Hyperkalemia in hospitalized patients.

OBJECTIVE

Evaluate the prevalence of hyperkalemia (potassium > 5.5 mmol/l) in hospitalized patients not on dialysis, as well as the association of medications, impaired renal function and comorbid conditions with hyperkalemia.

DESIGN

A retrospective case-control method.

SETTING

A tertiary care teaching hospital.

PATIENTS

Hyperkalemic adults not on dialysis with age and sex matched controls.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The use of medications associated with hyperkalemia and renal function using a calculated creatinine clearance were compared in the hyperkalemic and control groups.

RESULTS

35 adult patients with hyperkalemia who were not receiving dialysis were identified, with a prevalence in the hospitalized population of 3.3%. The hyperkalemic patients were older than the general hospital population (p < 0.05). Compared with controls, hyperkalemic patients: had a lower creatinine clearance (p < 0.05), were more likely to be taking angiotensin-converting enzyme inhibitors (p < 0.05), and had an increased frequency of diabetes mellitus (p < 0.001). All of the control patients survived their hospitalization, but the mortality rate in the hyperkalemic group was 17% (p < 0.0001). None of the deaths were directly attributable to hyperkalemia.

CONCLUSIONS

Hyperkalemia is more frequent in older patients and is usually mild. Hyperkalemia is associated with diabetes mellitus, diminished renal function and the use of angiotensin-converting enzyme inhibitors. An elevated serum potassium level in a hospitalized patient may be a marker for a significantly increased risk of death, which is due to underlying medical problems and is not a consequence of the hyperkalemia.