The population sampling in randomised controlled trials by Fujii et al. have been shown to exhibit unusual distributions. This systematic review analysed the effectiveness of prophylactic
antiemetics in trials by Fujii et al. compared with other authors.
Granisetron was more effective in trials by Fujii et al., relative risk ratios (RRR (95% CI)):
nausea 0.53 (0.42-0.67), p=0.00021;
vomiting 0.60 (0.50-0.73), p=0.00094.
Ramosetron was also more effective in studies by Fujii et al.:
vomiting 0.60 (0.39-0.91), p=0.02;
nausea or
vomiting 0.71 (0.56-0.91); p=0.006. In comparison with
granisetron,
droperidol was less effective in trials by Fujii et al. than others:
nausea 2.41 (1.72-3.36),
p=2.5×10(-7);
vomiting 1.73 (1.26-2.38), p=6.4×10(-4).
Postoperative nausea and vomiting was less likely to trigger rescue antiemesis after
granisetron and
metoclopramide in studies by Fujii et al., 0.40 (0.27-0.60), p=9.7×10(-6). Triggered rates of rescue were not different in studies by others for
droperidol,
granisetron and
metoclopramide, but were less common after
granisetron than
droperidol and
metoclopramide in studies by Fujii et al., 0.50 (0.38-0.66), p=1.7×10(-6) and 0.47 (0.34-0.64),
p=2.6×10(-6), respectively. There was no synergism between
antiemetics in trials by other authors. In contrast, in studies by Fujii et al.,
postoperative nausea and vomiting was more likely if
granisetron was administered alone:
nausea 4.20 (1.94-9.08),
p=2.6×10(-4) ;
vomiting 4.50 (2.55-7.97),
p=2.3×10(-7);
nausea or
vomiting 5.00 (2.84-8.81),
p=2.5×10(-8). Similarly,
droperidol was less effective in studies by Fujii et al. if administered alone:
vomiting 2.76 (1.25-6.11), p=0.01;
nausea or
vomiting 2.96 (1.46-6.00),
p=2.7×10(-3). The conclusion is that if, as recommended, data with unusual distributions are removed from meta-analysis and articles by Fujii et al. excluded, then the
antiemetic effects of
granisetron and
ramosetron are greatly reduced; further, there is no evidence of synergism between
antiemetics and indeed, some evidence of antagonism between
antiemetic agents.