The diagnostic and early warning value of IL-6, IL-18, IL-33 and osteopontin in renal injury of gout patients

Objective To investigate the diagnostic and prognostic value of serum interleukin (IL)-6, IL-18, IL-33, and osteopontin (OPN) in gout complicated with renal injury.

Methods A total of 113 gout patients were divided into the gout complicated with renal injury group (Combined Group, GFR ＜ 90 mL/min, n = 54) and gout complicated without renal injury group (Gout Group, GFR ≥ 90 mL/min, n = 59) based on the glomerular filtration rate (GFR). Additionally, 34 healthy individuals with physical examinations at our hospital during the same period were selected as the control group. The serum levels of IL-6, IL-33, IL-18 and OPN in three groups were measured using the ELISA. The estimated glomerular filtration rate (eGFR) of patients were calculated, and the diagnostic value of IL-6, IL-33, IL-18, and OPN for gout complicated with renal injury were evaluated.

Results The levels of serum IL-6, IL-18, IL-33 and OPN in the combined group and gout group were higher than those in control group (P ＜ 0.05). In the combined group, the levels of IL-6 and IL-18 were higher than those in gout group (P ＜ 0.05), the level of IL-33 was lower than that in gout group (P ＜ 0.05), and the eGFR was lower than that in both the gout group and control group (P ＜ 0.05).The results of Spearman correlation analysis showed that in the combined group, the serum IL-33 level was negatively correlated with the levels of serum creatinine, cystatin C and β2 microglobulin (P ＜ 0.05 to P ＜ 0.01), and significantly positively correlated with eGFR (P ＜ 0.01). The IL-18, IL-6 and OPN were positively correlated with serum creatinine, cystatin C and β2 microglobulin (P ＜ 0.05 to P ＜ 0.01), and negatively correlated with eGFR (P ＜ 0.05 to P ＜ 0.01). The results of ROC curve analysis showed that the AUC of serum IL-33, L-18, and IL-6 for diagnosing gout combined with renal injury separately was all lower than that of the combined detection of three. The results of logistic regression analysis showed that the IL-33 was the independent protective factor of renal injury, and the CysC was the independent risk factor of renal injury in gout patients (P ＜ 0.05).

Conclusions The levels of serum IL-6 and IL-18 in patients with gout complicated with renal injury increase, while the level of IL-33 decreases. The three have a significant correlation with renal injury indicators, and all have certain diagnostic value for gout complicated with renal injury. The combined diagnostic value of the three is relatively high.