Determination of the Value of Color Doppler Ultrasound in Patients With a Clinical Suspicion of Giant Cell Arteritis.

OBJECTIVE: It is urgent to diagnose giant cell arteritis (GCA) as quickly as possible to prevent irreversible blindness. The traditional gold standard for diagnosing GCA is temporal artery biopsy (TAB). However, TAB lacks diagnostic performance and carries out risks of surgical intervention. The noninvasive color Doppler ultrasound (CDU) seems to be a promising alternative. This study is designed to assess the diagnostic value of CDU in daily clinical practice. METHODS: In this prospective cohort study, patients with a clinical suspicion of active GCA were included and underwent a CDU of the temporal arteries. If deemed necessary by the referrer, a TAB and/or 18F-fluorodeoxyglucose positron emission tomography with computed tomography was performed. The retrospective clinical diagnosis was determined 1 year after inclusion by two physicians experienced in the field of vasculitis. RESULTS: 242 patients were included and GCA was diagnosed in 73 (30%) patients by the defined retrospective clinical diagnosis. Compared with the retrospective diagnosis, CDU has a sensitivity of 60% (48-72), specificity of 94% (89-97), positive predictive value (PPV) of 81% (70-89), negative predictive value (NPV) of 85% (80-88), and an accuracy of 84% (78-88). A total of 84 (35%) patients underwent TAB. TAB has a sensitivity of 66% (51-79), specificity of 100% (90-100), PPV of 100% (100), NPV of 67% (58-75), and an accuracy of 80% (70-88). CONCLUSION: This study shows comparable diagnostic performance for CDU and TAB and even better CDU results with a bilateral halo present. Considering the advantages of the noninvasive CDU, it is the diagnostic tool of choice.

Three-month tapering and discontinuation of long- term, low-dose glucocorticoids in senior patients with rheumatoid arthritis is feasible and safe: placebo-controlled double blind tapering after the GLORIA trial.

OBJECTIVE: The randomised placebo-controlled GLORIA (Glucocorticoid LOw-dose in RheumatoId Arthritis) trial evaluated the benefits and harms of prednisolone 5 mg/day added to standard care for 2 years in patients aged 65+ years with rheumatoid arthritis (RA). Here, we studied disease activity, flares and possible adrenal insufficiency after blinded withdrawal of study medication. METHODS: Per protocol, patients successfully completing the 2-year trial period linearly tapered and stopped blinded study medication in 3 months. We compared changes in disease activity after taper between treatment groups (one-sided testing). Secondary outcomes (two-sided tests) comprised disease flares (DAS28 (Disease Activity Score 28 joints) increase >0.6, open-label glucocorticoids or disease-modifying antirheumatic drug (DMARD) increase/switch after week 4 of tapering) and symptoms/signs of adrenal insufficiency. In a subset of patients from 3 Dutch centres, cortisol and ACTH were measured in spot serum samples after tapering. RESULTS: 191 patients were eligible; 36 met treatment-related flare criteria and were only included in the flare analysis. Mean (SD) DAS28 change at follow-up: 0.2 (1.0) in the prednisolone group (n=76) vs 0.0 (1.2) in placebo (n=79). Adjusted for baseline, the between-group difference in DAS28 increase was 0.16 (95% confidence limit -0.06, p=0.12). Flares occurred in 45% of prednisolone patients compared with 33% in placebo, relative risk (RR) 1.37 (95% CI 0.95 to 1.98; p=0.12). We found no evidence for adrenal insufficiency. CONCLUSIONS: Tapering prednisolone moderately increases disease activity to the levels of the placebo group (mean still at low disease activity levels) and numerically increases the risk of flare without evidence for adrenal insufficiency. This suggests that withdrawal of low-dose prednisolone is feasible and safe after 2 years of administration.

Low dose, add-on prednisolone in patients with rheumatoid arthritis aged 65+: the pragmatic randomised, double-blind placebo-controlled GLORIA trial.

BACKGROUND: Low-dose glucocorticoid (GC) therapy is widely used in rheumatoid arthritis (RA) but the balance of benefit and harm is still unclear. METHODS: The GLORIA (Glucocorticoid LOw-dose in RheumatoId Arthritis) pragmatic double-blind randomised trial compared 2 years of prednisolone, 5 mg/day, to placebo in patients aged 65+ with active RA. We allowed all cotreatments except long-term open label GC and minimised exclusion criteria, tailored to seniors. Benefit outcomes included disease activity (disease activity score; DAS28, coprimary) and joint damage (Sharp/van der Heijde, secondary). The other coprimary outcome was harm, expressed as the proportion of patients with ≥1 adverse event (AE) of special interest. Such events comprised serious events, GC-specific events and those causing study discontinuation. Longitudinal models analysed the data, with one-sided testing and 95% confidence limits (95% CL). RESULTS: We randomised 451 patients with established RA and mean 2.1 comorbidities, age 72, disease duration 11 years and DAS28 4.5. 79% were on disease-modifying treatment, including 14% on biologics. 63% prednisolone versus 61% placebo patients completed the trial. Discontinuations were for AE (both, 14%), active disease (3 vs 4%) and for other (including covid pandemic-related disease) reasons (19 vs 21%); mean time in study was 19 months. Disease activity was 0.37 points lower on prednisolone (95% CL 0.23, p<0.0001); joint damage progression was 1.7 points lower (95% CL 0.7, p=0.003). 60% versus 49% of patients experienced the harm outcome, adjusted relative risk 1.24 (95% CL 1.04, p=0.02), with the largest contrast in (mostly non-severe) infections. Other GC-specific events were rare. CONCLUSION: Add-on low-dose prednisolone has beneficial long-term effects in senior patients with established RA, with a trade-off of 24% increase in patients with mostly non-severe AE; this suggests a favourable balance of benefit and harm. TRIAL REGISTRATION NUMBER: NCT02585258.

Effects of targeted therapies on bone in rheumatic and musculoskeletal diseases.

Generalized bone loss (osteoporosis) and fragility fractures can occur in rheumatic and musculoskeletal diseases including rheumatoid arthritis and spondyloarthritis (SpA; including ankylosing spondylitis and psoriatic arthritis). In addition, rheumatoid arthritis can involve localized, periarticular bone erosion and, in SpA, local (pathological) bone formation can occur. The RANK-RANKL-osteoprotegerin axis and the Wnt-ß-catenin signalling pathway (along with its inhibitors sclerostin and Dickkopf 1) have been implicated in inflammatory bone loss and formation, respectively. Targeted therapies including biologic DMARDs and Janus kinase (JAK) inhibitors can stabilize bone turnover and inhibit radiographic joint damage, and potentially also prevent generalized bone loss. Targeted therapies interfere at various points in the mechanisms of local and generalized bone changes in systemic rheumatic diseases, and they effect biomarkers of bone resorption and formation, bone mass and risk of fragility fractures. Studies on the effects of targeted therapies on rates of fragility fracture are scarce. The efficacy of biologic DMARDs for arresting bone formation in axial SpA is debated. Improved understanding of the most relevant therapeutic targets and identification of important targeted therapies could lead to the preservation of bone in inflammatory rheumatic and musculoskeletal diseases.

Associations of vascular and bone status in arthritis patients.

Cardiovascular (CV) disease and osteoporosis (OP) have been associated with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Bone and vascular biomarkers and parameters along with the effect of 1-year anti-TNF therapy on these markers were assessed in order to determine correlations between vascular pathophysiology and bone metabolism in RA and AS. Thirty-six patients treated with etanercept or certolizumab pegol and 17 AS patients treated with ETN were included in a 12-month follow-up study. Bone and vascular markers were previously assessed by ELISA. Bone density was measured by DXA and quantitative CT (QCT). Flow-mediated vasodilation (FMD), common carotid intima-media thickness (IMT) and pulse-wave velocity (PWV) were assessed by ultrasound. Multiple correlation analyses indicated associations between bone and vascular markers. Osteoprotegerin, sclerostin and cathepsin K were significantly associated with FMD, IMT and PWV, respectively (p < 0.05). Moreover, total and trabecular BMD determined by QCT inversely correlated with IMT (p < 0.05). On the other hand, among vascular parameters, platelet-derived growth factor BB and IMT correlated with DXA femoral and QCT total BMD, respectively (p < 0.05). In the RM-ANOVA analysis, anti-TNF treatment together with baseline osteocalcin, procollagen 1 N-terminal propeptide (P1NP) or vitamin D3 levels determined one-year changes in IMT (p < 0.05). In the MANOVA analysis, baseline disease activity indices (DAS28, BASDAI), the one-year changes in these indices, as well as CRP exerted effects on multiple correlations between bone and vascular markers (p < 0.05). As the pattern of interactions between bone and vascular biomarkers differed between baseline and after 12 months, anti-TNF therapy influenced these associations. We found a great number of correlations in our RA and AS patients undergoing anti-TNF therapy. Some of the bone markers have been associated with vascular pathophysiology, while some vascular markers correlated with bone status. In arthritis, systemic inflammation and disease activity may drive both vascular and bone disease.

Peripheral quantitative computed tomography in the assessment of bone mineral density in anti-TNF-treated rheumatoid arthritis and ankylosing spondylitis patients.

INTRODUCTION: Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are associated with osteoporosis. There have not been many peripheral quantitative computed tomography (QCT) studies in patients receiving biologics. We assessed volumetric and areal bone mineral density (BMD) by forearm QCT and dual-energy X-ray absorptiometry (DXA), respectively in addition to laboratory biomarkers in these arthritides. METHODS: Forty RA and AS patients treated with either etanercept (ETN) or certolizumab pegol (CZP) were undergoing follow-ups for one year. Volumetric and areal BMD, as well as parathyroid hormone (PTH), osteocalcin, RANKL, 25-hydroxyvitamin D (VITD), P1NP, CTX, sclerostin (SOST), Dickkopf 1 (DKK-1) and cathepsin K (CATHK) were determined. RESULTS: We did not observe any further bone loss during the 12-month treatment period. Volumetric and areal BMD showed significant correlations with each other (p<0.017 after Bonferroni's correction). Trabecular QCT BMD at baseline (p=0.015) and cortical QCT BMD after 12 months (p=0.005) were inversely determined by disease activity at baseline in the full cohort. Trabecular QCT BMD at baseline also correlated with CTX (p=0.011). In RA, CRP negatively (p=0.014), while SOST positively (p=0.013) correlated with different QCT parameters. In AS, RANKL at baseline (p=0.014) and after 12 months (p=0.007) correlated with cortical QCT BMD. In the full cohort, 12-month change in QTRABBMD was related to TNF inhibition together with elevated VITD-0 levels (p=0.031). Treatment and lower CATHK correlated with QCORTBMD changes (p=0.006). In RA, TNF inhibition together with VITD-0 (p<0.01) or CATHK-0 (p=0.002), while in AS, treatment and RANKL-0 (p<0.05) determined one-year changes in QCT BMD. CONCLUSIONS: BMD as determined by QCT did not change over one year of anti-TNF treatment. Disease activity, CATHK, RANKL and VITD may be associated with the effects of anti-TNF treatment on QCT BMD changes. RA and AS may differ in this respect.

Bone Mineral Density Loss and Fracture Risk After Discontinuation of Anti-osteoporotic Drug Treatment: A Narrative Review.

The number of patients on long-term anti-osteoporotic drug therapy is rising. Unfortunately, there are few data to guide decisions about duration of pharmacologic therapy for osteoporosis. Many practitioners discontinue therapy after a period of 5 years because of the risk of rare but severe side effects that may occur in long-term users. The objective of this narrative review was to describe the effects of discontinuation of anti-osteoporotic drugs and to investigate what is not yet known on this topic. For each anti-osteoporotic agent, PubMed was searched for evidence from randomized clinical trials in patients with osteoporosis on osteoporotic drugs lasting ≥ 3 years, followed by ≥ 1 year of follow-up after discontinuation of therapy and reported at least one item of the following: changes in bone mineral density, bone turnover markers and/or the risk of vertebral and/or nonvertebral fractures after discontinuation of therapy. The% change in bone mineral density (BMD) after 1 year of discontinuation of therapy is - 0.4% or less at the hip and femoral neck in both alendronate- and zoledronic acid-treated patients. In the other reported agents (risedronate, ibandronate, raloxifene, teriparatide, denosumab and romosozumab) this percentage of bone loss at the femoral neck and total hip was at least 1%, with the largest decrease in BMD after discontinuation of denosumab and romosozumab. In all studies reporting bone turnover markers, a substantial rapid rise in these markers was observed after discontinuation of therapy, with a large rebound increase to far above baseline levels in the denosumab-treated patients. There were few data on fracture risk after discontinuation of therapy; data showed that discontinuing alendronate, zoledronic acid and especially denosumab significantly increases the risk of vertebral fractures. In conclusion, osteoporosis should be considered more as a chronic condition. Therefore, in modern fracture risk management, continuous monitoring and treatment is required, as is the case with other chronic diseases, to sustain the benefits of therapy, especially in denosumab- and romosozumab-treated patients. The exception is alendronate and zoledronic acid, in these patients a discontinuation of drug therapy of 1 year or more might be acceptable.

Management of glucocorticoid-induced osteoporosis.

Long-term glucocorticoid (GC) therapy is frequently indicated to treat autoimmune and chronic inflammatory diseases in daily clinical practice. Two of the most devastating untoward effects are bone loss and fractures. Doses as low as 2.5 mg of prednisone for more than 3 months can impair bone integrity. Population at risk is defined based on the dose and duration of GC therapy and should be stratified according to FRAX (Fracture Risk Assessment Tool), major osteoporotic fracture, prior fractures, and bone mineral density values (BMD). General measures include to prescribe the lowest dose of GC to control the underlying disease for the shortest possible time, maintain adequate vitamin D levels and calcium intake, maintain mobility, and prescribe a bone acting agent in patients at high risk of fracture. These agents include oral and intravenous bisphosphonates, denosumab, and teriparatide.

Medication adherence in older people with rheumatoid arthritis is lower according to electronic monitoring than according to pill count.

OBJECTIVES: Suboptimal medication adherence is a serious problem in the treatment of chronic inflammatory diseases. To measure medication adherence, electronic monitoring is regarded as superior to pill count. GLORIA is an ongoing two-year trial on the addition of low-dose (5 mg/d) prednisolone or placebo to standard care in older people (65+ years) with RA. During the entire trial, adherence is measured with electronic caps, and with pill counts. The objective is to describe medication adherence patterns, and to compare the adherence results of the two methods. METHODS: The recorded adherence patterns of patients (blinded for treatment group) were classified according to descriptive categories. The cutoff for good adherence was set at 80% of prescribed pills taken. RESULTS: Trial inclusion closed in 2018 at 451 patients, but trial follow-up is ongoing; the current dataset contains adherence data of 371 patients. Mean number of recorded 90-day periods per patient was 4 (range 1-8). Based on pill count over all periods, 90% of the patients had good adherence; based on cap data, only 20%. Cap data classified 30% of patients as non-user (<20% of days an opening) and 40% as irregular user (different adherence patterns, in or between periods). CONCLUSION: In our trial of older people with RA, the majority appeared to be adherent to medication according to pill count. Results from caps conflicted with those of pill counts, with patterns suggesting patients did not use the bottle for daily dispensing, despite specific advice to do so. TRIAL REGISTRATION: NCT02585258. ClinicalTrials.gov (https://www.clinicaltrials.gov/).

Osteoporosis in patients with rheumatoid arthritis: an update in epidemiology, pathogenesis, and fracture prevention.

INTRODUCTION: Rheumatoid arthritis (RA) is a chronic disabling disease characterized by a symmetrical articular involvement due to ongoing joint inflammation, if left insufficiently treated. Local and generalized bone loss is one of the main extra-articular complications of RA and leads to an increased risk for fragility fractures, which further impair functional ability, quality of life, and life expectancy. Therefore, there is an urgent need for good fracture risk management in the vulnerable RA patient. AREAS COVERED: The authors review: the epidemiology and pathophysiology (i.e. risk factors) of osteoporosis (OP), fracture, and vertebral fracture risk assessment, the effects of anti-rheumatic drugs on bone loss, pharmacological treatment of OP in RA including both bisphosphonates (BP) and newer drugs including anti-resorptives and osteoanabolic treatment options. EXPERT OPINION: Patients with active RA have elevated bone resorption and local bone loss. Moreover, these patients are at increased risk for generalized bone loss, vertebral and non-vertebral fractures. Since general risk factors (such as low BMI, fall risk) and RA-related factors play a role, optimal fracture prevention in RA patients is based on optimal diagnostics based on both of these factors, and on the use of adequate non-medical and medical treatment options.

Pharmacological Management of Osteoporosis in Rheumatoid Arthritis Patients: A Review of the Literature and Practical Guide.

Rheumatoid arthritis (RA) is a chronic disabling disease that is associated with increased localized and generalized osteoporosis (OP). Previous studies estimated that approximately one-third of the RA population experience bone loss. Moreover, RA patients suffer from a doubled fracture incidence depending on several clinical factors, such as disease severity, age, glucocorticoid (GC) use, and immobility. As OP fractures are related to impaired quality of life and increased mortality rates, OP has an enormous impact on global health status. Therefore, there is an urgent need for a holistic approach in daily clinical practice. In other words, both OP- and RA-related factors should be taken into account in treatment guidelines for OP in RA. First, to determine the actual fracture risk, dual-energy X-ray absorptiometry (DXA), including vertebral fracture assessment (VFA) and calculation of the 10-year fracture risk with FRAX®, should be performed. In case of high fracture risk, calcium and vitamin D should be supplemented alongside anti-osteoporotic treatment. Importantly, RA treatment should be optimal, aiming at low disease activity or remission. Moreover, GC treatment should be at the lowest possible dose. In this way, good fracture risk management will lead to fracture risk reduction in RA patients. This review provides a practical guide for clinicians regarding pharmacological treatment options in RA patients with OP, taking into account both osteoporotic-related factors and factors related to RA.

Current Treatments and New Developments in the Management of Glucocorticoid-induced Osteoporosis.

Glucocorticoids (GCs) are often used for improvement of quality of life, particularly in the elderly, but long-term GC use may cause harm; bone loss and fractures are among the most devastating side effects. Fracture risk is particularly high in patients with a severe underlying disease with an urgent need for treatment with high-dose GCs. Moreover, it is important to realize that these patients suffer from an augmented background fracture risk as these patients have a high presence of traditional risk factors for osteoporosis, such as high age, low body mass index (BMI), smoking and relatives with osteoporosis or hip fractures. It is thus crucial for prevention of osteoporotic fractures to use the lowest dose of GC for a short period of time to prevent fractures. Another important task is optimal treatment of the underlying disease; for instance, fracture risk is higher in patients with active rheumatoid arthritis than in patients in whom rheumatoid arthritis is in remission. Thus, fracture risk is generally highest in the early phase, when GC dosage and the disease activity of the underlying disease are high. Finally, some of the traditional risk factors can be modulated, e.g., smoking and low BMI. Life-style measures, such as adequate amounts of calcium and vitamin D and exercise therapy are also crucial. In some patients, anti-osteoporotic drugs are also indicated. In general, oral bisphosphonates (BPs) are the first choice, because of their efficacy and safety combined with the low cost of the drug. However, for those patients who do not tolerate oral BPs, alternatives ("second-line therapies") are available: BP intravenously (zoledronic acid), denosumab (Dmab), and teriparatide. Both zoledronic acid and Dmab have been proven to be superior to oral bisphosphonates like risedronate in improvement of bone mineral density. For teriparatide, vertebral fracture reduction has been shown in comparison with alendronate. Thus, to reduce the global burden of GC use and fracture risk, fracture risk management in GC users should involve at least involve life-style measures and the use of the lowest possible dose of GC. In high-risk patients, anti-osteoporotic drugs should be initiated. First choice drugs are oral BPs; however, in those with contraindications and those who do not tolerate oral BPs, second-line therapies should be started. Although this is a reasonable treatment algorithm, an unmet need is that the most pivotal (second-line) drugs are not used in daily clinical practice at the initial phase, usually characterized by high-dose GC and active underlying disease, when they are most needed. In some patients second-line drugs are started later in the disease course, with lower GC dosages and higher disease activity. As this is a paradox, we think it is a challenge for physicians and expert committees to develop an algorithm with clear indications in which specific patient groups second-line anti-osteoporotic drugs should or could be initiated as first-choice treatment.

Common mechanisms and holistic care in atherosclerosis and osteoporosis.

Cardiovascular (CV) disease and osteoporosis (OP) have become increasing challenges in the aging population and even more in patients with inflammatory rheumatic diseases, such as rheumatoid arthritis, spondyloarthropathies, and systemic lupus erythematosus. In this review, we discuss how the epidemiology and pathogenesis of CV events and OP are overlapping. Smoking, diabetes mellitus, physical inactivity as conventional risk factors as well as systemic inflammation are among the modifiable risk factors for both CV events and bone loss. In rheumatic patients, systemic "high-grade" inflammation may be the primary driver of accelerated atherogenesis and bone resorption. In the general population, in which some individuals might have low-grade systemic inflammation, a holistic approach to drug treatment and lifestyle modifications may have beneficial effects on the bone as well as the vasculature. In rheumatic patients with accelerated inflammatory atherosclerosis and bone loss, the rapid and effective suppression of inflammation in a treat-to-target regime, aiming at clinical remission, is necessary to effectively control comorbidities.

Critical issues and current challenges in osteoporosis and fracture prevention. An overview of unmet needs.

Osteoporosis is a silent disease with increasing prevalence due to the global ageing population. Decreased bone strength and bone quality is the hallmark of osteoporosis which leads to an increased risk of fragility fractures in elderly. It has been estimated that approximately ~50% of women will suffer during their lifetime from an osteoporotic fracture. This must be considered as a major health concern, as it has previously been established that fragility fracture has been associated with decreased quality of life due to increased disability, more frequent hospital admission and most importantly, osteoporotic fractures have been related to an augmented mortality risk. Anti-osteoporotic drugs are available for improving bone quality. Although there is access to these therapeutic options, there remain multiple unmet needs in the field of osteoporosis and fracture care, for example, the primary prevention of osteoporosis in young individuals (to reach a high peak bone mass), the optimization of the use of imaging techniques [dual-energy X-ray absorptiometry (DXA), vertebral fracture assessment (VFA) and new techniques measuring bone quality], the use of nonmedical treatment options and surgical techniques of fracture healing. In this review, we will discuss topics that play a role in the occurrence and prevention of fractures, and we give an overview of and insight into the critical issues and challenges around osteoporosis and fracture prevention.

HDL protein composition alters from proatherogenic into less atherogenic and proinflammatory in rheumatoid arthritis patients responding to rituximab.

OBJECTIVE: An atherogenic lipid profile is an established risk factor for cardiovascular (CV) diseases. Interestingly, high inflammatory states as present in rheumatoid arthritis (RA) are associated with unfavourable lipid profile. Data about effects of novel immunomodulating agents as rituximab (RTX) on lipid profile are limited. Therefore, changes in lipids in RTX treated RA patients were evaluated. METHODS: In 49 consecutive RTX treated RA patients, serum and EDTA plasma samples were collected at baseline, 1, 3 and 6 months. In these samples, lipid and levels were assessed to determine changes in time. Surface-enhanced laser desorption/ionisation time-of-flight (SELDI-TOF) MS analysis was performed in six good and six non-responding RA patients to study functional high density lipoprotein (HDL) protein composition changes in time. RESULTS: In the total group (n=49), the atherogenic index decreased from 4.3 to 3.9 (∼9%) after 6 months. Testing for effect modification revealed a difference in the effect on lipid levels between responders and non-responders upon RTX (p<0.001). ApoB to ApoA-I ratios decreased significantly (∼9%) in good responding (n=32) patients. SELDI-TOF MS analysis revealed a significant decrease in density of mass charge (m/z) marker 11743, representing a decrease in serum amyloid A, in good responding patients. CONCLUSION: This study indicates beneficial effects on cholesterol profile upon RTX treatment along with improvement of disease activity. Proteomic analysis of the HDL particle reveals composition changes from proatherogenic to a less proatherogenic composition during 6 months RTX treatment. Whether these HDL particle alterations during immunotherapies result in a lower CV event rate remains to be established.

The interferon type I signature towards prediction of non-response to rituximab in rheumatoid arthritis patients.

INTRODUCTION: B cell depletion therapy is efficacious in rheumatoid arthritis (RA) patients failing on tumor necrosis factor (TNF) blocking agents. However, approximately 40% to 50% of rituximab (RTX) treated RA patients have a poor response. We investigated whether baseline gene expression levels can discriminate between clinical non-responders and responders to RTX. METHODS: In 14 consecutive RA patients starting on RTX (test cohort), gene expression profiling on whole peripheral blood RNA was performed by Illumina® HumanHT beadchip microarrays. Supervised cluster analysis was used to identify genes expressed differentially at baseline between responders and non-responders based on both a difference in 28 joints disease activity score (ΔDAS28 < 1.2) and European League against Rheumatism (EULAR) response criteria after six months RTX. Genes of interest were measured by quantitative real-time PCR and tested for their predictive value using receiver operating characteristics (ROC) curves in an independent validation cohort (n = 26). RESULTS: Genome-wide microarray analysis revealed a marked variation in the peripheral blood cells between RA patients before the start of RTX treatment. Here, we demonstrated that only a cluster consisting of interferon (IFN) type I network genes, represented by a set of IFN type I response genes (IRGs), that is, LY6E, HERC5, IFI44L, ISG15, MxA, MxB, EPSTI1 and RSAD2, was associated with ΔDAS28 and EULAR response outcome (P = 0.0074 and P = 0.0599, respectively). Based on the eight IRGs an IFN-score was calculated that reached an area under the curve (AUC) of 0.82 to separate non-responders from responders in an independent validation cohort of 26 patients using Receiver Operator Characteristics (ROC) curves analysis according to ΔDAS28 < 1.2 criteria. Advanced classifier analysis yielded a three IRG-set that reached an AUC of 87%. Comparable findings applied to EULAR non-response criteria. CONCLUSIONS: This study demonstrates clinical utility for the use of baseline IRG expression levels as a predictive biomarker for non-response to RTX in RA.