Characteristics of study cohort.

Background
We sought to evaluate the long-term effects of COVID-19 on renal function in patients with biopsy-proven kidney diseases.
Methods
A total of 451 patients with biopsy-proven kidney disease and at least 12 months of follow-up subsequent to COVID-19 pandemic onset were included in the study. The primary study endpoint was a composite of a persistent decline of more than 30% in eGFR or ESRD.
Results
23.1% of patients had COVID-19 during a follow-up period of 2.5 y (0.8–2.6), while 17.6% of patients reached the composite endpoint. Those with COVID-19 were more likely to reach the composite endpoint [26.7% vs. 14.8%; OR, 2.1 (95%CI, 1.23–3.58), p = 0.006). There was a significant eGFR change in the first year of follow-up between the two study groups [-2.24 (95%CI,-4.86; 0.37) vs. +2.31 (95%CI, 0.78; 3.85) ml/min, p = 0.004], with an adjusted mean difference of -4.68 ml/min (95%CI,-7.7; -1.59)(p = 0.03). The trend for worse renal outcomes remained consistent in patients with IgAN, MN and FSGS, but not in those with LN. After multivariate adjustment, the independent predictors of the composite endpoint were baseline eGFR (HR, 0.94; 95%CI, 0.92–0.95), COVID-19 (HR, 1.91; 1.16–3.12) and male gender (HR, 1.64; 95%CI, 1.01–2.66). In multivariate linear regression analysis, COVID-19 independently determined a reduction of eGFR at 12 months by 4.62 ml/min/1.73m2 (β coefficient, -4.62; 95%CI, -7.74 to -1.5, p = 0.004).
Conclusions
There is a significant impact of COVID-19 on long-term renal function in patients with biopsy-proven kidney diseases, leading to a greater decline of eGFR and a worse renal survival.

背景
本研究旨在评估新型冠状病毒肺炎（COVID-19）对经活检证实的肾脏疾病患者肾功能的长期影响。

方法
本研究共纳入451例经活检证实的肾脏疾病患者，且这些患者在新型冠状病毒肺炎大流行暴发后至少接受了12个月的随访。本研究的主要终点为估算肾小球滤过率（estimated glomerular filtration rate, eGFR）持续下降超过30%或进展为终末期肾病（end-stage renal disease, ESRD）的复合终点。

结果
在2.5年（四分位距0.8~2.6）的随访期间，23.1%的患者感染了新型冠状病毒肺炎，另有17.6%的患者达到了复合终点。感染新冠病毒的患者更易达到复合终点（26.7% vs. 14.8%；比值比（odds ratio, OR）=2.1，95%置信区间（95% confidence interval, 95%CI）：1.23~3.58，P=0.006）。两组患者在随访第一年的估算肾小球滤过率变化存在显著差异[-2.24（95%CI：-4.86~0.37）ml/min vs. +2.31（95%CI：0.78~3.85）ml/min，P=0.004]，校正后的平均差值为-4.68 ml/min（95%CI：-7.7~-1.59，P=0.03）。在IgA肾病（IgA nephropathy, IgAN）、膜性肾病（membranous nephropathy, MN）及局灶节段性肾小球硬化（focal segmental glomerulosclerosis, FSGS）患者中，不良肾脏预后的趋势保持一致，但在狼疮性肾炎（lupus nephritis, LN）患者中未观察到此趋势。经多变量校正后，复合终点的独立预测因素为基线估算肾小球滤过率（风险比（hazard ratio, HR）=0.94，95%CI：0.92~0.95）、新型冠状病毒肺炎感染（HR=1.91，95%CI：1.16~3.12）及男性性别（HR=1.64，95%CI：1.01~2.66）。多变量线性回归分析显示，新型冠状病毒肺炎感染可独立导致12个月时的估算肾小球滤过率降低4.62 ml/min/1.73m²（β系数=-4.62，95%CI：-7.74~-1.5，P=0.004）。

结论
新型冠状病毒肺炎对经活检证实的肾脏疾病患者的长期肾功能存在显著不良影响，可导致估算肾小球滤过率下降幅度更大，肾脏生存率更低。