|
|
What
is the most appropriate way to compute the average time
of onset of pain relief and statistically compare the drug
group to the placebo group?
You
answered:
Calculate
the mean times to onset and compare the means for the drug
and placebo groups using an unpaired t test.
INCORRECT
Most
pain researchers continue to use means to represent the
magnitude of pain reduction because the distribution of
pain scores usually approaches normality and this analysis
has the most power. For the analysis of time of analgesic
onset, however, the work of (Laska
et al., 1991) has generated a consensus that a group
of nonparametric techniques called "survival analyses"
are most appropriate. In these methods, adapted from the
analysis of long-term cancer and cardiovascular disease
trials, the median and 25th and 75th
percentile scores are used to represent the group result.
Such analysis of analgesic onset and duration is now done
routinely in single-dose studies of new drugs (Ganju
et al., 1999). The same principles are applicable to
chronic treatment of any disease (Laska
and Siegel, 1995), but have not yet been adopted in
chronic analgesic studies.
|