Department of Nephrology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan.
Preventive Medicine and Epidemiology, National Cerebral and Cardiovascular Center, 6-1 Kishibe-Shimmachi, Suita, Osaka, 564-8565, Japan.
Arthritis Res Ther. 2020 Nov 5;22(1):261. doi: 10.1186/s13075-020-02320-x.
The present study aimed to investigate associations between long-term renal function, whether IgG4-related tubulointerstitial nephritis (TIN) was diagnosed by renal biopsy at initial examination, chronic kidney disease (CKD) stage, and histological stage in patients with IgG4-related TIN.
This study used a retrospective cohort design including almost all patients who underwent renal biopsy at Fujita Health University Hospital and Nagoya University or its affiliated hospitals in Aichi between April 2003 and March 2015 (n = 6977 renal biopsies). The primary outcome was longitudinal changes in eGFR. Main exposures were whether IgG4-related TIN was diagnosed by renal biopsy at the initial examination, CKD stage, and its histological stage. Linear mixed models were performed to examine associations.
Of the 6977 samples, there were 24 patients (with 201 records due to repeated measures) with IgG4-related TIN (20 men, mean age, 68.7 ± 9.7 years). They were followed up 6.6 ± 2.8 years after the renal biopsy and underwent glucocorticoid treatment. We found significant increase in eGFR from the baseline to 2 and 6 months after treatment initiation, which was maintained until 60 months. Patients initially diagnosed with IgG4-related TIN had higher eGFR from the baseline (at the start of treatment) to 60 months than those who were not. Compared with patients with CKD stage 3, patients with CKD stages 4 and 5 had lower eGFR at the baseline and other time points. Patients with histological stage B had comparatively lower eGFR at each point than stage A patients. Those mean differences of eGFR were stable from the baseline to 60 months.
After the treatment initiation, renal function rapidly improved and maintained for a long period, even with advanced CKD stage. We showed importance of early diagnosis of IgG4-related TIN in maintaining eGFR.
本研究旨在探讨 IgG4 相关肾小管间质性肾炎（TIN）患者的长期肾功能、初次检查时是否通过肾活检诊断 IgG4 相关 TIN、慢性肾脏病（CKD）分期和组织学分期之间的关系。
本研究采用回顾性队列设计，纳入 2003 年 4 月至 2015 年 3 月期间在藤田保健卫生大学医院和名古屋大学及其附属医院接受肾活检的几乎所有患者（n=6977 例肾活检）。主要结局为 eGFR 的纵向变化。主要暴露因素为初次检查时是否通过肾活检诊断为 IgG4 相关 TIN、CKD 分期及其组织学分期。采用线性混合模型来检验关联。
在 6977 例样本中，有 24 例患者（因重复测量有 201 个记录）被诊断为 IgG4 相关 TIN（20 例男性，平均年龄 68.7±9.7 岁）。他们在肾活检后随访 6.6±2.8 年，并接受了糖皮质激素治疗。我们发现，从基线到治疗开始后 2 个月和 6 个月，eGFR 显著增加，并且一直持续到 60 个月。初次诊断为 IgG4 相关 TIN 的患者在基线（治疗开始时）到 60 个月时的 eGFR 高于未诊断为 IgG4 相关 TIN 的患者。与 CKD 分期 3 期患者相比，CKD 分期 4 期和 5 期患者的基线和其他时间点的 eGFR 较低。组织学分期 B 的患者在各时间点的 eGFR 均低于分期 A 的患者。这些 eGFR 的平均差异从基线到 60 个月是稳定的。
在开始治疗后，肾功能迅速改善并长期维持，即使是在 CKD 晚期也是如此。我们表明，早期诊断 IgG4 相关 TIN 对于维持 eGFR 非常重要。
