We assessed serum procalcitonin (PCT) levels to distinguish bacterial infections from non-bacterial infections in patients with fever and flare of chronic gouty arthritis.
One hundred febrile patients with chronic tophaceous gout flare-ups were collected consecutively between November 2011 and January 2014 from the Department of Rheumatology and Immunology, Sichuan Provincial People's Hospital. These patients were divided into non-infectious febrile group (68 patients) and bacterial infectious febrile group (32 patients, including 6 cases of pulmonary infection, 3 cases of infectious arthritis and 21 cases of skin infection, 2 patients died from severe infection were excluded), and 30 patients with flare of chronic gouty arthritis without fever and infection. Serum PCT, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), white blood cell (WBC) count and neutrophil ratio were determined.
57.3% (39/68) patients in the non-infectious febrile group had PCT levels ≥ 0.5 × 10³ ng/L and the ratio in the infectious febrile group was 66.7% (20/30) . No statistically significant difference was detected between them (P>0.05). 16.7% (5/30) patients had PCT levels ≥ 0.5 × 10³ ng/L in the afebrile group and both the differences between the afebrile group and the two febrile groups were significant (P<0.05). The differences of ESR, CRP, WBC count and neutrophil ratio between the two febrile groups were not statistically significant (P>0.05). In the chronic gouty arthritis patients with fever, the sensitivity and specificity of high PCT level (≥ 0.5 × 10³ ng/L) for detection of bacterial infections was 33.9% and 74.4%, the positive predictive value was 36.9% and the negative predictive value was 71.9%. The area under the curve (AUC) of PCT, CRP, ESR, WBC count and neutrophil ratio in patients with fever and chronic gouty arthritis was 0.598, 0.636, 0.612, 0.596 and 0.727, respectively.
Serum PCT levels may be not a good marker for detection of bacterial infections in the patients with fever and flare of chronic gouty arthritis. Larger studies are needed to evaluate the value of PCT measurement in the patients with fever and flare of chronic gouty arthritis.