C-reactive protein to serum albumin ratio is an independent predictor of all-cause mortality in patients with ANCA-associated vasculitis

Purpose: We investigated whether C-reactive protein (CRP) to serum albumin ratio (CAR) could be an independent predictor of all-cause mortality in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Materials and Methods: We retrospectively reviewed the medical records of 170 patients with AAV. We collected clinical and laboratory data. We also examined AAV-related and traditional risk factors of all-cause mortality. To assess the hazard ratios of variables, we performed univariable and multivariable Cox hazard model analyses. Results: The mean age was 55.0 years and 53 patients (31.2%) were male among 170 patients with AAV (88 microscopic polyangiitis, 43 granulomatosis with polyangiitis, and 39 eosinophilic granulomatosis with polyangiitis). ANCA was detected in 129 patients (75.9%). The initial mean CRP and serum albumin were 41.1 (mg/L) and 3.6 (g/dL), and the mean CAR at diagnosis was 14.8. The most common risk factor of mortality was hypertension (42.4%), followed by chronic kidney disease ≥stage 3 (25.9%). Fourteen patients (8.2%) died during the mean follow-up of 56.7 months. In both multivariable Cox hazard model analyses, CAR at diagnosis was identified as an independent predictor of all-cause of mortality comparable to diabetes mellitus (DM). Moreover, patients with CAR ≥10.35 and having DM exhibited a higher frequency of all-cause mortality than those without. Conclusion: CAR at diagnosis can be an independent predictor of all-cause mortality, comparable to DM, the conventional risk factor of mortality.