Nephrology Unit, Advanced Surgical and Medical Sciences Department of University of Campania "Luigi Vanvitelli", Piazza Miraglia, 80137 Naples, Italy.
Nephrology Unit, Department of Health Sciences, "Magna Grecia" University, 88100 Catanzaro, Italy.
Int J Mol Sci. 2020 Jul 3;21(13):4744. doi: 10.3390/ijms21134744.
In Chronic Kidney Disease (CKD) patients, elevated blood pressure (BP) is a frequent finding and is traditionally considered a direct consequence of their sodium sensitivity. Indeed, sodium and fluid retention, causing hypervolemia, leads to the development of hypertension in CKD. On the other hand, in non-dialysis CKD patients, salt restriction reduces BP levels and enhances anti-proteinuric effect of renin-angiotensin-aldosterone system inhibitors in non-dialysis CKD patients. However, studies on the long-term effect of low salt diet (LSD) on cardio-renal prognosis showed controversial findings. The negative results might be the consequence of measurement bias (spot urine and/or single measurement), reverse epidemiology, as well as poor adherence to diet. In end-stage kidney disease (ESKD), dialysis remains the only effective means to remove dietary sodium intake. The mismatch between intake and removal of sodium leads to fluid overload, hypertension and left ventricular hypertrophy, therefore worsening the prognosis of ESKD patients. This imposes the implementation of a LSD in these patients, irrespective of the lack of trials proving the efficacy of this measure in these patients. LSD is, therefore, a rational and basic tool to correct fluid overload and hypertension in all CKD stages. The implementation of LSD should be personalized, similarly to diuretic treatment, keeping into account the volume status and true burden of hypertension evaluated by ambulatory BP monitoring.
在慢性肾脏病（CKD）患者中，血压升高是一种常见现象，传统上被认为是其钠敏感性的直接后果。事实上，钠和液体潴留导致血容量增加，从而导致 CKD 患者发生高血压。另一方面，在非透析 CKD 患者中，盐限制降低血压水平，并增强非透析 CKD 患者肾素-血管紧张素-醛固酮系统抑制剂的抗蛋白尿作用。然而，关于低盐饮食（LSD）对心脏肾脏预后的长期影响的研究结果存在争议。负面结果可能是由于测量偏差（随机尿和/或单次测量）、反向流行病学以及饮食依从性差所致。在终末期肾脏病（ESKD）中，透析仍然是去除饮食钠摄入的唯一有效手段。钠的摄入和清除之间的不匹配会导致液体超负荷、高血压和左心室肥厚，从而恶化 ESKD 患者的预后。这就要求在这些患者中实施 LSD，尽管缺乏证明该措施在这些患者中有效的确切试验。因此，LSD 是纠正所有 CKD 阶段液体超负荷和高血压的合理且基本的工具。实施 LSD 应个体化，类似于利尿剂治疗，要考虑到通过动态血压监测评估的容量状态和真正的高血压负担。
