Influence of spironolactone therapy on thiamine blood levels in patients with heart failure.

BACKGROUND The nonpharmacological management of heart failure (HF) has been understudied. The importance of micronutrients such as thiamine has long been known since its deficiency is associated with the development of high-output HF. OBJECTIVE We studied the relationship between adding to ACE inhibition further aldosterone suppression with spironolactone and thiamine blood levels (pmol/ml). METHODS A total of 22 patients (pts) with HF (NYHA III/IV) were divided in two groups [group I-spironolactone 25mg/qd (n=11) and group II - no spironolactone (n=11)]. Thiamine levels were determined using the erythrocyte transketolase activity. The groups were compared regarding food intake, demographics, furosemide doses and thiamine blood levels using Mann-Whitney and student's T-test. The proportions were analyzed with Chi-square and Kruskal-Wallis tests to associate thiamine with demographics and furosemide doses as dependent variables. RESULTS Group I and II were similar regarding food intake, daily furosemide doses (110.9+/-30.2 and 105.5+/-26.9 mg, respectively; p>0.05), demographics (etiology, age, hypertension, diabetes, smoking, alcohol abuse, dyslipidemia and adjuvant drug HF treatment). Pts in group I showed significantly higher thiamine levels when compared to pts in group II (277.2+/-89.8 and 154.7+/-35.7, respectively) (p<0.001). None of the dependent variables cited above were associated with thiamine. CONCLUSION In a cohort of ambulatory HF patients on high dose of loop diuretics, the use of spironolactone is associated with higher thiamine blood levels. The significance of this finding remains to be established by future studies with prospective design and larger sample sizes.