dress if a low urine acid/base score can be improved and if this translates into clinically meaningful effects. Background Acidosis is associated with exacerbated loss of kidney function in CKD. Currently, acid/base status is assessed by plasma measures, although organ-damaging covert acidosis, subclinical acidosis, may be present before reflected in plasma. Low urine NH4+ excretion associates with poor kidney outcomes in CKD and is proposed as a marker for subclinical acidosis. However, low NH4+ excretion could result from either a low capacity or a low demand for acid excretion. We hypothesized that a urine acid/base score reflecting both the demand and capacity for acid excretion would better predict CKD progression. Methods Twenty-four–hour urine collections were included from three clinical studies of patients with CKD stage 3 and 4: a development cohort (N=82), a variation cohort (N=58), and a validation cohort (N=73). A urine acid/base score was derived and calculated from urinary pH and [NH4+]. Subclinical acidosis was defined as an acid/base score below the lower limit of the 95% prediction interval of healthy controls. The main outcomes were change in measured GFR after 18 months and CKD progression (defined as ≥50% decline in eGFR, initiation of long-term dialysis, or kidney transplantation) during up to 10 years of follow-up. Results Subclinical acidosis was prevalent in all cohorts (n=54/82, 48/73, and 40/58, respectively, approximately 67%). Subclinical acidosis was associated with an 18% (95% confidence interval [CI], 2 to 32) larger decrease of measured GFR after 18 months. During a median follow-up of 6 years, subclinical acidosis was associated with a higher risk of CKD progression. Adjusted hazard ratios were 9.88 (95% CI, 1.27 to 76.7) in the development cohort and 11.1 (95% CI, 2.88 to 42.5) in the validation cohort. The acid/base score had a higher predictive value for CKD progression than NH4+ excretion alone. Conclusions Subclinical acidosis, defined by a new urine acid/base score, was associated with a higher risk of CKD progression in patients with CKD stage 3 and 4....

中文翻译：

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A 尿液 pH-铵态氮酸/碱评分和 CKD 进展


如果可以改善低尿酸/尿碱评分，以及这是否转化为具有临床意义的效果，请着装。背景 酸中毒与 CKD 患者肾功能丧失加剧有关。目前，酸/碱状态是通过血浆测量评估的，尽管器官损伤性隐性酸中毒，亚临床酸中毒，可能在反映在血浆之前存在。尿 NH4 + 排泄量低与 CKD 患者的不良肾脏结局相关，并被提议作为亚临床酸中毒的标志物。然而，低 NH4+ 排泄可能是由于低容量或对酸排泄的需求低造成的。我们假设反映酸排泄需求和能力的尿酸/碱评分可以更好地预测 CKD 进展。方法 纳入来自 CKD 3 期和 4 期患者的 3 项临床研究的 24 小时尿液收集： 开发队列 （N=82） 、变异队列 （N=58） 和验证队列 （N=73）。根据尿 pH 值和 [NH4+] 得出并计算尿酸/碱评分。亚临床酸中毒定义为酸/碱评分低于健康对照者 95% 预测区间的下限。主要结局是 18 个月后测得的 GFR 的变化和长达 10 年的随访期间 CKD 进展 （定义为 eGFR 下降 ≥50%、开始长期透析或肾移植）。结果 亚临床酸中毒在所有队列中均普遍存在 （n=54/82 、 48/73 和 40/58，分别约为 67%）。亚临床酸中毒与 18 个月后测得的 GFR 降低 18% （95% 置信区间 [CI]，2 至 32） 相关。在中位随访 6 年期间，亚临床酸中毒与 CKD 进展风险较高相关。调整后的风险比为 9.88 （95% CI，1.27 至 76。7） 在开发队列中，在验证队列中为 11.1 （95% CI，2.88 至 42.5）。酸/碱评分对 CKD 进展的预测价值高于单独的 NH4+ 排泄。结论 亚临床酸中毒（由新的尿酸/碱评分定义）与 CKD 3 期和 4 期患者 CKD 进展风险升高相关。