干燥综合征患者的低柠檬酸尿症作为肾小管酸中毒的生物标志物。
Hypocitraturia as a biomarker of renal tubular acidosis in patients with Sjögren's disease.
机构信息
Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil.
出版信息
Adv Rheumatol. 2024 Jun 3;64(1):45. doi: 10.1186/s42358-024-00387-7.
INTRODUCTION
Sjögren's disease (SD) is an immune-mediated chronic inflammatory disease that affects epithelial tissues, mainly salivary and lacrimal glands. It also presents extraglandular manifestations. The main renal manifestation is tubulointerstitial nephritis (TIN), which can manifest as renal tubular acidosis (RTA). Urinary citrate may be a biomarker of RTA in these patients. The objective of this study was to evaluate whether hypocitraturia is a predictive biomarker of RTA in a sample of patients with SD in a tertiary hospital in southern Brazil.
METHODS
All patients with SD who met the inclusion criteria and who participated in the rheumatology outpatient clinic of the Irmandade Santa Casa de Misericórdia de Porto Alegre were included. Demographic, SD, serological and urinary data were obtained. RTA was considered in those patients who persistently presented urinary pH above 5.5 and serum pH below 7.35. Patients who persistently had urinary pH above 5.5 underwent a urinary acidification test with furosemide and fludrocortisone. These patients received 1 mg of fludrocortisone and 40 mg of furosemide and had their urine samples tested 2, 4 and 6 h after taking the medications. The test was stopped at any urine sample with pH 5.5 or less. The variables were expressed as mean and standard deviation or interquartile range. The association between hypocitraturia and RTA was assessed using the chi-square.
RESULTS
Forty-two patients were included, 95.2% female with a median age of 61.73 years. The prevalence of complete distal RTA was 4.88%. Twenty-eight patients underwent urine acidification testing. Five patients had hypocitraturia, and two of them had complete distal RTA. The association between hypocitraturia and RTA was statistically significant (p < 0.012), with a sensitivity of 100%, specificity of 91.2% and accuracy of 91.7%. The negative predictive value was 100%. The global renal assessment of the population demonstrated two patients with RTA, one patient with decreased renal function and six patients with proteinuria greater than 0.5 g/24 h.
CONCLUSION
The prevalence of RTA in the studied population was 4.88%. Hypocitraturia had high sensitivity and accuracy for the diagnosis of RTA.
简介
干燥综合征（Sjögren's disease，SD）是一种免疫介导的慢性炎症性疾病，主要影响上皮组织，特别是唾液腺和泪腺。它也存在外分泌腺表现。主要的肾表现是肾小管间质性肾炎（Tubulointerstitial nephritis，TIN），可表现为肾小管性酸中毒（Renal tubular acidosis，RTA）。尿柠檬酸盐可能是这些患者 RTA 的生物标志物。本研究的目的是评估在巴西南部一家三级医院的 SD 患者样本中，低柠檬酸尿是否是 RTA 的预测生物标志物。
方法
所有符合纳入标准并参加 Irmandade Santa Casa de Misericórdia de Porto Alegre 风湿病门诊的 SD 患者均被纳入研究。收集人口统计学、SD、血清学和尿液数据。在那些持续存在尿 pH 值高于 5.5 和血清 pH 值低于 7.35 的患者中考虑 RTA。持续尿 pH 值高于 5.5 的患者进行呋塞米和氟氢可的松的尿液酸化试验。这些患者接受 1 毫克氟氢可的松和 40 毫克呋塞米，并在服药后 2、4 和 6 小时检测尿液样本。任何尿液样本 pH 值降至 5.5 或以下时，试验即停止。变量以平均值和标准差或四分位间距表示。使用卡方检验评估低柠檬酸尿与 RTA 之间的关系。
结果
共纳入 42 例患者，95.2%为女性，中位年龄为 61.73 岁。完全性远端 RTA 的患病率为 4.88%。28 例患者进行了尿液酸化试验。5 例患者存在低柠檬酸尿，其中 2 例存在完全性远端 RTA。低柠檬酸尿与 RTA 之间的关联具有统计学意义（p<0.012），敏感性为 100%，特异性为 91.2%，准确性为 91.7%。阴性预测值为 100%。对人群的整体肾脏评估显示，有 2 例患者存在 RTA，1 例患者存在肾功能下降，6 例患者存在蛋白尿大于 0.5 g/24 h。
结论
在研究人群中，RTA 的患病率为 4.88%。低柠檬酸尿对 RTA 的诊断具有高敏感性和准确性。
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