Department of Medicine, Emory School of Medicine, Atlanta, GA 30322, USA.
JAMA. 2012 Jan 11;307(2):157-64. doi: 10.1001/jama.2011.1967.
Clinical practice guidelines recommend maintaining serum potassium levels between 4.0 and 5.0 mEq/L in patients with acute myocardial infarction (AMI). These guidelines are based on small studies that associated low potassium levels with ventricular arrhythmias in the pre-β-blocker and prereperfusion era. Current studies examining the relationship between potassium levels and mortality in AMI patients are lacking.
To determine the relationship between serum potassium levels and in-hospital mortality in AMI patients in the era of β-blocker and reperfusion therapy.
DESIGN, SETTING, AND PATIENTS: Retrospective cohort study using the Cerner Health Facts database, which included 38,689 patients with biomarker-confirmed AMI, admitted to 67 US hospitals between January 1, 2000, and December 31, 2008. All patients had in-hospital serum potassium measurements and were categorized by mean postadmission serum potassium level (<3.0, 3.0-<3.5, 3.5-<4.0, 4.0-<4.5, 4.5-<5.0, 5.0-<5.5, and ≥5.5 mEq/L). Hierarchical logistic regression was used to determine the association between potassium levels and outcomes after adjusting for patient- and hospital-level factors.
All-cause in-hospital mortality and the composite of ventricular fibrillation or cardiac arrest.
There was a U-shaped relationship between mean postadmission serum potassium level and in-hospital mortality that persisted after multivariable adjustment. Compared with the reference group of 3.5 to less than 4.0 mEq/L (mortality rate, 4.8%; 95% CI, 4.4%-5.2%), mortality was comparable for mean postadmission potassium of 4.0 to less than 4.5 mEq/L (5.0%; 95% CI, 4.7%-5.3%), multivariable-adjusted odds ratio (OR), 1.19 (95% CI, 1.04-1.36). Mortality was twice as great for potassium of 4.5 to less than 5.0 mEq/L (10.0%; 95% CI, 9.1%-10.9%; multivariable-adjusted OR, 1.99; 95% CI, 1.68-2.36), and even greater for higher potassium strata. Similarly, mortality rates were higher for potassium levels of less than 3.5 mEq/L. In contrast, rates of ventricular fibrillation or cardiac arrest were higher only among patients with potassium levels of less than 3.0 mEq/L and at levels of 5.0 mEq/L or greater.
Among inpatients with AMI, the lowest mortality was observed in those with postadmission serum potassium levels between 3.5 and <4.5 mEq/L compared with those who had higher or lower potassium levels.
临床实践指南建议急性心肌梗死（AMI）患者的血清钾水平维持在 4.0 至 5.0 mEq/L 之间。这些指南基于小样本研究，这些研究表明在β受体阻滞剂和再灌注前时代低钾血症与室性心律失常有关。目前缺乏研究检查 AMI 患者血钾水平与死亡率之间的关系。
确定在接受β受体阻滞剂和再灌注治疗的 AMI 患者中，血清钾水平与院内死亡率之间的关系。
设计、地点和患者：使用 Cerner Health Facts 数据库进行回顾性队列研究，该数据库包括 2000 年 1 月 1 日至 2008 年 12 月 31 日期间 67 家美国医院收治的 38689 名生物标志物确诊的 AMI 患者。所有患者均有院内血清钾测量值，并根据入院后平均血清钾水平进行分类（<3.0、3.0-<3.5、3.5-<4.0、4.0-<4.5、4.5-<5.0、5.0-<5.5 和≥5.5 mEq/L）。使用分层逻辑回归确定在调整患者和医院水平因素后钾水平与结局之间的关联。
全因院内死亡率和室性颤动或心脏骤停的复合终点。
入院后平均血清钾水平与院内死亡率之间呈 U 型关系，即使在多变量调整后仍保持不变。与 3.5 至<4.0 mEq/L 的参考组（死亡率，4.8%；95%CI，4.4%-5.2%）相比，4.0 至<4.5 mEq/L 的平均入院后钾水平死亡率相当（5.0%；95%CI，4.7%-5.3%），多变量调整后的比值比（OR）为 1.19（95%CI，1.04-1.36）。钾水平为 4.5 至<5.0 mEq/L 时，死亡率是前者的两倍（10.0%；95%CI，9.1%-10.9%；多变量调整后的 OR，1.99；95%CI，1.68-2.36），而更高的钾水平死亡率更高。同样，钾水平<3.5 mEq/L 时的死亡率也更高。相比之下，钾水平<3.0 mEq/L 和 5.0 mEq/L 或更高水平的患者中，室性颤动或心脏骤停的发生率更高。
在患有 AMI 的住院患者中，与血钾水平较高或较低的患者相比，入院后血清钾水平在 3.5 至<4.5 mEq/L 之间的患者死亡率最低。
