Doesn't Answer the Question. Again. Chiropractic and Stroke.

Doesn't Answer the Question.  Again. Chiropractic and Stroke.

Does chiropractic care cause a stroke? No. Because chiropractic care covers a lot of interventions, from the realigning nonexistent subluxations to advising against vaccinations to the uber-silliness that is applied kinesiology.

Does neck manipulation, the high velocity low amplitude (chiro speak for a quick neck snap) manipulation that most resembles a brief hanging lead to occasional stroke? Now that is the question.

Chiropractors love to point to the Cassidy study as evidence that neck manipulation does not cause stoke.

A careful reading, such I as did over at Science-Based Medicine, suggests that the Cassidy points to an increase risk for stroke following chiropractic manipulation, especially in the young. It was a flawed study, but if you are a chiropractor who doesn’t read carefully or beyond the abstract, you might think the paper supports the safety of chiropractic.


The authors of Chiropractic care and the risk of vertebrobasilar stroke: results of a case–control study in U.S. commercial and Medicare Advantage populations also like the Cassidy study,

The work by Cassidy, et al. [32] has been qualitatively appraised as one of the most robustly designed investigations of the association between chiropractic manipulative treatment and VBA stroke

which was done in Canada.

Hey. Lets see if we can reproduce the same flawed in the US.  Then we can have two bad studies, which is better than one bad study.

They looked at stoke 30 days following a PCP visit or a chiropractic visit and found no difference.

Among the commercially insured, 1.6% of stroke cases had visited chiropractors within 30 days of being admitted to the hospital, as compared to 1.3% of controls visiting chiropractors within 30 days prior to their index date. Of the stroke cases, 18.9% had visited a PCP within 30 days prior to their index date, while only 6.8% of controls had visited a PCP

Which really says nothing. There is no information about why those who had a stoke were visiting either provider, not is there clear information about who had neck manipulation and

Although, our results did lend credence to previous reports that VBA stroke occurs more frequently in patients under the age of 45 years. Additionally, the results from the present study did not identify a relevant temporal impact.

As the authors note

Our results add weight to the view that chiropractic care is an unlikely cause of VBA strokes. However, the current study does not exclude cervical manipulation as a possible cause or contributory factor in the occurrence of VBA stroke.

It adds nothing the likeliness of of causing a VBA stroke given the rarity of the complication, of the difficulty in determining as association on the basis of clinic visits. 

I can’t see where the paper adds any information about the safety of chiropractic neck manipulation and will stick with the preponderance of data and the AHA/ASA Guidelines. But it does add FUD and I am sure there will be no end of blog entries trumpeting the paper and concluding chiropractic is safe.

We do need better data. Many hospitals have stroke programs to maximize care for patients with stroke. When I last asked, the programs do not enquire into recent neck manipulation. Some clever epidemiologist needs to leverage information from all the stoke programs to help determine what the real risk of a brief hanging is.

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