Active-control equivalence trials and antihypertensive agents.
OBJECTIVE
To identify methodological features that affect the validity of conclusions drawn from active-control equivalence trials and to apply these criteria to recently published trials comparing antihypertensive agents from different classes.


METHODS
Standard methodological criteria for randomized clinical trials and six additional methodological features that affect the validity of active-control equivalence trials were applied to four recently published large trials that compared different antihypertensive classes and that concluded that their results showed equivalence.


RESULTS
All four of these trials fulfilled standard criteria for randomized trials. However, none fulfilled all of the six additional methodological criteria that affect the validity of active-control equivalence trials, one fulfilled five criteria, two fulfilled two criteria, and one failed to fulfill any of the criteria.


CONCLUSIONS
Standard methodological criteria for evaluating superiority trials are inadequate for the interpretation of active-control equivalence trials. The methodological criteria outlined in this article for judging the validity of active-control equivalence trials are not specific to antihypertensive trials and may be applied to trials that test a wide variety of interventions.
McAlister
F A
FA
Division of General Internal Medicine, University of Alberta, Alberta, Canada.
Sackett
D L
DL
D000959:Antihypertensive Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019317:Evidence-Based Medicine; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D012107:Research Design; D013810:Therapeutic Equivalency
D000959:Antihypertensive Agents