The Utility of CRP Velocity for the Prognostication in Patients with Acute Pyelonephritis

ABSTRACT

PURPOSE: C-reactive protein (CRP) velocity is value of the CRP level divided by the time after fever start. The aim of this study was to attempt to determine the usefulness of CRP velocity to predict the severity of acute pyelonephritis (APN). METHODS: We retrospectively reviewed medical records of patients who visited the emergency department (ED) and were diagnosed with APN for five years. The patients underwent computed tomography (CT) in the ED. The characteristics and laboratory findings compared with the CT group were classified from group I to group V as severity of APN. The patients were grouped according to mild and severe based on the CT groups for comparison of area under the curve. Patients who had fever within 24 hours were extracted and the same analysis was performed. RESULTS: A total of 199 patients were enrolled in our study. The CT groups were classified as follows group 1 (N=24); group 2 (N=25); group 3 (N=80); group 4 (N=58); group 5 (N=12). Statistically significant differences in laboratory results including CRP, CRP velocity, age, and past history of hypertension were found between mild and severe group. The area under ROC curve of CRP and CRP velocity was 0.888 and 0.841 (p<0.05). For APN patients within 24 hours, AUROC of CRP and CRP velocity were 0.871 and 0.949 (p<0.05). However, AUROC comparison did not show statistically significant differences within CRP and CRP velocity (p=0.1410). CONCLUSION: In APN patients who had fever within 24 hours, CRP and CRP velocity had predictive value for severity of APN.