Low Dose Aldosterone Antagonism Reduces Diuretic Requirements in Heart Failure

Background: The effect of low doses of aldosterone antagonists (AA) on loop diuretic (LD) dosing in heart failure (HF) has not been reported. If AA have a natriuretic effect at low doses, there is the potential for an unexpected diuresis with continuation of baseline diuretic therapy. The objective of this study was to evaluate the effects of AA on loop diuretic dose requirements and risk for dehydration/acute renal failure (ARF) in the treatment of heart failure. Methods: We reviewed the medical records of HF subjects who where on a LD at the time of AA initiation. Baseline data included demographics, medications, renal status and co-morbidities. Loop diuretic dose changes, renal function and number of hospital admissions for dehydration/ ARF over a 12-month period after AA initiation was evaluated. Results: Sixty subjects, 60% black, 57% male, mean age 54 were included in the study. Baseline characteristics include average BP of 124/73, weight 226 pounds, BUN 19 and, SrCr 1.23 mg/dL and 83% had moderate to severe left ventricular dysfunction. Concomitant therapy included beta-blockers (93%) and ACEI (98%). Furosemide was the only LD used. As shown in the table, there was a significant reduction in LD dose over the 12-months following AA initiation. Diuretic doses were unchanged (NC) in 19 (32%) subjects, increased (INC) in 14 (23%) and decreased (DEC) in 27 (45%). The INC/NC group was on a lower LD dose compared to the DEC group at baseline (92 6 53 mg vs. 132 6 69 mg, p 5 0.012). The INC/NC subjects were more likely to have 2-co-morbidities versus 1 in the DEC group. The DEC group had a significant decline in renal function at the time of first LD dose change compared to baseline (p ! 0.05). There were 4 hospitalizations due to dehydration/ARF with no significant difference between DEC and INC/NC groups. Conclusions: Data from this study showed that 45% of subjects required a decrease in LD dose over a 12-month period and 7% of subjects were hospitalized due to dehydration/ARF. Renal dysfunction was significant among the DEC group. Careful monitoring of renal function and fluid status, in addition to potassium, is warranted in this population.