A multitude of systematic distortions (biases) may effect the results and conclusions drawn from case-control studies. Other criteria must be used to determine whether an association is actually causative because an association, no matter how strong, does not prove causation. At this point in time due to the rarity with which neck dissections occur, experimental evidence in humans and prospective cohort studies examining the hypothesis that chiropractic adjustments cause stroke - do not exist. If such studies were to be carried out they would take a number of years to complete and would require thousandsof subjects because of the rarity of the occurrence.
Regarding advising on risks - a risk should be disclosed if a reasonable patient in what the doctor knows or should know to be the patient’s position, would be likely to attach significance to the risk or cluster of risks in deciding whether to forego the proposed therapy. Patients and doctors must make this decision based upon appropriate information. Since there is no human experimental evidence that chiropractic adjustments or neck manipulations are causally related to strokes, suggesting that such a risk exists is poor public health practice.
In addition, the same risk of stroke has been shown to be associated with visits to medical doctors as well. This research indicates that patients may be consulting medical doctors and chiropractors when they are in the early stages of a dissection or stroke, perhaps because of headaches or neck pain. In essence, there is a stroke already in process.
We encourage and support a shared decision making process between doctors and patients regarding health needs. As a part of that process patients have a right to be informed about the state of their health as well as the risks, benefits and alternatives related to care. Chiropractors are thoroughly trained to recognize when a patient’s symptoms are from an ominous cause such as dissection and are well trained to make the appropriate referral to a medical specialist.