ABSTRACT
Cardiae ACE INHIBITORS HYPERKALEM IA
In a two year retrospective case-control study, 1818 internal medicine outpatients taking ACE inhibitors were evaluated to identify the frequency and risk factors for hypokalemia. Control patients had potassium levels lower than 5.0 mmol/L. Approximately 194 case patients (11%) were identified as hyperkalemic (5.1 mmol/L). When compared to controls, the case patients had a significantly higher baseline mean serum urea nitrogen (8.0 mmol/L vs 6.2 mmol/L), and baseline mean creatinine (1.3 mg/dL vs 1.1 mg/dL). Longacting ACE inhibitors (lisinopril and enalapril) were more frequently used in hyperkalemic patients (91% vs 83%). Congestive heart failure, peripheral vascular disease, and cerebrovascular disease were also more common in the case group. Hypertension, diabetes, the use of potassium supplements, and age were not significantly different between the two groups. A decreased risk of hyperkalemia was associated with concurrent use of loop or thiazide diuretics. Follow-up data, available for 88% (171/194) of the cases, revealed no signifi cant differences in mean maximum potassium levels with increased, decreased, unchanged, or discontinued ACE inhibitor doses. Elevated serum nitrogen or creatinine levels, increased glucose levels (190 mg/dL) and advanced age (70 years) were associated with an increased risk of hyperkalemia during follow up. A serum bicarbonate level higher than 28 mmol/L was also associated with a reduced risk of hyperkalemia.
