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Charles Vincent Clinical Risk Unit, Department of Psychology,
University College London, London WC1E 6BT
Correspondence to: C Vincent c.vincent{at}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.
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.
Design and procedure
Review process
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)
Table 1.
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
Top
Abstract
Introduction
Methods
Results
Discussion
References
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Methods
Top
Abstract
Introduction
Methods
Results
Discussion
References
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.
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.
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Results
Top
Abstract
Introduction
Methods
Results
Discussion
References
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 addsIn 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 |
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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 |
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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[Abstract]. |
| 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[Abstract]. |
| 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[CrossRef][Medline]. |
| 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). |
| 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[Medline]. |
| 6. |
Weingart SN, Wilson RMcL, Gibberd RW, Harrison B.
Epidemiology of medical error.
BMJ
2000;
320:
774-777 |
| 7. |
Vincent CA.
Risk, safety and the dark side of quality.
BMJ
1997;
314:
1775-1776 |
| 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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