Objectives Proteinuria is a marker of lupus nephritis (LN) activity and damage. We aimed to explore the impact of baseline proteinuria level on long-term outcomes. Methods We included 249 patients diagnosed with their first biopsy-proven LN. We divided patients based on baseline proteinuria into low-level (≤1 g/day, group 1; 62 patients), moderate-level (>1 and <3 g/day, group 2; 90 patients), and high-level proteinuria (≥3 g/day, group 3; 97 patients). Outcomes included complete proteinuria recovery (CPR) at 1 year, an adverse composite outcome (ESKD, a sustained ≥40% decline in eGFR, or death), and LN flares. Cox proportional hazard models were used to examine the association between baseline characteristics and long-term outcomes. Results At baseline, the median [IQR] age was 33.2 [26.4, 42.4] years; median proteinuria level was 2.2 [1.0, 3.8] g/day. 177 (71%) patients had proliferative lesions on biopsy; 59.7% in group 1, 78.9% in group 2, and 71.4% in group 3. The rate of achievement of CPR at 1 year was highest for group 1 and lowest for group 3. For long-term outcomes (median follow-up 8.4 years), the frequency of the adverse composite outcome was 27.4%, 26.7%, and 48.5% in groups 1, 2, and 3, respectively; p= 0.003. The corresponding frequency of flares was 27.4%, 38.2%, and 61.9%, respectively; p< 0.001. In the multivariable model for factors associated with long-term outcomes, there was no significant difference between groups 1 and 2; group 3 was associated with the worst prognosis. Conclusions Low-level proteinuria is commonly associated with proliferative LN and adverse long-term outcomes.

中文翻译：

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基线蛋白尿水平对狼疮性肾炎远期结局的影响


目的 蛋白尿是狼疮性肾炎 （LN） 活性和损伤的标志物。我们旨在探讨基线蛋白尿水平对长期结局的影响。方法 我们纳入了 249 例诊断为首次活检证实的 LN 的患者。我们根据基线蛋白尿将患者分为低水平 （≤1 g/d，第 1 组;62 例患者）、中水平 （>1 和 <3 g/d，第 2 组;90 例患者）和高水平蛋白尿 （≥3 g/d，第 3 组;97 例患者）。结局包括 1 年蛋白尿完全恢复 （CPR）、不良复合结局 （ESKD，eGFR 持续下降 ≥40% 或死亡）和 LN 发作。使用 Cox 比例风险模型检查基线特征与长期结果之间的关联。结果 基线时，中位 [IQR] 年龄为 33.2 [26.4， 42.4] 岁;中位蛋白尿水平为 2.2 [1.0， 3.8] g/d。177 例 （71%） 患者活检有增生性病灶;第 1 组为 59.7%，第 2 组为 78.9%，第 3 组为 71.4%。第 1 组 1 的 CPR 达标率最高，第 3 组最低。对于长期结局（中位随访 8.4 年），第 1 组、第 2 组和第 3 组不良复合结局的频率分别为 27.4% 、 26.7% 和 48.5%;p = 0.003 的。相应的耀斑频率分别为 27.4% 、 38.2% 和 61.9%;p< 0.001.在与长期结局相关的因素的多变量模型中，第 1 组和第 2 组之间没有显著差异;第 3 组与最差的 预测 相关。结论 低水平蛋白尿通常与增殖性 LN 和不良远期结局相关。