Table 3

Design and conduct of β blocker heart failure trials

USCP CIBIS II MERIT-HF
Estimated annual mortality in placebo group (%)12.011.29.4
Estimated risk reduction with β blocker (%)N/A5-150 2530
Estimated duration of trial (years)
 Recruitment–11.2
 Follow up–22.5
Estimated number of patients required110125003500
Power of study to detect pre-specified risk reduction (%)N/A5-151 9580
Early stopping rules for benefit (significance level)?NoYes (p < 0.001)Yes (p < 0.0036)
Recruitment started23 April 199327 November 199514 February 1997
Recruitment stoppedN/A5-152 13 May 199714 April 1998
Study programme stopped prematurelyYesYesYes
Date study stopped3 February 19955 March 199831 October 1998

  • ↵5-150 Trial designed to exclude a 33% increase in mortality;

  • ↵5-151 95% power to detect a 33% increase in mortality;

  • ↵5-152 some component studies still recruiting at time USCP terminated.