Canadian Adverse Events Study
=============================

* J.A. Chris Delaney
* Mark Palko
* Andrei S.P. Brennan

*   © 2004 Canadian Medical Association or its licensors

In Table 1 of their recent article reporting results of the Canadian Adverse Events Study, Ross Baker and associates1 show that AE rates were lower in the United States and higher in Canada, Britain, Australia and New Zealand.

However, such differences between countries may be due more to differences in the medical systems rather than differences in the quality of patient care. The United States has a very different medical environment, partly because of the highly litigious nature of US culture.2 The fear of being sued may reduce the incidence of hindsight bias3 in US studies, since physicians may order more tests than are strictly necessary, which makes it more difficult for researchers such as Baker and associates to second-guess their decisions.

In addition, people of lower socio-economic status consume more medical resources than wealthy people.4 It may be that economically disadvantaged people with complex ailments cannot obtain care in the United States. Given that these people are at greater risk of an AE,5 this difference might reduce the apparent rate of AEs in the United States simply because these people never receive care at all.

Such differences in medical cultures may not be well captured by these types of studies. Therefore, we should be cautious in comparing AE rates between the United States and Canada.

**J.A. Chris Delaney** Statistician Department of Clinical Epidemiology Royal Victoria Hospital Montréal, Que. **Mark Palko** Statistician Atlanta, Ga. **Andrei S.P. Brennan** Research Ethics Quality Assurance Officer Research Institute of the McGill University Health Centre Montréal, Que. 

## Footnotes

*   *Competing interests:* None declared.

## References

1.  1. Baker GR, Norton PG, Flintoft V, Blais R, Brown A, Cox J, et al. The Canadian Adverse Events Study: the incidence of adverse events among hospital patients in Canada. CMAJ 2004; 170 (11):1678-86. 
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMToiMTcwLzExLzE2NzgiO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTcxLzgvODMzLjIuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

2.  2. Abood S, Tehan T. Medical malpractice crisis. Am J Nurs 2003;103(5):29. 
    
    

3.  3. Hébert PC, Levin AV, Robertson G. Bioethics for clinicians: 23. Disclosure of medical error. CMAJ 2001;164(4):509-13. 
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNjQvNC81MDkiO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTcxLzgvODMzLjIuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

4.  4. Roos NP, Forget E, Walld R, MacWilliam L. Does universal comprehensive insurance encourage unnecessary use? Evidence from Manitoba says “no.” CMAJ 2004;170(2):209-14. 
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNzAvMi8yMDkiO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTcxLzgvODMzLjIuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

5.  5. Burstin HR, Lipsitz SR, Brennan TA. Socioeconomic status and risk for substandard medical care. JAMA 1992;268:2383-7.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1001/jama.1992.03490170055025&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=1404794&link_type=MED&atom=%2Fcmaj%2F171%2F8%2F833.2.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=A1992JV69400023&link_type=ISI)