#785 Long term survival and predictors of all-cause mortality in a Swedish cohort of patients with ANCA-associated vasculitis and kidney involvement

Abstract Background and Aims Poor patient outcomes in ANCA-associated vasculitis (AAV) with kidney involvement is attributed to factors such as delay in diagnosis, inadequate response to treatment and long-term complications due to the disease progression and the side effects of immunosuppressive therapy. The aim of the present study was to evaluate the clinical characteristics of a Swedish cohort of patients with AAV and kidney involvement and to study long-term survival and predictors of all-cause mortality. Method This retrospective study included 190 patients from two nephrology centers in mid-Sweden (Uppsala and Gothenburg), diagnosed with AAV and kidney involvement between 1993 and 2023. Clinical and laboratory variables were obtained from review of electronic medical records as well as patient follow-up visits. Kaplan-Meier analysis and multivariate Cox regression models were performed to evaluate the cumulative patient survival and influence of risk factors of interest on all-cause mortality. Results Among 190 patients (56% men, age 67 years), 57% had anti-proteinase 3-ANCA and 43% had anti-myeloperoxidase-ANCA positive AAV. eGFR at diagnosis was 23 ml/min/1.73 m2 (IQR 11–43) and 16% of patients required dialysis. Patients who were MPO-ANCA positive were more often smokers (36 vs 27%, P < 0.001). Induction therapy with cyclophosphamide and plasmapheresis treatment were given more often in PR3-ANCA positive patients (92 vs 73% respectively, P < 0.001). The follow-up time was 7 years (IQR 3–12), during which there were 106 deaths (56%). The main causes of death were infections (28%), followed by cardiovascular disease (24%) and malignancy (18%) (Fig. 1). Kaplan-Meier estimations showed that the 5-year and 10-year patient survival was 71% and 52%, respectively, and the median survival time was 11 years (95% CI 8.5–13.4). The 5-year and 10-year renal survival (end-stage kidney disease; ESKD or death) was 70% and 49%, respectively. Patient survival appears to be worse with older age and advanced CKD stage at diagnosis (Fig. 1a and b). A multivariate cox regression analysis adjusting for sex and type of AAV showed that older age (HR 1.1, 95% CI 1.08–1.14, P < 0.001), increased levels of albuminuria (U-ACR) (HR 1.88, 95% CI 1.11–3.18, P = 0.019), advanced kidney disease (CKD 4–5) (HR 1.81, 95% CI 1.15–2.84, P = 0.009) and need for dialysis at diagnosis significantly predicted all-cause mortality (HR 2.69, 95% CI 1.61–4.51, P < 0.001) (Fig. 1c–e). Conclusion Older age and more severe kidney involvement at diagnosis significantly predicted long-term patient survival in this Swedish cohort of patients diagnosed with AAV and kidney involvement. Early diagnosis and start of treatment are therefore important in order to improve patient outcomes.