ABSTRACT
Evidence-based evaluation of treatment is a pivotal component of an effective and
satisfying clinical practice. When the best evidence has been identified, it can be
efficiently assessed on three levels: Are the methods valid? Is the effect sufficiently
large to be meaningful to patients? Are the patients, intervention(s), and outcomes
studied applicable to our own patients? These criteria were applied to a multicenter
trial that evaluated whether intracytoplasmic sperm injection (ICSI) was superior
to in vitro fertilization (IVF) among infertile couples with no known male factor
who were on a waiting list for IVF. The study was a well-designed randomized controlled
trial that effectively concealed the randomization list and took reasonable steps
to exclude bias. The results seemed important because the number needed to treat (13)
was relatively low and significant, but the primary outcome (implantation rate) was
not clinically meaningful. The trial results would have been relevant to most infertile
couples with no known male factor if it had been powered to evaluate a difference
in a more relevant clinical outcome, such as live birth. Thus, it has not been shown
definitively that ICSI is inferior to IVF among couples with no known male factor,
and clinical demand for ICSI may continue to rise.
KEYWORDS
Evidence-based medicine - treatment - effectivness - randomized controlled trials
- risk difference - number needed to treat
