Serum potassium and cardiovascular mortality.
BACKGROUND
The impact of serum potassium on mortality is inadequately defined.


OBJECTIVE
To determine the association of serum potassium with mortality.


METHODS
We analyzed NHANES I Epidemiological Follow-up Study data from 1974-1992. Of 2,992 subjects with baseline serum potassium, 156 were excluded because their vital status was not known. A total of 2,836 subjects with serum potassium within 2.7-5.4 mmol/L were studied. All-cause and cardiovascular mortality were assessed controlling for sociodemographic status, smoking, medical history, and clinical characteristics.


RESULTS
At baseline, mean age was 46.6 years, and mean serum potassium was 4.07 mmol/L. Subjects were stratified into three groups by mean +/-1 standard deviation of serum potassium: low, 2.7-3.7 mmol/L (N = 477); middle, 3.8-4.4 mmol/L (N = 1,982); and high, 4.5-5.4 mmol/L (N = 377). The cardiovascular mortality rate per 1,000 person-years adjusted for age, gender, and race for the high serum potassium group (8.1) was significantly higher than the middle (5.3) and low (6.5) serum potassium groups. Further analysis, controlling for age, gender, race, smoking status, cholesterol, and history of diabetes, renal disease, and cardiovascular disease, revealed that the increased cardiovascular mortality among subjects with moderately increased serum potassium was most prominent in those reporting use of diuretics (hazard ratio, 2.65; 95% confidence interval [95% CI], 1.20 to 5.85) and those with abnormal renal function (hazard ratio, 1.89; 95% CI, 1.05 to 3.41).


CONCLUSIONS
In this general population sample with mostly normal serum potassium, higher serum potassium was independently associated with increased cardiovascular mortality.
Fang
J
J
Department of Epidemiology and Social Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA. fang@aecom.yu.edu
Madhavan
S
S
Cohen
H
H
Alderman
M H
MH
D002318:Cardiovascular Diseases / Q000097:blood* / Q000401:mortality*; D002423:Cause of Death; D004232:Diuretics / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007674:Kidney Diseases / Q000401:mortality; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000401:mortality; D009369:Neoplasms / Q000097:blood / Q000401:mortality; D011188:Potassium / Q000097:blood*; D016016:Proportional Hazards Models; D012306:Risk; D012307:Risk Factors; D012494:Sampling Studies; D020521:Stroke / Q000097:blood / Q000401:mortality; D014481:United States / Q000453:epidemiology
D004232:Diuretics; D011188:Potassium