Objectives: To assess the long-term continuation of methotrexate (MTX) in a cohort of patients with giant cell arteritis (GCA) in daily clinical practice. Factors associated with its discontinuation rate were also investigated.
Methods: A longitudinal study from 1991-2014, was performed. GCA patients with MTX and followed-up in a rheumatology outpatient clinic of Madrid during the study period were included.
Primary outcome: discontinuation of MTX due to: adverse drug reactions (ADR moderate and severe); inefficacy; sustained clinical response; patient decision. Covariables: sociodemographic, clinical and therapy. Incidence rates (IR) of MTX discontinuation per 100 patient-years with their 95% confidence interval (CI) were estimated using survival techniques. Factors associated to specific discontinuation causes were analysed using Cox models.
Results: We included 108 patients (244 patient-years). The IR was 37.2 [30.3-45.7]. The IR due to ADR, severe ADR, sustained clinical response and inefficacy was 20.8 [15.8-27.4]; 5.7 [3.3-9.6]; 8.2 [5.3-12.7] and 2.8 [1.3-6.0], respectively. Regarding multivariate analysis, younger patients, baseline cardiovascular disease, taking more glucocorticoids and lower initial doses of MTX were associated to a higher discontinuation rate due to inefficacy. Factors influencing the suspension due to ADRs were: older age, baseline. Chronic obstructive pulmonary disease, higher baseline erythrocyte sedimentation rate, several specific clinical patterns at diagnosis, and higher maximum dose of MTX during the follow up. In the final model for sustained clinical response older patients and more recurrences were independently associated to less discontinuation rate.
Conclusions: We provide further data of the potential safety of long-term MTX in the management of GCA. We have also found several factors influencing the continuation of MTX.