ABSTRACT
BACKGROUND: Abnormal serum potassium levels (K+) in patients with heart failure (HF) relate to worse prognosis. We evaluated whether admission K+ levels predict 1-year outcomes in elderly patients admitted for acute HF. METHODS: We evaluated 2865 patients aged >74â¯years from the RICA Spanish Heart Failure Registry, classified according to admission serum K+ levels: hyperkalemia (>5.5â¯mmol/L), normokalemia (3.5-5.5â¯mmol/L) and hypokalemia (<3.5â¯mmol/L). We explored whether K+ levels were significantly associated with one-year all-cause mortality or hospital readmission and their combination. RESULTS: Mean admission K+ value was 4.3⯱â¯0.6â¯mmol/L; 97 patients (3.38%) presented with hyperkalemia and 174 (6.06%) with hypokalemia. Overall, 43% of the patients died or were readmitted for HF during the follow-up period; the risk was higher for those with hyperkalemia (59% vs 41% in hypokalemic patients). The HR for one-year mortality was 1.43 (pâ¯=â¯.073) and 1.67 for readmissions (pâ¯=â¯.007) when K+ was >5.5â¯mmol/L and 1.08 (pâ¯=â¯.618) and 0.90 (pâ¯=â¯.533) respectively for K+â¯<â¯3.5â¯mmol/L. The HR for the combined outcome was 1.59 (1.19-2.13); pâ¯=â¯.002 in hyperkalemic patients and 0.96 (0.75-1.23); pâ¯=â¯.751in hypokalemic patients. Multivariate analysis showed a significant association of admission K+ values >5.5â¯mmol/L with the combined outcome of mortality and readmission (HR 1.15 [95% CI 1.04-1.27], pâ¯=â¯.008). CONCLUSION: In patients hospitalized for decompensated HF, admission hyperkalemia predicts a higher mid-term risk for HF readmission and mortality, probably related to the significant higher risk of readmission.