BMJ publiserte nylig en meta-analyse av forskning på akupunktur og prøverørsbefruktning.
Underlig nok har den ikke slått gjennom i det norske nyhetsbildet ennå. Det kommer nok, ettersom den ser ut til å konkludere positivt for akupunktur på et lite intuitivt felt:
Data synthesis Seven trials with 1366 women undergoing in vitro fertilisation were included in the meta-analyses. There was little clinical heterogeneity. Trials with sham acupuncture and no adjuvant treatment as controls were pooled for the primary analysis. Complementing the embryo transfer process with acupuncture was associated with significant and clinically relevant improvements in clinical pregnancy (odds ratio 1.65, 95% confidence interval 1.27 to 2.14; number needed to treat (NNT) 10 (7 to 17); seven trials), ongoing pregnancy (1.87, 1.40 to 2.49; NNT 9 (6 to 15); five trials), and live birth (1.91, 1.39 to 2.64; NNT 9 (6 to 17); four trials). Because we were unable to obtain outcome data on live births for three of the included trials, the pooled odds ratio for clinical pregnancy more accurately represents the true combined effect from these trials rather than the odds ratio for live birth. The results were robust to sensitivity analyses on study validity variables. A prespecified subgroup analysis restricted to the three trials with the higher rates of clinical pregnancy in the control group, however, suggested a smaller non-significant benefit of acupuncture (odds ratio 1.24, 0.86 to 1.77).
Conclusions Current preliminary evidence suggests that acupuncture given with embryo transfer improves rates of pregnancy and live birth among women undergoing in vitro fertilisation.
Hvor sterk er slutningen? David Gorski på Science-Based Medicine kommenterer saken her.
Etter først å ha notert noen poeng relatert til at EBM ikke er laget til å ta for seg CAM fordi «it does not take into account scientific prior probability», går han inn på selve metaanalysen. Jeg hopper direkte til oppsummeringen.
A combination of failure to blind in most of the studies included coupled with the likelihood of publication bias serve to cast extreme doubt on the conclusion of this study. It also shows the peril of applying meta-analysis to CAM modalities. Here we have researchers going to huge effort to apply the scientific method to a hypothesis for which there is no plausible mechanism, which is based on a concept that has never been detected or measured (meridians through which life force, or qi, flows), and studies that are most likely dominated by noise and false positives of the type Dr. John Ioannidis warned us about. In other words, it’s a really long run for a really short slide.
Argumentene kan være verdt å se nærmere på, så les hele.
I mellomtiden skal jeg forsøke å lese gjennom Atwoods avslutning på artiklene om homøopati og EBM, hvor han diskuterer dette spørsmålet om «prior probability» og CAM – et tema som både generelt og spesielt bør være av interesse for skeptikere.