Hyperkalaemia on admission tied to higher mortality in heart failure
Serum potassium concentrations greater than 5.5 mEq/L at admission is independently correlated with elevated short- and long-term mortality in heart failure (HF) patients, a recent study suggests.
The study included 4,031 heart failure patients, 83 percent (n=3,349) of whom had low-normal potassium levels at admission, 11 percent (n=461) had borderline-high levels and 6 percent (n=221) had hyperkalaemia. Patients without serum potassium measurements at admission were excluded.
Hyperkalaemia patients had significantly higher unadjusted 30-day mortality rates compared with low-normal potassium patients (13 vs 7 percent; p=0.002). However, after adjusting for comorbidities, gender and age, the significant relationship was attenuated (hazard ratio [HR], 1.57; 95 percent CI, 0.73 to 3.35).
According to Kaplan-Meier survival analysis, hyperkalaemia and borderline-high potassium patients had significantly higher rates of 1-year all-cause mortality than those with low-normal potassium (40 vs 34 vs 27 percent, respectively; log rank p<0.01).
Adjusting for comorbidities, age and gender showed that only hyperkalaemia remained significantly related to 1-year mortality risk (HR, 1.51; 1.04 to 2.2), while borderline-high potassium levels did not (HR, 0.79; 0.57 to 1.09).
Ten-year all-cause mortality rates were also significantly higher in patients with hyperkalaemia and borderline-high potassium levels than in those with low-normal potassium levels (92 vs 88 vs 82 percent, respectively; log rank p<0.001). The difference between hyperkalaemia and borderline-high potassium level patients also reached significance (p=0.016).
Similarly, multivariate analysis adjusted for age, gender and comorbidities found that only hyperkalaemia was associated with higher all-cause mortality (HR, 1.31; 1.035 to 1.66; p=0.025), while borderline-high potassium was not (HR, 0.985; 0.83 to 1.16; p=0.86).