Can I tempt you to run a little (hopefully instructive) thought-experiment with you? It is quite simple: I will tell you about the design of a clinical trial, and you will tell me what the likely outcome of this study would be.
Are you game?
Here we go:
Imagine we conduct a trial of acupuncture for persistent pain (any type of pain really). We want to find out whether acupuncture is more than a placebo when it comes to pain-control. Of course, we want our trial to look as rigorous as possible. So, we design it as a randomised, sham-controlled, partially-blinded study. To be really ‘cutting edge’, our study will not have two but three parallel groups:
1. Standard needle acupuncture administered according to a protocol recommended by a team of expert acupuncturists.
2. Minimally invasive sham-acupuncture employing shallow needle insertion using short needles at non-acupuncture points. Patients in groups 1 and 2 are blinded, i. e. they are not supposed to know whether they receive the sham or real acupuncture.
3. No treatment at all.
We apply the treatments for a sufficiently long time, say 12 weeks. Before we start, after 6 and 12 weeks, we measure our patients’ pain with a validated method. We use sound statistical methods to compare the outcomes between the three groups.
WHAT DO YOU THINK THE RESULT WOULD BE?
You are not sure?
Well, let me give you some hints:
Group 3 is not going to do very well; not only do they receive no therapy at all, but they are also disappointed to have ended up in this group as they joined the study in the hope to get acupuncture. Therefore, they will (claim to) feel a lot of pain.
Group 2 will be pleased to receive some treatment. However, during the course of the 6 weeks, they will get more and more suspicious. As they were told during the process of obtaining informed consent that the trial entails treating some patients with a sham/placebo, they are bound to ask themselves whether they ended up in this group. They will see the short needles and the shallow needling, and a percentage of patients from this group will doubtlessly suspect that they are getting the sham treatment. The doubters will not show a powerful placebo response. Therefore, the average pain scores in this group will decrease – but only a little.
Group 1 will also be pleased to receive some treatment. As the therapists cannot be blinded, they will do their best to meet the high expectations of their patients. Consequently, they will benefit fully from the placebo effect of the intervention and the pain score of this group will decrease significantly.
So, now we can surely predict the most likely result of this trial without even conducting it. Assuming that acupuncture is a placebo-therapy, as many people do, we now see that group 3 will suffer the most pain. In comparison, groups 1 and 2 will show better outcomes.
Of course, the main question is, how do groups 1 and 2 compare to each other? After all, we designed our sham-controlled trial in order to answer exactly this issue: is acupuncture more than a placebo? As pointed out above, some patients in group 2 would have become suspicious and therefore would not have experienced the full placebo-response. This means that, provided the sample sizes are sufficiently large, there should be a significant difference between these two groups favouring real acupuncture over sham. In other words, our trial will conclude that acupuncture is better than placebo, even if acupuncture is a placebo.
THANK YOU FOR DOING THIS THOUGHT EXPERIMENT WITH ME.
Now I can tell you that it has a very real basis. The leading medical journal, JAMA, just published such a study and, to make matters worse, the trial was even sponsored by one of the most prestigious funding agencies: the NIH.
Here is the abstract:
Musculoskeletal symptoms are the most common adverse effects of aromatase inhibitors and often result in therapy discontinuation. Small studies suggest that acupuncture may decrease aromatase inhibitor-related joint symptoms.
To determine the effect of acupuncture in reducing aromatase inhibitor-related joint pain.
Design, Setting, and Patients:
Randomized clinical trial conducted at 11 academic centers and clinical sites in the United States from March 2012 to February 2017 (final date of follow-up, September 5, 2017). Eligible patients were postmenopausal women with early-stage breast cancer who were taking an aromatase inhibitor and scored at least 3 on the Brief Pain Inventory Worst Pain (BPI-WP) item (score range, 0-10; higher scores indicate greater pain).
Patients were randomized 2:1:1 to the true acupuncture (n = 110), sham acupuncture (n = 59), or waitlist control (n = 57) group. True acupuncture and sham acupuncture protocols consisted of 12 acupuncture sessions over 6 weeks (2 sessions per week), followed by 1 session per week for 6 weeks. The waitlist control group did not receive any intervention. All participants were offered 10 acupuncture sessions to be used between weeks 24 and 52.
Main Outcomes and Measures:
The primary end point was the 6-week BPI-WP score. Mean 6-week BPI-WP scores were compared by study group using linear regression, adjusted for baseline pain and stratification factors (clinically meaningful difference specified as 2 points).
Among 226 randomized patients (mean [SD] age, 60.7 [8.6] years; 88% white; mean [SD] baseline BPI-WP score, 6.6 [1.5]), 206 (91.1%) completed the trial. From baseline to 6 weeks, the mean observed BPI-WP score decreased by 2.05 points (reduced pain) in the true acupuncture group, by 1.07 points in the sham acupuncture group, and by 0.99 points in the waitlist control group. The adjusted difference for true acupuncture vs sham acupuncture was 0.92 points (95% CI, 0.20-1.65; P = .01) and for true acupuncture vs waitlist control was 0.96 points (95% CI, 0.24-1.67; P = .01). Patients in the true acupuncture group experienced more grade 1 bruising compared with patients in the sham acupuncture group (47% vs 25%; P = .01).
Conclusions and Relevance:
Among postmenopausal women with early-stage breast cancer and aromatase inhibitor-related arthralgias, true acupuncture compared with sham acupuncture or with waitlist control resulted in a statistically significant reduction in joint pain at 6 weeks, although the observed improvement was of uncertain clinical importance.
Do you see how easy it is to deceive (almost) everyone with a trial that looks rigorous to (almost) everyone?
My lesson from all this is as follows: whether consciously or unconsciously, SCAM-researchers often build into their trials more or less well-hidden little loopholes that ensure they generate a positive outcome. Thus even a placebo can appear to be effective. They are true masters of producing false-positive findings which later become part of a meta-analysis which is, of course, equally false-positive. It is a great shame, in my view, that even top journals (in the above case JAMA) and prestigious funders (in the above case the NIH) cannot (or want not to?) see behind this type of trickery.