The sister posting to this one, “Unintentional and Intentional Injuries: 1.” Is based on the same study and reflects the primary purpose of that investigation (to determine whether intentional and unintentional injuries are related). The findings reported here were serendipitous and uncovered the surprising involvement  of health system errors. 
    While there was no consistent international format for grouping injury causes at the time of our study, the Alberta Center for Injury Control & Research, in partnership with Alberta Health & Wellness, had developed standard injury groupings for their use. The 25 injury groupings were based on the International Classification of Diseases, Version 9, external causes of injury and were applied here to all hospitalizations due to injury in  Alberta during calendar year 1999.
    The accompanying figure shows the 15 most relevant injury admissions expressed as the Provincial rate per 100,000 persons. Excluded were classifications that were not specific/vague (i.e. Other Transportation Related, Late Effects of Injury, Unspecified Cause, and Other Classifiable Injury), as well as those showing a very low rate (<10 per 100,000; Bike - Non-Traffic, Undetermined Intent, Pedestrian - Non Traffic, Drowning, Firearm (unintentional), and legal intervention). The excluded groups made up a total of only 8.3% of all injury hospitalizations.
    Across all causes the resulting distribution is highly skewed with three categories   (medical misadventures, falls, and drug effects) making up 68% of all injury admissions. Notably, medical misadventures and drug effects can be classified as medical errors that, together, were deemed to be causal in 45% of all the Provincial injury admissions in a one-year period. Shocking as this finding may seem, it corresponds with findings from other jurisdictions and has led to increasing attention to safety measures in hospitals in, at least, Canada and the United States.