AB0390 CHARACTERISTICS AND PROGNOSIS OF AGE-DEPENDED ANCA-ASSOCIATED VASCULITIS IN JAPAN

Abstract

Background:It is known that most of ANCA-associated vasculitis (AAV) patients are elderly. A cohort study showed that the mean age of onset was 71.1 years, especially in patients with microscopic polyangiitis (MPA)1). However, the characteristics and prognosis of age-depended AAV patients are still unclear.Objectives:To clarify the differences in age-related characteristics and prognosis between Japanese patients with AAV.Methods:We enrolled 44 patients with AAV who underwent remission induction therapy at our hospital from January 2016 to December 2020. They were divided with under 70 years old group (<70 yo group, n=12) and over 70 years old group (≥70 yo group, n=32). We investigated between two groups as follows; clinical characteristics and laboratory data at diagnosis, rates of complete remission (CR) at 6 months, defined as Birmingham Vasculitis Activity Score (BVAS)=0 and prednisone ≤7.5 mg/day, adverse events, and relapse free survival.Results:Mean age were 61.9 ± 9.74 years old in <70 yo group and 77.5 ± 4.61 years old in ≥70 yo group (p<0.01). There were significantly fewer newly diagnosed cases in the <70 yo group, and half of the patients with relapsing disease. There was no difference in the type of ANCA, organ involvement, or BVAS. Remission induction therapy was performed with CY or RTX, and no difference was observed between these two groups. In addition, there was also no difference in maintenance therapy (Table 1). CR rate in <70 yo group and in ≥70 yo group were 55% and 46 % respectively (p=0.73). Severe infections occurred with no patient (0%) in <70 yo group and with 5 patients (16%) in ≥70 yo group (p=0.30). 5 patients of relapse were observed in the <70 yo group and 1 patient in the ≥70 yo group, and relapse free survival was significantly lower in the <70 yo group (p=0.001) (Figure 1).<70 yo (n=12)≥70 yo (n=32)p valueAge (year)61.9 ± 9.7477.5 ± 4.61< 0.01*Female, n (%)10 (83)28 (87)0.66AAV typeMPA, n (%) / GPA, n (%)6 (50) / 6 (50)26 (81) / 6 (19)0.06Newly diagnosed, n (%)6 (50)27 (84)0.045*ANCA positivity MPO, n (%) / PR3, n (%)11 (92) / 0 (0)30 (94) / 3 (9)1 / 0.55 negative, n (%)1 (8)1 (3)0.48CRP (mg/dl)3.34 ± 4.018.15 ± 6.860.03*eGFR (mL/min)55.8 ± 25.357.7 ± 24.70.93BVAS12.0 ± 8.014.8 ± 6.80.23Remission induction therapyCY, n (%) / RTX, n (%)5 (42) / 7 (58)16 (50) / 16 (50)0.74Maintenance therapy AZA, n (%)7 (58)14 (44)0.50 RTX, n (%)1 (8)6 (19)0.65 others, n (%)2 (17)3 (9)0.60 without IS, n (%)2 (17)9 (28)0.70The p-value was estimated using Fisher’s exact or Wilcoxson rank sum test. yo, years old; AAV, ANCA-associated vasculitis; MPA, microscopic polyangiitis; GPA, granulomatosis with polyangiitis; CY, cyclophosphamide; RTX, rituximab; AZA, azathioprine; IS, immunosuppressants. *p<0.05Conclusion:There was no difference in remission rate between two groups. Severe infections were observed only in the ≥70 yo group. We suggest that younger AAV patients need attention to relapse after the remission because of lower relapse free survival in <70 yo group.