Heritability of spinal curvature and its relationship to disc degeneration and bone mineral density in female adult twins.

PURPOSE: To determine the heritability of spine curve using plain radiographs and to identify risk factors for spine curvature including age, body mass index, smoking, bone mineral density (BMD), and lumbar disc degeneration (LDD). METHODS: A classical twin study of 110 MZ and 136 DZ adult female twins. Demographic and clinical information obtained from long spine radiographs, lumbar spine degeneration on spine MR scan, and BMD assessed by DEXA at hip and lumbar spine were included in multiple logistic regression models to determine risk factors for spine curvature. RESULTS: Heritability estimates ranged between 41 (19-59) % for pelvic incidence to 61 (46-72) % for thoracic kyphosis; with lumbar lordosis and cervical lordosis having 59 (42-71) % and 43 (23-59) % heritability, respectively. For each spine curve, the model showing the best fit contained additive genetic and shared environmental components with no contribution from the unique environment. Significant risk factors for increased thoracic kyphosis were lumbar spine BMD, age, and cervical lordosis; for pelvic incidence were lumbar spine BMD and lumbar lordosis; for lumbar lordosis were cervical lordosis, pelvic incidence and LDD; and age alone predicted cervical lordosis (p = 0.001). CONCLUSION: In this sample of middle-aged and elderly women, there were significant genetic influences on all spine curves but particularly thoracic kyphosis and lumbar lordosis. The strongest predictor for lumbar lordosis was LDD (p < 0.0001) which is itself genetically determined in part. For thoracic kyphosis, BMD was strongly associated and remained so (for lumbar BMD) with the inclusion of age, showing BMD to be an independent risk factor. This work highlights the genetic factors influencing normal spine curvature in women.

Prevalence of inflammatory back pain in a cohort of patients with anterior uveitis.

PURPOSE: To determine the prevalence of inflammatory back pain in an anterior uveitis cohort. DESIGN: Retrospective cohort study. METHODS: Patients with anterior uveitis were recruited from the clinic of an ophthalmologist to complete a survey between March and December 2008. Patients were classified with inflammatory back pain if they had ≥2 positive responses to 4 validated inflammatory back pain questions: presence of morning stiffness >30 minutes in duration; improvement in back pain with exercise but not with rest; awakening from back pain during the second half of the night only; and presence of alternating buttock pain. Disease activity was assessed using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The impact of disease on quality of life was measured using the EuroQOL (EQ-5D) questionnaire. Twenty-five patients underwent further rheumatologic examination. RESULTS: One hundred forty-one of 167 patients (84.4%) completed the survey. Sixty-six of 141 patients (46.8%) were classified to have inflammatory back pain. Mean BASDAI (4.2, SD 2.41) and EQ-5D scores (0.73, SD 0.21) were lower than patients with no inflammatory back pain (0.82, SD 0.16, P = .0048). In the subgroup that underwent rheumatologic assessment, a classification of inflammatory back pain was 92% sensitive and 67% specific for a diagnosis of inflammatory back pain. CONCLUSIONS: The prevalence of inflammatory back pain in a cohort of anterior uveitis patients was found to be 46.8%. Patients with inflammatory back pain had worse quality of life than those without. Ophthalmologists may use these questions on back pain to select patients classified to have inflammatory back pain to refer for early rheumatologic assessment.

Interaction between ERAP1 and HLA-B27 in ankylosing spondylitis implicates peptide handling in the mechanism for HLA-B27 in disease susceptibility.

Ankylosing spondylitis is a common form of inflammatory arthritis predominantly affecting the spine and pelvis that occurs in approximately 5 out of 1,000 adults of European descent. Here we report the identification of three variants in the RUNX3, LTBR-TNFRSF1A and IL12B regions convincingly associated with ankylosing spondylitis (P < 5 × 10(-8) in the combined discovery and replication datasets) and a further four loci at PTGER4, TBKBP1, ANTXR2 and CARD9 that show strong association across all our datasets (P < 5 × 10(-6) overall, with support in each of the three datasets studied). We also show that polymorphisms of ERAP1, which encodes an endoplasmic reticulum aminopeptidase involved in peptide trimming before HLA class I presentation, only affect ankylosing spondylitis risk in HLA-B27-positive individuals. These findings provide strong evidence that HLA-B27 operates in ankylosing spondylitis through a mechanism involving aberrant processing of antigenic peptides.

Association of variants at 1q32 and STAT3 with ankylosing spondylitis suggests genetic overlap with Crohn's disease.

Ankylosing spondylitis (AS) is a common inflammatory arthritic condition. Overt inflammatory bowel disease (IBD) occurs in about 10% of AS patients, and in addition 70% of AS cases may have subclinical terminal ileitis. Spondyloarthritis is also common in IBD patients. We therefore tested Crohn's disease susceptibility genes for association with AS, aiming to identify pleiotropic genetic associations with both diseases. Genotyping was carried out using Sequenom and Applied Biosystems TaqMan and OpenArray technologies on 53 markers selected from 30 Crohn's disease associated genomic regions. We tested genotypes in a population of unrelated individual cases (n = 2,773) and controls (n = 2,215) of white European ancestry for association with AS. Statistical analysis was carried out using a Cochran-Armitage test for trend in PLINK. Strong association was detected at chr1q32 near KIF21B (rs11584383, P = 1.6 × 10(-10), odds ratio (OR) = 0.74, 95% CI:0.68-0.82). Association with disease was also detected for 2 variants within STAT3 (rs6503695, P = 4.6 × 10(-4). OR = 0.86 (95% CI:0.79-0.93); rs744166, P = 2.6 × 10(-5), OR = 0.84 (95% CI:0.77-0.91)). Association was confirmed for IL23R (rs11465804, P = 1.2 × 10(-5), OR = 0.65 (95% CI:0.54-0.79)), and further associations were detected for IL12B (rs10045431, P = 5.2 × 10(-5), OR = 0.83 (95% CI:0.76-0.91)), CDKAL1 (rs6908425, P = 1.1 × 10(-4), OR = 0.82 (95% CI:0.74-0.91)), LRRK2/MUC19 (rs11175593, P = 9.9 × 10(-5), OR = 1.92 (95% CI: 1.38-2.67)), and chr13q14 (rs3764147, P = 5.9 × 10(-4), OR = 1.19 (95% CI: 1.08-1.31)). Excluding cases with clinical IBD did not significantly affect these findings. This study identifies chr1q32 and STAT3 as ankylosing spondylitis susceptibility loci. It also further confirms association for IL23R and detects suggestive association with another 4 loci. STAT3 is a key signaling molecule within the Th17 lymphocyte differentiation pathway and further enhances the case for a major role of this T-lymphocyte subset in ankylosing spondylitis. Finally these findings suggest common aetiopathogenic pathways for AS and Crohn's disease and further highlight the involvement of common risk variants across multiple diseases.

Visual assessment of the spine bruckel instrument, a novel status tool to reflect appearance of the spine in patients with ankylosing spondylitis.

OBJECTIVE: The Visual Assessment of the Spine Bruckel Instrument (VASBI) is a new status tool developed by the Spondylitis Association of America and the University of Toronto to reflect spinal appearance in patients with ankylosing spondylitis (AS). Our objective was to validate the VASBI according to the Outcome Measures in Rheumatoid Arthritis Clinical Trials filter (truth, discrimination, and feasibility). METHODS: Three hundred patients with AS were asked to rate their degree of perceived spinal deformity using the VASBI. To evaluate construct validity, VASBI scores were compared with functional outcome, spinal mobility, and radiographic spinal damage. Test-retest reliability was evaluated using kappa statistic (kappa). RESULTS: Patient VASBI demonstrated strong correlation with spinal mobility (r = 0.543) and moderate correlation with functional impairment (r = 0.490) and structural damage (r = 0.309). Reliability for VASBI was very good (kappa = 0.973, p < 0.001). CONCLUSION: The VASBI is a novel tool with practical applications in a busy clinical setting as it simplifies assessment of AS spinal deformity. Our study demonstrates that the VASBI has good feasibility, construct validity, and reliability.

Genome-wide association study of ankylosing spondylitis identifies non-MHC susceptibility loci.

To identify susceptibility loci for ankylosing spondylitis, we undertook a genome-wide association study in 2,053 unrelated ankylosing spondylitis cases among people of European descent and 5,140 ethnically matched controls, with replication in an independent cohort of 898 ankylosing spondylitis cases and 1,518 controls. Cases were genotyped with Illumina HumHap370 genotyping chips. In addition to strong association with the major histocompatibility complex (MHC; P < 10(-800)), we found association with SNPs in two gene deserts at 2p15 (rs10865331; combined P = 1.9 x 10(-19)) and 21q22 (rs2242944; P = 8.3 x 10(-20)), as well as in the genes ANTXR2 (rs4333130; P = 9.3 x 10(-8)) and IL1R2 (rs2310173; P = 4.8 x 10(-7)). We also replicated previously reported associations at IL23R (rs11209026; P = 9.1 x 10(-14)) and ERAP1 (rs27434; P = 5.3 x 10(-12)). This study reports four genetic loci associated with ankylosing spondylitis risk and identifies a major role for the interleukin (IL)-23 and IL-1 cytokine pathways in disease susceptibility.

The chromosome 16q region associated with ankylosing spondylitis includes the candidate gene tumour necrosis factor receptor type 1-associated death domain (TRADD).

OBJECTIVE: To replicate and refine the reported association of ankylosing spondylitis (AS) with two non-synonymous single nucleotide polymorphisms (nsSNPs) on chromosome 16q22.1. METHODS: Firstly, 730 independent UK patients with AS were genotyped for rs9939768 and rs6979 and allele frequencies were compared with 2879 previously typed historic disease controls. Secondly, the two data sets were combined in meta-analyses. Finally, 5 tagging SNPs, located between rs9939768 and rs6979, were analysed in 1604 cases and 1020 controls. RESULTS: The association of rs6979 with AS was replicated, p=0.03, OR=1.14 (95% CI 1.01 to 1.28), and a trend for association with rs9939768 detected, p=0.06, OR=1.25 (95% CI 0.99 to 1.57). Meta-analyses revealed association of both SNPs with AS, p=0.0008, OR=1.31 (95% CI 1.12 to 1.54) and p=0.0009, OR=1.15 (95% CI 1.06 to 1.23) for rs9939768 and rs6979, respectively. New associations with rs9033 and rs868213 (p=0.00002, OR=1.23 (95% CI 1.12 to 1.36) and p=0.00002 OR=1.45 (95% CI 1.22 to 1.72), respectively, were identified. CONCLUSIONS: The region on chromosome 16 that has been replicated in the present work is interesting as the highly plausible candidate gene, tumour necrosis factor receptor type 1 (TNFR1)-associated death domain (TRADD), is located between rs9033 and rs868213. It will require additional work to identify the primary genetic association(s) with AS.

Significance of clinical evaluation of the metacarpophalangeal joint in relation to synovial/bone pathology in rheumatoid and psoriatic arthritis detected by magnetic resonance imaging.

OBJECTIVE: Rheumatologists base many clinical decisions regarding the management of inflammatory joint diseases on joint counts performed at clinic. We investigated the reliability and accuracy of physically examining the metacarpophalangeal (MCP) joints to detect inflammatory synovitis using magnetic resonance imaging (MRI) as the gold standard. METHODS: MCP joints 2 to 5 in both hands of 5 patients with rheumatoid arthritis (RA) and 5 with psoriatic arthritis (PsA) were assessed by 5 independent examiners for joint-line swelling (visually and by palpation); joint-line tenderness by palpation (tender joint count, TJC) and stress pain; and by MRI (1.5 Tesla superconducting magnet). Interrater reliability was assessed using kappa statistics, and agreement between examination and corresponding MRI assessment was assessed by Fisher's exact tests (p < 0.05 considered statistically significant). RESULTS: Interrater agreement was highest for visual assessment of swelling (kappa = 0.55-0.63), slight-fair for assessment of swelling by palpation (kappa = 0.19-0.41), and moderate (kappa = 0.41-0.58) for assessment of joint tenderness. In patients with RA, TJC, stress pain, and visual swelling assessment were strongly associated with MRI evaluation of synovitis. Visual swelling assessment demonstrated high specificity (> 0.8) and positive predictive value (= 0.8). For PsA, significant associations exist between TJC and MRI synovitis scores (p < 0.01) and stress pain and MRI edema scores (p < 0.04). Assessment of swelling by palpation was not significantly associated with synovitis or edema as determined by MRI in RA or PsA (p = 0.54-1.0). CONCLUSION: In inflammatory arthritis, disease activity in MCP joints can be reliably assessed at the bedside by examining for joint-line tenderness (TJC) and visual inspection for swelling. Clinical assessment may have to be complemented by other methods for evaluating disease activity in the joint, such as MRI, particularly in patients with PsA.

Investigating the genetic association between ERAP1 and ankylosing spondylitis.

A strong association between ERAP1 and ankylosing spondylitis (AS) was recently identified by the Wellcome Trust Case Control Consortium and the Australo-Anglo-American Spondylitis Consortium (WTCCC-TASC) study. ERAP1 is highly polymorphic with strong linkage disequilibrium evident across the gene. We therefore conducted a series of experiments to try to identify the primary genetic association(s) with ERAP1. We replicated the original associations in an independent set of 730 patients and 1021 controls, resequenced ERAP1 to define the full extent of coding polymorphisms and tested all variants in additional association studies. The genetic association with ERAP1 was independently confirmed; the strongest association was with rs30187 in the replication set (P = 3.4 x 10(-3)). When the data were combined with the original WTCCC-TASC study the strongest association was with rs27044 (P = 1.1 x 10(-9)). We identified 33 sequence polymorphisms in ERAP1, including three novel and eight known non-synonymous polymorphisms. We report several new associations between AS and polymorphisms distributed across ERAP1 from the extended case-control study, the most significant of which was with rs27434 (P = 4.7 x 10(-7)). Regression analysis failed to identify a primary association clearly; we therefore used data from HapMap to impute genotypes for an additional 205 non-coding SNPs located within and adjacent to ERAP1. A number of highly significant associations (P < 5 x 10(-9)) were identified in regulatory sequences which are good candidates for causing susceptibility to AS, possibly by regulating ERAP1 expression.

Association between the interleukin 23 receptor and ankylosing spondylitis is confirmed by a new UK case-control study and meta-analysis of published series.

OBJECTIVES: It has been shown previously that IL-23R variants are associated with AS. We conducted an extended analysis in the UK population and a meta-analysis with the previously published studies, in order to refine these IL-23R associations with AS. METHODS: The UK case-control study included 730 new cases and 1331 healthy controls. In the extended study, the 730 cases were combined with 1088 published cases. Allelic associations were analysed using contingency tables. In the meta-analysis, 3482 cases and 3150 controls from four different published studies and the new UK cases were combined. DerSimonian-Laird test was used to calculate random effects pooled odds ratios (ORs). RESULTS: In the UK case-control study with new cases, four of the eight SNPs showed significant associations, whereas in the extended UK study, seven of the eight IL-23R SNPs showed significant associations (P < 0.05) with AS, maximal with rs11209032 (P < 10(-5), OR 1.3), when cases with IBD and/or psoriasis were excluded. The meta-analysis showed significant associations with all eight SNPs; the strongest associations were again seen not only with rs11209032 (P = 4.06 x 10(-9), OR approximately 1.2) but also with rs11209026 (P < 10(-10), OR approximately 0.6). CONCLUSIONS: IL-23R polymorphisms are clearly associated with AS, but the primary causal association(s) is(are) still not established. These polymorphisms could contribute either increased or decreased susceptibility to AS; functional studies will be required for their full evaluation. Additionally, observed stronger associations with SNPs rs11209026 and rs11465804 upon exclusion of IBD and/or psoriasis cases may represent an independent association with AS.

The assessment of ankylosing spondylitis in clinical practice.

Ankylosing Spondylitis (AS) is a chronic inflammatory arthritis that predominantly affects the axial skeleton in adolescent patients causing spinal pain and stiffness. There is a marked delay, on average 8 years, between onset of disease symptoms and clinical diagnosis. The distinction between the symptoms of mechanical and inflammatory back pain remains one of the main contributing factors for the delay in diagnosis. Several classification criteria exist to aid the diagnosis of AS, but their accuracy is poor. The Ankylosing Spondylitis Assessment Study group (ASAS) has defined a core set of domains for clinical outcome measurement in AS in order to assess the disease process in individual patients and to identify those with rapidly progressive disease. New therapies, such as the tumor necrosis factor (TNF) inhibitors, have transformed the treatment paradigm in AS, especially for those patients with aggressive disease. Thus, the definition of both patient selection criteria for these agents and the development of clinical methods to assess response to therapy have become a priority. This Review focuses on measuring the degree of disease activity, function and damage in patients with AS in an ambulatory care setting, and the assessment of suitability of various outcome measures for monitoring response to treatment with TNF inhibitors.

International spondyloarthritis interobserver reliability exercise--the INSPIRE study: I. Assessment of spinal measures.

OBJECTIVE: To determine whether the axial measures used in primary ankylosing spondylitis (AS) were reproducible for both AS and psoriatic arthritis (PsA) with axial disease. METHODS: A group of 20 rheumatologists from 11 countries with expertise in spondyloarthritis (SpA) met for a combined physical examination exercise to assess 10 patients with PsA with axial involvement (9 men, 1 woman, mean age 52 yrs, mean disease duration 17 yrs) and 9 AS patients (7 men, 2 women, mean age 38 yrs, mean disease duration 16 yrs). A modified Latin-square design was used. Measures included were occiput to wall, tragus to wall, cervical rotation, chest expansion, lateral spinal bending, modified Schober, and hip mobility. Data were analyzed using intraclass correlation coefficients (ICC) adjusted for order of measurements. RESULTS: The majority of the variance was contributed by the patients. There was no order effect. Observer effect was noted especially for chest expansion for both AS and PsA patients, and for the modified Schober in PsA. The ICC demonstrated very good to excellent agreement for most measures for both AS and PsA. Chest expansion provided only moderate agreement for AS and PsA. CONCLUSION: Overall, measures of spinal mobility used in primary AS perform well with respect to interobserver reliability, and are equally reproducible when applied to PsA patients with axial involvement. Thus, these measures should now be evaluated in therapeutic trials of patients with PsA to determine sensitivity to change and concordance with other measures of structural damage.

International spondyloarthritis interobserver reliability exercise--the INSPIRE study: II. Assessment of peripheral joints, enthesitis, and dactylitis.

OBJECTIVE: To determine whether the assessments of peripheral joints and enthesitis were reproducible for both AS and PsA with axial disease, and whether dactylitis assessment is reproducible in patients with PsA. METHODS: A group of 20 rheumatologists from 11 countries with expertise in spondyloarthritis (SpA) met for a combined physical examination exercise to assess 10 patients with PsA with axial involvement (9 men, 1 woman, mean age 52 yrs, disease duration 17 yrs) and 9 patients with AS (7 men, 2 women, mean age 38 yrs, disease duration 16 yrs). A modified Latin-square design that enabled assessment of patient, assessor, and order effect was used. Measures included were number of tender and swollen joints, presence of enthesitis using 6 different indices, and dactylitis score. Data were analyzed using intraclass correlation (ICC) adjusted for order of measurements. RESULTS: The majority of the variance was contributed by the patients. There was no order effect. The assessment of tender joints (ICC 0.69) was more reliable than the assessment of swollen joints (ICC 0.54). Moreover, there was better agreement in patients with PsA (ICC 0.78) than in patients with AS (ICC 0.62). There was excellent agreement on the number of active enthesitis sites (ICC 0.86). All the enthesitis indices provided substantial to excellent agreement among observers. Agreement for the dactylitis score was substantial (ICC 0.70). CONCLUSION: The assessment of peripheral joints is more reliable in patients with PsA. Enthesitis instruments can be used reliably in patients with AS and patients with PsA with spinal involvement. The Leeds dactylitis instrument functions well in PsA.

Interleukin 1 and nuclear factor-kappaB polymorphisms in ankylosing spondylitis in Canada and Korea.

OBJECTIVE: The interleukin 1alpha and 1beta (IL-1alpha, IL-1beta) are potent mediators of inflammation and immunity. IL-1 receptor antagonist (IL-1Ra) is a protein that binds to IL-1 receptors and competitively inhibits the binding of IL-1alpha and IL-1beta. There are reports of IL-1 complex gene polymorphisms in ankylosing spondylitis (AS), but the results have been inconsistent. NFKB1 encodes the genes for the p50 and p101 nuclear factor-kappaB (NF-kappaB) isoforms, which are recognized as critical to inflammatory disease. To date there have been no reports examining an association between NFKB1 and AS. We investigated polymorphisms of IL-1 complex and NF-kappaB1 with 2 genetically and geographically different populations. METHODS: Subjects with AS satisfied modified New York criteria for AS. Healthy controls were recruited at each respective site. Subjects with AS were genotyped for the following: IL-1alpha-889 single nucleotide polymorphism (SNP); IL-1beta +3953 SNP; IL-1Ra (86 base pair variable number tandem repeat within intron 2); and NFKB1 (-94 insertion/deletion polymorphism). RESULTS: In total, 205 subjects with AS and 200 controls from Seoul, Korea, and 68 subjects with AS and 164 controls from Toronto, Canada, were genotyped for the IL-1alpha and IL-1beta polymorphisms and 115 controls for the IL-1Ra and NF-kappaB polymorphisms. There were no differences of IL-1alpha, IL-1beta, IL-1Ra, and NF-kappaB polymorphisms between AS patients and controls in these populations. CONCLUSION: Our analysis of these SNP in the IL-1 complex and NF-kappaB genes does not support a major role for either in AS susceptibility in the Seoul and Toronto populations.

The clinical assessment of patients with psoriatic arthritis: results of a reliability study of the spondyloarthritis research consortium of Canada.

OBJECTIVES: To evaluate whether rheumatologists experienced in psoriatic arthritis (PsA) assess peripheral and axial involvement in the same way and to consider core clinical measurements that should be included in clinical trials in PsA. METHODS: Ten patients with PsA, representing a broad range of joint inflammation, joint damage, and spinal involvement, were selected for the study. Each patient was examined by each of 10 rheumatologists, members of the Spondyloarthritis Research Consortium of Canada, according to a Latin Square design. Assessments included scoring actively inflamed joints and damaged joints, dactylitis, enthesitis, and spinal measurements. Variance components analyses were conducted for continuous measurements based on models with observer, patient, and order effects. Estimates of intraclass correlation coefficients and associated 95% confidence intervals were obtained. RESULTS: There was substantial reliability in the assessment of the number of actively inflamed joints and excellent agreement in the number of damaged joints. Only moderate agreement was found for the number of digits with dactylitis. There was excellent agreement among observers in the intermalleolar distance measurements, but there was not as good agreement in the other measurements of spinal mobility. There was good agreement among the observers in detecting plantar fasciitis, however, the other entheses did not fare as well. CONCLUSION: In this first multicenter study of the assessment of clinical evaluation of patients with PsA we found that the assessment of peripheral joint disease is reliable although training should be performed prior to initiation of drug trials or comparative studies in this disease. The assessment of back measurements in PsA and other spondyloarthritis requires further study.

Recent advances in the treatment of the spondyloarthropathies.

PURPOSE OF REVIEW: Recently, there has been renewed interest in the spondyloarthropathy family of chronic inflammatory rheumatic conditions, which has been fueled to a large extent by the biologic era. Over the period of the past 2 years in particular, there have been several notable advances. First, there have been a number of large, high-quality randomized controlled trials evaluating the tumor necrosis factor (TNF) blockers and conservative treatments such as physiotherapy and nonsteroidal anti-inflammatory drugs for use in spondyloarthropathy. This has paved the way for the development of better tools to assess outcome in these patients both in daily practice and in the context of clinical trials. This review uses a systematic approach to outline the most recent (within the last 2 years) and the most pertinent advances in the treatments of the spondyloarthropathies, with particular emphasis on ankylosing spondylitis and psoriatic arthritis. RECENT FINDINGS: Supervised group exercise programs maintain flexibility and posture in patients with ankylosing spondylitis, and spa therapy is a cost-effective treatment option in ankylosing spondylitis. Nonsteroidal anti-inflammatory drugs have a role in symptom modification and, more importantly, may prevent structural disease progression in patients with ankylosing spondylitis when administered continuously at a fixed dose. TNF blockers have been evaluated in a number of randomized controlled trials in ankylosing spondylitis and psoriatic arthritis and have been demonstrated to be safe and effective in the short-term management of these diseases. Longer-term trials are awaited with radiographic outcomes to comment on their disease-modifying properties and their long-term safety and efficacy profiles. SUMMARY: There has been renewed interest in the spondyloarthropathy family of disorders, with an explosion in the number of trials evaluating outcome with the TNF blockers. To date, no cure has been found for the disease, but these agents are emerging as the best therapeutic option available for patients with ankylosing spondylitis and psoriatic arthritis to date.

Validation exercise of the Ankylosing Spondylitis Assessment Study (ASAS) group response criteria in ankylosing spondylitis patients treated with biologics.

OBJECTIVES: To define what expert clinicians consider a dramatic response in ankylosing spondylitis (AS) patients treated with biologic therapies based on patient and physician assessments of global disease activity. To compare this expert clinician-derived criteria to the Ankylosing Spondylitis Assessment Study (ASAS) Group criteria for improvement. METHODS: Forty consecutive AS patients were treated in a 1-year open-label protocol with infliximab. Response to treatment at week 52 was defined using ASAS response criteria. For the purpose of this exercise, improvement using ASAS criteria was defined by consensus among experts as good with 50% improvement from baseline (ASAS(50)) and dramatic with 70% improvement from baseline (ASAS(70)). Experts established separate criteria for improvement in disease activity as good or dramatic based on patient and physician global assessment of disease activity. RESULTS: Twelve of 40 patients met the ASAS(70) criteria, however, only 8 met the expert definition of a dramatic improvement based on physician global scores and 5 met the expert definition of a dramatic improvement based on patient global assessment of disease activity. Agreement was poor between ASAS(50) or ASAS(70) and expert definition of improvement based on physician global scores (kappa < 0.3), but agreement was moderate to good between ASAS(50) or ASAS(70) and expert definition of improvement based on patient global scores, (kappa = 0.6-0.7). CONCLUSIONS: Differential response experienced by AS patients treated with infliximab was adequately captured by the ASAS composite improvement criteria. Overall, this study demonstrates the validity of the ASAS criteria for the detection of improvement in AS patients treated with biologics. However, the patient global assessment of disease activity may be sufficient to monitor changes in disease activity in these patients.