Diagnostic Accuracy of Symptoms, Physical Signs, and Laboratory Tests for Giant Cell Arteritis

This systematic review and meta-analysis evaluate the diagnostic accuracy of symptoms, physical signs, and laboratory tests in patients with suspected giant cell arteritis.

This supplementary material has been provided by the authors to give readers additional information about their work. Consultant rheumatologist diagnosis at 6 months following initial presentation was considered as the reference standard for the diagnosis of GCA for the purposes of this study. An experienced rheumatologist performed a pre-treatment clinical evaluation to confirm eligibility criteria and establish the clinical diagnosis. The evaluation included history taking, physical examination, extensive laboratory screening, the FDG PET/CT report and TAB. US was not considered for establishing the clinical diagnosis. A clinical GCA diagnosis could be dismissed, even in patients fulfilling ACR criteria, if another more reasonable diagnosis was established. The clinical diagnosis of GCA was confirmed at a 6-month follow-up visit in 51/56 patients. Five patients were lost to follow-up, all of whom were TAB positive.

TAB and PET/CT
Oiwa et al. 2019 50 The inclusion criteria for the GCA group were 1) new-onset cases with a clinical diagnosis of GCA and 2) no change in the diagnosis of GCA until the final observation. All of the cases that did not meet these criteria were defined as the non-GCA group. The clinical diagnosis was confirmed after a minimum of 6 months of follow-up based on the biopsy, corticosteroid dose at 3 months, treating clinician and expert reviewer diagnoses. Clinicians and the expert reviewers were blinded to PET/CT vascular findings. Reviewers included five rheumatologists and one neuro-ophthalmologist not involved in the patient's care. The final diagnosis required consensus between the treating clinician and at least one of two reviewers. Final diagnosis of GCA was retained for patients who improved or were cured by corticosteroid therapy according to the follow-up data. Alternative diagnoses were defined by medical re-view of patient files. For the purposes of the study, a partially independent approach was used, which combined elements of a clinician's final diagnosis, the ACR classification criteria (incorporating the biopsy result), the emergence of complications consistent with GCA during follow-up, the emergence of alternative vasculitis diagnoses during follow-up and expert review to determine the reference diagnosis. The process started with the clinician's final diagnosis for the patient as reported on the 6-month (or in its absence, 2-week) assessment. Note: data on index tests was obtained with the clinical diagnosis at 2 weeks follow-up as the reference standard. For the current systematic review, only a follow-up duration of 3 months or more was considered relevant. As the gold diagnostic standard, we used the positive clinical evaluation for GCA at 6 months after the initial evaluation performed by 3 rheumatologists. The 3 physicians made their diagnostic decision without knowing the results of the CDUS findings. Each assessed patient was mainly judged by 1 rheumatologist and not by all 3. Patients were also classified according to ACR 1990 criteria for the classification of GCA. According to the clinical findings and the results of the biopsy, the patients were divided into three groups. Group I represents patients with histologically confirmed GCA. Group 2 included patients with a good clinical evidence of GCA despite a negative biopsy, whereas in group 3 were patients where the biopsy was negative and the clinical examination revealed either other diseases than GCA, or the etiology of the symptoms remained unclear.

TAB
Roth et al. 1984 54 The patients were divided into three groups depending on the biopsy results and on their response to steroid therapy. (A positive response to therapy was considered to be resolution of symptoms within 48 hours and reduction of the ESR within three weeks after the start of treatment.) Group 1 comprised those patients who had abnormal biopsy specimens and were clinically responsive to treatment. The condition of these patients was diagnosed as GCA. Group 2 consisted of those patients who had normal biopsy specimens but who were clinically responsive to treatment. Presumed GCA was diagnosed for these patients. Group 3 contained those patients with normal biopsy specimens who were clinically unresponsive to treatment. These patients were considered not to have GCA and their ultimate diagnoses were determined from the chart review. Examination of available clinical information from these cases showed that were 91 cases in which there was an adequate proof (record) of the history taken when the patient was initially seen and the physical examination, and in which followup of at least two years could be obtained by chart review and by contacting the patients, their families and their physicians.
[…] In addition to making the diagnosis of temporal arteritis based on a positive temporal artery biopsy specimen, the diagnosis of arteritis was accepted in patients who had an initial negative biopsy specimen either on the basis of subsequent pathologic proof of the disease or when the clinical course during the follow-up period was consistent with temporal arteritis. Patients with a negative temporal artery biopsy specimen were not considered to have the disease if there was resolution of their symptoms and signs within a one-month period, or if their symptoms and signs (including abnormal laboratory test results) were subsequently found to be due to other diseases.

TAB
Details regarding the clinical diagnosis are provided for all 30 studies using this reference standard. Information on follow-up is highlighted in bold. TAB = temporal artery biopsy.
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Data are shown for physical findings reported by less than four studies. In this case, meta-analysis with the bivariate model could not be performed. Therefore, pooled estimates of diagnostic accuracy parameters were determined with an univariate random-effects model (DerSimonian Laird method) 69

eFigure 2. Overall Summary of QUADAS-2 Items
Risk of bias and concern of applicability was evaluated for the 68 studies included in the systematic review and meta-analysis. Risk of bias and concern of applicability was evaluated for the 68 studies included in the systematic review and meta-analysis 1-68 .    Effective sample size (ESS) funnel plots and the associated regression test of asymmetry, as reported by Deeks et al. 71 , are shown. Plots are shown in alphabetical order for all demographic features, symptoms, physical findings and laboratory findings reported in Table  2-3. A p value < 0.10 was considered evidence of asymmetry and potential publication bias. Weight loss