Prospective cohort study.
SETTING: Blood samples were obtained at baseline, 1 week after
spironolactone initiation, and 1 week after
spironolactone dose titration for assessment of baseline
aldosterone level, serum chemistry, and
angiotensinogen (AGT) c.-6G>A and p.M268T and
mineralocorticoid receptor (NR3C2) c.215C>G and p.I180V genotypes. Patient characteristics, laboratory values, and genotypes were compared between those whose
potassium levels increased by more than 0.5 mEq/L (15 patients) and those with lower
potassium level elevations (47 patients) after
spironolactone initiation and dose titration. Patients with a greater
potassium level elevation had a higher mean +/- SD
aldosterone concentration (178 +/- 92 vs 102 +/- 57 pg/ml, p=0.007) and NR3C2 215G allele frequency (50% vs 22%, p<0.01).
Aldosterone concentrations positively correlated with
diuretic dose (r=0.313, p=0.014) and negatively correlated with serum
potassium level (r= -0.319, p=0.012). On regression analysis, factors predictive of
potassium level increases greater than 0.5 mEq/L with
spironolactone were
aldosterone level greater than 150 pg/ml (odds ratio [OR] 30, 95% confidence interval [CI] 3.2-287] and NR3C2 215G carrier status (OR 17, 95% CI 1.6-167).
CONCLUSION: