Serum creatinine level and ESR values associated to clinical pathology types and prognosis of patients with renal injury caused by ANCA-associated vasculitis

The correlation between serum creatinine and erythrocyte sedimentation rate (ESR) values and clinical pathology and prognosis in patients with renal injury caused by anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis were analyzed. Eighty-six patients with ANCA-associated vasculitis (AAV) treated in the Affiliated Hospital of Qingdao University were enrolled in the study. Patients were assigned into an elderly group (n=45) or a non-elderly group (n=41) according to age. The serum creatinine (Scr) level was measured via the sarcosine oxidase method, and the erythrocyte sedimentation rate (ESR) was measured using the full-automatic ESR analyzer; the relationship between Scr and ESR values and the pathology type of patients was statistically analyzed. The mean levels of Scr and ESR in the 86 patients were 406.87±12.37 µmol/l and 83.83±7.64 mm/1 h, respectively. Importantly, the levels of Scr and the ESR in the elderly group were significantly higher than those in the non-elderly group (P<0.05). In addition, patients with high levels of Scr and accelerated ESR presented mainly the crescentic and sclerotic pathological types, while in the same patients the numbers of focal and mixed types were lower (P<0.05). Kaplan-Meier analysis showed that the survival rate in the elderly group was significantly lower than that in the non-elderly group, and likewise patients with high levels of Scr and accelerated ESR had significantly lower survival rates than those with low levels of Scr and normal ESR (P<0.05). The AUC of the Scr level was 0.901, the sensitivity 90.2%, the specificity 89.5% and the cut-off value was 392.5 µmol/l; while the AUC of the ESR level was 0.864, the sensitivity 89.2%, the specificity 88.5% and the cut-off value 72.8 mm/1 h. Logistic regression analysis showed that the levels of Scr (OR=2.315, P<0.01) and ESR (OR=1.847, P<0.01) were independent factors affecting the prognosis of patients. Based on our findings, the seric Scr level and the ESR are closely related to the clinicopathological features of the disease in patients with renal injury caused by ANCA-associated vasculitis, and they can be used as prognosis and treatment evaluation markers.