Prevalence of thiamine deficiency in heart failure patients on long-term diuretic therapy

Abstract

Background: Loop diuretics are an integral part of heart failure management. It has been shown that loop diuretics cause thiamine deficiency (TD) by increasing its urinary loss. The aim of this study was to determine the prevalence of TD in heart failure patients on long-term oral loop diuretics. Methods: Heart failure patients (cases) on oral loop diuretics (furosemide ≥40 mg/day or torsemide ≥20 mg/day), irrespective of the cause of heart failure, were compared to non-heart failure patients (controls) not on loop diuretics in a 1:1 ratio. Whole blood free thiamine level was determined by liquid chromatography-tandem mass spectrometry method. Results: A total of 100 subjects were enrolled in a 1:1 ratio (50 cases and 50 controls). 67% of the total study population had TD, (defined as whole blood free thiamine level <0.7 ng/ml). There was no difference in mean thiamine level between cases and controls. On comparing patients with TD in both groups, patients on diuretics had significantly lower thiamine level compared to the patients, not on diuretics (P < 0.0001). Conclusions: There was no difference in the thiamine level when patients on loop diuretics were compared to controls. However, very low thiamine levels (<0.1 ng/ml) was significantly more common in patients on loop diuretics.