Development of a diagnostic prediction model for giant cell arteritis by sequential application of Southend Giant Cell Arteritis Probability Score and ultrasonography: a prospective multicentre study.

BACKGROUND: Giant cell arteritis is a critically ischaemic disease with protean manifestations that require urgent diagnosis and treatment. European Alliance of Associations for Rheumatology (EULAR) recommendations advocate ultrasonography as the first investigation for suspected giant cell arteritis. We developed a prediction tool that sequentially combines clinical assessment, as determined by the Southend Giant Cell Arteritis Probability Score (SGCAPS), with results of quantitative ultrasonography. METHODS: This prospective, multicentre, inception cohort study included consecutive patients with suspected new onset giant cell arteritis referred to fast-track clinics (seven centres in Italy, the Netherlands, Spain, and UK). Final clinical diagnosis was established at 6 months. SGCAPS and quantitative ultrasonography of temporal and axillary arteries with three scores (ie, halo count, halo score, and OMERACT GCA Score [OGUS]) were performed at diagnosis. We developed prediction models for diagnosis of giant cell arteritis by multivariable logistic regression analysis with SGCAPS and each of the three ultrasonographic scores as predicting variables. We obtained intraclass correlation coefficient for inter-rater and intra-rater reliability in a separate patient-based reliability exercise with five patients and five observers. FINDINGS: Between Oct 1, 2019, and June 30, 2022, we recruited and followed up 229 patients (150 [66%] women and 79 [34%] men; mean age 71 years [SD 10]), of whom 84 were diagnosed with giant cell arteritis and 145 with giant cell arteritis mimics (controls) at 6 months. SGCAPS and all three ultrasonographic scores discriminated well between patients with and without giant cell arteritis. A reliability exercise showed that the inter-rater and intra-rater reliability was high for all three ultrasonographic scores. The prediction model combining SGCAPS with the halo count, which was termed HAS-GCA score, was the most accurate model, with an optimism-adjusted C statistic of 0·969 (95% CI 0·952 to 0·990). The HAS-GCA score could classify 169 (74%) of 229 patients into either the low or high probability groups, with misclassification observed in two (2%) of 105 patients in the low probability group and two (3%) of 64 of patients in the high probability group. A nomogram for easy application of the score in daily practice was created. INTERPRETATION: A prediction tool for giant cell arteritis (the HAS-GCA score), combining SGCAPS and the halo count, reliably confirms and excludes giant cell arteritis from giant cell arteritis mimics in fast-track clinics. These findings require confirmation in an independent, multicentre study. FUNDING: Royal College of Physicians of Ireland, FOREUM.

Subclinical giant cell arteritis increases the risk of relapse in polymyalgia rheumatica.

OBJECTIVE: The aim of the present study was to determine the clinical significance of subclinical giant cell arteritis (GCA) in polymyalgia rheumatica (PMR) and ascertain its optimal treatment approach. METHODS: Patients with PMR who fulfilled the 2012 European Alliance of Associations for Rheumatology/American College of Rheumatology Provisional Classification Criteria for PMR, did not have GCA symptoms and were routinely followed up for 2 years and were stratified into two groups, according to their ultrasound results: isolated PMR and PMR with subclinical GCA. The outcomes (relapses, glucocorticoid use and disease-modifying antirheumatic drug treatments) between groups were compared. RESULTS: We included 150 patients with PMR (50 with subclinical GCA) with a median (IQR) follow-up of 22 (20-24) months. Overall, 47 patients (31.3 %) had a relapse, 31 (62%) in the subclinical GCA group and 16 (16%) in the isolated PMR group (p<0.001). Among patients with subclinical GCA, no differences were found in the mean (SD) prednisone starting dosage between relapsed and non-relapsed patients (32.4±15.6 vs 35.5±12.1 mg, respectively, p=0.722). Patients with subclinical GCA who relapsed had a faster prednisone dose tapering in the first 3 months compared with the non-relapsed patients, with a mean dose at the third month of 10.0±5.2 versus 15.2±7.9 mg daily (p<0.001). No differences were found between relapsing and non-relapsed patients with subclinical GCA regarding age, sex, C reactive protein and erythrocyte sedimentation rate. CONCLUSIONS: Patients with PMR and subclinical GCA had a significantly higher number of relapses during a 2-year follow-up than patients with isolated PMR. Lower starting doses and rapid glucocorticoid tapering in the first 3 months emerged as risk factors for relapse.

Prevalence and characteristics of subclinical giant cell arteritis in polymyalgia rheumatica.

OBJECTIVE: The main objective of this study was to analyse the prevalence and characteristics of subclinical GCA in patients with PMR. METHODS: This was a cross-sectional multicentre international study of consecutive patients with newly diagnosed PMR without symptoms or signs suggestive of GCA. All patients underwent US of the temporal superficial, common carotid, subclavian and axillary arteries. Patients with halo signs in at least one examined artery were considered to have subclinical GCA. The clinical, demographic and laboratory characteristics of the PMR group without subclinical vasculitis were compared with subclinical GCA, and the pattern of vessel involvement was compared with that of a classical single-centre GCA cohort. RESULTS: We included 346 PMR patients, 267 (77.2%) without subclinical GCA and 79 (22.8%) with subclinical GCA. The PMR patients with subclinical GCA were significantly older, had a longer duration of morning stiffness and more frequently reported hip pain than PMR without subclinical GCA. PMR with subclinical GCA showed a predominant extracranial large vessel pattern of vasculitic involvement compared with classical GCA, where the cranial phenotype predominated. The patients with PMR in the classical GCA group showed a pattern of vessel involvement similar to classical GCA without PMR but different from PMR with subclinical involvement. CONCLUSION: More than a fifth of the pure PMR patients had US findings consistent with subclinical GCA. This specific subset of patients showed a predilection for extracranial artery involvement. The optimal screening strategy to assess the presence of vasculitis in PMR remains to be determined.

Takayasu arteritis and large-vessel giant cell arteritis in Italian population. Comprehensive analysis from a single institutional cohort of 184 cases.

OBJECTIVE: To compare clinical and imaging characteristics in patients with Takayasu arteritis (TAK) and large vessel-giant cell arteritis (LV-GCA) in an Italian population. METHODS: We conducted a retrospective monocenter study comparing characteristics and outcomes of a cohort of 59 patients with TAK and a cohort of 127 patients with LV-GCA diagnosed between 1996 and 2016. Most of them (92%) were followed up for at least 24 months at Reggio Emilia Hospital (Italy). We also reviewed the literature discussing the results of the published manuscripts comparing LV-GCA to TAK RESULTS: LV-GCA patients had a higher prevalence of males (p = 0.003), and more frequently presented with cranial symptoms (p = 0.001), fever ≥38 °C (p = 0.007), polymyalgia rheumatica (p = 0.001), and hypertension (p = 0.001), and they had higher ESR levels at diagnosis (p = 0.0001). Differently, TAK patients had longer delay to diagnosis from the beginning of symptoms (p = 0.048), they presented more frequently with loss of pulses of large arteries (p = 0.0001), vascular bruits (p = 0.001), limb claudication (p = 0.003), myocardial infarction/angina (p = 0.03), and hypertension induced by renal artery stenosis (p = 0.001). Regarding treatment, TAK patients received a higher total and at 1 year cumulative prednisone doses (p = 0.0001 and p = 0.001, respectively), they had a longer duration of prednisone therapy (p = 0.008), and received during follow-up more frequently traditional immunosuppressants (p = 0.0001) and biological agents (p = 0.0001). Flares were more frequently observed in TAK patient (p = 0.001), while no differences were observed for long-term remission. New vascular procedures during the follow-up were more frequently performed in TAK patients (p = 0.0001). Regarding imaging at diagnosis, TAK patients had more frequently vascular stenosis/occlusion (p = 0.0001) and a higher number of vessels with structural damage per person (p = 0.0001), while LV-GCA patients had a higher number of inflamed vessels per person (p = 0.0001). Comparing the involved vascular districts at diagnosis for the presence of vessel inflammation and/or arterial damage, patients with LV-GCA had a more frequent involvement of thoracic and abdominal aorta (p = 0.024 and p = 0.007, respectively), and axillary, iliac and femoral arteries (p = 0.018, p = 0.002, and p = 0.0001. respectively), while in TAK patients, brachiocephalic, celiac, mesenteric and renal arteries were more frequently involved (p = 0.011, p = 0.019, p = 0.019, and p = 0.005, respectively). At imaging arterial damage at diagnosis was more frequently observed in TAK patients, specifically at common carotid, brachiocephalic, and subclavian arteries (p = 0.0001, p = 0.006, p = 0.0001, respectively) and descending aorta (p = 0.022). Regarding imaging during the follow-up, TAK patients developed more frequently new vascular stenosis/occlusion (p = 0.0001) and new vascular thickening (p = 0.002), no differences were observed for the development of new dilatation/aneurysm between the two vasculitides. CONCLUSION: Patients with TAK and LV-GCA show a number of similarities and also differences. Indeed, it is unclear whether they are part of the same disease spectrum or they are different conditions. As more information regarding the pathogenesis and etiology becomes known, answers to these questions are like to be forthcoming.