Clarifying chiropractic manipulation risks

Stroke

Background and Purpose-Several reports have linked chiropractic manipulation of the neck to dissection or occlusion of the vertebral artery. However, previous studies linking such strokes to neck manipulation consist primarily of uncontrolled case series. We designed a population-based nested case-control study to test the association. Methods-Hospitalization records were used to identify vertebrobasilar accidents (VBAs) in Ontario, Canada, during 1993Canada, during -1998. Each of 582 cases was age and sex matched to 4 controls from the Ontario population with no history of stroke at the event date. Public health insurance billing records were used to document use of chiropractic services before the event date. Results-Results for those aged Ͻ45 years showed VBA cases to be 5 times more likely than controls to have visited a chiropractor within 1 week of the VBA (95% CI from bootstrapping, 1.32 to 43.87). Additionally, in the younger age group, cases were 5 times as likely to have had Ն3 visits with a cervical diagnosis in the month before the case's VBA date (95% CI from bootstrapping, 1.34 to 18.57). No significant associations were found for those aged Ն45 years. Conclusions-While our analysis is consistent with a positive association in young adults, potential sources of bias are also discussed. The rarity of VBAs makes this association difficult to study despite high volumes of chiropractic treatment.

2016

Background and Purpose—Several reports have linked chiropractic manipulation of the neck to dissection or occlusion of the vertebral artery. However, previous studies linking such strokes to neck manipulation consist primarily of uncontrolled case series. We designed a population-based nested case-control study to test the association. Methods—Hospitalization records were used to identify vertebrobasilar accidents (VBAs) in Ontario, Canada, during 1993–1998. Each of 582 cases was age and sex matched to 4 controls from the Ontario population with no history of stroke at the event date. Public health insurance billing records were used to document use of chiropractic services before the event date. Results—Results for those aged,45 years showed VBA cases to be 5 times more likely than controls to have visited a chiropractor within 1 week of the VBA (95 % CI from bootstrapping, 1.32 to 43.87). Additionally, in the younger age group, cases were 5 times as likely to have had $3 visits wi...

Stroke, 2001

Background and Purpose-Several reports have linked chiropractic manipulation of the neck to dissection or occlusion of the vertebral artery. However, previous studies linking such strokes to neck manipulation consist primarily of uncontrolled case series. We designed a population-based nested case-control study to test the association. Methods-Hospitalization records were used to identify vertebrobasilar accidents (VBAs) in Ontario, Canada, during 1993Canada, during -1998. Each of 582 cases was age and sex matched to 4 controls from the Ontario population with no history of stroke at the event date. Public health insurance billing records were used to document use of chiropractic services before the event date. Results-Results for those aged Ͻ45 years showed VBA cases to be 5 times more likely than controls to have visited a chiropractor within 1 week of the VBA (95% CI from bootstrapping, 1.32 to 43.87). Additionally, in the younger age group, cases were 5 times as likely to have had Ն3 visits with a cervical diagnosis in the month before the case's VBA date (95% CI from bootstrapping, 1.34 to 18.57). No significant associations were found for those aged Ն45 years. Conclusions-While our analysis is consistent with a positive association in young adults, potential sources of bias are also discussed. The rarity of VBAs makes this association difficult to study despite high volumes of chiropractic treatment.

J Vertebral Subluxation Res, 2001

Although the issues of harm and cause-effect are widely believed to be best studied using randomized clinical trials (RCTs), that design is often impossible in the case of rare events, and unethical when adverse outcomes are being investigated. Instead, case-control studies have come to form the cornerstone of epidemiological research. Case-control studies have become popular amongst epidemiologists because they are easier, quicker, and much less expensive than experimental and cohort studies. As a result, from headlines in the popular press, to recommendations made by the Center for Disease Control (CDC) and World Health Organization (WHO), the public along with health care practitioners are bombarded by statements and claims based largely on case-control studies. However, case-control studies pay a price for their savings in time and dollars. A multitude of systematic distortions (biases) may effect the results and conclusions drawn from case-control studies. 1 The present article aims to provide examples of the kind of structured critical appraisal guides that allow readers to better assess the validity of a case-control study and the extent to which it is effected Abstract -Observational research suggests that there may exist an association between neck manipulation and stroke. Although the issue of harm is best studied using randomized trials, the rarity of such accidents often make the use of that design impossible. As a result, whether an association exists between an intervention and harmful side-effects is often assessed with controlled observational studies (cohort and case-control studies).This article aims to provide a guide for practicing chiropractors on how to assess the validity of case-control studies concerning harm. Furthermore, this article provides a guide on how to assess the extent to which causal inferences can be made from such studies.The example used is the possible relationship between chiropractic adjustments and stroke.This article is structured through the use of two critical appraisal guidelines, the likes of which are widely promoted and used by the proponents of Evidence-based Medicine.The guidelines propose a series of questions and criteria that allow the different research designs used in studies reporting an association between neck manipulation and vertebrobasilar accidents(VBA's) to be critically appraised. The critical appraisal of a study concerning harm is best achieved using a structured guideline that facilitates assessment of the validity of individual papers and consideration of the extent to which causal inferences can be made. There is no human experimental evidence that chiropractic adjustments, or neck manipulations, are causally related to VBA's.The strength of the inferences that can be made from observational studies carried out to date are severely limited by design issues. Although there may exist a weak association between neck manipulation and VBA's we know very little about the nature of that relationship. The recent publication of a case-control study by Rothwell et al. provides little insight into whether a causal relationship exists between chiropractic adjustments and VBA's.

European Spine Journal, 2008

Study Design. Population-based, case-control and case-crossover study.

Chiropractic & manual therapies, 2015

There is controversy surrounding the risk of manipulation, which is often used by chiropractors, with respect to its association with vertebrobasilar artery system (VBA) stroke. The objective of this study was to compare the associations between chiropractic care and VBA stroke with recent primary care physician (PCP) care and VBA stroke. The study design was a case-control study of commercially insured and Medicare Advantage (MA) health plan members in the U.S. population between January 1, 2011 and December 31, 2013. Administrative data were used to identify exposures to chiropractic and PCP care. Separate analyses using conditional logistic regression were conducted for the commercially insured and the MA populations. The analysis of the commercial population was further stratified by age (<45 years; ≥45 years). Odds ratios were calculated to measure associations for different hazard periods. A secondary descriptive analysis was conducted to determine the relevance of using ch...

International Journal of Clinical Practice, 2013

Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, 2017

Chiropractic manipulation is a popular treatment for neck pain and headache, but may increase the risk of cervical artery dissection and stroke. Patients with carotid artery dissection can present with neck pain and/or headache before experiencing a stroke. These are common symptoms seen by both chiropractors and primary care physicians (PCPs). We aimed to assess the risk of carotid artery stroke after chiropractic care by comparing association between chiropractic and PCP visits and subsequent stroke. A population-based, case-crossover study was undertaken in Ontario, Canada. All incident cases of carotid artery stroke admitted to hospitals over a 9-year period were identified. Cases served as their own controls. Exposures to chiropractic and PCP services were determined from health billing records. We compared 15,523 cases to 62,092 control periods using exposure windows of 1, 3, 7, and 14 days prior to the stroke. Positive associations were found for both chiropractic and PCP vis...

PubMed, 2003

Although rare, vertebrobasilar stroke is the best known of the possible side effects of cervical manipulation. Due to the serious sequelae that may result from cervical manipulation, chiropractors and osteopaths must take the appropriate steps to ensure the risk is minimised. This article outlines how the astute practitioner can minimise this risk. Practitioners must decide on the options for treatment of a patient with neck problems. Practitioners must also advise the patient of these options as part of an appropriate informed consent.

Journal of manipulative and physiological therapeutics, 2004