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Unformatted text preview: SPINE Volume 33, Number 4S, pp S176–S183 ©2008, Lippincott Williams & Wilkins Risk of Vertebrobasilar Stroke and Chiropractic Care Results of a Population-Based Case-Control and Case-Crossover Study J. David Cassidy, DC, PhD, DrMedSc,*†‡ Eleanor Boyle, PhD,* Pierre Co ˆte ´, DC, PhD,*†‡ § Yaohua He, MD, PhD,* Sheilah Hogg-Johnson, PhD,† § Frank L. Silver, MD, FRCPC,¶ \ and Susan J. Bondy, PhD† Study Design. Population-based, case-control and case-crossover study. Objective. To investigate associations between chiro- practic visits and vertebrobasilar artery (VBA) stroke and to contrast this with primary care physician (PCP) visits and VBA stroke. Summary of Background Data. Chiropractic care is popular for neck pain and headache, but may increase the risk for VBA dissection and stroke. Neck pain and head- ache are common symptoms of VBA dissection, which commonly precedes VBA stroke. Methods. Cases included eligible incident VBA strokes admitted to Ontario hospitals from April 1, 1993 to March 31, 2002. Four controls were age and gender matched to each case. Case and control exposures to chiropractors and PCPs were determined from health billing records in the year before the stroke date. In the case-crossover analysis, cases acted as their own controls. Results. There were 818 VBA strokes hospitalized in a population of more than 100 million person-years. In those aged , 45 years, cases were about three times more likely to see a chiropractor or a PCP before their stroke than controls. Results were similar in the case control and case crossover analyses. There was no increased association between chiropractic visits and VBA stroke in those older than 45 years. Positive associations were found between PCP visits and VBA stroke in all age groups. Practitioner visits billed for headache and neck complaints were highly associated with subsequent VBA stroke. Conclusion. VBA stroke is a very rare event in the population. The increased risks of VBA stroke associated with chiropractic and PCP visits is likely due to patients with headache and neck pain from VBA dissection seek- ing care before their stroke. We found no evidence of excess risk of VBA stroke associated chiropractic care compared to primary care. Key words: vertebrobasilar stroke, case control stud- ies, case crossover studies, chiropractic, primary care, complications, neck pain. Spine 2008;33:S176–S183 Neck pain is a common problem associated with consid- erable comorbidity, disability, and cost to society. 1–5 In North America, the clinical management of back pain is provided mainly by medical physicians, physi- cal therapists and chiropractors. 6 Approximately 12% of American and Canadian adults seek chiropractic care annually and 80% of these visits result in spinal manipulation....
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This note was uploaded on 01/07/2012 for the course PHPR 1212 taught by Professor Young during the Summer '11 term at Palmer Chiropractic.
- Summer '11