RALES study

• randomised double-blind controlled trial
  
  
• patients involved in the study had severe heart failure (New York Heart Association Class IV) - all patients were being treated with a loop diuretic; most were also being treated with an ACE inhibitor. The ejection fraction of patients was less than 35%
  
  
• patients were randomised to placebo or spironolactone 25-50mg - other treatments were continued. Potassium levels were monitored regularly throughout the study. The dose of spironolactone was increased to 50mg after one month if serum potassium level allowed
  
  
• 1663 patients with severe heart failure were recruited to the study and the mean follow up was 24 months
  
  
• in the spironolactone treatment group there was a 30% reduction in all-cause mortality, lowered hospitalisation rates and improved symptomatic control
  
  
• the incidence of serious hyperkalaemia was uncommon - 1% in the placebo group and 2% in the spironolactone treatment group

Reference:

• NEJM (1999), 341, 709-17.