Value of the chewing gum test for the diagnosis of giant cell arteritis: a multicentre pilot study

OBJECTIVE: Giant cell arteritis (GCA) is a vasculitis that can lead to visual impairment. Jaw claudication (JC), a key clinical feature of GCA, is associated with an increased risk of visual complications. We hypothesized that the chewing gum test (CGT) could reveal JC that is not identified through anamnesis alone. METHOD: We conducted a prospective multicentre study including patients with suspected GCA between October 2019 and December 2021. The CGT was performed twice, in a blinded manner, before the initiation of any corticosteroid therapy. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the CGT were assessed. RESULTS: In total, 48 patients were included: 33 with confirmed GCA and 15 controls. Fifteen of the 33 patients with GCA had JC identified by conventional questioning, yielding a sensitivity, specificity, PPV, and NPV of 45%, 73%, 79%, and 38%, respectively. When at least one CGT was positive, the sensitivity, specificity, PPV, and NPV were 36%, 79%, 80%, and 34%, respectively. Three cases of JC not detected by conventional questioning were identified using the CGT; however, three CGT results were false positives. The combination of conventional questioning and at least one positive CGT significantly increased sensitivity from 45% to 55% (p < 0.0001). CONCLUSION: Although the relatively low sensitivity of the CGT limits its stand-alone clinical applicability, its association with conventional questioning may help to identify JC in patients with suspected GCA, thereby facilitating earlier diagnosis and potentially reducing visual complications. Large-scale studies are required to confirm these findings.