THIAMIN STATUS, DIURETIC MEDICATIONS, AND THE MANAGEMENT OF CONGESTIVE-HEART-FAILURE

Objective To assess the prevalence of thiamin deficiency in patients w ith congestive heart failure who are treated with diuretics that. inhi bit sodium and chloride reabsorption in the thick ascending limb of th e loop of Henle (loop diuretic therapy). Design A cross-sectional inve stigation of thiamin status of consecutive patients with congestive he art failure being treated with loop diuretic therapy. Setting Cardiolo gy clinic of a midwestern tertiary-care medical center. Subjects Thirt y-eight patients were recruited (mean age +/- standard deviation = 55 +/- 14 years). Validation of methodology was conducted with nine age-m atched control subjects. Main outcome measures Thiamin status was asse ssed biochemically by in vitro erythrocyte transketolase activity assa y. Assessment of dietary intake of thiamin was accomplished with a sem iquantitative food frequency questionnaire. Statistical analyses perfo rmed Fisher's exact test and logistic regression were used to evaluate relationships between thiamin status and variables of interest. Resul ts Biochemical evidence of thiamin deficiency was found in 8 of 38 (21 %) patients. Evidence of risk for dietary thiamin inadequacy was found in 10 of 38 patients (25%). Seven of the 8 patients with biochemical evidence of thiamin deficiency met study criteria for dietary adequacy , although quantified data suggested that only 4 of the patients achie ved two thirds of the Recommended Dietary Allowance. Biochemical evide nce of thiamin deficiency tended to be more common among patients with poor left ventricular ejection fractions (P=.07). Conclusions Thiamin deficiency may occur in a substantial proportion of patients with con gestive heart failure, and dietary inadequacy may contribute to increa sed risk.