Effects of long-term low-dose spironolactone treatment in patients with New York Heart Association functional class II heart failure : a 10-year prospective study

Background: Before 2012, spironolactone has been only recommended for patients with New York Heart Association functional class (NYHA) III-IV congestive heart failure (CHF). This study began in 2004 to test the hypothesis that long-term low-dose spironolactone in CHF patients with NYHA class II are associated with better prognosis. Methods: The present study began in 2004 and ended in 2013, which was divided into two periods: from 2004 to 2008, and from 2009 to 2013. A total of 139 patients with NYHA class II and an ejection fraction of ≤45% were randomly assigned to the spironolactone (n=69) or non-spironolactone (n=70) group, with a standard treatment regimen from 2004 to 2008. Patients with non-spironolactone began to accept the same treatment as patients in the spironolactone group from 2009 to 2013. Primary outcomes were all-cause mortality, cardiovascular mortality and hospitalization. The secondary endpoint was life-threatening hyperkalemia. Results: From January 2004 to December 2008, all-cause mortality, cardiovascular mortality and hospitalization were significantly lower in the spironolactone (10-20 mg/day) group than in the non-spironolactone group (all P<0.05, 15.8% vs. 32.3%, 14.0% vs. 30.6%, 21.1% vs. 37.1%, respectively). From January 2009 to December 2013, there was no difference between the two groups at all end points. The occurrence of serum potassium levels >5.0 mmol/L was similar between the two groups during the 10-year follow-up. Conclusion: Long-term low-dose spironolactone added to standard treatment in patients with NYHA class II heart failure significantly reduced all-cause mortality, cardiovascular mortality and hospitalization without inducing life-threatening hyperkalemia.