British Society for Rheumatology guideline on managing patients with giant cell arteritis

Reference

Mackie SL, Dejaco C, Appenzeller S, et al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Rheumatology (Oxford) 2020;59(3):e1-e23.

Synopsis

The British Society for Rheumatology (BSR) funded the development of this guideline, accredited by the National Institute for Clinical Excellence (NICE). Many of the members of the panel, however, declared ties with industry. Like other NICE guideline panels, this panel followed an explicit process of identifying the key questions, conducting systematic literature reviews, and synthesizing recommendations based on the available data. The guideline addresses issues of diagnosis, interventions, and prognosis. Additionally, the panelists identified some basic principles that were not necessarily evidence-derived. The key general principle is that giant cell arteritis (GCA) is a medical emergency requiring immediate treatment with high-dose corticosteroids and that patients should be evaluated by a specialist within 3 working days (ideally, the same day) and by an ophthalmologist immediately if visual symptoms develop. The BSR also recommends immediate laboratory testing (complete blood count, C-reactive protein, and sedimentation rate) and treatment before test results are available. The BSR addressed the imperfect nature of the gold standard, temporal artery biopsy ("substantially less than 100% sensitive"), and identified multiple studies of ultrasound, computed tomographic angiography, and magnetic resonance imaging. In patients with a GCA likelihood of less than 20%, the BSR recommends an ultrasound, and a biopsy if the ultrasound result is abnormal. In patients with intermediate probability of GCA or with an equivocal ultrasound result, the BSR recommends a biopsy. In patients whose likelihood of GCA is more than 50%, the BSR recommends treating if the ultrasound result is abnormal and only doing the biopsy if the ultrasound is negative. Of course, they don't really tell you how to come up with these pretest probabilities, and reference another guideline that basically says there are no validated tools for this. Sheesh. The BSR also recommends the initial corticosteroid dose should be 40 mg to 60 mg of prednisone or prednisolone once daily and then tapered completely off over 12 months to 18 months. In patients with relapsing symptoms or at high risk of corticosteroid toxicity, the BSR recommends tapering off the corticosteroids and using methotrexate or tocilizumab. The BSR also concluded there is insufficient evidence about the use of other immunosuppressants, such as azathioprine, leflunomide, or mycophenolate mofetil, or for the use of other biologics. Finally, the BSR makes no recommendations on corticosteroid-induced osteoporosis.