Polymyalgia rheumatica shows metabolomic alterations that are further altered by glucocorticoid treatment: Identification of metabolic correlates of fatigue.

OBJECTIVE: In polymyalgia rheumatica (PMR), glucocorticoids (GCs) relieve pain and stiffness, but fatigue may persist. We aimed to explore the effect of disease, GCs and PMR symptoms in the metabolite signatures of peripheral blood from patients with PMR or the related disease, giant cell arteritis (GCA). METHODS: Nuclear magnetic resonance spectroscopy was performed on serum from 40 patients with untreated PMR, 84 with new-onset confirmed GCA, and 53 with suspected GCA who later were clinically confirmed non-GCA, and 39 age-matched controls. Further samples from PMR patients were taken one and six months into glucocorticoid therapy to explore relationship of metabolites to persistent fatigue. 100 metabolites were identified using Chenomx and statistical analysis performed in SIMCA-P to examine the relationship between metabolic profiles and, disease, GC treatment or symptoms. RESULTS: The metabolite signature of patients with PMR and GCA differed from that of age-matched non-inflammatory controls (R2 > 0.7). There was a smaller separation between patients with clinically confirmed GCA and those with suspected GCA who later were clinically confirmed non-GCA (R2 = 0.135). In PMR, metabolite signatures were further altered with glucocorticoid treatment (R2 = 0.42) but did not return to that seen in controls. Metabolites correlated with CRP, pain, stiffness, and fatigue (R2 ≥ 0.39). CRP, pain, and stiffness declined with treatment and were associated with 3-hydroxybutyrate and acetoacetate, but fatigue did not. Metabolites differentiated patients with high and low fatigue both before and after treatment (R2 > 0.9). Low serum glutamine was predictive of high fatigue at both time points (0.79-fold change). CONCLUSION: PMR and GCA alter the metabolite signature. In PMR, this is further altered by glucocorticoid therapy. Treatment-induced metabolite changes were linked to measures of inflammation (CRP, pain and stiffness), but not to fatigue. Furthermore, metabolite signatures distinguished patients with high or low fatigue.

Modifiable risk factors and inflammation-related proteins in polymyalgia rheumatica: genome-wide meta-analysis and Mendelian randomisation.

OBJECTIVE: Polymyalgia rheumatica (PMR) is an age-related inflammatory disease of unknown cause. We aimed to identify potentially modifiable risk factors and therapeutic targets for preventing or treating PMR. METHODS: We meta-analysed genetic association data from 8,156 cases of PMR (defined using diagnostic codes and self-report) and 416,495 controls of European ancestry from the UK Biobank and FinnGen. We then performed Mendelian randomization analyses to estimate the association between eight modifiable risk factors (using data from up to 1.2 million individuals) and 65 inflammation-related circulating proteins (up to 55,792 individuals), using the inverse variance weighted and pleiotropy robust methods. RESULTS: We identified three novel genome-wide significant loci in the IL1R1, NEK6 and CCDC88B genes and confirmation of previously described associations with HLA-DRB1 and ANKRD55. Genetically predicted smoking intensity (OR 1.32; 95%CI 1.08-1.60; p = 0.006) and visceral adiposity (OR 1.22; 95%CI 1.10-1.37; p = 3.10x10-4) were associated with PMR susceptibility. Multiple circulating proteins related to IL-1 family signaling were associated with PMR. IL-1 receptor-like 2, also known as IL-36 receptor (OR 1.25; p = 1.89x10-32), serum amyloid A2 (OR 1.06, 9.91x10-10) and CXCL6 (OR 1.09, p = 4.85x10-7) retained significance after correction for multiple testing. CONCLUSION: Reducing smoking and visceral adiposity at a population level might reduce incidence of PMR. We identified proteins that may play causal roles in PMR, potentially suggesting new therapeutic opportunities. Further research is needed before these findings are applied to clinical practice.

Risk loci involved in giant cell arteritis susceptibility: a genome-wide association study.

BACKGROUND: Giant cell arteritis is an age-related vasculitis that mainly affects the aorta and its branches in individuals aged 50 years and older. Current options for diagnosis and treatment are scarce, highlighting the need to better understand its underlying pathogenesis. Genome-wide association studies (GWAS) have emerged as a powerful tool for unravelling the pathogenic mechanisms involved in complex diseases. We aimed to characterise the genetic basis of giant cell arteritis by performing the largest GWAS of this vasculitis to date and to assess the functional consequences and clinical implications of identified risk loci. METHODS: We collected and meta-analysed genomic data from patients with giant cell arteritis and healthy controls of European ancestry from ten cohorts across Europe and North America. Eligible patients required confirmation of giant cell arteritis diagnosis by positive temporal artery biopsy, positive temporal artery doppler ultrasonography, or imaging techniques confirming large-vessel vasculitis. We assessed the functional consequences of loci associated with giant cell arteritis using cell enrichment analysis, fine-mapping, and causal gene prioritisation. We also performed a drug repurposing analysis and developed a polygenic risk score to explore the clinical implications of our findings. FINDINGS: We included a total of 3498 patients with giant cell arteritis and 15 550 controls. We identified three novel loci associated with risk of giant cell arteritis. Two loci, MFGE8 (rs8029053; p=4·96 × 10-8; OR 1·19 [95% CI 1·12-1·26]) and VTN (rs704; p=2·75 × 10-9; OR 0·84 [0·79-0·89]), were related to angiogenesis pathways and the third locus, CCDC25 (rs11782624; p=1·28 × 10-8; OR 1·18 [1·12-1·25]), was related to neutrophil extracellular traps (NETs). We also found an association between this vasculitis and HLA region and PLG. Variants associated with giant cell arteritis seemed to fulfil a specific regulatory role in crucial immune cell types. Furthermore, we identified several drugs that could represent promising candidates for treatment of this disease. The polygenic risk score model was able to identify individuals at increased risk of developing giant cell arteritis (90th percentile OR 2·87 [95% CI 2·15-3·82]; p=1·73 × 10-13). INTERPRETATION: We have found several additional loci associated with giant cell arteritis, highlighting the crucial role of angiogenesis in disease susceptibility. Our study represents a step forward in the translation of genomic findings to clinical practice in giant cell arteritis, proposing new treatments and a method to measure genetic predisposition to this vasculitis. FUNDING: Institute of Health Carlos III, Spanish Ministry of Science and Innovation, UK Medical Research Council, and National Institute for Health and Care Research.

Immune Checkpoint Inhibitor-induced Polymyalgia Rheumatica.

Polymyalgia rheumatica (PMR) immune-related adverse events (ICI-PMRs) represent a novel, distinct entity, despite many clinical, laboratory, and imaging similarities to classical PMR. Important questions remain in differentiating ICI-PMR from classical PMR, as well as other immune-related adverse events and PMR mimics. Despite this, ICI-PMR currently takes treatment cues from classical PMR, albeit with considerations relevant to cancer immunotherapy. Comparisons between ICI-PMR and classical PMR may provide further bidirectional insights, especially given that important questions remain unanswered about both diseases. The cause of classical PMR remains poorly understood, and ICI-PMR may represent a model of induced PMR, with important therapeutic implications.

Treatment of polymyalgia rheumatica: British Society for Rheumatology guideline scope.

The last British Society for Rheumatology (BSR) guideline on PMR was published in 2009. The guideline needs to be updated to provide a summary of the current evidence for pharmacological and non-pharmacological management of adults with PMR. This guideline is aimed at healthcare professionals in the UK who directly care for people with PMR, including general practitioners, rheumatologists, nurses, physiotherapists, occupational therapists, pharmacists, psychologists and other health professionals. It will also be relevant to people living with PMR and organisations that support them in the public and third sector, including charities and informal patient support groups. This guideline will be developed using the methods and processes outlined in the BSR Guidelines Protocol. Here we provide a brief summary of the scope of the guideline update in development.

Validation of a new glucocorticoid-specific Patient-Reported Outcome Questionnaire (the Steroid PRO).

OBJECTIVES: Glucocorticoids used in the treatment of inflammatory rheumatic conditions can impact on health-related quality of life. An underpinning qualitative study developed a long-list of candidate items for a treatment-specific patient-reported outcome (PRO) measure. The objective of this paper is to determine scale structure and psychometric properties of the Steroid PRO. METHODS: A cross-sectional survey of adults from the UK, USA, Australia and New Zealand, taking glucocorticoids for a rheumatic disease. Initial survey collected demographics, clinical information, 40 Steroid PRO candidate items and EuroQol-5 Dimensions- 5 levels (EQ-5D-5L). Follow-up, 3-5 days later, collected Steroid PRO candidate items and a condition-change ('transition') question. Analysis included Rasch measurement model, exploratory factor analysis (EFA), and hypothesis testing for discriminative validity, convergence validity and test-retest reliability. RESULTS: Total responses 946: UK n=743 (79%); USA n=139 (15%); Australia/New Zealand n=64 (7%); mean age 57.6 (SD=13.6); 833 (88%) women. Participants with inflammatory arthritis n=197 (21%), connective tissue disease and/or vasculitis n=402 (42%), giant cell arteritis and/or polymyalgia rheumatica n=347 (37%). Twenty-five items were removed due to lack of fit to Rasch model. Of the remaining items, EFA suggested four subscales: Social impact (4 items); Impact on appearance (3 items); Psychological impact (5 items); Treatment concerns (3 items). Rasch modelling supported a four-subscale structure and total score, confirming construct validity and reliability. Hypothesis testing confirmed discriminant and convergence validity. Intraclass correlation coefficient (total score) was 0.809 demonstrating excellent (test-retest) reliability. CONCLUSIONS: The Steroid PRO is a 15-item, valid and reliable scale for measuring the impact of glucocorticoid therapy in people with rheumatic diseases.

Consensus of the definitions of the OMERACT glucocorticoid impact core domain set for people with rheumatic and musculoskeletal diseases.

BACKGROUND: The Outcome Measures in Rheumatology (OMERACT) Glucocorticoid (GC) Impact Working Group has been working to develop a core domain set to measure the impact of GCs on patients living with rheumatic and musculoskeletal diseases. The mandatory domains previously identified for inclusion in all clinical trials measuring the GC effects include infection, bone fragility, mood disturbance, hypertension, diabetes, weight, fatigue, and mortality. Before progressing to instrument selection, the Working Group sought to establish precise definitions of all mandatory domains within the core domain set. METHODS: OMERACT methodology was applied with the use of evidence and consensus-based decision making of all stakeholder groups (patient research partners, health care professionals, clinician researchers, industry members and methodologists) to develop detailed definitions for the broad domain, target domain and domain components, taking into consideration sources of variability that could affect measurement of the domain.  The working group synthesized prior qualitative studies, quantitative work, and results from Delphi rounds, to develop a rich definition of 'what' is to be measured. RESULTS: Between 2021 and 2023, the OMERACT Working Group on GC Impact conducted virtual meetings to establish domain definitions. First, we mapped each domain onto an OMERACT Core Area. All domains were primarily represented within the Pathophysiological Manifestations Core Area, except from Fatigue which was primarily Life Impact and Weight which spanned both Core Areas. Sources of variability included cultural factors, age, gender, education level, socioeconomic status, personal experiences, emotional state, and language barriers. The domain definitions will form the foundation for instrument selection and the initial step of domain / concept match and content validity in the OMERACT pillar of 'truth' before moving on to feasibility and discrimination. CONCLUSION: The OMERACT GC Impact Working Group has developed and agreed upon detailed domain definitions for core domains. Future steps of the working group are to select instruments and develop the core outcome measurement set for clinical trials measuring the impact of GC on patients with rheumatic and musculoskeletal diseases.

Jaw claudication and jaw stiffness in giant cell arteritis: secondary analysis of a qualitative research dataset.

Objective: Jaw symptoms can be a vital clue to the diagnosis of GCA. Guidelines recommend more intensive treatment if jaw claudication is present. We sought to explore how patients with GCA described their jaw symptoms. Methods: We carried out a secondary, qualitative analysis of interview data from 36 participants from the UK (n = 25) and Australia (n = 11), originally collected in order to develop a patient-reported outcome measure for GCA. In all cases, GCA had been confirmed by biopsy/imaging. Interview transcripts were organized within QSR NVivo 12 software and analysed using template analysis. Themes were refined through discussion among the research team, including a patient partner. Results: Twenty of 36 participants reported jaw symptoms associated with GCA. The median age of these 20 participants was 76.5 years; 60% were female. Five themes were identified: physical sensations; impact on function; impact on diet; symptom response with CSs; and attribution to other causes. Physical sensations included ache, cramp, stiffness and 'lockjaw'. Functional impacts included difficulty in eating/chewing, cleaning teeth, speaking or opening the mouth. Dietary impacts included switching to softer food. Response to CSs was not always immediate. Jaw symptoms were initially mis-attributed by some participants to arthritis, age or viral illnesses; or by health-care professionals to a dental cavity, ear infection or teeth-grinding. Conclusion: Jaw symptoms in GCA are diverse and can lead to diagnostic confusion with primary temporomandibular joint disorder, potentially contributing to delay in GCA diagnosis. Further research is needed to determine the relationship of jaw stiffness to jaw claudication.

Estimating overdiagnosis in giant cell arteritis diagnostic pathways using genetic data: genetic association study.

OBJECTIVES: Giant cell arteritis (GCA) may be confirmed by temporal artery biopsy (TAB) but false negatives can occur. GCA may be overdiagnosed in TAB-negative cases, or if neither TAB nor imaging is done. We used Human Leucocyte Antigen (HLA) genetic association of TAB-positive GCA as an "unbiased umpire" test to estimate historic overdiagnosis of GCA. METHODS: Patients diagnosed with GCA between 1990-2014 were genotyped. During this era, vascular imaging alone was rarely used to diagnose GCA. HLA region variants were jointly imputed from genome-wide genotypic data of cases and controls. Per-allele frequencies across all HLA variants with p< 1.0x1 0 -5 were compared with population control data to estimate overdiagnosis rates in cases without a positive TAB. RESULTS: Genetic data from 663 GCA patients were compared with data from 2619 population controls. TAB-negative GCA (n = 147) and GCA without TAB result (n = 160) had variant frequencies intermediate between TAB-positive GCA (n = 356) and population controls. For example, the allele frequency of HLA-DRB1*04 was 32% for TAB-positive GCA, 29% for GCA without TAB result, 27% for TAB-negative GCA and 20% in population controls. Making several strong assumptions, we estimated that around two-thirds of TAB-negative cases and one-third of cases without TAB result may have been overdiagnosed. From these data, TAB sensitivity is estimated as 88%. CONCLUSIONS: Conservatively assuming 95% specificity, TAB has a negative likelihood ratio of around 0.12. Our method for utilising standard genotyping data as an "unbiased umpire" might be used as a way of comparing the accuracy of different diagnostic pathways.

Relapse after cessation of weekly tocilizumab for giant cell arteritis: a multicentre service evaluation in England.

OBJECTIVES: The National Health Service in England funds 12 months of weekly subcutaneous tocilizumab (qwTCZ) for patients with relapsing or refractory giant cell arteritis (GCA). During the COVID-19 pandemic, some patients were allowed longer treatment. We sought to describe what happened to patients after cessation of qwTCZ. METHODS: Multicentre service evaluation of relapse after stopping qwTCZ for GCA. The log-rank test was used to identify significant differences in time to relapse. RESULTS: 336 GCA patients were analysed from 40 centres, treated with qwTCZ for a median (interquartile range, IQR) of 12 (12-17) months. At time of stopping qwTCZ, median (IQR) prednisolone dose was 2 (0-5) mg/day. By 6, 12 and 24 months after stopping qwTCZ, 21.4%, 35.4% and 48.6% respectively had relapsed, requiring an increase in prednisolone dose to a median (IQR) of 20 (10-40) mg/day. 33.6% of relapsers had a major relapse as defined by EULAR. Time to relapse was shorter in those that had previously also relapsed during qwTCZ treatment (P = 0.0017); in those not in remission at qwTCZ cessation (P = 0.0036); and in those with large vessel involvement on imaging (P = 0.0296). Age ≥65, gender, GCA-related sight loss, qwTCZ treatment duration, TCZ taper, prednisolone dosing, and conventional synthetic DMARD use were not associated with time to relapse. CONCLUSION: Up to half our patients with GCA relapsed after stopping qwTCZ, often requiring a substantial increase in prednisolone dose. One third of relapsers had a major relapse. Extended use of TCZ or repeat treatment for relapse should be considered for these patients.

Micro-RNA content of circulating extracellular vesicles in early rheumatoid arthritis as biomarkers and mediators of methotrexate efficacy.

OBJECTIVES: Extracellular vesicles (EVs) are abundant in body fluids, contributing to intercellular signalling by transferring cargo that includes microRNAs (miRs) - themselves implicated in pathobiology. For the first time we evaluated the potential of EV miRs to contribute diagnostic information in early RA, predict methotrexate (MTX) efficacy or shed light on the drug's mechanism of action. METHODS: 798 miRs isolated from serum-derived EVs of 46 patients with untreated RA, 23 with untreated polymyalgia rheumatica (PMR; inflammatory disease control group) and 12 in whom significant inflammatory disease had been excluded (non-inflammatory controls; NICs) were profiled (Nanostring); the same measurements were made for RA patients after 6 months' MTX treatment. Analyses took multiple testing into account. RESULTS: 28 EV miRs were robustly differentially expressed between early RA (but not PMR) patients and NICs after correction for age and sex, suggesting discriminatory value. Cross-validated partial least squared-discriminant analysis also indicated the predictive potential of a distinct baseline EV miR signature with respect to MTX-induced remission at 6 months. The change in expression of 13 miRs over the course of MTX treatment differed significantly between responders and non-responders, and four of those exhibiting increased relative abundance amongst responders have known roles in regulating the pathogenic potential of synovial fibroblasts, namely miR-212-3p, miR-338-5p, miR-410-3p, and miR-537. CONCLUSION: Our data highlight the potential of serum EV miRs as diagnostic and therapeutic biomarkers, highlighting a novel potential mechanism via which MTX may exert its therapeutic effect in early RA that warrants further investigation.

Common co-morbidities in polymyalgia rheumatica and giant cell arteritis: cross-sectional study in UK Biobank.

Objective: The aim was to determine prevalent co-morbidities in cases with PMR or GCA compared with matched controls. Methods: This was a nested, cross-sectional case-control study within the UK Biobank, which recruited participants aged 40-69 years. Case status was defined as self-reported prior diagnosis of PMR or GCA. Ten controls per case were matched for age, sex, ethnicity and assessment centre. Associations with selected self-reported co-morbidities were studied using conditional logistic regression. Results: Of PMR (n = 1036) or GCA (n = 102) cases, 72% were female, 98% White, and 58% reported current use of glucocorticoids. Mean age was 63 years. At the time of the assessment visit, compared with controls, PMR/GCA cases were more likely to report poor general health and at least several days of low mood in the past 2 weeks. PMR was associated with hypothyroidism [odds ratio (OR) = 1.34; 95% CI = 1.07, 1.67] and ever-use of HRT (OR = 1.26; 95% CI = 1.07, 1.47). Regarding common co-morbidities, PMR and GCA were both associated with hypertension (PMR: OR = 1.21; 95% CI = 1.06, 1.39; GCA: OR = 1.86; 95% CI = 1.23, 2.81) and cataract (PMR: OR = 1.51; 95% CI = 1.19, 1.93; GCA: OR = 3.84; 95% CI = 2.23, 6.60). Additionally, GCA was associated with depression (OR = 3.05; 95% CI = 1.59, 5.85). Neither condition was associated with diabetes. Conclusion: Participants with a history of PMR/GCA, including those not currently taking glucocorticoids, rated their health as poorer than matched controls. Some previously described disease associations (hypothyroidism and early menopause) were replicated. Hypertension and cataract, both of which can be exacerbated by long-term glucocorticoid therapy, were over-represented in both diseases, particularly GCA.

A phase 3 randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of sarilumab in patients with giant cell arteritis.

BACKGROUND: Giant cell arteritis (GCA) is primarily treated with glucocorticoids (GCs), which have substantial toxicity. Tocilizumab, an interleukin-6-receptor inhibitor (IL-6Ri), showed beneficial effects in GCA, leading to its approval. This study investigated the efficacy and safety of sarilumab (another IL-6Ri) in GCA. METHODS: This Phase 3, double-blind study comprised a 52-week treatment period and a 24-week follow-up phase. Eligible GCA patients were randomized to receive sarilumab 200 mg (SAR200 + 26W) or 150 mg (SAR150 + 26W) with a 26-week GC taper, or placebo with a 52-week (PBO + 52W) or 26-week (PBO + 26W) GC taper. The primary efficacy endpoint was sustained remission (SR) at week 52. Additional endpoints were SR at week 24, cumulative GC dose, and safety. The study was discontinued prematurely due to protracted recruitment timelines, because of the impact of COVID-19. Therefore, only descriptive statistics were summarized. RESULTS: Of the planned 360 subjects, only 83 were randomized and 36 were included in the week 52 analysis. At week 52, 46% (n = 6/13) of patients in SAR200 + 26W, 43% (n = 3/7) in SAR150 + 26W, 30% (n = 3/10) in PBO + 52W, and 0 (n = 0/6) in PBO + 26W taper groups achieved SR. Sensitivity analyses, excluding acute-phase reactants from the SR definition, showed similar results for SAR groups, but 60% (n = 6/10) in PBO + 52W and 17% (n = 1/6) in PBO + 26W taper groups achieved SR at week 52. Similar findings were noted at week 24. The proportions of patients who adhered to GC taper from week 12 through week 52 in each group were as follows: 46% (n = 6/13, SAR200 + 26W), 43% (n = 3/7, SAR150 + 26W), 60% (n = 6/10, PBO + 52W), and 33% (n = 2/6, PBO + 26W). The median actual cumulative GC dose received in the SAR200 + 26W group was lower than other groups. Most patients (80-100%) experienced treatment-emergent adverse events, with similar incidences reported across groups. CONCLUSIONS: Owing to the small sample size due to the early termination, it is difficult to draw clear conclusions from this study. There were no unexpected safety findings. TRIAL REGISTRATION: ClinicalTrials.gov NCT03600805. Registered on July 26, 2018.

Polymyalgia rheumatica.

Polymyalgia rheumatica is an inflammatory disease producing pain and stiffness, mainly in the shoulders and pelvic girdle, in people older than 50 years. Elevation of acute phase reactants is common due to the inflammatory nature of the disease. Since there are no specific diagnostic tests, diagnosis requires the exclusion of other diseases with similar presentations. Imaging has helped to identify the pathological substrate of polymyalgia rheumatica and it is increasingly used to support clinical diagnosis or to detect coexistent giant cell arteritis. Although polymyalgia rheumatica does not clearly impair survival or organ function, it can have a detrimental effect on quality of life. Glucocorticoids at 12·5-25·0 mg prednisone per day are effective in inducing remission in most individuals but, when tapered, relapses occur in 40-60% of those affected and side-effects are common. Assessment of disease activity can be difficult because pain related to common comorbidities such as osteoarthritis and tendinopathies, can return when glucocorticoids are reduced, and acute phase reactants are increased less during flares in individuals undergoing treatment or might increase for other reasons. The role of imaging in assessing disease activity is not yet completely defined. In the search for more efficient and safer therapies, tocilizumab and sarilumab have shown efficacy in randomised controlled trials and additional targeted therapies are emerging. However, judicious risk-benefit balance is essential in applying therapeutic innovations to people with polymyalgia rheumatica.

Test-retest reliability of pain VAS/NRS, stiffness VAS/NRS, HAQ-DI and mHAQ in polymyalgia rheumatica: An OMERACT study.

OBJECTIVE: To examine the test-retest reliability of four measurement instruments in polymyalgia rheumatica (PMR): pain severity visual analogue scale (VAS) / numerical rating score (NRS), stiffness severity VAS/NRS, the Health Assessment Questionnaire-Disability Index (HAQ-DI) and the modified Health Assessment Questionnaire (mHAQ). METHOD: Two prospectively collected datasets were used. All participants had a diagnosis of PMR and only those with stable disease were included in analyses. Measurement instruments were administered twice, with a testing interval of two to six weeks. The intra-class correlation coefficient (ICC) was calculated using a two-way mixed effects model looking for absolute agreement. ICC values of 0.8-0.9 were deemed representative of good test-retest reliability, whilst values >0.9 were representative of excellent test-retest reliability. RESULTS: From the first dataset, 38 participants were analysed. The ICC between baseline and 2 weeks for pain VAS, stiffness VAS, HAQ-DI and mHAQ were 0.84, 0.82, 0.92 and 0.92 respectively. From the second dataset, 58 participants were included in the analysis for pain NRS, 59 for stiffness NRS and 78 for mHAQ. The ICC between baseline and follow-up for pain NRS, stiffness NRS and mHAQ were 0.80, 0.83 and 0.87 respectively. CONCLUSION: Pain severity VAS/NRS, stiffness severity VAS/NRS, HAQ-DI and mHAQ all demonstrate good to excellent test-retest reliability in a PMR patient population.

Imaging of giant cell arteritis - recent advances.

Imaging is increasingly being used to guide clinical decision-making in patients with giant cell arteritis (GCA). While ultrasound has been rapidly adopted in fast-track clinics worldwide as an alternative to temporal artery biopsy for the diagnosis of cranial disease, whole-body PET/CT is emerging as a potential gold standard test for establishing large vessel involvement. However, many unanswered questions remain about the optimal approach to imaging in GCA. For example, it is uncertain how best to monitor disease activity, given there is frequent discordance between imaging findings and conventional disease activity measures, and imaging changes typically fail to resolve completely with treatment. This chapter addresses the current body of evidence for the use of imaging modalities in GCA across the spectrum of diagnosis, monitoring disease activity, and long-term surveillance for structural changes of aortic dilatation and aneurysm formation and provides suggestions for future research directions.

Does the halo count on temporal and axillary ultrasound predict time to relapse in giant cell arteritis?

OBJECTIVES: To determine whether the halo count (HC) on temporal and axillary artery US (TAUS) predicts time to relapse in giant cell arteritis (GCA). METHODS: We conducted a single-centre retrospective study of GCA patients. HC, the number of vessels with non-compressible halo on the TAUS at diagnosis, was determined by retrospective review of the US report and images. Relapse was defined as increase in GCA disease activity requiring treatment escalation. Cox proportional hazard regression was used to identify predictors of time to relapse. RESULTS: A total of 72 patients with confirmed GCA were followed up for a median of 20.9 months. Thirty-seven of 72 (51.4%) relapsed during follow-up, at a median prednisolone dose of 9 mg (range 0-40 mg). Large-vessel (axillary artery) involvement did not predict relapse. On univariable analysis, a higher HC was associated with shorter time to relapse (per-halo hazard ratio 1.15, 95% CI 1.02, 1.30; P = 0.028). However, statistical significance was lost when the 10 GCA patients with an HC of zero were excluded from analysis. CONCLUSION: In this real-world setting, relapse occurred at a wide range of glucocorticoid doses and was not predicted by axillary artery involvement. GCA patients with a higher HC at diagnosis were significantly more likely to relapse, but significance was lost on excluding those with HC of zero. HC is feasible in routine care and may be worth incorporating into future prognostic scores. Further research is required to determine whether confirmed GCA patients with negative TAUS represent a qualitatively different subphenotype within the GCA disease spectrum.

An Automated Method for Artifical Intelligence Assisted Diagnosis of Active Aortitis Using Radiomic Analysis of FDG PET-CT Images.

The aim of this study was to develop and validate an automated pipeline that could assist the diagnosis of active aortitis using radiomic imaging biomarkers derived from [18F]-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) images. The aorta was automatically segmented by convolutional neural network (CNN) on FDG PET-CT of aortitis and control patients. The FDG PET-CT dataset was split into training (43 aortitis:21 control), test (12 aortitis:5 control) and validation (24 aortitis:14 control) cohorts. Radiomic features (RF), including SUV metrics, were extracted from the segmented data and harmonized. Three radiomic fingerprints were constructed: A-RFs with high diagnostic utility removing highly correlated RFs; B used principal component analysis (PCA); C-Random Forest intrinsic feature selection. The diagnostic utility was evaluated with accuracy and area under the receiver operating characteristic curve (AUC). Several RFs and Fingerprints had high AUC values (AUC > 0.8), confirmed by balanced accuracy, across training, test and external validation datasets. Good diagnostic performance achieved across several multi-centre datasets suggests that a radiomic pipeline can be generalizable. These findings could be used to build an automated clinical decision tool to facilitate objective and standardized assessment regardless of observer experience.