The Prognosis of Granulomatosis With Polyangiitis: The Risk of Relapse and Mortality Based on Baseline Clinical Manifestations, Laboratory Findings, and Disease Severity: A Retrospective Cohort Study

Granulomatosis with polyangiitis (GPA) is a highly relapsing disease with risk of mortality. The aim of the current study is to determine the relationship between baseline demographic characteristics, clinical manifestations, laboratory findings, and disease severity with patients' risk of relapse and mortality. A retrospective cohort study was performed in GPA patients diagnosed with American College of Rheumatology 1990 criteria who were referred to a tertiary care center between 2012 and April 2020. Birmingham vasculitis activity score (BVAS), clinical features, involved organs, laboratory findings, induction treatment and demographic characteristics of patients were recorded at the onset of diagnosis. Cox proportional hazards model was used to determine the factors affecting patient mortality. The predictors of relapse were analyzed using cumulative incidence function in a competing risk setting (with mortality without relapse as a competing event). The cohort included 147 patients (54% male, median age: 45 [IQR: 34-61]) with a median follow-up time of 18 months (IQR: 6-38). Overall, 55 patients died during the follow-up leading to a survival rate of 62.5% and 179 relapses occurred among 117 patients (mean number of relapse per patient = 1.53). Independent factors for relapse included: Age > 55 (relative risk (RR): 2.50; 95% CI [1.20-2.51]), male gender (RR: 2.17; 95% CI [1.10-4.28]), rise of creatinine at baseline (RR: 2.24; 95% CI [1.15-4.35]) and nervous system involvement (RR: 2.18; 95% CI [1.21-3.96]). Significant factors for mortality were age ≥ 55 years (hazard ratio (HR): 2.40; 95% CI[1.24-4.61]), male gender (HR: 2.23; 95% CI[1.17-4.25]) rise of creatinine over 1.3 mg/dL (HR: 2.48; 95% CI [1.22-5.05), and nervous system involvement at baseline (HR: 2.16; 95% CI [1.20-3.89). Older age, male gender, nervous system involvement at onset and rise of creatinine are for factors that predict higher risks of relapse and mortality in patients with GPA. More intensive treatment is recommended in these subgroups of patients.