Background Giant cell arteritis (GCA) is the most common form of primary systemic vasculitis in people aged 50 years or older. Glucocorticoids are the mainstay of initial management; however, the optimal corticosteroid initial dose has not been comprehensively defined.
Objectives To evaluate and compare the characteristics of glucocorticoid use and associated complications between biopsy-proven GCA patients treated with initial prednisone dose >40 mg/day versus ≤40 mg/day during long term followup in a large single-institution cohort.
Methods A retrospective review was performed to identify all patients with biopsy-proven GCA from 1 January 1998 through 31 December 2013. Demographic, clinical, laboratory, and treatment data at baseline and subsequent followup visits were collected. Complications secondary to glucocorticoid therapy and time to daily dose of <5 mg and 0 mg of prednisone were assessed by time-to-event analyses using Kaplan-Meier methods. Patients with initial daily oral prednisone dose of ≤40 mg and >40mg were compared using Cox models.
Results The cohort included 286 patients with biopsy-proven GCA (213 females and 73 males, mean [±SD] age 75.0 [±7.6] years) with a mean (±SD) followup of 6.0 (±3.9) years. Twenty-two patients (7.7%) received pulse dose (≥1.5 g methylprednisolone) at diagnosis. Of the remaining 264 patients, 155 (58.7%) initially received >40 mg and 109 (41.3%) ≤40 mg of daily oral prednisone. Mean (±SD) initial oral prednisone dose was 50.8 (±13.1) mg/day and mean (±SD) total cumulative dose prednisone was 9.42 g (±5.1). Comparing patients treated with an initial oral prednisone dose of ≤40mg/day with patients receiving >40 mg/day, the mean (±SD) prednisone dose was lower at the following intervals: one year [5.8 (±2.1) g vs. 7.4 (±2.3) g; p<0.001], during the first two years [7.7 (±2.7) g vs. 9.6 (±3.5) g; p=0.01] and total follow up duration [8.2 (±5.2) g vs. 10.0 (±4.9) g; p=0.03] Overall, patients reached <5 mg prednisone daily with a mean (±SE) frequency of 17% (±2.4), 55% (±3), and 82% (±3) at 1 year, 2 years, and 5 years respectively. Prednisone discontinuation occurred with a mean (±SE) frequency of 6% (±1.5), 24% (±3), and 54% (±4) over the same intervals. Patients started on >40 mg/day reached <5 mg/day [HR 1.46 (1.09, 1.96); p=0.01] and 0 mg [HR 1.56 (1.09, 2.23); p=0.02] earlier than those started on ≤40 mg/day (figure). At five years of follow up, complications secondary to glucocorticoid use including osteoporosis (21%), fragility fracture (18%), secondary Cushing's (14%), and infection requiring hospitalization (11%) were frequently observed. No difference in glucocorticoid associated complications was seen between the two groups. By one year, 47% of patients had relapsed. Time to first relapse based on initial oral prednisone dose did not differ [HR 1.18 (0.88, 1.57); p=0.27].
Conclusions Patients treated with an initial oral prednisone dose of >40 mg/day had higher cumulative doses but achieved earlier discontinuation without an increased risk of steroid associated adverse events.
Disclosure of Interest None declared