Perhaps the biggest hurdle to broader acceptance of the need for a consistent scientific basis for medical interventions is the attitude that worthless treatments are harmless. I often have the experience, after reviewing the evidence showing lack of efficacy for a specific intervention, of getting the head-tilt and shrug along with some variation of the dismissive attitude,  “Well, if people feel better, then what’s the harm?” In my opinion, ethics and intellectual honesty indicate that we have to do better than that.

The “what’s the harm” refrain is so tired and overused that it prompted a website by that name, documenting direct harm caused by unscientific treatment modalities. This is a helpful reminder that any intervention that actually does something (has biological activity) must also contain some risks. But this site also has significant limitations. First, it is anecdotal. But also it emphasizes direct harm, while the indirect harm of unscientific methods (for example by delaying definitive treatment) likely vastly outweighs the direct harm. However, indirect harm is extremely difficult to quantify.

Studies looking at the net clinical effects of using or relying upon unscientific methods is therefore desirable. Recently Danish researchers have published one such study:  Use of complementary and alternative medicines associated with a 30% lower ongoing pregnancy/live birth rate during 12 months of fertility treatment.

The study is a prospective follow-up cohort study, which means they followed a group of in-vitro fertilization (IVF) patients for 12 months and tracked their outcomes. (This is also a follow up of earlier data they presented two years ago with the same results.) They assessed their use of so-called CAM at the onset and at 12 months, and found:

About 30.6% (n = 223) of women used CAMs during the observation period. At T2 the ongoing pregnancy and live birth rate was 31.3% lower in CAM users (42.2%) compared with non-users (61.4%). Adjusted odds of pregnancy/live birth remained lower in CAM users versus non-users, odds ratio = 0.467 (95% confidence interval 0.306–0.711) after controlling for prognostic indicators (age, parity, years infertile).

The effect size is substantial – 31.3%, and the power of the study was robust. There are weaknesses, however. While they report that CAM modalities include acupuncture, reflexology, herbal and aromatherapy, they did not collect data in such a way as to assess the effect of specific CAM modalities on IVF success rate. Also, this study is not randomized. This means that the door is open for confounding factors. While the researchers controlled for obvious things, such as known prognostic factors for IVF success, it is always the unknown factors that cannot be controlled for. In other words, it is possible that another factor leads to CAM use and low IVF success, rather than CAM use directly causing low IVF success. But of course the latter interpretation is possible also – we just cannot tell from this one study.

Specific CAM modalities, like the use of herbal drugs, may have a direct adverse effect on IVF success. Herbal drugs are poorly controlled and are known in some cases to cause drug-drug interactions. There may also be indirect effects, such as reliance upon an ineffective CAM modality reducing compliance with the IVF procedure.

While this one study does not prove a specific adverse effect, it does reinforce what mainstream medical researchers already understand – a treatment that is unproven may in fact be harmful. This is precisely why unproven interventions should be used with extreme caution – either in the context of a clinical trial, for compassionate use, or perhaps with high plausibility in the absence of proven alternatives – and always with proper informed consent.

A major problem with proponents of CAM therapies is that the usual ethics of clinical care seem not to apply – as if they practice by a separate standard where treatments either work or have yet to be proven to work, but risks are generally ignored.

As an example, a recent study comparing acupuncture to placebo acupuncture showed that patients receiving placebo acupuncture had a higher pregnancy rate. In reality, most outcome measures were not statistically different – the study is consistent with a negative result and noisy data that just happened to favor placebo. The best scientific conclusion from this study is that acupuncture does not work for IVF, however the authors concluded: “Placebo acupuncture may not be inert.”

Although I think it’s most likely that this study is just negative, it may also be true that placebo acupuncture did better because real acupuncture has a negative effect on IVF rates. This latest study might lend support to this conclusion.

The authors concluded that CAM use in IVF patients should be monitored, but I think we can make a stronger conclusion that it should be discouraged. There is no evidence for benefit, and there is a suggestion of harm – in the real world of medicine this should lead to a suspension of using these techniques, at least until better studies show they are safe and effective. This is even without considering the extreme scientific implausibility of many CAM modalities, which makes the case for their continued use even worse.

Continued research into implausible treatments remain controversial precisely because those using these modalities in the first place do not follow standard medical ethics – they don’t base their practice on the evidence. I am still waiting for proponents to abandon a CAM modality because research shows it is not safe or that it is ineffective.

Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the president and co-founder of the New England Skeptical Society, the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also contributes every Sunday to The Rogues Gallery, the official blog of the SGU.