Introduction: To describe the clinical characteristics of a Swedish cohort of patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) and kidney involvement and to study long-term survival and predictors of all-cause mortality.

Methods: An observational study including patients with AAV and kidney involvement between 1993 and 2023 from two centres in mid-Sweden. Data were obtained from electronic health care records and follow-up visits. Multivariable Cox regression models and Kaplan-Meier analysis were performed to evaluate risk factors of interest predicting all-cause mortality.

Results: Among 190 patients (56% men, median age 67 years, 43% PR3-ANCA (Proteinase 3 Anti-Neutrophil Cytoplasmic Antibody), and 57% MPO -ANCA (Myeloperoxidase Anti-Neutrophil Cytoplasmic Antibody) positive, estimated glomerular filtration rate at diagnosis was 23 ml/min/1.73 m² [interquartile range (IQR) 11-42] and 16% required dialysis. Median follow-up 20 was 7.5 years (IQR 3.6-12.3) and 106 deaths occurred. Main causes of death were infections (28%), cardiovascular disease (24%) and malignancy (18%). Cox hazard regression models showed that older age [hazard ratio (HR) 1.10, 95% CI 1.06-1.14] was a strong, consistent, and independent predictor of all-cause mortality, irrespective of sex, ANCA type, and kidney function. In the Uppsala cohort (n = 91) serum albumin levels at diagnosis emerged also as an independent risk factor when adjusting for age, kidney function and other inflammatory parameters (HR 0.86, 95% CI 0.79-0.94).

Conclusion: Long-term patient and kidney survival was associated mainly with age and serum albumin levels at diagnosis in this Swedish cohort of patients with AAV. Infections and cardiovascular disease were the most common causes of death, underscoring the importance of infection monitoring and cardiovascular risk management.