Sex and Age Differences in Serum Potassium in the United States

An association between low serum potassium and prolongation of the electrocardiographic QT interval and cardiac arrhythmia has been known for some time (1)(2)(3). High serum potassium has also been found to be independently associated with increased cardiovascular mortality (4). However, population distributions of serum potassium have not been published recently, and as a result, physicians may not appreciate the prevalence of abnormal concentrations in the population. Knowledge of the prevalence of abnormal serum potassium concentrations is important when prescribing diuretics or drugs that are arrhythmogenic in the presence of hypo- or hyperkalemia. This report describes the distribution by age and sex of serum potassium concentrations in the US population and provides data on the prevalence of abnormal concentrations. The National Health and Nutrition Examination Survey (NHANES) is a nationwide probability sample of the noninstitutionalized civilian population of the US. NHANES has been conducted on a periodic basis since the early 1970s. Baseline data collection usually includes a medical history, standardized medical examination, dietary assessment, laboratory tests, and anthropometric measurements. Serum potassium was measured in participants of the third survey (NHANES III), which was performed during the period 1988–1994. Frozen sera were collected and sent for analyses to the CDC. Potassium values were obtained only …