Association Study Between Uric Acid Fluctuations And Renal Function In Patients With Gout

ObjectiveUsing data from Electronic Medical Record System to explore the association of serum uric acidfluctuations and renal dysfunction in patients with gout,the relationship between substandard uric acid control and renal damage,and the proposed target level of uric acid from the perspective of preventing kidney injury.MethodsData on gout patients since the establishment of the Huzhou City Electronic Medical Record Data Sharing Platform System was collected,and information of relevant diagnostic,examination and image results,and prescriptions were extracted.The baseline renal function of the enrolled patients was normal,and the estimated glomerular filtration rate(eGFR)<60 mL/min/1.73m2 was used to define renal dysfunction and serve as an outcome indicator.The subjects were divided into two groups based on baseline uric acid levels,with abnormal group to be>420 μmol/L(=7 mg/dL).The terminal uric acid levels were divided into four groups,with intervals to be<6,6～8(excluding 8),8～10(excluding 10),≥10 mg/dL respectively.The generalized estimating equation was used to analyze the repeated measures,and the proportional hazard model,Cox regression analysis was used to analyze the effects of baseline uric acid and uric acid fluctuations on renal function during follow-up.The adjustment covariates with missing data were filled by mean substitution method in each group according to genders and ages,and subgroup analysis was performed on subjects with definite diagnosis of hypertension and diabetes.ResultsA total of 1009 patients with gout were enrolled,including 366 patients with normal uric acid at baseline and 643 patients with abnormal uric acid at baseline.After adjusting for age,gender,testing times,hemoglobin and cholesterol covariates,the generalized estimating equation analysis showed that comparing with the baseline uric acid normal group,the eGFR decreased by-4.79(0.64)mL/min/1.73m2(p(se))(P<0.001)when the uric acid increased by 1 μmol/L in the baseline uric acid abnormal population.Compared with the group of normal uric acid with the end point uric acid to be<6 mg/dL,the βs of uric acid≥10 mg/dL were at least twice as high as that of the other groups,regardless of the baseline uric acid levels.After adjustment for age,gender,baseline uric acid,baseline eGFR,hemoglobin,and cholesterol covariates,Cox regression analysis suggested that higher uric acid was a significant risk factor for renal dysfunction compared with the normal baseline uric acid group,with HR[95%Cl]to be 1.49[1.04,2.15](P=0.030).Larger sample data analysis after mean substitution of missing data demonstrated that compared with normal baseline uric acid with the end point uric acid to be<6 mg/dL,the endpoint uric aci≥10 mg/dL was a significant risk factor for renal dysfunction regardless of the baseline uric acid status(P<0.05),HR[95%CI]were 3.28[1.21,8.91](baseline uric acid normal group),and 3.01[1.43,6.35](baseline uric acid abnormal group)respectively.ConclusionRegardless of the baseline uric acid levels of gout patients,uric acid>10 mg/dL is a significant risk factor for renal dysfunction compared with the target value of uric acid<6 mg/dL.Uric acid in the interval of 6～10 mg/dL is a potential risk factor for renal dysfunction.