European Spondylarthropathy Study Group Criteria Research Articles

Achilles tendinitis in systemic lupus erythematosus: search for an associated inflammatory disease.

Except for traumatic and iatrogenic causes, Achilles tendinitis (AT) is mostly encountered in the context of inflammatory rheumatic diseases. This study aimed to describe AT in systemic lupus erythematosus (SLE). Among 158 SLE patients who fulfilled the SLE criteria of the ACR classification followed between 1980 and 2013, we selected those who experienced at least one episode of AT not caused by traumatic or toxicity factors. Eight patients (one male, seven females), median age 52 years (range: 35-68), presented with 11 episodes of AT within an average of 10.5 (0-21) years after SLE diagnosis. Clinical presentation of SLE was mainly cutaneous (eight of eight), and articular (seven of eight). Axial symptoms were reported in six patients, two of whom had HLA-B27-positive status, and fulfilled the Amor and European Spondylarthropathy Study Group criteria. Resolution of AT was good with nonsteroidal anti-inflammatory topical or systemic drug therapies, which kept SLE quiescent and avoided any increase of specific treatment. Although the association is rare, when AT occurs in SLE patients, physicians should look for associated spondylarthritis.

Increase in Bone Density in Patients with Spondyloarthritis During Anti-Tumor Necrosis Factor Therapy: 6-year Followup Study

To assess the effects on bone mineral density (BMD) of prolonged anti-tumor necrosis factor (anti-TNF) therapy in patients with spondyloarthritis (SpA); to compare the BMD changes to those observed in SpA patients not treated with anti-TNF; and to identify the predictors of these changes. Fifty-nine patients with SpA according to the European Spondylarthropathy Study Group criteria who were treated with anti-TNF therapy for at least 4 years were included. Thirty-four patients with SpA from an international longitudinal observational study (OASIS cohort) were used as a control group. Lumbar spine and hip BMD were measured by dual-energy x-ray absorptiometry at baseline, after 1 year, and after at least 4 years. Over an average 6.5 years' followup, the increase in BMD was 11.8% (± 12.8%) at the lumbar spine (p < 0.0001) and 3.6% (± 9.3%) at the great trochanter (p = 0.0001) in patients treated with anti-TNF. At the lumbar spine, the increase was similar in patients with and those without syndesmophytes. BMD changes were significantly higher in the anti-TNF group than in the control group at lumbar spine (p < 0.0001), at femoral neck (p = 0.002), and at trochanter (p = 0.011), but not at total hip (p = 0.062). Multivariate analysis showed that the predictors of lumbar spine BMD changes in the total population were the use of anti-TNF (p < 0.0001) and, in the anti-TNF therapy group, the 1-year lumbar spine BMD change (p = 0.007). This study shows that prolonged anti-TNF therapy increases lumbar spine and trochanter BMD. This effect should be taken into account before introducing antiosteoporotic treatment in these patients.

The prevalence of inflammatory back pain: population-based estimates from the US National Health and Nutrition Examination Survey, 2009–10

ObjectiveTo estimate the current US inflammatory back pain (IBP) prevalence using four published case definitions.MethodsAnalysis of an IBP data collection instrument specifically designed for the 2009–10 National Health and Nutrition...

Prevalence of axial spondylarthritis in the United States: Estimates from a cross‐sectional survey

The US national prevalence of spondylarthritis (SpA) was estimated for 2 published sets of classification criteria: the Amor criteria and the European Spondylarthropathy Study Group (ESSG) criteria. These 2 SpA criteria sets have been the most widely utilized in previous population-based studies of SpA. The US SpA prevalence estimates were based on a representative sample of 5,013 US adults ages 20-69 years who were examined in the US National Health and Nutrition Examination Survey (NHANES) 2009-2010. The overall age-adjusted prevalence of definite and probable SpA by the Amor criteria was 0.9% (95% confidence interval [95% CI] 0.7-1.1%), corresponding to an estimated 1.7 million persons (95% CI 1.4-2.1 million persons). The age-adjusted prevalence of SpA by the ESSG criteria was 1.4% (95% CI 1.0-1.9%), corresponding to an estimated 2.7 million persons (95% CI 1.9-3.7 million persons). There were no statistically significant sex differences in SpA prevalence. The SpA prevalence among non-Hispanic white persons was 1.0% (95% CI 0.7-1.5%) by the Amor criteria and 1.5% (95% CI 1.0-2.3%) by the ESSG criteria. SpA prevalence could not be reliably estimated in other race/ethnicity subgroups due to sample size imitations. The SpA prevalence estimates are in the range of SpA prevalence estimates reported elsewhere in population-based surveys and it is likely that SpA may affect up to 1% of US adults, a prevalence similar to that reported for rheumatoid arthritis. The current US SpA prevalence estimates may be lower than the true value because the NHANES 2009-2010 data collection did not capture a complete set of the elements specified in the 2 SpA criteria sets.

Performance of the Assessment in Spondyloarthritis International Society Classification for Axial and Peripheral Spondyloarthritis in an Established Clinical Cohort: Comparison with Criteria Sets of Amor and the European Spondylarthropathy Study Group

To evaluate the performance of the Assessment in Spondyloarthritis International Society (ASAS) criteria (axial or peripheral) against the Amor and European Spondylarthropathy Study Group criteria in established spondyloarthritis (SpA). Rheumatologist-diagnosed patients with SpA were retrospectively classified according to the different criteria sets. Clinical characteristics of patients fulfilling all 3 criteria were compared with those who did not, by nonparametric statistics. ASAS classified 90% of the 231 patients, with 169 (73%) fulfilling all 3 criteria sets. Multivariate analysis showed the 62 patients not fulfilling all criteria sets were older at symptom onset (p < 0.001) and less likely to have inflammatory back pain (p < 0.001), peripheral arthritis (p < 0.001), or elevated C-reactive protein levels (p = 0.034). ASAS criteria can be used in established disease.

Clinical features of axial undifferentiated spondyloarthritis (USpA) in China: HLA-B27 is more useful for classification than MRI of the sacroiliac joint

Objectives: To analyse the clinical features of Chinese undifferentiated spondyloarthritis (USpA) patients with predominantly axial involvement, and in particular the influence of human leucocyte antigen (HLA)-B27 and magnetic resonance imaging (MRI) of the sacroiliac joint (SIJ) on the classification of axial USpA.Methods: Patients with low back pain for ≥ 3 months and no definite radiographic sacroiliitis were enrolled in this study. They were diagnosed as USpA based on rheumatologists' findings. Correlations between clinical features and HLA-B27 status or MRI manifestations were analysed.Results: A total of 197 USpA patients were recruited, of whom 135 (70.3%) were positive for HLA-B27. Acute inflammation, structural damage lesions, and normal findings on SIJ MRI were recorded in 64.5, 13.2 and 22.3% of patients, respectively. Classification criteria for axial SpA according to the European Spondylarthropathy Study Group (ESSG), Amor, and the Assessment of SpondyloArthritis International Society (ASAS) were fulfilled by 63.5, 64.5 and 83.2% patients, respectively. Cross-validation showed significant correlation among these three criteria. Patients positive for HLA-B27 included more males, with earlier onset age, better response to non-steroidal anti-inflammatory drugs (NSAIDs), and higher erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP) levels. In addition, more HLA-B27-positive than HLA-B27-negative patients fulfilled the ESSG, Amor, and ASAS criteria. Patients with acute inflammation on SIJ MRI had a higher level of ESR/CRP, and a greater proportion of them fulfilled the Amor and ASAS criteria. However, the proportion of those fulfilling the ESSG criteria did not differ with different MRI manifestations.Conclusion: Both HLA-B27 status and SIJ MRI findings influence the classification of Chinese axial USpA patients, but HLA-B27 seems of more value.

Profile of Indian Patients with Juvenile Onset Chronic Inflammatory Joint Disease Using the ILAR Classification Criteria for JIA: A Community-based Cohort Study

To assess the current International League of Associations for Rheumatology (ILAR) classification criteria (Edmonton, 2001) for juvenile idiopathic arthritis (JIA) in Indian patients. Out of 441 children, 330 with chronic joint pains were diagnosed with juvenile onset chronic inflammatory arthritis and followed in an observational cohort. Our study was carried out from 1994 to 2006 in a community rheumatology clinic. Emphasis was placed on obtaining data required by the ILAR system. Of the original group, 235 children were eventually classified as having JIA; 108 were examined during the first year of illness. We assigned 224 children (95%) to discrete JIA categories: enthesitis-related arthritis (ERA; 36%), oligoarthritis (OLA-persistent; 17%), polyarthritis rheumatoid factor (RF)-negative (17%), polyarthritis RF-positive (12%), systemic arthritis (8%), OLA-extended (4%), and psoriatic arthritis (1%). The remaining 11 children (5%) were classified with undifferentiated arthritis (mostly an overlap due to seropositive RF and/or HLA-B27). The prevalence of ERA (89% HLA-B27-positive) and seropositive RF was unexpectedly high. Although agreement (kappa > 0.79) with the American College of Rheumatology criteria and the European Spondylarthropathy Study Group criteria was good to excellent, the ILAR system was found to be more comprehensive and clinically homogeneous. However, some problems appear unique in our scenario. A wide-spectrum phenotype of JIA is demonstrated by an Indian cohort. Although useful, RF and HLA-B27 in this population proved problematic to the ILAR classification.

Magnetic resonance imaging grading system for active and chronic spondylarthritis changes in the sacroiliac joint

To develop a new grading method to quantify activity and chronic spondylarthritis (SpA) changes in the sacroiliac (SI) joints identified by magnetic resonance imaging (MRI), taking into account the complex joint anatomy, and to compare the findings with radiographic changes. A total of 37 patients (15 men, 22 women) fulfilling the European Spondylarthropathy Study Group criteria for SpA were examined by MRI of the SI joint using a semicoronal T1-weighted and T1-weighted fat-saturated (T1FS) sequence, a semiaxial STIR sequence, and postcontrast semicoronal and semiaxial T1FS sequences. The images were assessed independently by 2 radiologists for presence of bone marrow edema and enhancement, fatty marrow deposition, and joint erosion at both the cartilaginous and the ligamentous joint portion. Conventional radiographs were scored in accordance with the modified New York criteria. Inter- and intraobserver agreements for grading activity and chronic changes were good, with kappa values between 0.72 and 0.86 and between 0.83 and 0.90, respectively. Nearly half of the disease activity changes were due to inflammation in the ligamentous joint portion, which was significantly related to ankylosing spondylitis (AS). Patients with AS had significantly higher erosion and fatty marrow deposition scores than patients with nonprimary AS forms of SpA. The degree of erosion by MRI was significantly related to radiographic stages. Separate assessment of the ligamentous joint portion by MRI may be valuable for differentiating AS from nonprimary AS forms of SpA. Erosive changes on MRI were significantly related to radiographic changes, implying a possibility for substituting radiography with MRI.

Chlamydiae as etiologic agents in chronic undifferentiated spondylarthritis

The majority of patients with Chlamydia-induced reactive arthritis do not present with the classic triad of arthritis, conjunctivitis/iritis, and urethritis. Moreover, acute chlamydial infections are often asymptomatic. The aim of the present study was to assess the prevalence of synovial Chlamydia trachomatis and Chlamydia pneumoniae infections in patients with chronic undifferentiated spondylarthritis (uSpA). Study patients met the European Spondylarthropathy Study Group criteria for SpA, without evidence of ankylosing spondylitis, psoriasis, inflammatory bowel disease, or preceding dysentery. Symptoms were present for >or=6 months. Each patient underwent a synovial biopsy; tissue and concomitantly obtained peripheral blood mononuclear cells (PBMCs) were analyzed by polymerase chain reaction (PCR) for C trachomatis and C pneumoniae DNA. Other data collected on the day of the biopsy included standard demographic information and medical history, including any known history of C trachomatis or C pneumoniae. Physical examination (including joint count, evaluation for dactylitis and/or enthesitis, and skin examination) and HLA-B27 typing were performed. Synovial tissue (ST) samples from 167 patients with osteoarthritis (OA) were used as controls. Twenty-six patients met the entry criteria and underwent synovial biopsy (25 knee, 1 wrist). Sixteen of them (62%) were positive for C trachomatis and/or C pneumoniae DNA (10 for C trachomatis, 4 for C pneumoniae, and 2 for both). PCR analysis of ST revealed the presence of Chlamydia significantly more frequently in patients with uSpA than in OA controls (P<0.0001). No specific clinical characteristics differentiated Chlamydia-positive from Chlamydia-negative patients. PBMCs from 4 of the 26 uSpA patients (15%) were positive for Chlamydia, and Chlamydia was found in ST from 2 of these 4 patients. No significant correlation between PCR positivity and HLA-B27 positivity was found. The frequency of Chlamydia-positive ST samples, as determined by PCR, was found to be significantly higher in patients with uSpA than in patients with OA. Our results suggest that in many patients with uSpA, chlamydial infection, which is often occult, may be the cause.

Severity of baseline magnetic resonance imaging–evident sacroiliitis and HLA–B27 status in early inflammatory back pain predict radiographically evident ankylosing spondylitis at eight years

Magnetic resonance imaging (MRI) is increasingly used to detect sacroiliitis earlier. This study was undertaken to investigate what proportion of patients with MRI-evident sacroiliitis develop ankylosing spondylitis (AS) in the long term and whether there are predictors of outcome. Consecutive undiagnosed patients with early inflammatory back pain (IBP) (of <2 years' duration) were assessed clinically and radiologically. Baseline imaging assessments included fat-suppressed MRI sequences of the sacroiliac joints and lumbar spine that were scored for active bone marrow edema representative of acute inflammation, and anteroposterior radiographs of the pelvis and lateral radiographs of the lumbar spine, which were scored using the Stoke Ankylosing Spondylitis Spine Score. Patients were reassessed clinically and radiographically after 8 years. The primary outcome was the modified New York criteria for AS at followup. Fifty patients were assessed at the beginning of the study, and 40 patients were followed up after a mean of 7.7 years. Of these 40 patients, 58% were HLA-B27 positive, and 98% met the European Spondylarthropathy Study Group criteria. At baseline, 33 (83%) of the 40 patients followed up had MRI-evident sacroiliitis, and 6 (12%) had unequivocal AS according to the modified New York criteria. At followup, despite significant improvements in clinical outcomes, 13 of 39 patients (33.3%) had AS according to the modified New York criteria. The combination of severe sacroiliitis seen on MRI with HLA-B27 positivity was an excellent predictor of future AS (likelihood ratio [LR] 8.0, specificity 92%), while mild or no sacroiliitis, regardless of HLA-B27 status, was a predictor of not having AS (LR 0.4, specificity 38%). Our findings indicate that in patients with early IBP, a combination of severe sacroiliitis and HLA-B27 positivity has a high specificity for development of AS, compared with mild or no sacroiliitis, regardless of HLA-B27 status, which confers a low likelihood of developing AS. This has implications for the diagnosis of "early" AS and possibly for selection of more aggressive therapies.

Sonographic-detected joint effusion compared with physical examination in the assessment of sacroiliac joints in spondyloarthritis

Objective:An observational case–control study was designed to analyse the discriminative value of ultrasound (US)-detected joint effusion compared with physical examination in the assessment of sacroiliac joints (SIJ) in patients with...

The Bath metrology index as assessed by a trained and an untrained rater in patients with spondylarthropathy: a study of intra- and inter-rater agreements

The Bath ankylosing spondylitis metrology index (BASMI; range 0-10) has gained widespread use in daily clinical practice as an objective measure of spinal stiffness not only in patients with ankylosing spondylitis (AS) but also in patients with other spondylarthropathies (SpA). We examined intra-rater and inter-rater reproducibility of BASMI scoring in 30 Danish patients with SpA (median age 40 years, range 22-56 years) fulfilling the European Spondylarthropathy Study Group criteria, 25 of them satisfying the modified New York Criteria for AS. Measurements were performed twice on two different days (median interval 7 days, range 4-11) by a trained physiotherapist (PT) and by an untrained nurse who had undergone a single 1-h training session with the PT. The median BASMI score obtained by the PT on the two test days was 3.5 (range 1-8) and 3.0 (range 1-8), respectively (NS). Test-retest BASMI scores from the PT were significantly correlated (r(s) = 0.95, p < 0.0001). The 95% likely range for the difference between a patient's BASMI scores from two tests was +/-1.4 corresponding to a minimal detectable difference of +/-2 in the individual patient as the scale consists of intervals of 1. Similar results were achieved by the nurse. BASMI scores obtained by the two raters were significantly inter-correlated (r(s) = 0.95, p < 0.0001). The mean difference between paired BASMI scores obtained by the nurse and the PT on test day 1 was -0.2 with a minimal detectable difference of +/-2. A similar result was found using data from test day 2. In conclusion, a change in BASMI less than 2 may be due solely to expected random measurement error. A single 1-h training session allowed an untrained nurse to obtain BASMI results almost identical to those of an experienced PT.

A study of ten Japanese patients with seronegative spondylarthropathy: a tentative proposal

We reviewed ten patients with seronegative spondylarthropathy (SNSA), who all fulfilled the European Spondylarthropathy Study Group criteria for spondylarthropathy (SpA); seven patients also met the Amor criteria for SpA. Seronegative spondylarthropathy was not a uniform syndrome but rather a wide spectrum of complex disease with characteristics of sacroiliitis and enthesopathy. The most frequent symptom at diagnosis of SNSA was inflammatory low back pain, followed by asymmetric oligoarthralgia and Achilles tendonitis and/or plantar fasciitis. Systemic complications were revealed as eye and skin involvement. Imaging methods including pelvic radiography, scintigraphy, and computed tomography scanning were useful in detecting spondylarthropathic changes, which were characteristic of SNSA. Human leukocyte antigen (HLA) typing showed various patterns among patients, in which HLA-B27 was positive in three patients with ankylosing spondylitis. HLA-B51, which is a well-known genetic factor associated with Behçet's disease (BD), was positive in two patients who were apparently distinct from BD. Two patients with palmoplantar pustulosis showed symptoms and signs characteristic of SNSA. Although we have few SNSA patients in the present study, we would like to propose that HLA-B51 positive SpA would be considered as a subset of SNSA, and that pustulotic SpA also would be classified as a member of SNSA. This led us to suggest the possibility to change the concept of SNSA proposed by Moll et al. The optimal treatment remains to be defined, but sulfasalazine was effectively used with almost all patients in combination with nonsteroidal anti-inflammatory drugs.

A study of ten Japanese patients with seronegative spondylarthropathy: a tentative proposal

We reviewed ten patients with seronegative spondylarthropathy (SNSA), who all fulfilled the European Spondylarthropathy Study Group criteria for spondylarthropathy (SpA); seven patients also met the Amor criteria for SpA. Seronegative spondylarthropathy was not a uniform syndrome but rather a wide spectrum of complex disease with characteristics of sacroiliitis and enthesopathy. The most frequent symptom at diagnosis of SNSA was inflammatory low back pain, followed by asymmetric oligoarthralgia and Achilles tendonitis and/or plantar fasciitis. Systemic complications were revealed as eye and skin involvement. Imaging methods including pelvic radiography, scintigraphy, and computed tomography scanning were useful in detecting spondylarthropathic changes, which were characteristic of SNSA. Human leukocyte antigen (HLA) typing showed various patterns among patients, in which HLA-B27 was positive in three patients with ankylosing spondylitis. HLA-B51, which is a well-known genetic factor associated with Behçet's disease (BD), was positive in two patients who were apparently distinct from BD. Two patients with palmoplantar pustulosis showed symptoms and signs characteristic of SNSA. Although we have few SNSA patients in the present study, we would like to propose that HLA-B51 positive SpA would be considered as a subset of SNSA, and that pustulotic SpA also would be classified as a member of SNSA. This led us to suggest the possibility to change the concept of SNSA proposed by Moll et al. The optimal treatment remains to be defined, but sulfasalazine was effectively used with almost all patients in combination with nonsteroidal anti-inflammatory drugs.

Ankylosing spondylitis and undifferentiated spondyloarthropathies: a clinical review and description of a disease subset with older age at onset.

The onset of ankylosing spondylitis, as defined by the currently used criteria, after the age of 50 years is uncommon. Late-onset undifferentiated spondyloarthropathy is relatively more frequent. Its clinical spectrum seems to be as wide as it is in children and young and middle-aged adults. Most patients have two or more manifestations of spondyloarthropathy and meet the Amor criteria or the European Spondylarthropathy Study Group criteria. Some patients show only one manifestation of the B27-associated disease process for years and need more sensitive criteria. A subset of patients shows distal inflammatory swelling with pitting edema on the dorsum of feet or hands together with peripheral arthritis and peripheral enthesitis. In these cases spondyloarthropathy must be differentiated from other inflammatory rheumatic diseases with elderly onset showing the same distal inflammatory swelling with pitting edema.

Musculoskeletal Manifestations in a Population-based Cohort of Inflammatory Bowel Disease Patients

Background: Musculoskeletal disorders are the most common extra-intestinal manifestation of inflammatory bowel disease (IBD). Wide ranges of prevalence have been reported depending on the criteria used to define spondylarthropathy and on the selection of patients. We aimed to evaluate the prevalence and clinical spectrum of musculoskeletal manifestations in an inception cohort of European IBD patients. Methods: From 1 October 1991 to 30 September 1993, 202 IBD patients were diagnosed in three centres of two countries (Italy and The Netherlands) by means of a population-based inception cohort study. Of this group of patients, 160 (79%) were interviewed and examined by a rheumatologist and a gastroenterologist in the period June-September 1996. A total of 139/160 patients had an anteroposterior radiograph of the pelvis, and in 140/160 HLA-B27 was determined. Results: 53 (33.1%) of the 160 patients had experienced at least one musculoskeletal manifestation, 29 (18.1%) satisfied the European Spondylarthropathy Study Group (ESSG) criteria for spondylarthropathy and 5 (3.1%) satisfied the modified New York criteria for ankylosing spondylitis. However, 23 (14.4%) patients developed one or more spondylarthropathy-related manifestations without fulfilling any of the classification criteria. In patients satisfying ESSG criteria a significantly higher frequency of women ( P = 0.03), of ocular and liver involvement ( P = 0.01 and P = 0.03, respectively), and use of immunosuppressive drugs ( P = 0.02) was observed. Conclusion: Our study shows a high prevalence of musculoskeletal manifestations in an inception cohort of IBD patients. The clinical spectrum is broader than that defined by spondylarthropathy criteria.

Particularités cliniques, radiologiques et biologiques des spondylarthropathies libanaises selon la présence ou l'absence du HLA-B27

Clinical, radiological, and laboratory findings in Lebanese spondylarthropathy patients according to HLA-B27 status. — Objective. To evaluate clinical, radiological, and laboratory features in Lebanese spondylarthropathy patients according to HLA-B27 status. Methods. We retrospectively compared demographic, clinical, radiological, and severity data in 40 HLA-B27-positive and 58 HLA-B27-negative patients. All 98 patients met Amor's or European Spondylarthropathy Study Group criteria for spondylarthropathy, and 51.7% met New York modified criteria for ankylosing spondylitis. Results. Onset before 16 years of age, hip involvement, and an elevated mean erythrocyte sedimentation rate were significantly associated with the presence of the HLA-B27 (32.5 vs 13.8%, p = 0.02; 45 vs 7.5%, p = 0.001; and 47.7 vs 25.4, p = 0.02; respectively). The two groups were comparable for age, sex ratio, prevalence and distribution of spondylarthropathy types, family history, sacroiliitis, bamboo spine, syndesmophytes, peripheral joint involvement, enthesopathies, extraarticular involvement, response to nonsteroidal antiinflammatory drugs, and need for other medications. Conclusion. In Lebanon, spondylarthropathy patients positive for HLA-B27 experience disease onset at an earlier age, are more likely to develop hip involvement, and have laboratory evidence of more severe inflammation than their HLA-B27-negative counterparts. None of the other clinical and radiological parameters are modified by HLA-B27 status.

Evolution of chronic recurrent multifocal osteitis toward spondylarthropathy over the long term.

To retrospectively assess, with a sufficiently long followup (mean 11.6 years; median 9 years), the long-term outcome of chronic recurrent multifocal osteitis (CRMO), a multifocal, inflammatory bone disease. Patients included were 8 children/adolescents and 7 adults with no family history of rheumatic disease who had been diagnosed as having CRMO between 1979 and 1995. Ten patients had undergone at least 1 bone biopsy of the lesions, with histologic examination and multiple cultures. In 1996, in addition to an in-depth interview, 12 patients underwent an extensive physical examination, laboratory evaluation, HLA-A, B, C, and DR typing, bone radiography and scintigraphy, and computed tomography scan of the sternoclavicular and sacroiliac joints. Remission was observed in 3 patients. The other 12 patients developed various associations of vertebral (n = 10), sacroiliac (n = 6), anterior thoracic (n = 7), peripheral articular (n = 2), enthesopathic (n = 4), or dermatologic (palmoplantar pustulosis in 3 cases and psoriasis in 2) involvements. Spine involvement was the most common and occurred the earliest (median time to appearance after the onset of osteitis 5.63 years). Clinical sacroiliitis was always unilateral. No patients carried the HLA-B27 haplotype. CRMO responded well to nonsteroidal antiinflammatory drugs. Twelve patients met the European Spondylarthropathy Study Group criteria for spondylarthopathy. After 10 years, CRMO had usually evolved to spondylarthropathy, but with certain features not usually seen in the latter: predominantly, unilateral sacroiliitis, no familial form, and no link with HLA-B27.

Association of HLA alleles and clinical features in patients with synovitis of recent onset.

To determine how HLA alleles are associated with the clinical disease patterns of patients with synovitis of recent onset. The HLA alleles A, B, C, DRbeta1, and DQbeta1 were determined in a cohort of 211 patients (mean age 42 years, 64% female, 79% white) with recent-onset synovitis in 1 or more peripheral joints. At a mean disease duration of 33 weeks, 98 patients (46%) met the American College of Rheumatology (ACR) criteria for rheumatoid arthritis (RA), 38 (18%) met the European Spondylarthropathy Study Group criteria for spondylarthropathy (SpA), and 75 (36%) were classified as having undifferentiated arthropathy (UA). Controls were racially matched healthy individuals (n = 244). Shared epitope (SE) alleles were significantly more common in rheumatoid factor-positive (RF+) patients fulfilling the ACR RA criteria than in other patients with early arthritis (65% versus 35%; P < 0.001). In addition, the RA patients had by far the highest frequency of radiographic erosions (52% and 39% in RF+ and RF- RA, respectively, versus 3% and 9% in SpA and UA patients, respectively; P < 0.0001). The presence of SE alleles was a particularly strong predictor of early erosions in the RF- RA patients (odds ratio [OR] 6.8, 95% confidence interval [95% CI] 1.2-45). The presence of 2 SE alleles or an associated DQbeta1*0301 (DQ7) or DQbeta1*0302 (DQ8) allele appeared to modestly increase the risk of early erosions, although these DQ alleles were in strong linkage disequilibrium with DRbeta1*0401, both in the patient and in the control populations. B27 was linked with the presence of SE alleles in the patients, including those patients fulfilling the RA criteria, but not in the controls (12% versus 3%; P < 0.001). Enthesitis was present in 23 (11%) of 211 patients, was highly associated with B27 (OR 4.2, 95% CI 1.5-11.5), and surprisingly, was not a feature specific only to the SpA group. The B8-DR3 haplotype was significantly increased in the patient subgroups compared with controls (17% versus 7%; P < 0.01), although the clinical significance of this association is unclear. This study of HLA associations in a diverse cohort of early synovitis patients emphasizes the complex degree of genetic interaction between alleles at several major histocompatibility complex loci, which regulates clinical phenotypes. In particular, SE and B27, while predisposing patients to characteristic clinical syndromes, had an unexpected degree of association in this cohort, perhaps explaining the overlap in clinical features in many patients.

Prevalence of spondylarthropathies in HLA‐B27 positive and negative blood donors

Objective To determine the overall prevalence of spondylarthropathy (SpA) among whites. Methods To screen for SpA symptoms, such as inflammatory back pain (IBP), joint swelling, psoriasis, and uveitis, or a specific family history, questionnaires were mailed to 348 blood donors (174 HLA-B27 positive and 174 HLA-B27 negative). From the responding 273 persons (78%; 140 B27 positive, 133 B27 negative), 126 were selected for further evaluation based on the symptoms reported. Of this group, 90 persons agreed to undergo physical examination (71.4%; 46 B27 positive, 44 B27 negative). There was no difference between the B27-positive and -negative groups in terms of age (mean ± SD 38.4 ± 10 versus 39.5 ± 11 years) and sex ratio (67% versus 68% were men). In addition, 58 donors (32 B27 positive, 26 B27 negative) agreed to undergo magnetic resonance imaging (MRI) of the sacroiliac joints. A diagnosis of SpA and ankylosing spondylitis (AS) was made according to the European Spondylarthropathy Study Group criteria and the New York criteria. Results SpA was diagnosed in 20 persons: 19 of 140 B27-positive (13.6%) and 1 of 133 B27-negative (0.7%) subjects (15 male and 5 female). AS was diagnosed in 9 persons (7 male and 2 female; 45%), undifferentiated SpA (USpA) in 7 (5 male and 2 female; 35%), psoriatic arthritis (PsA) in 3 (2 male and 1 female; 15%), and chronic reactive arthritis (ReA; Reiter's syndrome) in 1 (male; 5%). On the basis of a B27 frequency of 9.3% among the population of Berlin (3.47 million persons), the estimated prevalence of SpA was 1.9%, AS was 0.86%, USpA was 0.67%, and PsA was 0.29%. The relative risk of developing SpA in B27-positive subjects was calculated as 20.7 (95% confidence interval 4.6-94.2; P = 0.001). Of 58 persons with IBP, sacroiliitis was detected by MRI in 15 of 32 B27-positive (46.9%) and 1 of 26 B27-negative (3.9%) subjects (P = 0.002). Four of these 16 donors did not fulfill diagnostic criteria for SpA. Conclusion With a calculated prevalence of 1.9%, spondylarthropathies are among the most frequent rheumatic diseases in the white population. HLA-B27 positive persons carry a 20-fold increased risk of developing SpA. AS and USpA are the most frequent SpA subtypes. Persons with IBP who are B27 positive have a 50% likelihood of having sacroiliitis.