Predictive Factors of Giant Cell Arteritis in Polymyalgia Rheumatica Patients.

Polymyalgia rheumatica (PMR) is an inflammatory rheumatism of the shoulder and pelvic girdles. In 16 to 21% of cases, PMR is associated with giant cell arteritis (GCA) that can lead to severe vascular complications. Ruling out GCA in patients with PMR is currently a critical challenge for clinicians. Two GCA phenotypes can be distinguished: cranial GCA (C-GCA) and large vessel GCA (LV-GCA). C-GCA is usually suspected when cranial manifestations (temporal headaches, jaw claudication, scalp tenderness, or visual disturbances) occur. Isolated LV-GCA is more difficult to diagnose, due to the lack of specificity of clinical features which can be limited to constitutional symptoms and/or unexplained fever. Furthermore, many studies have demonstrated the existence-in varying proportions-of subclinical GCA in patients with apparently isolated PMR features. In PMR patients, the occurrence of clinical features of C-GCA (new onset temporal headaches, jaw claudication, or abnormality of temporal arteries) are highly predictive of C-GCA. Additionally, glucocorticoids' resistance occurring during follow-up of PMR patients, the occurrence of constitutional symptoms, or acute phase reactants elevation are suggestive of associated GCA. Research into the predictive biomarkers of GCA in PMR patients is critical for selecting PMR patients for whom imaging and/or temporal artery biopsy is necessary. To date, Angiopoietin-2 and MMP-3 are powerful for predicting GCA in PMR patients, but these results need to be confirmed in further cohorts. In this review, we discuss the diagnostic challenges of subclinical GCA in PMR patients and will review the predictive factors of GCA in PMR patients.

Gait analysis dataset of healthy volunteers and patients before and 6 months after total hip arthroplasty.

Clinical gait analysis is a promising approach for quantifying gait deviations and assessing the impairments altering gait in patients with osteoarthritis. There is a lack of consensus on the identification of kinematic outcomes that could be used for the diagnosis and follow up in patients. The proposed dataset has been established on 80 asymptomatic participants and 106 patients with unilateral hip osteoarthritis before and 6 months after arthroplasty. All volunteers walked along a 6 meters straight line at their self-selected speed. Three dimensional trajectories of 35 reflective markers were simultaneously recorded and Plugin Gait Bones, angles, Center of Mass trajectories and ground reaction forces were computed. Gait video recordings, when available, anthropometric and demographic descriptions are also available. A minimum of 10 trials have been made available in the weka file format and C3D file to enhance the use of machine learning algorithms. We aim to share this dataset to facilitate the identification of new movement-related kinematic outcomes for improving the diagnosis and follow up in patients with hip OA.

Optimization of dual energy computed tomography post-processing to reduce lower limb artifacts in gout.

BACKGROUND: In gout, several types of dual-energy computed tomography (DECT) artifacts have been described (nail bed, skin, beam hardening, submillimeter and vascular artifacts), which can lead to overdiagnosis. The objective of this study was to determine the optimal DECT settings for post processing in order to reduce the frequency of some common artifacts in patients with suspected gout. METHODS: Seventy-seven patients hospitalized for suspected gout (feet/ankles and/or knees) who received a DECT imaging were included (final diagnosis of 43 gout and 34 other rheumatic disorders). Different post-processing settings were evaluated using Syngovia software: nine settings (R1 to R9) were evaluated with a combination of different ratio (1.28, 1.36 and 1.55) and attenuation coefficient (120, 150, 170 HU). RESULTS: Among the nine settings tested, the R2 setting (170 HU, ratio =1.28) significantly reduced the presence of knee and foot/ankle artifacts compared to the standard R1 setting (85% and 94% decrease in beam hardening and clumpy artifacts in the ankle and foot, respectively (P<0.001); a decrease of 71%, 60% and 88% respectively of meniscal beam hardening, beam hardening and submillimeter artifacts in the knee (P<0.001). Compared to standard settings, the use of R2 settings decreased sensitivity [0.79 (95% CI: 0.65, 0.88) versus 0.90 (95% CI: 0.78, 0.96)] and increased specificity [0.86 (95% CI: 0.71, 0.93) versus 0.63 (95% CI: 0.47, 0.77)] (P<0.001). Settings using an attenuation coefficient to 120 HU and/or a ratio to 1.55 were all associated with a significant increasing of artifacts, especially clumpy and beam hardening artifacts. CONCLUSIONS: Applying a ratio of 1.28 and a minimum attenuation of 170 HU in DECT post-processing eliminates the majority of artifacts located in the lower limbs, particularly clumpy artifacts and beam hardening.

Dynamic global sagittal alignment in patients with lumbar spinal stenosis: Analysis of the effects of decompression surgery on gait adaptations.

BACKGROUND: Lumbar spinal stenosis (LSS) leads patients to adapt their posture and walking parameters. Pelvic retroversion might be a compensation mechanism of pain. Pelvic and lower limbs compensations during gait are still not precisely understood, as well as the effect of a surgical decompression on them. These dynamic parameters can be studied through three-dimensional gait analysis. RESEARCH QUESTION: Is the dynamic pelvic tilt modified after decompression surgery in LSS patients compared to asymptomatic subjects? MATERIAL AND METHODS: 50 asymptomatic subjects (C-group) and 37 patients operated on for lumbar decompression underwent a three-dimensional gait analysis one month before (M0) and six months after (M6) the surgery. 3D gait analysis was performed and hip and knee flexion, trunk kinematics, walking speed, stride length and pelvic tilt during gait or dynamic pelvic tilt (dPT) were recorded. Health-related quality of life (HRQL) scores (Oswestry Disability Index (ODI) and Visual Analogic Scales (VAS)) and radiological assessment were performed preoperatively and postoperatively. RESULTS: Mean values of maximum and minimum dPT in the LSS-group preoperatively were significantly higher compared to the C-group (respectively 10.9 (6.2)° versus 7.3 (5.6)°, p = 0.003; 7.7 (6.1)° versus 4.8 (5.8)°, p = 0.011), and were significantly lowered at M6 (respectively 10.9 (6.2)° versus 8.1 (4.8)°, p = 0.0087; and 7.7 (6.1)° versus 5.1 (4.7)°, p = 0.012), and became similar to the C-group. The dPT range of motion at M0 and M6 were similar, and were both significantly higher than control values. Mean values of maximum and minimum hip flexion were significantly higher at M0 compared to the C-group, and were significantly lowered at M6. No difference was found between the pre- and postoperative radiographic pelvic tilt. The VAS for lumbar pain, the VAS for radicular pain and the ODI were significantly decreased at M6. SIGNIFICANCE: Compared to asymptomatic people, LSS patients walked with a pelvic anteversion, a hip flessum and a knee flessum before surgery, which tended to disappear after the surgical decompression. These differences were not noticed on static radiographs.

The frequency of occult solid malignancy in patients with polymyalgia rheumatica-like symptoms.

AIMS: We aim to evaluate the clinical usefulness of systematic screening for occult cancer in patients with polymyalgia rheumatic (PMR)-like symptoms in real-life practice. METHODS: All patients seen by rheumatologists in Burgundy, France, between March 2016 and December 2018 for new-onset PMR that met the 2012 ACR/EULAR classification criteria were prospectively included. Patients underwent systematic screening including determination of the erythrocyte sedimentation rate, serum C-reactive protein levels, thoracic, abdominal and pelvic computed tomography (CT-TAP) and, in men, serum prostate-specific antigen. The standardized incidence ratio (SIR) for cancers was calculated using 2012 national estimates of cancer incidence. Potential predictive factors for the diagnosis of cancer were then evaluated using univariate and multivariate analyses. RESULTS: Among the 118 patients included, nine cases of cancer were confirmed and diagnosed with CT-TAP: kidney carcinoma (n = 4), lung cancer (n = 2), pancreatic, colon, and ampullary carcinoma (n = 1 each). Among these cancers, five were localized (four kidney, and one ampullary carcinoma) and were treated with complete surgical resection. The expected incidence of cancer in the general population was 1.95, leading to an overall SIR of 4.6 (95% CI 2.4-8.9, p < 0.0001). An additional analysis was performed for the kidney carcinoma, and it showed a highly significant increase in SIR: 80.8 (95% CI 30.3-215.4). In 80% of patients, the PMR-like syndrome regressed during cancer treatment. No other predictive factors for cancer were found. CONCLUSION: Systematic screening for cancer including CT-TAP in real-life practice revealed occult solid malignancy, mostly early-stage cancer, in a relevant proportion of patients presenting PMR-like symptoms. The high proportion of kidney cancer (40%) is worth highlighting, especially considering that it is not one of the most frequent cancers after 50 years of age.

A single nucleotide polymorphism of IL6-receptor is associated with response to tocilizumab in rheumatoid arthritis patients.

Biological disease-modifying anti-rheumatic drugs (bDMARDs) have changed care of patients with rheumatoid arthritis (RA). However, bDMARDs are costly, can lead to serious infections, and induce a sustained remission in only 30% of RA patients. In this study, we sought to determine if the clinical response to treatment with Tocilizumab (TCZ), an IL-6 inhibitor, varied with genetic background. The efficacy of TCZ was assessed using the European League Against Rheumatism (EULAR) response criteria, measured after 3 months of treatment in two samples of French RA patients (TOCI and ROC studies). Single nucleotide polymorphisms (SNPs) in 21 candidate genes were genotyped using KasPar method (LGC-genomics, UK) and then analyzed to determine their contribution to variation in the response to treatment. One hundred twenty-three patients in the TOCI group (79.8%) and 48 patients in the ROC group (80%) experienced good or moderate EULAR response. The clinical response to treatment was associated with SNP genotype in the gene IL6R, with patients with the homozygous AA-genotype for rs12083537 (IL6R) showing a significantly better response than homozygous or heterozygous patients with the G allele [TOCI: 87.5% of responders for AA genotype vs. 72.2% for AG or GG genotype (p = 0.018); ROC patients: 89.2% of responders for AA genotype vs. 65.2% for AG or GG genotype, p = 0.044]. A meta-analysis combining data from the two cohorts confirmed the lower response rate in patients carrying a copy of the G allele (OR (95% CI) = 0.35 (0.16-0.61), p = 0.001). No association was found with any of the other SNPs tested.

Influence of body mass index on sagittal hip range of motion and gait speed recovery six months after total hip arthroplasty.

PURPOSE: In practice, obesity leads to poor functional outcomes after total hip arthroplasty (THA). However, in clinical research, the influence of body mass index (BMI) on the gait recovery and kinematics for THA is not well documented. The purpose of this study was to assess the influence of BMI on gait parameters pre-operatively and six months after THA for hip osteoarthritis (OA) patients. METHODS: We included 76 THA for hip OA: non-obese group (G1): 49 (BMI < 30 kg/2) and obese group (G2): 37 (BMI ≥ 30 kg/m2) with a control group of 61 healthy people. Clinical evaluation (HOOS) and a 3D gait analysis (gait speed and flexion range of the hip (ROM)) were performed before and six months after THA: The gains between the two visits were calculated and we looked for correlations between outcomes and BMI. RESULTS: Preoperative gait speed and hip ROM were significantly lower in obese patients (speed G1: 0.81 ± 0.22 m/s vs. G2: 0.64 ± 0.23 m/s, p = 0.004 and hip ROM G1: 26.1° ± 7.3 vs. G2: 21.4° ± 6.6, p = 0.005), and obese patients were more symptomatic. At six months, gait speed and hip ROM were significantly lower for all patients compared with the control group. No correlation between gait velocity, hip ROM, and BMI was found. Biomechanical and clinical gains were comparable in the two groups. CONCLUSIONS: All patients, including obese patients, have significant functional improvement after THA, objectively assessed by gait speed. Even if patients did not fully recover to the level of a healthy control person after THA, functional gain is comparable irrespective of BMI.

Is the Pelvis-Thorax Coordination a Valuable Outcome Instrument to Assess Patients With Hip Osteoarthritis?

Objective: The evaluation of the disease severity in hip osteoarthritis (OA) patients being currently based on subjective instruments. It would be of interest to develop more objective instruments, for example based on gait analysis. The aims of this study were to explore if pelvis-thorax coordination parameters could be valuable instrument outcomes to achieve this evaluation by assessing their reliability, discriminant capacity and responsiveness. Methods: Three groups of subjects; healthy, hip OA patients with severe disease (defined as indication to surgery), hip OA patients with less severe disease (no indication to surgery) were included. Hip OA patients with severe disease were evaluated before and 6 months after surgery. Subjects had to perform a gait analysis at comfortable speed, and pelvis-thorax coordination was evaluated. The correlations with clinical and structural parameters, as well as reliability, discriminant capacities and responsiveness, were assessed. Results: The pelvis-thorax coordination in the coronal plane during walking was correlated to clinical and to structural severity in hip OA patients (R 2 = 0.13). The coronal plane coordination allowed to discriminate healthy subjects from all hip OA patients (sensibility = 0.86; specificity = 0.59). Moreover, when comparing OA patients only, coronal plane coordination allows to discriminate patients with indication of surgery from those with no indication of surgery (sensibility = 0.72; specificity = 0.72). Moreover, the pelvis-thorax coordination demonstrated an excellent reliability and a good responsiveness. Conclusion: Changes in the pelvis-thorax coordination might refer to different mechanisms, from analgesia to motor control plasticity, and might be a possible explanation for the weak correlation between structure and symptoms in hip OA patients. Moreover, such parameter might be used as an objective outcome in hip OA clinical trials. Clinical Trials Registration: www.ClinicalTrials.gov, identifier: NCT02042586 and NCT01907503.

Role of dual-energy CT in the diagnosis and follow-up of gout: systematic analysis of the literature.

The aim of this systematic review was to determine the potential role of dual-energy CT in the diagnosis and follow-up of gout with regard to the Outcome Measures in Rheumatology (OMERACT) filter. A systematic analysis of the literature was conducted using the MEDLINE and Cochrane databases and published abstracts of international congresses, according to the criteria of the OMERACT filter: feasibility, reproducibility, validity versus laboratory (serum urate, MSU synovial fluid aspirate) and other imaging modalities for gout, and its sensitivity to change in patients on urate lowering therapy (ULT). Thirty-two articles were found representing a total of 1502 patients. The data on feasibility showed that the examination took little time and involved low levels of radiation but had current limited availability. Intra- and inter-observer reproducibility was excellent, with intra-class correlation coefficients > 0.9. Validity in comparison with polarized-light microscopy showed good sensitivity and specificity (> 80%). The diagnostic performance was better than that of radiography and conventional CT-scan and at least equivalent to that of ultrasonography. The sensitivity to change varied with effect sizes from 0.05 (low) to 1.24 (high) for decrease in the tophus volume following different ULT in gout patients. Dual-energy CT-scan is a reproducible and accurate imaging modality for the diagnosis of gout, particularly for tophaceous gout (intra- or extra-articular). It can become a second-line imaging modality of choice in cases of diagnostic doubt, such as ultrasonography. Its role remains uncertain in the follow-up of gout patients treated with ULT and needs further clarification.

Factors influencing the use of tocilizumab as monotherapy in patients with rheumatoid arthritis in a real-life setting: results at 1†year of the ACT-SOLO study.

INTRODUCTION: Using a biologic disease-modifying antirheumatic drug (bDMARD) as monotherapy in clinical practice for patients with rheumatoid arthritis (RA) is common and recognised by health authorities although current guidelines recommend to combine them with conventional synthetic (cs)DMARDs. This study mainly aimed to search for real-life factors influencing the use of tocilizumab as MONO or in combination (COMBO). METHODS: In this non-interventional, prospective, national, multicentre study, data were collected every 3 months over a 12-month period in RA patients starting tocilizumab. The proportion of monotherapy patients was described, together with significant explicative factors. RESULTS: Among the 577 analysed patients recruited from January 2012 to August 2013 (228 monotherapy patients; 40%), 79% were women, mean RA duration was 11±9 years, previous RA treatments included bDMARDs and csDMARDs in 75% of cases and mean Disease Activity Score 28 joints-Erythrocyte Sedimentation Rate (DAS28-ESR) was 5.2±1.3 at inclusion. Explicative factors for monotherapy were at least 65 years (OR=1.47, p=0.0485), no methotrexate within the two last years (OR=5.96, p<0.0001), past severe infection (OR=1.99, p=0.0272) and higher baseline DAS28-ESR (OR=1.22, p=0.0086). Regarding clinical results (DAS28-ESR, Clinical Disease Activity Index (CDAI) and Simple Disease Activity Index (SDAI) low disease activity and remission; ACR20/50/70 and European League Against Rheumatism (EULAR) response; Health Assessment Questionnaire Disability Index (HAQ-DI) score), no relevant differences between monotherapy and combination patients were observed at 1 year. A total of 23 tocilizumab-treated patients (4%) experienced serious infections; no new safety signals were noted with no differences between groups. CONCLUSIONS: ACT-SOLO confirms the high proportion of RA patients receiving tocilizumab as MONO in clinical practice. The study also showed that clinical results at 1 year were similar between MONO and COMBO patients in a real-life setting. TRIAL REGISTRATION NUMBER: NCT01474291.

Röttinger approach with dual-mobility cup to improve functional recovery in hip osteoarthritis patients: biomechanical and clinical follow-up.

PURPOSE: We assumed that the combination of dual-mobility total hip arthroplasty (THA) using the minimally-invasive Röttinger anterolateral approach could guarantee hip stability with faster functional recovery. We objectively analyzed functional improvement after dual-mobility THA by quantitative gait analysis. METHODS: We compared the results achieved following two different surgical approaches: Röttinger's versus Moore's approach (posterolateral approach). We included 70 patients in an open prospective single-centre study: 38 by Rottinger's approach (age = 67yo) and 32 by Moores's approach (age = 68yo). Clinical and biomechanical analysis (kinematic and kinetic parameters of the hip) were conducted at the pre-operative period and at six months post-op RESULTS: We found a significant improvement in all clinical scores and all biomechanical parameters but no difference was found between the two approaches. However, the study showed marked clinical, biomechanical and functional improvements for patients treated with dual-mobility THA for osteoarthritis without complete hip recovery compared with a control group. CONCLUSIONS: The combination of the Röttinger approach with a dual-mobility cup remains a valid choice for primary THA without functional advantage at midterm.

Patient-perceived flares in rheumatoid arthritis: A sub-analysis of the STRASS treatment tapering strategy trial.

OBJECTIVES: Patient's and physician's perspective can differ in rheumatoid arthritis (RA). The aim was to define the concept of patient-reported flares. METHODS: Post-hoc analysis of a randomized controlled trial of a step-down strategy in RA patients treated with anti-TNF, in DAS28-remission for ≥6 months, randomized to either "spacing" or "maintaining" anti-TNF. The occurrence of patient-reported flares (PRF) was evaluated every 3 months for 18 months by: "Over the last 3 months, did you experience symptoms suggestive of disease exacerbation?". Visits with and without PRF were compared, using a linear mixed effects model, in terms of symptoms, disability based on the Health Assessment Questionnaire, quality of life based on Short Form 36 Health Survey and DAS28-based relapses (DBR), defined as an increase of DAS28>0.6 and an absolute value of DAS28>2.6. The agreement between PRF and DBR was measured by the kappa coefficient on repeated data. RESULTS: In all, 137 patients were analyzed: mean age 55±11 years, females 78%, mean RA duration 9.5±8.0 years. Over the 18 months, PRF concerned 27.2% of the 940 available visits. DBR and PRF were observed in 24% and 16% of 940 visits for 137 patients respectively. All the items were associated with PRF with standardized effect size between -0.58 (SF36 PCS) and 0.87 (DAS28). The agreement between PRF and DBR was moderate (κ=0.44). CONCLUSION: The concept of flare refers to more than just RA disease activity.

Validation of FLARE-RA, a Self-Administered Tool to Detect Recent or Current Rheumatoid Arthritis Flare.

OBJECTIVE: To validate the measurement properties and the detection performance of the FLARE-RA questionnaire in a longitudinal prospective study. METHODS: To validate the FLARE-RA self-administered questionnaire, we conducted a prospective trial in rheumatoid arthritis (RA) patients to document: 1) content and construct validity by factor analysis, convergent validity by Pearson's correlation with routine assessment of patient index data (Routine Assessment of Patient Index Data 3 [RAPID-3] questionnaire), RA Impact of Disease (RAID) score, Disease Activity Score in 28 joints (DAS28), and Health Assessment Questionnaire (HAQ), 2) reliability (intraclass correlation coefficient [ICC] and Bland-Altman plot), and 3) feasibility of use. Patients were examined and questionnaires were collected at baseline and 3 months, and every week in between for RAPID-3. RESULTS: We recruited 138 patients from 13 centers: 81.9% women, mean age 57.4 years, mean DAS28 2.9, mean C-reactive protein level 6.2 mg/liter, 84.4% rheumatoid factor positive, 78.0% anti-citrullinated protein antibody positive, and 78.8% with erosive disease. At baseline, the mean ± SD FLARE-RA score was 2.3 ± 2.3. The content and construct validity of FLARE-RA was good. A substantial floor effect, but no ceiling effect, was observed. Principal components analysis revealed 1 domain disentangled in 2 subdomains: physical and emotional. The FLARE-RA total score was correlated with the DAS28 (r = 0.63, P < 0.001), RAID (r = 0.80, P < 0.001), RAPID-3 (r = 0.77, P < 0.001), and HAQ (r = 0.53, P < 0.001). The ICC for reliability was 0.94 (95% confidence interval 0.92-0.96). CONCLUSION: The FLARE-RA self-administered questionnaire represents a valid and valuable instrument to detect RA flare between visits to the physician.

Involvement and prognosis value of CD8(+) T cells in giant cell arteritis.

CD8(+) T cells participate in the pathogenesis of some vasculitides. However, little is known about their role in Giant Cell Arteritis (GCA). This study was conducted to investigate CD8(+) T cell involvement in the pathogenesis of GCA. Analyses were performed at diagnosis and after 3 months of glucocorticoid treatment in 34 GCA patients and 26 age-matched healthy volunteers. Percentages of CD8(+) T-cell subsets, spectratype analysis of the TCR Vß families of CD8(+) T cells, levels of cytokines and chemokines and immunohistochemistry of temporal artery biopsies (TAB) were assessed. Among total CD8(+) T cells, percentages of circulating cytotoxic CD8 T lymphocytes (CTL, CD3(+)CD8(+)perforin(+)granzymeB(+)), Tc17 (CD3(+)CD8(+)IL-17(+)), CD63(+)CD8(+) T cells and levels of soluble granzymes A and B were higher in patients than in controls, whereas the percentage of Tc1 cells (CD3(+)CD8(+)IFN-γ(+)) was similar. Moreover, CD8(+) T cells displayed a restricted TCR repertoire in GCA patients. Percentages of circulating CTL, Tc17 and soluble levels of granzymes A and B decreased after treatment. CXCR3 expression on CD8(+) T cells and its serum ligands (CXCL9, -10, -11) were higher in patients. Analyses of TAB revealed high expression of CXCL9 and -10 associated with infiltration by CXCR3(+)CD8(+) T cells expressing granzyme B and TiA1. The intensity of the CD8 T-cell infiltrate in TAB was predictive of the severity of the disease. This study demonstrates the implication and the prognostic value of CD8(+) T-cells in GCA and suggests that CD8(+) T-cells are recruited within the vascular wall through an interaction between CXCR3 and its ligands.

Reliability, validity and feasibility of nail ultrasonography in psoriatic arthritis.

OBJECTIVE: To determine the feasibility, reliability and validity of nails ultrasonography in psoriatic arthritis as an outcome measure. METHODS: Pilot prospective single-centre study of eight ultrasonography parameters in B mode and power Doppler concerning the distal interphalangeal (DIP) joint, the matrix, the bed and nail plate. Intra-observer and inter-observer reliability was evaluated for the seven quantitative parameters (ICC and kappa). Correlations between ultrasonography and clinical variables were searched to assess external validity. Feasibility was assessed by the time to carry out the examination and the percentage of missing data. RESULTS: Twenty-seven patients with psoriatic arthritis (age 55.0±16.2 years, disease duration 13.4±9.4 years) were included. Of these, 67% presented nail involvement on ultrasonography vs 37% on physical examination (P<0.05). Reliability was good (ICC and weighted kappa>0.75) for the seven quantitative parameters, except for synovitis of the DIP joint in B mode. The synovitis of the DIP joint revealed by ultrasonography correlated with the total number of clinical synovitis and Doppler US of the nail (matrix and bed). Doppler US of the matrix correlated with VAS pain but not with the ASDAS-CRP or with clinical enthesitis. No significant correlation was found with US nail thickness. CONCLUSION: The feasibility and reliability of ultrasonography of the nail in psoriatic arthritis appear to be satisfactory. Among the eight parameters evaluated, power Doppler of the matrix which correlated with local inflammation (DIP joint and bed) and with VAS pain could become an interesting outcome measure, provided that it is also sensitive to change.

Response to tocilizumab in rheumatoid arthritis is not influenced by the body mass index of the patient.

OBJECTIVE: To assess the relationship between the body mass index (BMI) and the efficacy of tocilizumab (TCZ) in patients with rheumatoid arthritis (RA). METHODS: We conducted a retrospective study in 222 patients with RA followed by 5 centers. The European League Against Rheumatism response was evaluated at 6 months. Univariate and multivariate logistic regressions were performed. RESULTS: No significant association between the BMI and the response to TCZ at 6 months was found after adjustment for potential confounding factors (adjusted OR 0.45, 95% CI 0.16-1.24, p = 0.13 and OR 1.19, 95% CI 0.31-4.48, p = 0.78 for BMI 25-30 kg/m(2) and BMI > 30 kg/m(2), respectively, compared to BMI < 25 kg/m(2)). CONCLUSION: Response to TCZ in patients with RA is not influenced by the baseline BMI, in contrast to anti-tumor necrosis factor drugs.

Impact of repeated measures of joint space width on the sample size calculation: An application to hip osteoarthritis.

OBJECTIVE: The aims of the study were to investigate the impact of aggregation of repeated readings (a) on minimising variability of joint space width (JSW) measurements based on calculation of the smallest detectable difference (SDD) and (b) on sample size calculation in a hip OA randomized controlled trial (RCT). METHODS: (a) Post-hoc analysis of 50 radiographs from a hip OA RCT (ECHODIAH). JSW reliability was calculated by the SDD through the aggregation of repeated readings of hip OA radiographs by an experienced rheumatologist. (b) The observed SDDs were applied to the real ECHODIAH data, to determine the post-hoc theoretical sample sizes. RESULTS: (a) Although the intra-reader reliability did not improve, SDDs decreased from 0.75 mm to 0.27 mm when aggregating two or more consecutive readings. (b) A significant decrease of sample size was noticed until three consecutive paired JSW measurements, with a sample size ranging from 6588 patients per group (SDD=0.75 mm) to 377 patients (SDD=0.45 mm). However, an increase of the sample size was observed for smaller SDDs. CONCLUSION: In hip OA, the aggregation of repeated radiograph readings leads to a significant decrease in SDD, although the intra-reader reliability of the experienced reader remains stable. The decrease in SDD allowed to reduce significantly the post-hoc calculation of sample size until a SDD value of 0.45 mm. For smaller cut-offs of radiological progression, the sample size increased again indicating that gain in sensitivity does not automatically lead to gain in sample size, particularly if the treatment effect is limited.