The prevalence of medical error and medical malpractice is contentious and hotly debated, particularly by and among physicians. A confusing body of research literature on medical mistakes fuels the debate, and lack of widely-accepted definitions is part of the problem.
In the various major studies of prevalence, there is general agreement that an Adverse Event is "an injury - caused by - medical management1,2 (rather than a disease process3)." For purposes of the Harvard Medical Practice Study and the Colorado-Utah study, the researchers added, "and that prolonged the hospitalization, produced a disability at the time of discharge, or both." (my bolding)
The US Agency for Healthcare Research and Quality (AHRQ) would like to redefine4 Adverse Event as, "An untoward and usually unanticipated outcome that occurs in association with health care."
The Harvard Medical Practice Study defined5 "reasonably avoidable" as "a mistake in performance or thought", whereas the Adverse Drug Event Study Group went further6 by defining preventable as "due to an error or were preventable by any means currently available." (my bolding)
The Australian study3 blurred the distinction from Negligence by characterising preventability as, "an error in management due to the failure to follow accepted practice at an individual or system level." The AHRQ prefer4 the reasonableness test: "Harm that could be avoided through reasonable planning" but want the appropriateness element by adding "or proper execution of an action." (my bolding) However, they do not include Negligence or Malpractice in their Patient Safety Terms and Definitions.
The Harvard Medical Practice Study adopted1 the standard legal definition of Negligence as "care that fell below the standard expected of physicians in their community" and affirmed that "all [negligent injuries], in theory, are preventable."
The AHRQ instead define4 Medical Errors as "mistakes made in the process of care that result in, or have the potential to result in, harm to patients. Mistakes include the failure of a planned action to be completed as intended or the use of a wrong plan to achieve an aim. These can be the result of an action that is taken (error of commission) or an action that is not taken (error of omission)." Using the "potential to harm" criterion, Medical Error is of course much more common than Adverse Event.
Practice PointAn Adverse Event that was preventable was not necessarily caused by negligence. |
Calculated rates of Adverse Event should be considered a minimum figure, whereas prevalence of Preventable Adverse Event and Preventable Death remain uncertain and contentious.
The Institute of Medicine (IOM) assertion7 that "adverse events occurred in 2.9% and 3.7% of hospitalizations" is well-substantiated8 [full-text] by the sound methodology of the 2 major US studies1,2. Indeed, this range is probably an underestimate.
However, preventability is less well substantiated8 [full-text]. The proposal that 50-70% of Adverse Events are preventable is suspect because (1) there is uncertainty about the level of agreement between those judging preventability in the Harvard Practice Study, and (2) they used summaries of cases rather than original clinical documents. Because of their diversity, medical errors are necessarily identified by implicit review, rather than setting explicit criteria, and this method of subjective judgment inevitably introduces significant bias9.
The IOM assertion7 that ". . . at least 44,000 Americans die each year as a result of medical errors . . . the number may be as high as 98,000" is highly suspect10. The authors' method of arriving at those figures is not explicit in their report, "To Err is Human: Building a Safer Health System," and criteria are not given for judging which deaths would not have occurred but for the Adverse Event8 [full-text].
As the IOM authors acknowledge, preventable Adverse Event does not necessarily mean a preventable death. An undetermined number of those dying after an Adverse Event would have died anyway.
However, one of the principal authors of the Harvard Medical Practice Study points out11 that (1) the study was retrospective rather than prospective and (2) it was not designed to answer questions about preventable death. Nevertheless, such detailed prospective studies - of adverse drug events12,13, acute myocardial infarction, pneumonia or cerebrovascular accident14, intensive care unit patients15, and post-operative infection16 - suggest that record review considerably underestimates rather than overestimates the prevalence of preventable death and the IOM preventable death figures are too low.
Practice PointProspective studies of serious medical conditions suggest that preventable death is MORE common than the Institute of Medicine figures suggest |
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