Racial differences in patients' potassium concentrations during spironolactone therapy for heart failure.
OBJECTIVE
To determine whether the effects of spironolactone on potassium homeostasis vary by race by comparing serum potassium concentrations and potassium supplement use in African-American and Caucasian patients receiving spironolactone for heart failure.


METHODS
Retrospective medical record review.


METHODS
Two heart failure centers.


METHODS
Fifty African-American and 67 Caucasian patients with heart failure who were receiving a stable dosage of spironolactone in addition to standard heart failure therapy with an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker.


RESULTS
Medical records of eligible patients were reviewed by pharmacists and physicians who specialize in heart failure management. No significant differences were observed in diuretic therapy or renal function between racial groups; however, African-Americans were receiving higher doses of ACE inhibitors. African-Americans had lower serum potassium concentrations (4.2 +/- 0.4 vs 4.5 +/- 0.5 mEq/L, p<0.01) and a higher prevalence of potassium supplementation (48% vs 15%, p<0.01). In a subset of patients, spironolactone therapy was associated with a 2-fold greater increase in serum potassium concentration and a 3-fold greater reduction in potassium supplement use among Caucasians than African-Americans.


CONCLUSIONS
Our findings suggest that a large percentage of patients with heart failure, particularly African-Americans, still require potassium supplementation despite treatment with spironolactone and standard vasodilator therapy.
Cavallari
Larisa H
LH
Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, 60612-7230, USA. humma@uic.edu
Fashingbauer
Lucy A
LA
Beitelshees
Amber L
AL
Groo
Vicki L
VL
Southworth
Mary R
MR
Viana
Marlos A G
MA
Williams
Randall E
RE
Dunlap
Stephanie H
SH
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D001741:Black or African American; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D019587:Dietary Supplements; D004232:Diuretics / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006333:Heart Failure / Q000188:drug therapy* / Q000208:ethnology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000008:administration & dosage / Q000097:blood*; D012189:Retrospective Studies; D013148:Spironolactone / Q000494:pharmacology / Q000627:therapeutic use*; D044465:White People
D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D004232:Diuretics; D013148:Spironolactone; D011188:Potassium