BACKGROUND Previous studies have indicated bidirectional associations between urate levels and inflammatory bowel disease(IBD),including ulcerative colitis(UC)and Crohn’s disease(CD).However,it remains unclear whether the observations are causal because of confounding factors.AIM To investigate the causal associations between urate levels and IBD using bidirec-tional Mendelian randomization(MR).METHODS Independent genetic variants for urate levels and IBD were selected as instru-mental variables from published genome-wide association studies(GWASs).Summary statistics for instrument-outcome associations were retrieved from three separate databases for IBD(the UK Biobank,the FinnGen database and a large GWAS meta-analysis)and one for urate levels(a large GWAS meta-analysis).MR analyses included the inverse-variance-weighted method,weighted-median estimator,MR-Egger and sensitivity analyses(MR-PRESSO).A meta-analysis was also conducted to merge the data from separate outcome databases using a fixed-effects model.RESULTS Genetically higher serum urate levels were strongly associated with an increased risk of UC[odds ratio(OR):1.95,95%confidence interval(CI):1.86-2.05]after outlier correction,and the ORs(95%CIs)for IBD and CD were 0.94(95%CI:0.86-1.03)and 0.91(95%CI:0.80-1.04),respectively.Animal studies have confirmed the positive association between urate levels and UC.Moreover,genetically predicted IBD was inversely related to urate levels(OR:0.97,95%CI:0.94-0.99).However,no association was observed between genetically influenced UC or CD and urate levels.CONCLUSION Urate levels might be risk factors for UC,whereas genetically predicted IBD was inversely associated with urate levels.These findings provide essential new insight for treating and preventing IBD.
Song ZhangXue FangLe KangXiang-Yu SuiMiao LiuYu-Jia LuoShuo FuZhao-Shen LiSheng-BingZhaoYu Bai
Background:Dual-energy computed tomography(DECT)is purported to accurately distinguish uric acid stones from non-uric acid stones.However,whether DECT can accurately discriminate ammonium urate stones from uric acid stones remains unknown.Therefore,we aimed to explore whether they can be accurately identified by DECT and to develop a radiomics model to assist in distinguishing them.Methods:This research included two steps.For the first purpose to evaluate the accuracy of DECT in the diagnosis of uric acid stones,178 urolithiasis patients who underwent preoperative DECT between September 2016 and December 2019 were enrolled.For model construction,93,40,and 109 eligible urolithiasis patients treated between February 2013 and October 2022 were assigned to the training,internal validation,and external validation sets,respectively.Radiomics features were extracted from non-contrast CT images,and the least absolute shrinkage and selection operator(LASSO)algorithm was used to develop a radiomics signature.Then,a radiomics model incorporating the radiomics signature and clinical predictors was constructed.The performance of the model(discrimination,calibration,and clinical usefulness)was evaluated.Results:When patients with ammonium urate stones were included in the analysis,the accuracy of DECT in the diagnosis of uric acid stones was significantly decreased.Sixty-two percent of ammonium urate stones were mistakenly diagnosed as uric acid stones by DECT.A radiomics model incorporating the radiomics signature,urine pH value,and urine white blood cell count was constructed.The model achieved good calibration and discrimination{area under the receiver operating characteristic curve(AUC;95%confidence interval[CI]),0.944(0.899-0.989)},which was internally and externally validated with AUCs of 0.895(95%CI,0.796-0.995)and 0.870(95%CI,0.769-0.972),respectively.Decision curve analysis revealed the clinical usefulness of the model.Conclusions:DECT cannot accurately differentiate ammonium urate stones from uric acid stones.Our pro
