Hsieh Ming-Fang, Wu I-Wen, Lee Chin-Chan, Wang Shun-Yin, Wu Mai-Szu
Department of Nephrology, Chang Gung Memorial Hospital at Keelung, Chang Gung University College of Medicine, Taoyuan, Taiwan.
Chang Gung Med J. 2011 Jul-Aug;34(4):418-25.
The serum potassium (K+) level is kept in a narrow range to sustain normal physiology within the human body by the kidneys. The serum K+ level in different stages of chronic kidney disease (CKD) remains undefined.
We conducted a cross-sectional study to observe the serum K+ level in patients without clinical manifestations of hyperkalemia in the late stages of CKD (stages 3-5). A total of 531 patients with late stage CKD were included and followed up for at least 1 year, from March 2006 to May 2007. The patients were sub-grouped by stages of CKD, which were determined by a "Modification of Diet in Renal Disease" equation estimating the glomerular filtration rate (eGFR). The serum creatinine, eGFR and K+ levels were recorded at least twice during the study. We analyzed the average K+ level in these late-stage CKD patients.
The average K+ level increased along with renal function deterioration in the late stages of CKD (stage 3: 4.36 ± 0.49; stage 4: 4.50 ± 0.55; stage 5: 4.69 ± 0.73 mEq/L, p < 0.05). Men and patients with diabetes mellitus, a low eGFR, and a low hemoglobin might have higher levels of serum K+. We also noticed that there was a linear increase in the standard deviation of the serum K+ level as renal function deteriorated. The use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers was not associated with hyperkalemia in our patients.
Our results reflected that the serum K+ level increased in correlation with the decline in the eGFR in the late stages of CKD. Also, male gender, diabetes mellitus, and anemia might be risk factors for higher K+ levels in CKD patients. The variation in the serum K+ level became wider as renal failure progressed.
血清钾（K+）水平通过肾脏维持在一个狭窄范围内，以维持人体正常生理功能。慢性肾脏病（CKD）不同阶段的血清K+水平尚不明确。
我们进行了一项横断面研究，以观察CKD晚期（3 - 5期）无高钾血症临床表现患者的血清K+水平。2006年3月至2007年5月，共纳入531例CKD晚期患者并随访至少1年。患者根据CKD分期进行亚组划分，分期由估算肾小球滤过率（eGFR）的“肾脏病饮食改良”公式确定。研究期间至少记录两次血清肌酐、eGFR和K+水平。我们分析了这些CKD晚期患者的平均K+水平。
CKD晚期患者的平均K+水平随肾功能恶化而升高（3期：4.36±0.49；4期：4.50±0.55；5期：4.69±0.73 mEq/L，p<0.05）。男性、糖尿病患者、eGFR低和血红蛋白低者的血清K+水平可能更高。我们还注意到，随着肾功能恶化，血清K+水平的标准差呈线性增加。在我们的患者中，使用血管紧张素转换酶抑制剂和血管紧张素II受体阻滞剂与高钾血症无关。
我们的结果表明，CKD晚期血清K+水平的升高与eGFR的下降相关。此外，男性、糖尿病和贫血可能是CKD患者K+水平升高的危险因素。随着肾衰竭进展，血清K+水平的变化范围变宽。
