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 veri
fi
ed 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 mineralo-
corticoid 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% con
fi
dence 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 po-
tassium levels are common, and overall levels increase during hospitalization. In conclu-
sion, potassium levels at admission or its change during hospitalization are not associated
with mortality after multivariate adjustment.