Yusuf Akeem A, Hu Yan, Singh Bhupinder, Menoyo José A, Wetmore James B
Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minn., USA.
Am J Nephrol. 2016;44(3):179-86. doi: 10.1159/000448341. Epub 2016 Sep 3.
Hyperkalemia is common in patients receiving maintenance hemodialysis. However, few studies have examined the association between serum potassium level and mortality.
This study used annual cohorts of hemodialysis patients during 2007-2010. To determine hyperkalemia prevalence, monthly hyperkalemia was defined as serum potassium level ≥5.5 mEq/l; prevalence was calculated as a ratio of hyperkalemia episodes to follow-up time, reported separately by long and short interdialytic interval. To determine the impact of hyperkalemia on mortality, patients in the 2010 cohort were followed from first potassium measurement until death or a censoring event; hyperkalemia was defined, sequentially, by potassium levels 5.5-6.0 mEq/l at 0.1 mEq/l intervals. Time-dependent Cox proportional hazards modeling was used to estimate the association between hyperkalemia and mortality.
The 4 annual cohorts ranged from 28,774 to 36,888 patients. Mean age was approximately 63 years, about 56% were men, 51% were white and 44% had end-stage renal disease caused by diabetes. Hyperkalemia prevalence was consistently estimated at 16.3-16.8 events per 100 patient-months. Prevalence on the day after the long interdialytic interval was 2.0-2.4 times as high as on the day after the short interval. Hyperkalemia, when defined as serum potassium ≥5.7 mEq/l, was associated with all-cause mortality (adjusted hazards ratio (AHR) 1.13, 95% CI 1.01-1.28, p = 0.037, vs. <5.7 mEq/l) after adjustment. AHRs increased progressively as the hyperkalemia threshold increased, reaching 1.37 (95% CI 1.16-1.62, p < 0.0001) for ≥6.0 mEq/l.
The long interdialytic interval was associated with increased likelihood of hyperkalemia. Hyperkalemia was associated with all-cause mortality beginning at serum potassium ≥5.7 mEq/l; mortality risk estimates increased ordinally through ≥6.0 mEq/l, suggesting a threshold at which serum potassium becomes substantially more dangerous.
高钾血症在接受维持性血液透析的患者中很常见。然而，很少有研究探讨血清钾水平与死亡率之间的关联。
本研究使用了2007 - 2010年期间血液透析患者的年度队列。为确定高钾血症患病率，每月高钾血症定义为血清钾水平≥5.5 mEq/L；患病率计算为高钾血症发作次数与随访时间的比值，按长透析间期和短透析间期分别报告。为确定高钾血症对死亡率的影响，对2010年队列中的患者从首次测量血钾开始随访至死亡或截尾事件；高钾血症依次按血钾水平5.5 - 6.0 mEq/L，以0.1 mEq/L的间隔进行定义。采用时间依赖性Cox比例风险模型来估计高钾血症与死亡率之间的关联。
4个年度队列的患者人数在28,774至36,888之间。平均年龄约为63岁，约56%为男性，51%为白人，44%患有糖尿病所致的终末期肾病。高钾血症患病率持续估计为每100患者月16.3 - 16.8次发作。长透析间期后一天的患病率是短透析间期后一天的2.0 - 2.4倍。当高钾血症定义为血清钾≥5.7 mEq/L时，调整后与全因死亡率相关（调整后风险比[AHR] 1.13，95%可信区间1.01 - 1.28，p = 0.037，与<5.7 mEq/L相比）。随着高钾血症阈值升高，AHR逐渐增加，血钾≥6.0 mEq/L时达到1.37（95%可信区间1.16 - 1.62，p < 0.0001）。
长透析间期与高钾血症发生可能性增加相关。高钾血症从血清钾≥5.7 mEq/L开始与全因死亡率相关；死亡率风险估计值通过≥6.0 mEq/L依次增加，提示血清钾达到某一阈值时会变得更加危险。
