Disease Relapses among Patients with Giant Cell Arteritis: A Prospective, Longitudinal Cohort Study

OBJECTIVE: To evaluate the frequency, timing, and clinical features of relapses in giant cell arteritis (GCA). METHODS: Patients with GCA enrolled in a prospective, multicenter, longitudinal study were included in the analysis. Relapse was defined as either new disease activity after a period of remission or worsening disease activity. RESULTS: The study included 128 subjects: 102 women (80%) and 26 men (20%). Mean ± SD age at diagnosis of GCA was 69.9 ± 8.6 years. Mean followup for the cohort was 21.4 ± 13.9 months. Median (interquartile range) duration of disease at study enrollment was 4.6 months (1.2, 16.8). During followup, 59 relapses were observed in 44 patients (34%). Ten patients (8%) experienced 2 or more relapses. The most common symptoms at relapse were headache (42%) and polymyalgia rheumatica (51%), but ischemic (some transient) manifestations (visual symptoms, tongue or jaw claudication, and/or limb claudication) occurred in 29% of relapses (12% cohort). Forty-three relapses (73%) occurred while patients were taking glucocorticoid therapy at a median (range) prednisone dose of 7.5 (0-35) mg. In 21% of relapses, both erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were normal. Among 69 patients enrolled in the cohort with newly diagnosed disease, 24% experienced a first relapse within 12 months after diagnosis. CONCLUSION: Among patients with GCA, relapses are common, often occurring during treatment. ESR and CRP are frequently normal at times of clinical relapse, highlighting the need for better biomarkers to assess disease activity in GCA. There remains a need for effective therapeutic alternatives to glucocorticoids in GCA.