Objectives To assess the incidence rate of relapses and to analyze the risk of relapses in patients with Giant Cell Arteritis (GCA) treated with and without Methotrexate (MTX), in clinical practice. Other factors associated 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 Sept-2014. Main outcome: relapses defined as after an objective improvement, patient has again symptoms or signs of GCA with high ESR and the need to increase corticosteroids at least 10mg. The independent variable was exposure to MTX over time. Covariables: Sociodemographic, clinical, and treatment. Incidence rates of relapses (IR) per 100 patient-years with their 95% confidence intervals [CI] were estimated using survival techniques. Time of exposure comprised the period from diagnosis until: lost of follow-up, main outcome, exposure to MTX or the end of the study. MTX influence on IR was analyzed by multivariable Cox models.
Results 168 patients were included (675 patient-years). 80% of them were female, with a mean age of 76±7 years. 65% of the patients were on MTX, with mean dose of 10 mg/week. 31% of patients had relapses with an IR of 12 [9.6–14.9]. The median number of relapses was 1 [1–2], with a median lag time of 1.6 [0.6–6.3] years. In the multivariate analysis, exposure to MTX had less risk of flaring compared to those never on MTX (p<0.05). Other variables included in the final model were: visual alterations, constitutional symptoms or 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 flares.
Disclosure of Interest None declared