Blind men and the Elephant in the Room

Blind men and the Elephant in the Room

There was a recent PLOS article Decreased Risk of Stroke in Patients with Traumatic Brain Injury Receiving Acupuncture Treatment: A Population-Based Retrospective Cohort Study.

It was a

a retrospective cohort study of 7409 TBI patients receiving acupuncture treatment and 29,636 propensity-score-matched TBI patients without acupuncture treatment in 2000–2008 as controls.

and found that

TBI patients with acupuncture treatment (4.9 per 1000 person-years) had a lower incidence of stroke compared with those without acupuncture treatment (7.5 per 1000 person-years), with a HR of 0.59 (95% CI = 0.50–0.69) after adjustment for sociodemographics, coexisting medical conditions and medications.

Interesting. Why did they do the study? Well, In Taiwan acupuncture is a common treatment and no one had ever looked to see if it could prevent a stroke. It is a tough job, but someone had to do it.

Retrospective studies are always interesting, but not definitive, since there may be differences between the treatment and controls that would be potentially avoided in a prospective randomized trial. So were there differences in the two groups? Yep.

The acupuncture group was more likely to be on anti-coagulants, (p= 0.0003), antiplatelet drugs (p <0.0001), and lipid lowering drugs (p <0.0001).

Seriously. The treatment group was more likely to be on stroke preventing medications yet it was the acupuncture that was responsible for fewer stokes? Because the statistics suggested it?

To properly evaluate whether acupuncture treatment is associated with reduced stroke risk in TBI patients, we used propensity score to match the difference of age, sex, low income, and density of TCM physicians, mental disorders, hypertension, diabetes, ischemia heart disease, hyperlipidemia, migraine and epilepsy between TBI patients with and without acupuncture treatment. To accurately estimate risk of stroke after TBI for patients with and without acupuncture treatment, residual confounding effects were adjusted in the multivariable Cox proportional hazard models.

Seems so.  

They had 2 possible explanations for the effects of acupuncture. The first was that acupuncture had biologic effects. I would bet against it. There is no plausible reason acupuncture could prevent stoke. The other was that patients in the acupuncture group had better care.

patients with TBI who choose acupuncture treatment may have better knowledge, attitudes and practices regarding physical rehabilitation and disease prevention, which we believe could also contribute to reduce new-onset stroke event after TBI.

Given that the acupuncture patients were more likely to be on medical therapy that prevents stroke, that may be a more likely answer.

It wasn’t the acupuncture, it was the medications.

When I first read this article and looked at the table that demonstrated the marked difference in medication use between the two groups, I could not believe it. I read it over and over, thinking, no that couldn’t be, I must be missing something. Because that renders the conclusion so senselessly foolish.   I could not understand how anyone could be blind to what would appear to be a simple explanation of the difference in outcomes between the two groups. The most impressive example of confirmation bias I have ever seen.

Points of Interest: 2/28/2014
Points of Interest: 2/27/2014