Dimitriadis Chrysostomos, Sekercioglu Nigar, Pipili Chrysoula, Oreopoulos Dimitrios, Bargman Joanne M
The Home Peritoneal Dialysis Unit, University Health Network and University of Toronto, Toronto, Ontario, Canada.
Perit Dial Int. 2014 May;34(3):260-70. doi: 10.3747/pdi.2012.00095. Epub 2013 May 1.
Hyponatremia in peritoneal dialysis (PD) patients has previously been associated with water overload and weight gain, or with malnutrition and intracellular potassium depletion. Although there is a sizable literature about transmembrane sodium and water removal in PD, there are few reports about the incidence and characteristics of hyponatremia in the clinical setting.
We evaluated the incidence and factors associated with hyponatremia in PD patients in a single PD unit.
We retrospectively evaluated the records of all patients (n = 198) who were treated with PD in the Home PD Unit of the University Health Network at Toronto General Hospital during 2010. We identified 166 patients who had a minimum follow-up of 60 days during 2010 and at least 2 consecutive sodium measurements at least a month apart. We examined baseline differences between patients who developed hyponatremia and those who did not, and clinical and biochemical factors that correlated with mean sodium values. In the 24 patients who developed hyponatremia, we examined paired differences between the normonatremic and hyponatremic periods. Finally, we investigated any possible correlations of change in serum sodium with clinical and biochemical characteristics before and during the hyponatremic period.
The incidence of hyponatremia was 14.5%. In multivariate analysis, serum sodium correlated significantly and independently with residual renal function (RRF: r = 0.463, p = 0.0001) and negatively with the daily volume of instilled icodextrin (r = -0.476, p = 0.0001). Residual renal function was significantly lower in patients with hyponatremia than in those with normal serum sodium (1.97 ± 2.3 mL/min vs 4.31 ± 5.01 mL/min, p = 0.033). The mean paired difference in body weight was -1.113 kg and the median difference was -0.55 kg (range: -8.5 kg to +4.2 kg). Impressively, hyponatremia was not associated with an increase in body weight in most patients who developed this complication (13 of 16 for whom comparative weights were known). Moreover, the mean paired change in serum sodium (ΔNa) from normonatremia to hyponatremia was, contrary to our expectations, significantly correlated with a decrease in body weight (r = 0.584, p = 0.017). The ΔNa was also significantly correlated with serum potassium (r = 0.526, p = 0.008), the greatest drop in serum sodium being associated with lower serum potassium in the hyponatremic period, as predicted.
Hyponatremia is seen more often than expected in a clinical setting. Serum sodium is strongly correlated with RRF, hyponatremia being associated with lower RRF. In patients who experienced hyponatremia, the fall in serum sodium was associated with a decrease, not an increase, in body weight and was correlated with serum potassium, suggesting that sodium and potassium depletion-and, by inference, malnutrition-may be important contributors in the clinical setting.
腹膜透析（PD）患者的低钠血症此前一直与水负荷过重和体重增加，或与营养不良及细胞内钾缺乏有关。尽管有大量关于PD中跨膜钠和水清除的文献，但关于临床环境中低钠血症的发生率和特征的报道却很少。
我们评估了单一PD治疗单元中PD患者低钠血症的发生率及相关因素。
我们回顾性评估了2010年在多伦多综合医院大学健康网络家庭PD治疗单元接受PD治疗的所有患者（n = 198）的记录。我们确定了166例在2010年至少随访60天且至少相隔一个月进行至少2次连续钠测量的患者。我们检查了发生低钠血症的患者与未发生低钠血症患者之间的基线差异，以及与平均钠值相关的临床和生化因素。在24例发生低钠血症的患者中，我们检查了正常血钠期与低钠血症期之间的配对差异。最后，我们研究了低钠血症期前后血清钠变化与临床和生化特征之间的任何可能相关性。
低钠血症的发生率为14.5%。在多变量分析中，血清钠与残余肾功能显著且独立相关（RRF：r = 0.463，p = 0.0001），与每日注入艾考糊精的量呈负相关（r = -0.476，p = 0.0001）。低钠血症患者的残余肾功能显著低于血钠正常的患者（1.97 ± 2.3 mL/分钟对4.31 ± 5.01 mL/分钟，p = 0.033）。体重的平均配对差异为-1.113 kg，中位数差异为-0.55 kg（范围：-8.5 kg至+4.2 kg）。令人印象深刻的是，在大多数发生这种并发症的患者中（已知比较体重的16例中有13例），低钠血症与体重增加无关。此外，与我们的预期相反，从正常血钠到低钠血症的血清钠平均配对变化（ΔNa）与体重减轻显著相关（r = 0.584，p = 0.017）。ΔNa也与血清钾显著相关（r = 0.526，p = 0.008），如预期的那样，低钠血症期血清钠下降幅度最大与较低的血清钾相关。
在临床环境中，低钠血症的出现比预期更频繁。血清钠与残余肾功能密切相关（RRF），低钠血症与较低的RRF相关。在经历低钠血症的患者中，血清钠的下降与体重减轻而非增加相关，并且与血清钾相关，这表明钠和钾缺乏——以及由此推断的营养不良——可能是临床环境中的重要因素。
