http://www.bmj.com/cgi/content/full/322/7285/517
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Papers
Adverse events in British hospitals: preliminary retrospective record
review
Charles Vincent
Clinical Risk Unit, Department of Psychology,
University College London, London WC1E 6BT
Correspondence to: C Vincent c.vincent@ucl.ac.uk
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Abstract |
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Objectives: To examine the feasibility of detecting adverse events
through record review in British hospitals and to make preliminary
estimates of the incidence and costs of adverse events.
Design: Retrospective review of 1014 medical and nursing records.
Setting: Two acute hospitals in Greater London area.
Main outcome measure: Number of adverse events.
Results: 110 (10.8%) patients experienced an adverse event,
with an overall rate of adverse events of 11.7% when multiple adverse
events were included. About half of these events were judged
preventable with ordinary standards of care. A third of adverse
events led to moderate or greater disability or death.
Conclusions: These results suggest that adverse events are a
serious source of harm to patients and a large drain on NHS
resources. Some are major events; others are frequent, minor events
that go unnoticed in routine clinical care but together have massive
economic consequences.
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Introduction |
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Retrospective studies of hospital case records in the United States and
Australia have shown a substantial rate of adverse events, defined
as unintended injuries caused by medical management rather than the
disease process. The Harvard medical practice study found that 3.7%
of hospital admissions led to adverse events. 1 2 In 70%
of these patients the adverse event led to slight or short lived
disabilities, but in 7% the disabilities were permanent and in 14%
they contributed to death. Similar rates were found in a study from
Colorado and Utah. 3
4 The
quality in Australian healthcare study identified adverse events in
16.6% of admissions, half of which were considered preventable.5 This
study included a wider range of adverse events of minor or moderate
severity. Other methodological differences also exaggerate the
difference between the United States and Australian figures. 4 6 The
Australian study estimated that adverse events accounted for 8% of
hospital bed days and cost the Australian healthcare system $4.7bn a
year. Adverse events also result in huge personal cost to the
affected individuals, both patients and staff.7
The epidemiology of adverse events has not been studied in Britain. We
report preliminary findings from a pilot study that examined the
feasibility of applying United States and Australian methods and the
potential value of a parallel study in the United Kingdom.
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Methods |
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Design and procedure
The study was carried out at two acute hospitals in the London area.
We reviewed 500 randomly drawn records from site 1 between
July and September 1999 and 514 records from site 2 between
December 1999 and February 2000. In both sites the index admissions
studied occurred in two months in 1998, about a year before the
review periods. We reviewed 273 (26.9%) records from general
medicine (including geriatrics), 290 (28.6%) from general surgery,
277 (27.3%) from orthopaedic surgery, and 174 (17.2%) from
obstetrics. Admissions to the four specialties studied in 1998-9 were
19 397 in site 1 and 18 335 in site 2. The proportions
of admissions studied were 2.6% and 2.8% respectively.
Review process
The review team consisted of an experienced nurse who worked as
project manager with four part time research nurses. A consultant
physician acted as lead medical assessor, working with five part
time surgical and obstetric colleagues, each of whom had been
qualified for a minimum of 10 years. Each reviewer screened
sets of notes under supervision until they were judged to be fully
conversant with the review process.
The nurse reviewers used 18 predefined screening
criteria to assess the case records. Records that screened positive (n = 405)
were then reviewed by clinicians, who identified any adverse events
and completed a detailed questionnaire. The clinicians assessed the
impact of each adverse event on the patient in terms of disability
and additional bed days, likely cause, place and date of occurrence,
type of adverse event (for example, whether related to a particular
procedure or treatment), and preventability and recorded detailed
clinical information. Records were reviewed once only, although
difficult issues were resolved after duplicate review and discussion
between two or more assessors. Criteria for adverse events are given
on the BMJ 's website. A full description of the methods has
been published. 2
5
Copies of the British review forms are available from the authors.
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Results |
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In all, 110 (10.8%) of 1014 patients experienced an adverse event
(table 1).
However, some patients experienced multiple events, and the overall
number of events was 119 (11.7%). There was no significant
difference in sex between patients who did and did not experience an
adverse event. However, patients with adverse events were older than
those who did not experience an adverse event (P<0.001; see
tables A and B on BMJ 's website)
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Seventy three (66%) patients who suffered an adverse event had minimal
impairment or recovered within one month; 37 (34%) patients
developed an injury or complication that resulted in moderate
impairment (21 patients; 19%) or permanent impairment (seven
patients; 6%) or contributed to death (nine patients; 8%). Overall,
53 (48%) adverse events were judged preventable. The box shows
an example of a patient who experienced serious adverse events.
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Example of adverse
event A 53 year old man with a history of stroke, multiple resistant Staphylococcus
aureus infection, leg ulcers, and heart failure was admitted for
treatment of venous ulceration and cellulitis of both legs. He sustained two
adverse events: 1. Failure to manage the leg ulcers aggressively led to the development of
osteomyelitis. He subsequently had below knee amputation of both legs. 2. Incorrect management of his urinary catheter resulted in necrosis of
the tip of the penis. He had suprapubic catheterisation and developed an
infection. The patient's hospital stay was extended by 26 days. |
The 119 adverse events resulted in a total of
999 extra bed days, of which 460 (46%) were judged preventable and
therefore could have been saved. Each adverse event led to an
average of 8.5 additional days in hospital (range
0-70 days) with additional direct costs of £290 268 to the
trusts concerned (table 2).
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Discussion |
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Our pilot study has established the feasibility of conducting a major record
review of adverse events in the United Kingdom. We found that 10.8%
of patients admitted to hospital experience an adverse event, with
an overall 11.7% rate of adverse events when multiple adverse events
are included. About half of these events were judged preventable. A
third of adverse events led to moderate or greater disability or
death. Some adverse events are serious and are traumatic for both
staff and patients. Others are frequent, minor events that go
unnoticed in routine clinical care and yet together have massive
economic consequences.
This study is primarily a pilot and has certain limitations. The study was
small and based on only two hospitals. In addition, the case mix
does not accurately reflect hospital practice. The specialties
included in the review could have higher rates of adverse events
than other specialties. Nevertheless, the specialties we chose
constitute a large proportion of inpatient care.
Although we cannot extrapolate with any precision, our findings strongly
suggest that adverse events are a serious problem in the NHS, as
they are in the United States and Australia. We estimate that around
5% of the 8.5 million patients admitted to hospitals in England
and Wales each year experience preventable adverse events, leading
to an additional three million bed days. The total cost to the NHS
of these adverse events in extra bed days alone would be around £1bn
a year.
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What is already
known on this topic Substantial numbers of patients in hospital in the United States and
Australia have been found to suffer adverse events No data are available for the United Kingdom What this study
adds In this pilot study about 10% of patients admitted to acute hospitals
experienced an adverse event A third of these events led to moderate or greater impairment About half of the adverse events were preventable with current standards
of care Preventable adverse events could cost the NHS around £1bn a year in terms
of additional bed days |
In the United States and Australia retrospective case record
analysis has provided the foundation and driving force for initiatives to
reduce harm to patients and to make more efficient use of expensive hospital
resources. Our findings indicate that a full national study would be
justified in the United Kingdom, as indicated in the chief medical
officer's recent report.8 We
believe that the investigation should cover at least 20 general
hospitals (of varying size and type) and include
500 representative case records from each hospital. This would
yield around 1000 adverse events for detailed analysis. Such a
study would provide reliable information on the numbers, types, and
costs of adverse events occurring in NHS hospitals. This would allow
the principal causes to be explored and specific risk reduction
strategies to be identified and costed. The total cost of such a
study would probably be equivalent to the money lost through
preventable adverse events in less than eight hours in the NHS.
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Acknowledgments |
We thank our international colleagues Bob
Gibberd, John Hamilton, Bernie Harrison, Eric Thomas, and Ross Wilson for their
time and support, and Alastair Gray for advice on economic aspects of
the study. We also thank the clinical reviewers: Justice U-Lois, Sebastian
Borges, Aubyn Marath, Deirdre Murphy, and Robert Downes; the
nurse/midwife screeners: Jayne Moore, Jane Weaver, Sinéad Trainor,
Marcia Persaud, and Katie Major; and the staff at the two trusts.
Contributors: CV designed and wrote the original research proposal. GN was
lead clinician for the review. MW managed the project and was responsible for
data analysis. All authors contributed equally to the final report. CV and GN
are guarantors.
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Footnotes |
Funding: King's Fund, Nuffield Trust, London Region NHS Research and
Development Programme, and the Dunhill Medical Trust. The views and
opinions expressed in this article do not necessarily reflect those
of these bodies.
Competing interests: None declared.
The criteria for adverse events and
tables of results is available on the BMJ's website
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References |
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1. |
Brennan TA, Leape LL, Laird NM, Hebert L, Localio AR,
Lawthers AG, et al. Incidence of adverse events and negligence in
hospitalised patients. N Engl J Med 1991; 324: 370-376 |
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2. |
Leape LL, Brennan TA, Laird NM, Lawthers AG, Localio AR,
Barnes BA, et al. Incidence of adverse events and negligence in hospitalised
patients: results of the Harvard medical practice study II. N Engl J Med
1991; 324: 377-384 |
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3. |
Gawande AA, Thomas EJ, Zinner MJ, Brennan TA. The
incidence and nature of surgical adverse events in Colorado and Utah in 1992.
Surgery 1999; 126: 66-75 |
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4. |
Thomas EJ, Brennan TA. Errors and adverse events in
medicine. In Vincent CA, ed. Clinical risk management: enhancing patient
safety. 2nd ed. London: BMJ Publications (in press). |
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5. |
Wilson RM, Runciman WB, Gibberd RW, Harrison BT, Newby L,
Hamilton JD. The quality in Australian health care study. Med J Aust
1995; 163: 458-471 |
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6. |
Weingart SN, Wilson RMcL, Gibberd RW, Harrison B.
Epidemiology of medical error. BMJ 2000; 320: 774-777 |
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7. |
Vincent CA. Risk, safety and the dark side of quality. BMJ
1997; 314: 1775-1776 |
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8. |
Department of Health. An organisation with a memory:
report of an expert group on learning from adverse events in the NHS.
London: DoH, 2000. |
(Accepted 27 November 2000)
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Rapid Response responses to this article:
Read all Rapid
Response responses
Wow! - Stunning figures
Ron Law
bmj.com, 2 Mar 2001 [Response]
The value of data about adverse events
Ricardo Pardo, General Surgeon , Ciudad
Real. Spain
bmj.com, 2 Mar 2001 [Response]
Adverse events in British hospitals
K Sankar, Consultant in
Genitourinary Medicince , Newcastle General Hospital
bmj.com, 3 Mar 2001 [Response]
Were adverse drug reactions included?
John Wilson, Retired paediatric
neurologist , Great ormond Street
bmj.com, 6 Mar 2001 [Response]
Right in retrospect?
R E Ferner, J K Aronson
bmj.com, 7 Mar 2001 [Response]
Will the response to adverse events highlight double
Standards?
Dr Janet Richardson, Chairman of
the Research Council for Complementary Medicine. , Oxford Brookes
University
bmj.com, 8 Mar 2001 [Response]
"The eye of the beholder" - a threshold
effect
B T Collopy and I G McDonald, CQM
Consultants and Centre for the Study of Clinical Practice , Melbourne,
Australia
bmj.com, 8 Mar 2001 [Response]
Explaining the Evidence on Adverse Events
Stephen Heasell, Head of Economics
Division , Nottingham Trent University
bmj.com, 9 Mar 2001 [Response]
Sometimes "adverse events" may be
inevitable
David Griffith, Paul Diggory &
Anand Mehta, Consultant Physicians, Care of Older People , Mayday
Healthcare NHS Trust
bmj.com, 9 Mar 2001 [Response]
In-hospital adverse events: Preventive strategies,
not epidemiological studies, are needed
Tuan V. Nguyen, Senior Fellow , University
of New South Wales
bmj.com, 11 Mar 2001 [Response]
Radiological errors reporting does not identify
errors leading to complaints and litigation.
Sam Chakraverty, John Wright,
Consultant Radiologist, Associate Medical Director , Ninewells Hospital and
Medical School, Dundee, Bradford Hospitals NHS Trust, Bradford
bmj.com, 14 Mar 2001 [Response]
Adverse events in British hospitals
Rosalind Plowman, Jenny Roberts,
Nick Graves, Barry Cookson, Lynda Taylor, Mark Griffin
bmj.com, 26 Mar 2001 [Response]
Tip of the Iceberg, Need expanded definition of
adverse events.
Stephen Bezruchka, Department of
Health Services, School of Public Health and Community Medicine , University
of Washington, Seattle, USA
bmj.com, 1 Apr 2001 [Response]
Quick Risk Comparison
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, Home
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bmj.com, 9 Apr 2001 [Response]
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