BACKGROUND: Vasopressin levels are often elevated in heart failure patients and left ventricular dysfunction, and this may contribute to the increase in systemic vascular resistance via stimulation of the V1a receptor. Among the recent novel therapies for heart failure are the vasopressin receptor antagonists. Tolvaptan is an oral, non-petide, selective vasopressin V2-receptor antagonist that causes aquaresis by acting in the distal nephron to increase secretion of electrolyte-free water. this meta-analysis aimed to test the hypothesis that tolvaptan is beneficial and results in clinical improvement in the treatment of heart failure.
METHODS: This was a meta-analysis that included randomized controlled trials that compared the efficacy of tolvaptan 30 mg daily vs placebo among heart failure patients. We obtained relevant publications from PubMed, Cochrane and Australasian Medical Index. Abstracted data were assessed from the five (5) included studies using the JADAD Quality Scale. Outcomes measured were changes in body weight and serum sodium levels, from baseline to 24 hours of initiating treatment and at the end of the follow-up. Data analysis was done using the Review Manager 5 software version 5.1.7. Analysis of the mean difference was used as effect measure.
RESULTS: In this meta-analysis, the total pooled patient population was 4,899 patients (2,281 patients assigned to the tolvaptan group and 2,279 patients assigned to the placebo group). The outcome of the mean difference in body weight after 25 hours and at end of follow-up was -0.93 kg (95% CI: -1.12 to -0.74) and -1.34 kg (95% CI: -1.66 to -1.02) respectively. The outcome of the mean difference in serum sodium after 24 hours of treatment and at end of follow-up was 3.05 mEq/L (95% CI: 1.85 to 4.25) and 2.25 mEq/L (95% CI: 0.83 to 3.66) respectively.
CONCLUSION: This meta-analysis demonstrated significant weight reduction and increase in serum sodium in patients with heart failure treated with tolvaptan during the first day and up to the end of follow-up treatment. These are important properties for the treatment of heart failure.