Treatment with methotrexate and risk of relapses in patients with giant cell arteritis in clinical practice

OBJECTIVES: To assess the incidence and the risk of relapses in giant cell arteritis (GCA) patients treated with and without methotrexate (MTX) in clinical practice. Other associated factors were also investigated. METHODS: An inception cohort of GCA was assembled in the out-patient clinic at Hospital Clinico San Carlos, including patients from the date of diagnosis (Jan-1991 until Sept-2013), and followed-up until lost of follow up or Sept-2014. MAIN OUTCOME: relapse defined as recurrence of symptoms or signs of GCA with high ESR and the need to increase glucocorticoids at least 10mg over the previous dose. The independent variable was exposure to MTX over time. Covariables: Sociodemographic, clinical, and treatment. Incidence rates of relapses (IR) per 100 patient-year with their 95% confidence intervals [CI] were estimated using survival techniques. MTX influence on relapses was analysed by Cox models. RESULTS: 168 patients were included (675 patient-year). 31% of patients had relapses (IR of 12 [9.6-14.9]), and the median number of relapses was 1[1-2]. 65% of the patients were on MTX, (mean dose: 10mg). In the bivariate analysis, the risk of relapses in patients with and without MTX did not achieve statistical signification (p=0.1). After adjusting in the multivariate analysis, exposure to MTX had 72% less risk of relapse compared to those without MTX (p<0.05). Other variables included in the final model were: visual alterations and malaise at clinical presentation of GCA. CONCLUSIONS: The use of MTX seems to decrease the risk of recurrences. We also found other factors influencing on relapses.