Predictors of relapse and treatment outcomes in biopsy-proven giant cell arteritis: A retrospective cohort study

Objective. To evaluate characteristics of relapse, relapse rates, treatment and outcomes among patients with biopsy-proven GCA in a large, single-institution cohort. Methods. We conducted a retrospective review of all patients with biopsy-proven GCA from 1998 to 2013. Demographic, clinical, laboratory and treatment data at presentation and during follow-up were collected. Comparisons by relapse rate were performed using chi-square tests. Prednisone discontinuation by initial oral dose ≤40 and >40 mg/day was compared using Cox models. Results. The cohort included 286 patients [74% female, mean age at diagnosis 75.0 years (S.D. 7.6), median follow-up 5.1 years). During follow-up, 73 patients did not relapse, 80 patients had one relapse and 133 had two or more relapses. The first relapse occurred during the first year in 50% of patients, by 2 years in 68% and by 5 years in 79%. More patients with established hypertension (P = 0.007) and diabetes (P = 0.039) at GCA diagnosis were in the high relapse rate group (≥0.5 relapses/year) and more females were in the low or high relapse groups than in the no relapse group (P = 0.034). Patients receiving an initial oral prednisone dose>40 mg/day were able to reach a dose of<5 mg/day [hazard ratio (HR) 1.46 (95% CI 1.09, 1.96)] and discontinue prednisone [HR 1.56 (95% CI 1.09, 2.23)] sooner than patients receiving≤40 mg/day without an increase in observed glucocorticoid-associated adverse events. Conclusion. Females and patients with hypertension or diabetes at GCA diagnosis have more relapses during follow-up. Patients treated with an initial oral prednisone dose>40 mg/day achieved earlier prednisone discontinuation.