What’s New in the Patient Safety World

May  2011

Just How Frequent Are Hospital Medical Errors?



As you know, we have often stated that statistics don’t sell patient safety – stories do. We learned that after watching numerous and varied audiences zone out when we quoted the infamous statistics from the original IOM report “To Err is Human”.


But statistics do keep popping up. A new study (Classen 2011), using IHI’s Global Trigger Tool to identify hospital adverse events, found that the numbers may be 10-fold higher than what was noted in the IOM report. Potentially avoidable adverse events occurred in a third of hospital admissions. In addition to the human cost of iatrogenic adverse events, the financial costs are huge. A second study in the same issue of Health Affairs (Van Den Bos 2011) pegs that cost at $17.1 billion annually. And a third paper (Goodman 2011) estimates the annual social cost of medical errors ranges from $393 billion to $958 billion.


The IHI Global Trigger Tool clearly identifies more adverse events than are found either via voluntary reporting or using administrative data tools like AHRQ’s PSI indicators. In our January 2011 What’s New in the Patient Safety World column “No Improvement in Patient Safety: Why Not?” we noted a study (Landrigan 2010) that showed there has been little improvement in hospital adverse events overall over a long time frame. That study, done on data from 10 North Carolina hospitals, used IHI’s Global Trigger Tool to estimate rates of patient harm and preventable harm over a 6-year period. They found essentially no reduction in harm over that period. They had chosen North Carolina because many hospitals there had participated in patient safety collaboratives and North Carolina had a much higher percentage of hospitals participating in IHI’s patient safety programs.


While the IHI Global Trigger Tool measures events somewhat differently than in the studies that formed the basis of the IOM report, the global trigger tool methodology is “doable” with limited resources and provides a more reliable comparison over time. See our October 30, 2007 Patient Safety Tip of the Week “Using IHI's Global Trigger Tool” and our April 15, 2008 Patient Safety Tip of the Week Computerizing Trigger Tools” for more details on how to use it.


A related article by the group that did the North Carolina study (Sharek 2011) provides an excellent discussion on use of IHI’s Global Trigger Tool to measure hospital adverse events and allow for trending over time. It also provides a good description of how the tool is used, its performance characteristics, and its potential for use not only by hospitals but also by state or national groups to measure patient safety events. You’ll recall that the trigger tool just points to potential iatrogenic adverse events and then chart review is still necessary. One of the most interesting and unexpected findings in the Sharek study was that teams of internal reviewers actually performed better than the more experienced external reviewers.






Classen D, Resar R, Griffin F, et al. ‘Global Trigger Tool’ Shows That Adverse Events In Hospitals May Be Ten Times Greater Than Previously Measured. Health Affairs 2011; 30(4): 581-589




Van Den Bos J, et al "The $17.1 Billion Problem: The annual cost of measurable medical errors" Health Affairs 2011; 30(4): 596-630.




Goodman J, et al "The social cost of adverse medical events, and what we can do about it" Health Affairs 2011; 30(4): 590-595.




Christopher P. Landrigan CP, Parry GJ, Bones CB, et al. Temporal Trends in Rates of Patient Harm Resulting from Medical Care. N Engl J Med 2010; 363: 2124-2134




Sharek PJ, Parry G, Goldmann D, et al.Performance Characteristics of a Methodology to Quantify Adverse Events over Time in Hospitalized Patients. Health Services Research 2011; 46(2): 654-678














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