1999 Institute of
1999 Institute of Medicine Report
that from 44,000
to 98,000 people die annually due to errors in inpatient hospital
treatment. Hundreds of articles
errors have cited the Institute of Medicine Report.
to Dr. Lucien
Leape, lead the author of the Harvard study, the number of deaths
from medical errors in hospitals account for
the equivalent to the death toll from three jumbo jet crashes every
two days. Public Health Reports,
114: 302-317 July / August, 1999. One in every 10 patients
admitted to a hospital is the victim of at least one mistake.
National Public Radio (NPR) November
21, 2000, (Audio)
of patients who were harmed by medical treatment filed malpractice
Engl J Med 1989 Aug 17;321(7):480-4
years after I.O.M. report, medical errors still claiming many lives
the IOM arrived
their estimate of 44,000 - 98,00 deaths due to hospital errors.
in 3.7 percent of the
nature of adverse
events in hospitalized patients.
patients filed malpractice suits.
Summaries of the original data.
Articles Citing the IOM Report:
- Headlines: 1999.2000.2001.2002.2003.2004.2005.2006.2007.
- Leads: 1999.2000.2001.2002.2003.2004.2005.2006.2007.
From To Err Is Human: Building
Safer Health System
Summary - Page 1 Linda T. Kohn, Janet M.
Corrigan, and Molla S. Donaldson, Editors;
Committee on Quality of Health Care in America,
Institute of Medicine
Two large studies, one conducted in Colorado and Utah
and the other in New
York, found that adverse events occurred in 2.9 and 3.7 percent of
hospitalizations, respectively. In Colorado and Utah hospitals,
6.6 percent of adverse events led to death, as compared with 13.6
percent in New York hospitals. In both of these studies, over half of
these adverse events resulted from medical errors and could have been
When extrapolated to the over 33.6 million admissions to
U.S. hospitals in 1997, the results of the study in Colorado and Utah
imply that at least 44,000 Americans die each year as a result of
medical errors. The results of the New York Study suggest the
number may be
as high as 98,000. Even when using the lower estimate,
deaths due to medical errors exceed the number attributable to the
of death. More people die in a given year as a result of medical
than from motor vehicle accidents (43,458), breast cancer (42,297), or
Abstracts from New England Journal of Medicine presenting
original New York findings: I . II
. III .
adverse events and
Results of the Harvard Medical Practice
Brennan TA, Leape LL, Laird NM, Hebert L, Localio AR, Lawthers AG,
Newhouse JP, Weiler PC, Hiatt HH. Division of General Medicine, Brigham
and Women's Hospital, Boston, MA 02115.
N Engl J Med 1991 Feb 7;324(6):370-6
BACKGROUND. As part of an interdisciplinary study of
injury and malpractice litigation, we estimated the incidence of
adverse events, defined as injuries caused by medical management, and
of the subgroup of such injuries that resulted from negligent or
METHODS. We reviewed 30,121 randomly selected records from
51 randomly selected acute care, nonpsychiatric hospitals in New York
State in 1984. We then developed population estimates of injuries and
computed rates according to the age and sex of the patients as well as
the specialties of the physicians.
RESULTS. Adverse events occurred in 3.7 percent of the
hospitalizations (95 percent confidence interval, 3.2 to 4.2), and
27.6 percent of the adverse events were due to negligence (95 percent
confidence interval, 22.5 to
32.6). Although 70.5 percent of the adverse events gave rise to
lasting less than six months, 2.6 percent caused permanently disabling
injuries and 13.6 percent led to death. The percentage of
attributable to negligence increased in the categories of more severe
(Wald test chi 2 = 21.04, P less than 0.0001). Using weighted totals,
estimated that among the 2,671,863 patients discharged from New York
in 1984 there were 98,609 adverse events and 27,179 adverse events
negligence. Rates of adverse events rose with age (P less than 0.0001).
The percentage of adverse events due to negligence was markedly higher
the elderly (P less than 0.01). There were significant differences in
of adverse events among categories of clinical specialties (P less than
0.0001), but no differences in the percentage due to negligence.
CONCLUSIONS. There is a substantial amount of injury to
from medical management, and many injuries are the result of
substandard care. PMID: 1987460
adverse events in
Results of the Harvard Medical Practice Study II.
Leape LL, Brennan TA, Laird N, Lawthers AG, Localio AR, Barnes BA,
Hebert L, Newhouse JP, Weiler PC, Hiatt H.
Department of Health Policy and Management, Harvard School of
Public Health, Boston, MA 02115.
N Engl J Med 1991 Feb 7;324(6):377-84
BACKGROUND. In a sample of 30,195 randomly selected
records, we identified 1133 patients (3.7 percent) with disabling
injuries caused by medical treatment. We report here an analysis of
these adverse events and their relation to error, negligence, and
METHODS. Two physician-reviewers independently identified
adverse events and evaluated them with respect to negligence, errors in
management, and extent of disability. One of the authors classified
each event according to type of injury. We tested the significance of
differences in rates of negligence and disability among categories with
at least 30 adverse events.
RESULTS. Drug complications were the most common
adverse event (19 percent), followed by wound infections (14
percent) and technical complications (13 percent). Nearly half
adverse events (48 percent) were associated with an operation. Adverse
during surgery were less likely to be caused by negligence (17 percent)
than nonsurgical ones (37 percent). The proportion of adverse events
to negligence was highest for diagnostic mishaps (75 percent),
therapeutic mishaps ("errors of omission") (77 percent), and
occurring in the emergency room (70 percent). Errors in
were identified for 58 percent of the adverse events, among which
half were attributed to negligence.
CONCLUSIONS. Although the prevention of many adverse
await improvements in medical knowledge, the high proportion that are
due to management errors suggests that many others are potentially
preventable now. Reducing the incidence of these events will require
identifying their causes and developing methods to prevent error or
reduce its effects.
adverse events due to
Results of the Harvard Medical Practice
Localio AR, Lawthers AG, Brennan TA, Laird NM, Hebert LE,
Peterson LM, Newhouse JP, Weiler PC, Hiatt HH.
Center for Biostatistics and Epidemiology, Penn State University
College of Medicine, Hershey 17033.
N Engl J Med 1991 Jul 25;325(4):245-51
BACKGROUND AND METHODS. By matching the medical records
a random sample of 31,429 patients hospitalized in New York State
in 1984 with statewide data on medical-malpractice claims, we
identified patients who had filed claims against physicians and
These results were then compared with our findings, based on a review
of the same medical records, regarding the incidence of injuries
to patients caused by medical management (adverse events).
RESULTS. We identified 47 malpractice claims among 30,195
patients' records located on our initial visits to the hospitals,
and 4 claims among 580 additional records located during
follow-up visits. The overall rate of claims per discharge (weighted)
was 0.13 percent (95 percent confidence interval, 0.076 to 0.18
percent). Of the 280 patients who had adverse events
caused by medical negligence as defined by the study protocol, 8
filed malpractice claims (weighted rate, 1.53 percent;
95 percent confidence interval, 0 to 3.2 percent). By contrast,
our estimate of the statewide ratio of adverse events caused by
negligence (27,179) to malpractice claims (3570) is 7.6 to 1.
This relative frequency overstates the chances that a negligent
will produce a claim, however, because most of the events for
claims were made in the sample did not meet our definition of adverse
due to negligence.
CONCLUSIONS. Medical-malpractice litigation infrequently
compensates patients injured by medical negligence and rarely
identifies, and holds providers accountable for, substandard
care. PMID: 2057025
A study of medical injury and medical malpractice.
Hiatt HH, Barnes BA, Brennan TA, Laird NM, Lawthers AG, Leape LL,
Localio AR, Newhouse JP, Peterson LM, Thorpe KE, et al. Harvard
School of Public Health, Boston, MA 02115.
N Engl J Med 1989 Aug 17;321(7):480-4
Incidence and types of adverse events and negligent care
in Utah and
Thomas EJ, Studdert DM, Burstin HR, Orav EJ, Zeena T, Williams
EJ, Howard KM, Weiler PC, Brennan TA.
Department of Medicine, Brigham and Women's Hospital, Boston,
Med Care 2000 Mar;38(3):261-71
BACKGROUND: The ongoing debate on the incidence and types
iatrogenic injuries in American hospitals has been informed
primarily by the Harvard Medical Practice Study, which analyzed
hospitalizations in New York in 1984. The generalizability of these
findings is unknown and has been questioned by other studies.
OBJECTIVE: We used methods similar to the Harvard
Medical Practice Study to estimate the incidence and types of adverse
events and negligent adverse events in Utah and Colorado in 1992.
DESIGN AND SUBJECTS: We selected a representative
of hospitals from Utah and Colorado and then randomly sampled
15,000 nonpsychiatric 1992 discharges. Each record was screened by a
trained nurse-reviewer for 1 of 18 criteria associated with
adverse events. If
> or =1 criteria were present, the record was reviewed by a
trained physician to determine whether an adverse event or
negligent adverse event occurred and to classify the type of adverse
MEASURES: The measures were adverse events and
RESULTS: Adverse events occurred in 2.9+/-0.2%
(mean+/-SD) of hospitalizations in each state. In Utah, 32.6+/-4%
of adverse events were due to negligence; in Colorado,
27.4+/-2.4%. Death occurred in 6.6+/-1.2% of adverse
events and 8.8+/-2.5% of negligent adverse events. Operative
adverse events comprised 44.9% of all adverse events; 16.9% were
negligent, and 16.6% resulted in permanent disability. Adverse
drug events were the leading cause of nonoperative adverse events
(19.3% of all adverse events; 35.1% were negligent, and 9.7% caused
permanent disability). Most adverse events were attributed to
surgeons (46.1%, 22.3% negligent) and internists (23.2%, 44.9%
CONCLUSIONS: The incidence and types of adverse events
Utah and Colorado in 1992 were similar to those in New York State in
1984. Iatrogenic injury continues to be a significant public
health problem. Improving systems of surgical care and drug
delivery could substantially reduce the burden of iatrogenic
injury. PMID: 10718351
incidence and nature of
surgical adverse events in
and Utah in
Gawande AA, Thomas EJ, Zinner MJ, Brennan TA.
Department of Surgery, Brigham and Women's Hospital, Boston, MA
Surgery 1999 Jul;126(1):66-75
BACKGROUND: Despite more than three decades of research on
iatrogenesis, surgical adverse events have not been subjected to
detailed study to identify their characteristics. This
could be invaluable, however, for guiding quality assurance and
efforts aimed at reducing the occurrence of surgical adverse
Thus we conducted a retrospective chart review of 15,000 randomly
selected admissions to Colorado and Utah hospitals during 1992 to
identify and analyze these events.
METHODS: We selected a representative sample of
from Utah and Colorado and then randomly sampled 15,000 nonpsychiatric
discharges from 1992. With use of a 2-stage record-review process
previous adverse event studies, we estimated the incidence,
and preventability of surgical adverse events that caused death,
disability at the time of discharge, or prolonged hospital stay. We
their distribution by type of injury and by physician specialty
determined incidence rates by procedure.
RESULTS: Adverse events were no more likely in surgical
than in nonsurgical care. Nonetheless, 66% of all adverse events
were surgical, and the annual incidence among hospitalized
who underwent an operation or child delivery was 3.0% (confidence
interval 2.7% to 3.4%). Among surgical adverse events 54%
(confidence interval 48.9% to 58.9%) were preventable. We
identified 12 common operations with significantly elevated adverse
event incidence rates that ranged
from 4.4% for hysterectomy (confidence interval 2.9% to 6.8%) to
18.9% for abdominal aortic aneurysm repair (confidence interval 8.3% to
37.5%). Eight operations also carried a significantly higher risk
of a preventable adverse event: lower extremity bypass graft
abdominal aortic aneurysm repair (8.1%), colon resection (5.9%),
coronary artery bypass graft/cardiac valve surgery (4.7%),
transurethral resection of the prostate or of a bladder tumor
(3.9%), cholecystectomy (3.0%), hysterectomy (2.8%), and
appendectomy (1.5%). Among all surgical adverse events, 5.6%
(confidence interval 3.7% to 8.3%) resulted
in death, accounting for 12.2% (confidence interval 6.9% to 21.4%) of
all hospital deaths in Utah and Colorado. Technique-related
wound infections, and postoperative bleeding produced nearly half
of all surgical adverse events.
CONCLUSION: These findings provide direction for
to identify the causes of surgical adverse events and for
targeted quality improvement efforts. PMID: 10418594
Costs of medical injuries in Utah and Colorado.
Thomas EJ, Studdert DM, Newhouse JP, Zbar BI, Howard KM, Williams
EJ, Brennan TA.
University of Texas-Houston Medical School 77030, USA.
Inquiry 1999 Fall;36(3):255-64
Patient injuries are thought to have a substantial financial
impact on the health care system, but recent studies have been
limited to estimating the costs of adverse drug events in
teaching hospitals. This analysis estimated the costs of all
types of patient injuries from
a representative sample of hospitals in Utah and Colorado.
We detected 459 adverse events (of which 265 were preventable) by
reviewing the medical records of 14,732 randomly selected 1992
discharges from 28 hospitals. The total costs (all results are
discounted 1996 dollars) were $661,889,000 for adverse events,
and $308,382,000 for preventable adverse events. Health care costs
totaled $348,081,000 for all adverse events and $159,245,000 for
the preventable adverse events. Fifty-seven percent of the
adverse event health care costs, and 46% of the preventable
adverse event costs were attributed to outpatient medical care.
Surgical complications, adverse drug events, and delayed or
incorrect diagnoses and therapies were the most expensive types
of adverse events. The costs of adverse events were similar to
the national costs of caring for people with HIV/AIDS, and
totaled 4.8% of per capita health care expenditures in these
states. PMID: 10570659
How Many Medical Errors?.
What Kind?.Not FollowingGuidelines
SideSurgery.Reducing Errors.Doctor Discipline