Predictive potential of albumin-alkaline phosphatase ratio for cerebrovascular accident in patients with antineutrophil cytoplasmic antibody-associated vasculitis

Background This study investigated the predictive potential of the albumin-to-alkaline phosphatase ratio (AAPR) for cerebrovascular accident (CVA) occurrence in patients with antineutrophil cytoplasmic antibody-associated vasculitis. Methods This study included 239 AAV patients and reviewed their medical records retrospectively. AAPR was calculated using the following formula: AAPR = serum albumin (g/dL)/serum alkaline phosphatase (IU/L). CVA was defined only as cerebral infarction after AAV diagnosis in this study. In patients with CVA and those without CVA, the follow-up duration based on CVA was defined as the period from AAV diagnosis to CVA occurrence and to the last visit day, respectively. Results The median age of 239 AAV patients (130 microscopic polyangiitis, 64 granulomatosis with polyangiitis, and 45 eosinophilic granulomatosis with polyangiitis) was 59.0 years and 32.6% were men. The median serum albumin and alkaline phosphatase levels, and AAPR were 3.7 g/dL, 70.5 IU/L and 0.051, respectively. Nineteen patients had CVA during the median follow-up duration of 34.8 months. Using the receiver operator characteristic curve analysis, the optimal cut-off of AAPR for CVA occurrence was obtained as <= 0.035. AAV patients with AAPR <= 0.035 showed a significantly higher risk of CVA occurrence after AAV diagnosis than those with AAPR >0.035 (relative risk 5.000, p < 0.001). In the multivariable Cox analysis, only AAPR <= 0.035 was independently associated with CVA occurrence among AAV patients (hazard ratio 3.195, 95% confidence interval 1.014, 10.062). Conclusion This study demonstrated the predictive potential of AAPR calculated at AAV diagnosis for CVA occurrence after AAV diagnosis among AAV patients.