Change In Serum Uric Acid Levels In Patients With Crohn’s Disease And Its Potential Significance

Objective:To investigate the change in serum uric acid(UA)levels in patients with Crohn’s disease(CD)and its potential significance.Methods:one hundred and ninety-five CD patients who met the study criteria enrolled in.among 96 CD patients received Infliximab(IFX)treatment regularly.In these 96 IFX-treated CD patients,33 were in the induced remission phase and 57 in the sustained remission phase,and another 6 were excluded due to incomplete data or disease re-activity.one hundred and ninety-five healthy volunteer enrolled in.UA and Serum uric acid to creatinine ratio(UA/Cr)were used as a biomarker for serum uric acid levels,inorder to correc uric acid to creatinine to eliminate the noise caused by renal function and nutritional status.The clinical data and laboratory test results were collected to explore the relationship between CD and UA.Results:1.The UA level was 333.92±91.70umol/L in CD patients,and was lower than in healthy volunteer(369.17±81.52 umol/L,P=0.000).The UA/Cr ratio was 5.20(4.40,6.30)in CD patients,and was also lower than that in healthy vol-unteer(5.67(4.86,6.66))(P=0.002).Hoever,the difference in Cr level between CD patients and healthy volunteer was not statistically significant(P=0.322).2.The influencing factors of UA,Cr and UA/Cr levels in CD patients were analyzed in terms of gender,surgical history associated with CD,Montreal typing,disease activity,hematological indexes and whether 5-aminosalicylic acid(5-asa)was used.Hematology indexes including antibodies associated with chronic inflammatory bowel diseases(CIBD),anti-intestinal goblet cell antibody(GAB),anti-pancreatic antibody(PAB),antineutrophil cytoplasmic antibody(ANCA),ASCA,food-specific immunoglobulin G(Fs-IgG).The results showed:The UA level in male CD patients was 360.34±86.88umol/L,which was higher than263.17±62.44umol/L in female CD patients(P=0.000).The UA level in the patients with perianal lesions was 347.38±90.03umol/L,which was higher than300.40(257.50,364.50)in CD patients without perianal lesions(P=0.004).The UA level was 348.00(285.00,407.50)umol/L in remission CD patients,which also higher than 310.04±94.12umol/L in active CD patients(P=0.004).However,surgical history associated with CD,Age at diagnosis,The location of the lesion,Behavior of disease and hematological indexes have no significant relationship with uric acid level(P<0.05).The UA/Cr ratio was 5.47(4.63,6.38)in remission patients,which was higher than 5.03(4.18,6.11)in active patients(P=0.011).Gender,surgical history associated with CD,Montreal typing and hematological indexes have no significant relationship with uric acid level.3.According to UA level,CD patients were divided into normal UA group and hyperuricemia(HUA)group.The gender distribution in the two subgroups was statistically significant(χ~2=6.182,P=0.013).while there was no significant difference between the subgroups respectively in the course of disease,surgical history related to CD,Montreal typing,clinical stage or disease activity(P>0.05).4.Univariate analysis of risk factors for CD disease activity showed that the level of UA(r=-0.206,P=0.004),UA/Cr(r=-0.183,P=0.011)ALB(r=-0.414,P=0.000)was negatively correlated with disease activity respectively,and the level of CRP(r=0.540,P=0.000),PLT(r=0.480,P=0.000),ESR(r=0.449,P=0.000),FIB(r=0.419;P=0.000)was positively correlated with disease activity respectively.Logistic regression analysis showed that lower UA level(OR=0.994,95%CI:0.990~0.998,P=0.002)and lower UA/Cr ratio(OR=0.730,95%CI 0.555~0.968,P=0.025)was respectively an independent risk factor for disease activity.The sensitivity,specificity and diagnostic accuracy of-UA/Cr in predicting disease activity of CD patients were 32.93%,86.73%and 64.10%respectively.The sensitivity,specificity and diagnostic accuracy of CRP in predicting disease activity of CD patients were 76.83%,76.99%and 76.92%respectively.The sensitivity,specificity and diagnostic accuracy of-UA/Cr combined with CRP in predicting disease activity of CD patients were 74.39%,79.65%and 76.92%,respectively.5.UA/Cr values were increased in active CD patients after ifx-induced remission(Before the treatment:5.37±1.53,After the treatment:6.14±1.70,P=0.018).Conclusion:The metabolic disorder of uric acid in CD patients is common,however its significance is not completely clear up to now,which may be related to the clinical condition of CD.The increase of UA/Cr ratio in active CD patients may indicate the disease toward remission.