Procalcitonin may not be a differential diagnostic marker for bacterial infection in febrile patients with chronic gouty arthritis

Abstract

Objective This study aimed to examine the diagnostic value of serum procalcitonin (PCT) levels for identifying bacterial infection in febrile patients with chronic gouty arthritis. Methods Sixty-six febrile patients with chronic gouty arthritis were divided into non-bacterial infection (n = 45) and bacterial infection groups (n = 21). PCT levels were measured by an immunoassay. Other laboratory parameters, including the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), white blood cells (WBCs), and the neutrophil ratio were extracted from medical records. Receiver-operating characteristic curves were used to evaluate diagnostic values and accuracy. Results Serum PCT levels, the ESR, CRP levels, WBC count, and neutrophil ratio were not different between the groups. To assess the ability of PCT to discriminate bacterial infection in febrile patients with chronic gouty arthritis (cut-off value: 0.5 ng/mL), the sensitivity and specificity of PCT were 22.2% and 61.5%, respectively. The area under the curve (AUC) of serum PCT levels was 0.526. The AUCs of related inflammatory indicators were 0.530 for the ESR, 0.635 for CRP, 0.577 for the WBC count, and 0.712 for the neutrophil ratio. Conclusion Serum PCT levels may not be a good biomarker for bacterial infection in febrile patients with chronic gouty arthritis.

Keywords: Bacterial infection; biomarker; chronic gouty arthritis; fever; inflammation; procalcitonin.

Figure 1.

Receiver-operating characteristic curves for PCT, the ESR, CRP, WBCs, and the percentage of neutrophils for diagnosis of infection in patients with chronic gouty arthritis PCT: procalcitonin; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; WBCs: white blood cells

Figure 2.

Scatter plots for each biomarker of PCT, the ESR, CRP, WBCs, and the percentage of neutrophils for diagnosis of infection in patients with chronic gouty arthritis. Orange circles indicate infectious patients and blue circles indicate non-infectious patients. (a) Scatter plot for PCT levels; (b) scatter plot for the ESR; (c) scatter plot for CRP levels; (d) scatter plot for WBCs; (e) scatter plot for the percentage of neutrophils PCT: procalcitonin; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; WBCs: white blood cells