The Effect of Spironolactone Use on Heart Failure Mortality: A Population-Based Study

Background: Spironolactone use for heart failure (HF) has increased dramatically after the publication of the Randomized Aldactone Evaluation Study trial; yet, few studies have examined its real-world impact. We aimed to determine the population effect of spironolactone use on mortality in HF patients discharged from hospital. Methods and Results: All patients discharged alive between October 1997 and December 2001 in Nova Scotia, Canada, with a primary diagnosis of HF were enrolled in the Improving Cardiovascular Outcomes Study. Two year, all-cause mortality was the primary end point. A total of 7816 patients were identified, of whom 644 (8%) were discharged home on spironolactone. After adjusting for differences in clinical covariates, spironolactone use did not emerge as an independent predictor of long-term survival (OR 0.97, P = .80). When only the subgroup of patients enrolled in a HF clinic were included (n = 990), spironolactone use was associated with reduced rates of all-cause mortality at 2 years (OR 0.52, P = .003). Conclusions: Although spironolactone use was not associated with improved long-term survival in the general HF population, it was associated with improved long-term survival in patients enrolled in HF clinics. These data highlight the challenges of knowledge translation from a clinical trial into practice.