Combination of Uric Acid and Pro-Inflammatory Cytokines in Discriminating Patients with Gout from Healthy Controls

Figures & data

Table 1 Comparison of Mean Values of Demographic Data, Uric Acid, CRP, IL-6, and TNF-α Levels in Serum Between the Gout and Control Groups (Mean ± SEM)

Variables	Control Group	Gout Group	Statistics (t)	P
Age	51.24±1.92	49.07±1.75	0.780	0.437
BMI (kg/m^2)	25.93±3.06	25.09±3.15	1.534	0.127
Uric acid (μmol/L)	310.96±11.68	474.86±10.74	−9.579	<0.001
CRP (mg/L)	9.66±0.76	31.24±4.22	−5.032	<0.001
IL-6 (pg/mL)	25.48±1.36	31.04±2.36	−2.040	0.044
TNF-α (pg/mL)	42.53±2.03	80.21±2.75	−10.996	<0.001

Abbreviations: BMI, body mass index; CRP, C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.

Figure 1 Correlation between serum uric acid and pro-inflammatory cytokines levels (Pearson correlation analysis).

Abbreviations: CRP, C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.

Table 2 ROC Analysis of Various Indicators for Diagnosis of Gout

Variables	AUC	95% Confidence Interval	P	Cutoff	Sensitivity	Specificity
Uric acid	0.893	0.838–0.948	<0.001	378.50	85.1	85.7
CRP	0.681	0.595–0.766	0.004	18.09	51.1	92.0
IL-6	0.610	0.505–0.715	0.0443	32.21	49.2	84.0
TNF-α	0.956	0.910–1.000	<0.001	56.52	100.0	92.0
Uric acid + CRP	0.932	0.889–0.974	<0.001		88.3	89.8
Uric acid + IL-6	0.884	0.824–0.944	<0.001		75.4	91.8
Uric acid + TNF-α	0.972	0.929–1.000	<0.001		96.1	93.9
Uric acid+ CRP + TNF-α	0.982	0.964–1.000	<0.001		98.0	93.9

Abbreviations: CRP, C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α.

Figure 2 ROC curve of serum uric acid and pro-inflammatory cytokines in identification of the patients with gout. (A) ROC curve of uric acid; (B) ROC curve of CRP; (C) ROC curve of IL-6; (D) ROC curve of TNF-α.

Abbreviations: CRP, C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α; ROC, receiver operating characteristic.

Figure 3 ROC curve for the combination of uric acid and pro-inflammatory cytokines in identification of the patients with gout. (A) ROC curve for the combination of uric acid and CRP; (B) ROC curve for the combination of uric acid and IL-6; (C) ROC curve for the combination of uric acid and TNF-α; (D) ROC curve for the combination of uric acid, CRP, and TNF-α.

Abbreviations: CRP, C-reactive protein; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α; ROC, receiver operating characteristic.