrome (SEACr), and atypical spondyloarthropathies classification criteria (ASpCr) (proposed for JSpA).

METHODS

Sixty-two patients with JSpA (48 male and 14 female) and 64 with juvenile idiopathic arthritis (27 male and 37 female) (excluding enthesitis-related and psoriatic arthritis) were enrolled in the study group. Twenty-nine of the patients with JSpA were diagnosed with definite JSpA and the remaining 35 with undifferentiated JSpA. One hundred six patients in the study group were evaluated by one investigator, who was unaware of the diagnosis, according to the following: ESSGCr, ACr, G-PCr, ASpCr, and SEACr.

RESULTS

Analysis of the patients diagnosed with JSpA showed 83.9%, 82.3%, 95.2%, 61.3%, and 62.9% sensitivity and 87.5%, 95.3%, 78.1%, 98.4%, and 92.2% specificity for the ESSGCr, ACr, G-PCr, ASpCr, and SEACr sets, respectively.

CONCLUSION

None of the criteria evaluated above is sufficient for the classification of JSpA. There is a definite need for a new set of criteria with high specificity and sensitivity for early recognition and classification.

[Classification and pathogenensis of spondyloarthropathies]

The classification and pathogenesis of spondyloarthropathies are presented.

[Adaption and validation of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for use in Germany]

OBJECTIVE

The purpose of this study was the validation of a German translation of the Bath Ankylosing Spondylitis Index (BASDAI).

PATIENTS AND METHODS

The German translation of the BASDAI was validated using data of 134 patients with ankylosing spondylitis (AS) from a spondyloarthropathy cohort. For validation the BASDAI was compared with parameters assessed by physicians (physicians global, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), spinal mobility (BASMI), swollen joints, enthesitis (yes or no)), and parameters assessed by patients themselves (pain, function (BASFI) and quality of life (SF-12)). The discriminative validity was analyzed by comparison of BASDAI scores of patients subgroups who have different levels of disease severity. The sensibility to change was analyzed by using follow-up data of a clinical trial on efficacy of the anti-tumor necrosis factor (TNF) alpha agent infliximab in 70 AS-patients with active and severe disease.

RESULTS

The German translation of the BASDAI was easy to understand, the translation back to English corresponded well with the original English version. The 6 questions of the BASDAI represent different aspects of disease but correlated also well with each other (r < 0.65). There was a good internal consistency for all 6 questions (Cronbach's Alpha 0.82), strong correlations to the physician's global (r = 0.659), pain (r = 789), function (BASFI; r = 0.752) and to CRP and ESR confirming that the BASDAI assesses a comprehensive picture of patient's disease activity. For subgroups of patients with different levels of disease severity or with different manifestations the BASDAI showed good discriminative properties. The BASDAI was sensitive to change during treatment with infliximab (effect size 1.18).

CONCLUSION

The German translation of the BASDAI is easy to use, reliable, and sensitive to change for the assessment of disease activity in AS.

[The BASDAI-D--an instrument to defining disease status in ankylosing spondylitis and related diseases]

OBJECTIVE

Translation and validation of the Bath Ankylosing Spondylitis Disease Activity Index ( BASDAI) for defining disease status in ankylosing spondylitis (AS) and related diseases.

METHODS

The German version BASDAI-D was translated with only a few modifications. It contains six 10 cm horizontal visual analog scales to measure severity of fatigue, spinal and peripheral joint pain, tenderness and morning stiffness. A total of 318 patients with AS and other spondarthropathies completed the instrument at the beginning and at the end of their medical rehabilitation. Psychometric evaluation was performed separately for patients with AS corresponding to the modified New York Criteria ( SPA-NY, N=211) and for a second group of patients, which fulfilled the early diagnostic criteria for AS or the ESSG criteria of spondylarthropathies (Fd/Spond., N=86).

RESULTS

SPA-NY: Factor analysis yielded one factor explaining 54.8% of variance. The sum score with a standard deviation of 1.94 is nearly symmetrical distributed with mean of 4.7. Reliability analysis yielded high internal consistency (Cronbach's alpha=0.83). Corrected item-total correlations are also high and are large ranging from 0.48 to 0.71. Concerning concordant validity the BASDAI-D showed a substantial correlation with the scale bodily pain of the SF 36 (r = -0.72). There are no correlations with objective clinical parameters. Furthermore the assessment of disease activity by the physician correlates significantly, albeit low with the BASDAI-D. Sensitivity to change yields effect sizes up to 0.60. Fd/Spond.: The results for this group are almost identical with SPA-NY (one factor explaining 53.8% variance, mean 4.6+/-1.75; corrected item-total correlations from 0.50 to 0.75; correlation with the scale bodily pain r = -0.62). Analysis for subgroups showed higher scores for women in both groups SPA-NY and Fd/Spond.

CONCLUSION

BASDAI-D ist applicable for patients with AS and likewise for patients fulfilling the early diagnostic criteria for AS or the ESSG criteria of spondylarthropathies. In summary, BASDAID is reliable and valid. Because of its good acceptance and usability BASDAI-D is easy to use in research as well as in clinical practice.

Staging of patients with ankylosing spondylitis: a preliminary proposal

Patients with ankylosing spondylitis (AS) are characterised by a wide range of clinical presentations, radiographic profiles, and outcomes, which are not well differentiated by current diagnostic and classification systems for the disorder. Inadequacies in these systems may limit clinicians' ability to manage their patients with AS appropriately and act as an obstacle to reasonable comparison of therapeutic trial results. A standardised staging system for AS is therefore proposed that would provide a more detailed categorisation of patients based on assessment of structural damage, peripheral joint and organ involvement, presence of concomitant diseases, and the severity and extent of disease activity and functional impairment. The proposed system needs to be evaluated closely and amended as needed to assure its usefulness in clinical and research settings.

The Dougados Functional Index with the 5-point Likert scale is sensitive to change due to intensive physiotherapy and exercise in spondyloarthropathy

OBJECTIVE

The aim of the present study was to evaluate whether the Dougados Functional Index (DFI) with 5-point Likert scale is sensitive enough to demonstrate the efficacy of intensive physiotherapy and exercise.

METHODS

Eight-one consecutive patients with spondyloarthropathy (SpA) completed self-administered questionnaires on functional analysis, the Bath Ankylosing Spondylitis Functional Index (BASFI) and the DFI with 5-point Likert scale, at the beginning and end of a 3-week in-patient course based on intensive physiotherapy and exercise. The objective effect of the course was measured with 10 ranges of movement. After a 6-month follow-up the patients completed the questionnaires by mail for analysis of the lasting impact of rehabilitation on function.

RESULTS

The in-patient course was highly effective: all ranges of movement and both functional indices including the DFI with 5-point Likert scale improved to a highly significant degree. Six months later functional ability as measured by the DFI remained significantly better than at baseline before the in-patient course, but the BASFI had returned to the baseline level.

CONCLUSION

The DFI with 5-point Likert scale is sensitive enough to demonstrate the effect of intensive physiotherapy and exercise.

Confidence in the diagnosis of early spondylarthropathy: a prospective follow-up of 270 early arthritis patients

OBJECTIVE

To study the confidence of office-based rheumatologists (OBR) and a college of 5 experts in their diagnosis of spondylarthropathy (SpA) for early arthritis after more than 2 years of follow-up; to determine whether at that time the degree of confidence was improved by the fulfilment of the ESSG criteria.

METHODS

270 patients with early-onset (< 1 year) arthritis were prospectively followed-up for 29+/-11 months. At the final examination, OBR and the college of 5 experts rated their confidence in the diagnosis of SpA on a 0-10 analogue scale and on a 1-4 Likert scale, respectively.

RESULTS

After 29+/-11 months OBR had classified 56 patients (21%) as SpA, while a collegial diagnosis of probable (N = 32) or certain SpA (N = 14) was made for 46 patients (17%). At the final examination OBR confidence in their diagnosis (gold standard) was only 6.7+/-2.4 for all 56 cases of SpA. The cumulative fulfilment of ESSG criteria for SpA after 29+/-11 months correlated with the confidence of OBR and the experts in SpA, but improved only slightly the final confidence of OBR (7.1+/-2.3 versus 6.7+/-2.4 for all 56 SpA). Similarly, OBR confidence for the 18/56 SpA patients positive for HLA-B27 was only 7.1+/-2.0. Only 21 of these 56 patients were considered as SpA at baseline, although 37/56 (66%) had fulfilled ESSG criteria since thefirst examination.

CONCLUSION

This study indicates a probable lack of consensus on the nosology of early SpA and the limited help provided by the ESSG criteria to differentiate early SpA from otherforms of arthritis at baseline.

Differences in understanding and application of 1987 ACR criteria for rheumatoid arthritis and 1991 ESSG criteria for spondylarthropathy. A pilot survey

OBJECTIVES

To determine areas of agreement and disagreement among experts in the interpretation of the published criteria for RA (ACR) and spondylarthropathies ( ESSG).

METHODS

Thirty-two experts (16 from France and 16 from 10 other countries) replied anonymously to a mailed questionnaire.

RESULTS

Tenosynovitis and 'sausage-like' painless swelling of the toes were considered as criteria for RA by 18 and 14 experts, respectively. The definition of symmetry differed widely among experts (symmetry of only one group of joints was sufficient for 13). Twenty-five experts considered erosions of other joints than the wrists and fingers as a criterion for RA, 17 thought that fulfilment of criteria could be achieved cumulatively, and 19 would appreciate clarifications of the current criteria. Among possible clarifications for RA, it was frequently recommended that morning stiffness and nodules be eliminated and that new marker antibodies, X-rays of the feet, and exclusion criteria be added. Twenty-three of the 29 experts who gave an opinion (79%) agreed with the notion of SP in the absence of axial signs and sacroiliitis, 26/31 (84%) indicated that a patient can have both RA and SP, and 19/30 (63%) thought that RA and SP could be regarded as syndromes more than diseases. Only 5/32 experts relied more on the criteria than on their clinical judgement in diagnosing RA.

CONCLUSIONS

There would seem to be a needfor the optimisation of RA and ESSG criteria, particularly within the context of early arthritis.

The potential of ESSG spondyloarthropathy classification criteria as a diagnostic aid in rheumatological practice

OBJECTIVE

The European Spondylarthropathy Study Group (ESSG) criteria for the classification of spondyloarthropathies (SpA) were developed with the aim of unifying and facilitating international medical communication. We assessed the potential of ESSG criteria as a diagnostic aid for rheumatology practices in terms of sex and prevalence rate.

METHODS

Data from 2 similarly designed and developed studies conducted in France and Spain were examined. Data were obtained from 3,494 patients seen at rheumatology outpatient services (28 in each country). The sensitivity and specificity of each ESSG criterion (except the radiological one) were assessed in terms of sex and country. Patients were divided into 4 groups according to number of criteria present at the time of the study: Group I had neither inflammatory spinal pain (ISP) nor synovitis; Group 2 had ISP and/or synovitis; Group 3 ISP and/or synovitis plus one additional criterion; Group 4 ISP and/or synovitis plus more than one additional criterion. The predictive value was determined by using different prevalence rates.

RESULTS

A prevalence of 27.6% for male and 8.0% for female patients was found at Spanish services; prevalence in French services was 9.1% males and 3.2% females. No significant differences in sensitivity and specificity for each sex between French and Spanish individuals were detected; the overall sensitivity and specificity were similar for men and women. By contrast, there were differences between patients from the 2 countries regarding individual ESSG criteria; thus, inflammatory spinal pain and synovitis were less specific in the female and male Spanish patients, respectively, relative to the French patients.

CONCLUSION

ESSG criteria can be used meaningfully to aid diagnosis when the prevalence of SpA exceeds 10% and the patient meets more than one of the additional criteria, or when prevalence exceeds 30% and the patient meets only one additional criterion.

Imaging of the seronegative spondyloarthropathies

The group of seronegative spondyloarthropathies consists of ankylosing spondylitis, psoriatic arthritis, Reiter's disease, enteropathic spondylitis, and a fifth entity known as undifferentiated spondyloarthropathy. All of these diseases share common clinical and radiographic features with characteristic involvement of the sacroiliac joints, spine, and to various degrees, the peripheral joints. Although plain radiographs are the first line of imaging investigation, they are often insensitive for demonstrating the early changes of sacroiliitis, an important feature for establishing the early diagnosis of seronegative spondyloarthropathy. Other imaging modalities, including conventional tomography, bone scintigraphy, and computed tomography, have improved visualization of inflammatory changes at the sacroiliac joints. This article will review these modalities and emphasize the role of magnetic resonance imaging. By directly imaging changes in the synovium, articular cartilage, and subchondral bone, findings on magnetic resonance imaging are the most sensitive and specific for sacroiliitis and other changes in the axial skeleton. Its role and that of ultrasound in the assessment of the peripheral joints will also be highlighted.