Objective: To evaluate the relationship between 24 h urinary ion content and kidney stones, and to explore the diagnostic values of kidney stone in primary gout patients.
Methods: Patients diagnosed with primary gout had ultrasound scanning of both feet and kidneys in Peking University First Hospital from Jan. 2020 to May 2021. Their clinical characteristics were compared between the positive and negative kidney stone groups, and the relationship between kidney stone and urinary ion composition were analyzed. Risk factors of kidney stone were analyzed. The explored diagnostic values were evaluated for urinary oxalate and citrate according with uric acid kidney stones by dual-energy computed tomography (DECT).
Results: Among the 100 gouty patients, 80 patients had uric acid crystal deposition in lower joints of extremity by ultrasonography, 61 patients had kidney stone, and 34 had kidney uric acid stones by DECT. All the multiple kidney stones were proved as uric acid kidney stones by DECT. Compared with patients without kidney stone group proved by ultrasonography, patients with kidney stone had longer gouty duration [(48.7±26.6) months vs. (84.0±30.6) months, P=0.01], higher 24 h urinary oxalate [(20.1±9.6) mg vs. (28.6±20.7) mg, P=0.001] and lower 24 h urinary citrate [(506.3±315.4) mg vs. (355.7±219.6) mg, P=0.001]. Compared with the patients without kidney stone by DECT, the patients with uric acid kidney stone also had longer disease duration [(49.1±28.4) months vs. (108.3±72.2) months, P=0.001], higher 24 h urinary oxalate [(23.6±16.9) mg vs. (28.5±18.8) mg, P < 0.05], lower 24 h urinary citrate [(556.0±316.3) mg vs. (391.7±261.2) mg, P < 0.05], higher serum uric acid [(466.2±134.5) μmol/L vs. (517.2±18.1) μmol/L, P < 0.05] and higher 24 h urinary uric acid [(1 518.1±893.4) mg vs. (1 684.2±812.1) mg, P < 0.05]. Logistic regression analysis showed long gout disease duration (OR=1.229, 95%CI: 1.062-1.522, P < 0.05), high serum uric acid level (OR=1.137, 95%CI: 1.001-1.213, P=0.01), low 24 h urinary citrate (OR=0.821, 95%CI: 0.659-0.952, P=0.01) were all risk factors of kidney stones by ultrasonography. Also, long gout disease duration (OR=1.201, 95%CI: 1.101-1.437, P=0.005), high serum creatine uric level (OR=1.145, 95%CI: 1.001-1.182, P=0.04), low 24 h urinary citrate (OR=0.837, 95%CI: 0.739-0.931, P=0.02) were all risk factors of kidney uric acid stones by DECT.
Conclusion: Long disease duration and low 24 h urinary citrate were risk factors for kidney stones.
目的: 分析原发性痛风患者24 h尿液离子含量及其与肾结石的关系，探讨其在痛风合并肾结石诊断中的价值。
方法: 回顾性分析2020年1月至2021年5月在北京大学第一医院风湿免疫科门诊连续就诊且资料完整的痛风患者，根据临床和超声资料，分析肾结石与尿液离子成分的相关性以及肾结石形成的危险因素。进一步以双能CT证实的肾尿酸盐结石为金标准，探讨尿液离子异常对于痛风合并肾尿酸盐结石的诊断价值。
结果: 100例患者中80例超声发现下肢关节尿酸盐晶体沉积，61例超声发现肾结石，34例双能CT检查证实为尿酸盐结石。与超声检查无肾结石组患者相比，肾结石组的痛风病程更长[(48.7±26.6)个月vs. (84.0±30.6)个月，P=0.01]，24 h尿草酸总量更高[(20.1±9.6) mg vs. (28.6±20.7) mg，P=0.001]，24 h尿枸橼酸总量更低[(506.3±315.4) mg vs. (355.7±219.6) mg，P=0.001]。与双能CT无肾结石组患者相比，肾尿酸盐结石组痛风病程更长[(49.1±28.4)个月vs. (108.3±72.2)个月，P=0.001]，24 h尿草酸总量更高[(23.6±16.9) mg vs. (28.5±18.8) mg，P < 0.05]，24 h尿枸橼酸总量更低[(556.0±316.3) mg vs. (391.7±261.2) mg，P < 0.05]，平均血尿酸水平及24 h尿尿酸总量更高[(466.2±134.5) μmol/L vs. (517.2±18.1) μmol/L，P < 0.05；(1 518.1±893.4) mg vs. (1 684.2±812.1) mg，P < 0.05]。以病程、既往痛风发作频率、血尿酸、血肌酐及24 h尿草酸、枸橼酸、尿酸为自变量进行Logistic回归分析，结果显示长病程(OR=1.229，95%CI：1.062~1.522，P < 0.05)、高血尿酸(OR=1.137，95%CI：1.001~1.213，P=0.01)、低24 h尿枸橼酸总量(OR=0.821，95%CI：0.659~0.952，P=0.01)为痛风患者超声发现肾结石的危险因素；长病程(OR=1.201，95%CI：1.101~1.437，P=0.005)、高血肌酐(OR=1.145，95%CI：1.001~1.182，P=0.04)、低24 h尿枸橼酸总量(OR=0.837，95%CI：0.739~0.931，P=0.02)为痛风患者出现肾尿酸盐结石的危险因素。
结论: 长病程、低24 h尿枸橼酸的痛风患者更容易出现肾结石。
Keywords: Citrate; Dual-energy computed tomography; Gout; Kidney stone; Ultrasonography.