Zhao Fang, Bergstralh Eric J, Mehta Ramila A, Vaughan Lisa E, Olson Julie B, Seide Barbara M, Meek Alicia M, Cogal Andrea G, Lieske John C, Milliner Dawn S
Division of Nephrology and Hypertension.
Division of Biostatistics.
Clin J Am Soc Nephrol. 2016 Jan 7;11(1):119-26. doi: 10.2215/CJN.02810315. Epub 2015 Dec 10.
Overproduction of oxalate in patients with primary hyperoxaluria (PH) leads to calcium oxalate deposition in the kidney and ESRD in a substantial number of cases. However, the key determinants for renal outcome remain unclear. Thus, we performed a retrospective analysis to identify predictors for renal outcome among patients with PH participating in the Rare Kidney Stone Consortium (RKSC) PH Registry.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We characterized clinical and laboratory features of patients enrolled in the RKSC PH Registry. We assessed correlation between urinary measures and eGFR at diagnosis by Spearman rank correlation and estimated renal survival using the Kaplan-Meier method. We determined factors associated with renal survival by Cox proportional hazard models.
Of 409 patients enrolled in the RKSC Registry as of March 2014, we excluded 112 patients who had ESRD at PH diagnosis from analysis. Among the remaining 297 patients, 65% had PH type 1, 12% had type 2, 13% had type 3, and 11% had unclassified PH. Median (25th, 75th percentile) age at PH diagnosis was 8.1 (4.0, 18.2) years with an eGFR of 73.0 (56.4, 97.5) ml/min per 1.73 m(2) and urinary oxalate excretion rate of 1.64 (1.11, 2.44) mmol/1.73 m(2) per 24 hours. During a median follow-up of 3.9 (1.0, 12.8) years, 59 (20%) patients developed ESRD. Urinary oxalate excretion at diagnosis stratified by quartile was strongly associated with incident ESRD (hazard ratio [HR], 3.4; 95% confidence interval [95% CI], 1.4 to 7.9). During follow-up there was a significant association between urinary oxalate quartile (Q) and incident ESRD (Q4 versus Q1: HR, 3.3; 95% CI, 1.2 to 9.3). This association remained even when adjusted for sex, age, and baseline eGFR (HR, 4.2; 95% CI, 1.6 to 10.8).
Among patients with PH, higher urinary oxalate excretion is predictive of poor renal outcome.
原发性高草酸尿症（PH）患者草酸过度生成会导致草酸钙在肾脏沉积，在许多病例中会发展为终末期肾病（ESRD）。然而，肾脏预后的关键决定因素仍不明确。因此，我们进行了一项回顾性分析，以确定参与罕见肾结石联盟（RKSC）PH注册研究的PH患者肾脏预后的预测因素。
设计、地点、参与者及测量指标：我们对RKSC PH注册研究中纳入的患者的临床和实验室特征进行了描述。通过Spearman等级相关性评估诊断时尿液指标与估算肾小球滤过率（eGFR）之间的相关性，并使用Kaplan-Meier方法估计肾脏生存率。我们通过Cox比例风险模型确定与肾脏生存相关的因素。
截至2014年3月，在RKSC注册研究中登记的409例患者中，我们将112例在PH诊断时已患有ESRD的患者排除在分析之外。在其余297例患者中，65%为1型PH，12%为2型，13%为3型，11%为未分类的PH。PH诊断时的中位（第25、75百分位数）年龄为8.1（4.0，18.2）岁，eGFR为73.0（56.4，97.5）ml/（min·1.73m²），24小时尿草酸排泄率为1.64（1.11，2.44）mmol/（1.73m²）。在中位随访3.9（1.0，12.8）年期间，59例（20%）患者发展为ESRD。按四分位数分层的诊断时尿草酸排泄与新发ESRD密切相关（风险比[HR]，3.4；95%置信区间[95%CI]，1.4至7.9）。在随访期间，尿草酸四分位数（Q）与新发ESRD之间存在显著关联（Q4与Q1相比：HR，3.3；95%CI，1.2至9.3）。即使在对性别、年龄和基线eGFR进行校正后，这种关联仍然存在（HR，4.2；95%CI，1.6至10.8）。
在PH患者中，较高的尿草酸排泄可预测不良的肾脏预后。
