Disease and Treatment-Related Morbidity in Young and Elderly Patients With Granulomatosis With Polyangiitis and Microscopic Polyangiitis

Objective: Aging may be a risk factor for morbidity in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We compared the rate and better characterized the type of disease- and treatment-related complications affecting young and elderly patients with AAV. Methods: All new cases of granulomatosis with polyangiitis or microscopic polyangiitis diagnosed in three referral centers between 2000 2016 were included. Patients were stratified by age into young or elderly (0.05). Overall, the elderly group was associated to higher damage accrual assessed by Vasculitis Damage Index during follow-up (b=0.28, p<0.05). Sixty-three (44.7%) patients had acute kidney injury due to AAV-glomerulonephritis at diagnosis. In contrast to elderly, young patients showed significant improvement in renal function over time, particularly in the first 6 months while on treatment (DeGFR, median [25 75%IQR], 5.3 [0.4 14] versus 22.8 [5.9 52.1] induction ml/min/1.73m2 , p=0.008), without significant changes after ANCA type stratification. Despite similar immunosuppressive therapy approaches and relapse rates, elderly patients had a higher rate of severe infections compared to younger patients (HR 2.1, 95% CIs: 1.1 4.4, p=0.043). Conclusions: Elderly patients with AAV had higher susceptibility to disease- and treatment-related morbidity than younger patients, particularly to renal and infective morbidity.