Serum Potassium Levels and Outcome in Acute Heart Failure (Data from the PROTECT and COACH Trials)
Jasper Tromp1, Jozine M Ter Maaten1, Kevin Damman1
1Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
Insights
High serum potassium in acute heart failure patients is linked to poorer kidney function but better diuretic response. Potassium levels often rise during hospitalization but are not tied to mortality after adjustments.
Area of Science:
- Cardiology
- Nephrology
- Clinical Medicine
Background:
- Serum potassium is routinely measured in acute heart failure (AHF) patients.
- Limited data exists on potassium's association with clinical variables and prognosis in AHF.
Purpose of the Study:
- To investigate the association between serum potassium levels at admission and clinical variables, renal function, and prognosis in AHF.
- To analyze the impact of potassium level changes during hospitalization on outcomes.
Main Methods:
- Retrospective analysis of 1,867 AHF patients from the original "Patients Hospitalized with acute heart failure and Volume Overload to Assess Treatment Effect on Congestion and Renal FuncTion" trial cohort.
- Patients categorized into low (<3.5 mEq/l), normal (3.5-5.0 mEq/l), and high (>5.0 mEq/l) potassium groups.
- Results validated in an independent cohort of 1,023 patients; 180-day mortality assessed.
Main Results:
- High admission potassium was associated with impaired baseline renal function and a better diuretic response.
- Potassium levels increased during hospitalization (mean increase 0.18 ± 0.69 mEq/l).
- Admission potassium levels showed a univariate association with mortality, but this was not significant after multivariate adjustment. Changes in potassium or discharge levels were not associated with outcomes.
Conclusions:
- High admission serum potassium in AHF patients correlates with impaired renal function and improved diuretic response.
- While potassium levels can change during hospitalization, neither admission levels nor changes are independently associated with mortality in AHF.
- Routine potassium monitoring in AHF requires careful interpretation considering renal function and diuretic response.
Abstract:
Serum potassium is routinely measured at admission for acute heart failure (AHF), but information on association with clinical variables and prognosis is limited. Potassium measurements at admission were available in 1,867 patients with AHF in the original cohort of 2,033 patients included in the Patients Hospitalized with acute heart failure and Volume Overload to Assess Treatment Effect on Congestion and Renal FuncTion trial. Patients were grouped according to low potassium (<3.5 mEq/l), normal potassium (3.5 to 5.0 mEq/l), and high potassium (>5.0 mEq/l) levels. Results were verified in a validation cohort of 1,023 patients. Mean age of patients was 71 ± 11 years, and 66% were men. Low potassium was present in 115 patients (6%), normal potassium in 1,576 (84%), and high potassium in 176 (9%). Potassium levels increased during hospitalization (0.18 ± 0.69 mEq/l). Patients with high potassium more often used angiotensin-converting enzyme inhibitors and mineralocorticoid receptor antagonists before admission, had impaired baseline renal function and a better diuretic response (p = 0.005), independent of mineralocorticoid receptor antagonist usage. During 180-day follow-up, a total of 330 patients (18%) died. Potassium levels at admission showed a univariate linear association with mortality (hazard ratio [log] 2.36, 95% confidence interval 1.07 to 5.23; p = 0.034) but not after multivariate adjustment. Changes of potassium levels during hospitalization or potassium levels at discharge were not associated with outcome after multivariate analysis. Results in the validation cohort were similar to the index cohort. In conclusion, high potassium levels at admission are associated with an impaired renal function but a better diuretic response. Changes in potassium levels are common, and overall levels increase during hospitalization. In conclusion, potassium levels at admission or its change during hospitalization are not associated with mortality after multivariate adjustment.
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