Posted by Larry Hoover on September 13, 2007, at 20:04:04
In reply to Re: placebo vs. antidepressant » Larry Hoover, posted by linkadge on September 13, 2007, at 16:43:33
> Dr. Khan found that in only 48 percent of the 52 clinical trials was the antidepressant superior to the placebo.
>
> LinkadgeI've looked far and wide, and I can't find the full-text of the above. If anybody knows of it, please let me know.
I like Khan's work. Very straight forward. Doesn't overinterpret his findings. Anyway, I've collected a few brief blurbs from some of his abstracts, all reviews of that same FDA database. My comments, if any, in square parentheses[].
"A statistically significant positive correlation was seen between placebo and antidepressant response magnitude (r =.40, p <.001) and between placebo response magnitude and the advantage of antidepressants over placebo (r = -.592, p <.0001). Only 21.1% of antidepressant treatment arms in trials with high placebo response (>30% mean change from baseline) showed statistical superiority over placebo compared with 74.2% in trials with a low placebo response (< or =30)." [The placebo response is more variable than the antidepressant response.]
"In the flexible dose trials, 59.6% (34/57) of the antidepressant treatment arms were statistically significant compared to placebo, whereas in the fixed dose trials only 31.4% (11/35) of the antidepressant treatment arms were statistically significant compared to placebo (chi(2)=6.9, df=1, p<0.01). These data suggest that the antidepressant dose schedule may influence trial outcome due in part to a significantly lower magnitude of symptom reduction with placebo in flexible dose trials (F=4.08, df=1, 48, p&<0.05) compared to fixed dose trials." [fascinating!]
In this one, my comments are embedded:
"The severity of depressive symptoms before patient randomization [more severe syptoms, greater difference between antidepressant and placebo], the dosing schedule [flexible dosing greater difference to placebo than fixed dose], the number of treatment arms [more treatment arms, greater difference], and the percentage of female patients [more females, greater placebo response, and lower difference] were significantly associated with the difference in response to antidepressant and placebo.""In the antidepressant-treated groups, the magnitude of symptom reduction was significantly related to mean initial Hamilton Rating Scale for Depression (HAM-D) score; the higher the mean initial HAM-D score, the larger the change. With placebo treatment, however, the higher the mean initial HAM-D score, the smaller the change." [redundant, but more explicit]
Thought-provoking, all in all.
Lar
poster:Larry Hoover
thread:781684
URL: http://www.dr-bob.org/babble/20070911/msgs/782739.html