Background/Purpose: Clinical trials have shown the efficacy of Methotrexate (MTX) in giant cell arteritis (GCA) but it is necessary to corroborate these results in real life. The purpose of our study was to assess the incidence and the risk of ischemic relapses in GCA patients treated with and without MTX in clinical practice.

Methods: We performed a retrospective longitudinal observational study. Patients: all GCA patients diagnosed between January 1991 and September 2013 and followed at the Rheumatology department of Hospital Clínico San Carlos until loss of follow up or September 2014. Main outcome: relapses by ischemic event (RIE) defined by the presence of this three circumstances after having achieved an improvement: 1) clinically: mandibular claudication, visual manifestations (blurred vision, diplopia, transient or permanent loss of vision), cerebrovascular accident, ischemic heart disease or claudication of limbs, 2) laboratory test: increase in the erythrocyte sedimentation rate (ESR) and 3) treatment: need to increase corticosteroids (at least 10 mg over the previous dose). Independent variable: exposure to MTX over time. Secondary variables: sociodemographic, clinical and treatment. Statistical analysis: RIE rates were assessed by survival techniques, expressing the incidence per 100 patients-year with their 95% confidence interval [CI]. The influence of MTX on the REI was analysed by multivariate Cox regression models. Results were expressed as Hazard ratios (HR) with their respective CI.

Results:

168 patients were included with a follow-up of 675.6 patients-year. 80.4% were women (mean age: 76.8±7 years). The most prevalent comorbidities were arterial hypertension (64%), dyslipidaemia (34%) and cardiovascular disease (30%). The most common clinical GCA symptoms at diagnosis were headache (87.4%), systemic involvement (55%) and polymyalgia rheumatica (49.7%). At baseline, ESR was 78 ± 30.9 mmHg and the haemoglobin level was 12.06 ± 1.58 mg/dL. 46.4% patients had a positive biopsy and 64% received MTX (mean dose: 10 mg) during follow-up. The mean initial dose of corticosteroids was 50.7 ± 15.5 mg. There were 21 RIE in 20 patients with a frequency of 12.5% and the median time to first RIE was 1.1 [0.4-5.1] years. The main cause of RIE vas visual manifestations (61.9%). The incidence of RIE was 3.1 [2.0-4.8], being 1.92 [0.8-4.6] in patients exposed to MTX and 3.8 [2.4-6.3] in those without MTX. The incidence of REI in women was 3.4 [2.2-5.5] and in men was 1.9 [0.6-6]. In the multivariate analysis after adjusting by age, sex, disease activity and calendar time, exposure to MTX (HR 0.3 [0.1-0.9]; p = 0.048) had less risk of RIE compared to no exposure to MTX.

Conclusion: In our cohort, the frequency of REI was 12.5% and the incidence 3.1 per 100 patients-year with a median time to first REI of 1.1 years. The main cause of REI was visual manifestations. In patients with MTX, the incidence of REI was half that of patients without MTX (1.92 vs 3.84). With the results observed in this study, we can consider that the use of MTX decreases the risk of developing REI.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/treatment-with-methotrexate-and-risk-of-ischemic-relapses-in-patients-with-giant-cell-arteritis-in-clinical-practice/