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Timothy H Rainer a Accident and Emergency Medicine Academic Unit,
Chinese University of Hong Kong, Rooms G05/06, Cancer Center, Prince of
Wales Hospital, Shatin, NT, Hong Kong, b Department of Public Health Sciences, Faculty of Medicine and
Oral Health Sciences, University of Alberta, 13-103 Clinical Sciences
Building, Edmonton, Alberta, Canada T6G 2G3, c Department of Economics, Hong
Kong Baptist University, 224 Waterloo Road, Kowloon Tong, Kowloon, Hong
Kong, d Centre for Clinical Trials and
Epidemiological Research, Flat 7B, 7th floor, Block B, Staff Quarters,
Prince of Wales Hospital, Shatin, e Finance Department, Prince of Wales
Hospital, Shatin
Correspondence to: T H Rainer rainer1091{at}cuhk.edu.hk
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Abstract |
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Objectives:
To investigate the cost effectiveness of
intravenous ketorolac compared with intravenous morphine in relieving
pain after blunt limb injury in an accident and emergency department.
Clinical problem
Economic problem
Design:
Double blind, randomised, controlled study and
cost consequences analysis.
Setting:
Emergency department of a university hospital in the New Territories of Hong Kong.
Participants:
148 adult patients with painful isolated
limb injuries (limb injuries without other injuries).
Main outcome measures:
Primary outcome measure was a
cost consequences analysis comparing the use of ketorolac with
morphine; secondary outcome measures were pain relief at rest and with
limb movement, adverse events, patients' satisfaction, and time spent
in the emergency department.
Results:
No difference was found in the median time taken to achieve pain relief at rest between the group receiving ketorolac and the group receiving morphine, but with movement the
median reduction in pain score in the ketorolac group was 1.09 per hour
(95% confidence interval 1.05 to 2.02) compared with 0.87 (0.84 to
1.06) in the morphine group (P=0.003). The odds of experiencing adverse
events was 144.2 (41.5 to 501.6) times more likely with morphine than
with ketorolac. The median time from the initial delivery of
analgesia to the participant leaving the department was 20 (4.0 to
39.0) minutes shorter in the ketorolac group than in the morphine group
(P=0.02). The mean cost per person was $HK44 (£4; $5.6) in the
ketorolac group and $HK229 in the morphine group (P<0.0001). The
median score for patients' satisfaction was 6.0 for ketorolac and 5.0 for morphine (P<0.0001).
Conclusion:
Intravenous ketorolac is a more cost
effective analgesic than intravenous morphine in the management of
isolated limb injury in an emergency department in Hong Kong, and its
use may be considered as the dominant strategy.
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Introduction
Top
Abstract
Introduction
Methods
Results
Discussion
References
Patients commonly present to accident and emergency departments
with severe pain after limb injury and need early treatment with
effective analgesia. The use of analgesia in emergency departments and
intensive care units may be suboptimal.1-4 Some
analgesics, such as morphine (the opiate morphine sulphate), have a
perceived risk of dependency and therefore, although relatively cheap,
are regarded as "dangerous."
5 6
In repeated
frequent doses they may cause dependency, and in single doses they are associated with serious adverse effects that need monitoring and further treatment by both nursing and medical staff. Therefore these
drugs, although inexpensive to buy, may have a substantial financial
impact on health resources. The impact on emergency departments has
never been investigated quantitatively. Non-steroidal anti-inflammatory
drugs are also effective at relieving moderate to severe pain and are
believed to have fewer adverse effects than
opiates.7-10 In North America, the United Kingdom,
other parts of Europe, and in Hong Kong ketorolac (ketorolac
tromethamine) is the only non-steroidal anti-inflammatory drug
currently licensed for managing pain by rapid intravenous
administration.
5 10
A retrospective evaluation of the financial impact of ketorolac in
hospital inpatients showed that it was associated with reduced lengths
of stay and reduced use of narcotic, antipruritic, and antiemetic
drugs.11 These findings were supported by a more specific
study that showed that, although ketorolac was an expensive drug, its
use for postoperative lumbar spine surgery reduced hospital stay by
half a day with substantial financial savings.12 Both of
these studies investigated cost after admission. No studies have
investigated the relative economic effect of ketorolac and morphine in
emergency departments.
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Methods |
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We conducted the study in the accident and emergency department of
the Prince of Wales Hospital, Shatin, a 1400 bed university teaching
hospital in the New Territories of Hong Kong. The department receives
over 200 000 new patients a year
of whom a fifth are admitted to
hospital
and serves a population of about 1 500 000. Currently,
health care in the emergency department is free at the point of access,
and charges are made only if the patient is admitted to a ward or
referred for outpatient follow up.
We obtained ethical approval from the local institutional research ethics committee to conduct a pragmatic, prospective, randomised, controlled, double blind study comparing intravenous ketorolac with morphine in the management of pain after limb injury. We obtained informed written consent from each patient. The study started with a threefold difference in cost between ketorolac and morphine, and we sought to investigate whether the difference was negated when all associated additional costs were included in a cost effectiveness analysis.
Inclusion and exclusion criteria
All patients aged
16 years presenting to the emergency
department between 9 am and 5 pm, Monday to Friday, with an isolated
painful limb injury (limb injury without other injury) were considered
for the study. The investigators did not consider it reasonable within
the study budget to hire a research nurse for 24 hour or evening
surveillance. As painful injuries should be treated with analgesia
before specific diagnoses are made, recruitment inevitably included
some patients with a high clinical probability of a fracture but who
subsequently were found to have dislocations or soft tissue injuries
alone. All participants were studied on an intention to treat basis,
with one exception (see results section), and in the analysis both drug
groups were compared to ensure no difference in the proportion with or
without fractures. Patients were excluded if they had a history of
substance misuse, dementia, indigestion, peptic ulceration or
gastrointestinal haemorrhage, recent anticoagulation, pregnancy,
adverse reaction to morphine or ketorolac, renal or cardiac failure,
hepatic problems, rectal bleeding, recent (<24 hours) use of
non-steroidal anti-inflammatory drugs, asthma, chronic obstructive
airways disease, chronic pain syndromes, or previous treatment with
analgesia for the same injury. They were also excluded if they had a
physical, visual, or cognitive impairment, as use of the visual
analogue scale would have been unreliable.
Interventions and randomisation
Patients were randomly allocated to one of the two treatment
groups by using a random number table.21 Ketorolac was
prepared as a 2 mg/ml solution and morphine as a 1 mg/ml solution. One
group would receive intravenous ketorolac as a 10 mg (5 ml) loading
dose over 60 seconds followed by 5.0 mg (2.5 ml) every 5 minutes up to
20 minutes (maximum 30 mg) as required. The other group would receive
intravenous morphine as a 5 mg (5 ml) loading dose over 60 seconds
followed by 2.5 mg (2.5 ml) every 5 minutes up to 20 minutes (maximum
15 mg) as required. These doses were chosen partly as a result of
published reports and partly as a result of the findings from the pilot
study (n=40).
2-4 7-9
Also, the British
National Formulary recommends that ketorolac should not be
administered in an initial bolus of more than 30 mg and that this
should not be repeated until a further six hours has elapsed.5 Doctors at the Prince of Wales Hospital in
Shatin are reluctant to administer more than 15 mg of morphine as an initial slow bolus, so the selected doses were reasonable and practical.
that is, a pain score of 0
provided that
the maximum dose was not exceeded and there were no adverse effects.
Clinical measurements and data collection
A 10 inch (254 mm), numbered (0-10), horizontal, visual analogue
pain score was used for baseline measurements and at subsequent time
intervals after the first injection.22 A large scale
(inches rather than centimetres) was used because disability from poor
vision is particularly high in Hong Kong. Routine observations, pain
scores, and adverse effects were recorded every five minutes for the
first 30 minutes after drug administration, at 30 minute intervals for
the subsequent one and a half hours, and once more at six hours.
Participants were aware of their previous scores at all stages of
recording. The type, number, duration, and severity (based on the
Morrow index where appropriate23) of adverse effects were
documented. The physician on duty was free to give extra or alternative
doses of analgesia if clinically required, and this was documented.
Data were analysed with SAS Statview for Windows, version 5.0 (Abacus
Concepts, SAS Institute, Cary, NC, USA).
Clinical and perception outcomes
The primary clinical outcomes were pain relief measured as changes
in the pain score, and adverse effects. Pain relief is presented as
odds ratios of reaching 50%, 75%, and 100% reduction in pain
score (both at rest and with activity) and as median changes in the
pain score estimated with the Kaplan-Meier product limit method.
"Activity," for the purpose of this study, involved the research
nurse gently moving the injured limb to assess pain. The same nurse
performed all movements in a standardised manner. Adverse events were
assessed for number, duration, and severity (where applicable). The
perception outcome measures were participants' satisfaction with pain
relief and their satisfaction with the care given by staff in the
emergency department at the time of discharge from the department.
Cost measurements and data collection
Costs were calculated according to activities, which included the
preparation and administration of analgesics and other drugs, care
relating to adverse events, and admission to hospital. We obtained
estimates for the time required to use each resource in each activity
(table 1) and the unit costs for each of these resources. Drugs were
costed separately according to dose, and cost estimates were made for
the actual treatment time for adverse events.
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Cost effectiveness analysis
The primary efficiency measure was a cost consequences
analysis24
that is, a comparison of costs with several
different outcomes. Qualitative, rather than quantitative, descriptions
were made in comparing outcomes and efficiency measures.25 The sensitivity analysis of cost measures was conducted with regard to
observational periods. For the patients who were discharged from the
emergency department we relaxed the assumption that all possible events
could be observed within the six hour study period. The true end point,
however, may be six hours after the first injection, in which case the
previous defined end point would not capture all of the information for
the cost effectiveness analysis, especially in those discharged from
the emergency department within one to two hours (for whom we assumed
that any pain score after the first two hours would be the same for
both groups of participants). With the extra four hours of treatment we
recalculated the incremental cost effectiveness as stated above.
Statistical analysis
Data were analysed on an intention to treat basis, and we used two
tailed tests in all statistical analyses. As pain score and time data
did not conform to the Gaussian distribution, non-parametric tests were
used to analyse data.26 Baseline characteristics of the
two treatments were analysed using the
2 test or
Mann-Whitney U test.27 Time to event variables were evaluated by using the Kaplan-Meier product limit method, and the log
rank test was used to compare the treatment groups.28 A
regression line indicating the change in pain score over time was
found, and its slope was therefore a summary measure for each patient.29 The median slope for each treatment group was
compared and analysed by using the Mann-Whitney U test. The likelihood of achieving pain reduction was presented as hazard ratios.
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Results |
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During the defined study period 182 patients attended the emergency department with acute, painful limb injuries, 149 of whom were allocated to receive blinded analgesia (figure). The 33 patients excluded from the study were excluded for the following reasons: patient decided not to enter the trial (18 patients), asthma or chronic obstructive airways disease (6), renal disease (3), peptic ulceration or gastrointestinal haemorrhage (2), ischaemic heart disease (3), liver disease (1). A further patient agreed to enter the trial but was excluded by a visiting doctor who was not familiar with the study. Exceptional circumstances at the time meant that the issue was not resolved, and the patient received alternative drug treatment. The precoded envelope had been opened, but no study analgesia was administered. This patient was therefore excluded from the analysis because he received no study analgesia. In another case, the code was broken by an attending physician because the participant (in the morphine group) showed signs of severe drowsiness. All data were collected and the participant was included in the analysis.
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Baseline characteristics and clinical outcomes
Baseline characteristics of the 148 participants in the two groups
were similar (table 2). Seventy seven patients were admitted to
hospital
71 to an orthopaedic ward for orthopaedic reasons and not
because of adverse events after analgesia and 6 to the emergency ward.
One participant (from the ketorolac group) was admitted for four days
not because of adverse events after analgesia but because of poor
social circumstances and immobility. Five participants were admitted
from the morphine group (median stay 1 day)
two because of poor social
circumstances and mobility and three because of adverse events after
analgesia (dizziness, drowsiness, and vomiting).
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Cost analysis
Marginal costs were used to measure the difference in costs
between the two interventions (table 7). The mean cost per person,
excluding admissions, was $HK43.60 (£4; $5.6) for those in the
ketorolac group and $HK228.80 for those in the morphine group
(P<0.0001). Overall mean cost per person, including admissions unrelated to analgesia, was $HK11 361.20 for those in the ketorolac group and $HK7279.62 for those in the morphine group (P=0.451). If
admission costs are excluded, much of the difference between the costs
for the two groups was the result of the management of adverse effects.
Cost effectiveness
When we included admission costs we observed no significant
differences in costs between the two groups. We found a significant
reduction in pain with activity in the ketorolac group and
significantly fewer common adverse events. Additionally, the
participants in the ketorolac group showed a greater degree of
satisfaction with that drug than the participants in the morphine group
showed with their drug (table 8). Ketorolac administration therefore is
the "dominant" strategy, with significantly better outcomes, lower
costs when costs for the emergency department and pharmacy are
combined, but not significantly higher overall costs.
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Discussion |
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This study shows that, although intravenous morphine costs less than intravenous ketorolac in Hong Kong, ketorolac is a cheaper option than morphine once all additional costs incurred by the accident and emergency department and the pharmacy are taken into account. When admission costs are included, however, the difference in cost is not significant. When both drugs are administered intravenously in titrated doses according to individual patients' needs, ketorolac is at least as efficacious as morphine and may afford a small advantage when the injured limb is moved. Ketorolac had fewer adverse effects than morphine, made fewer demands on doctors' and nurses' management time, resulted in earlier discharge or admission to a ward, and was associated with greater satisfaction among patients. Morphine may afford a small clinical advantage, however, with better odds of relieving pain at rest than with ketorolac.
Originality of study
The study has the several original aspects. Firstly, it compares
intravenous ketorolac and intravenous morphine in a nurse controlled,
analgesic regimen with titrations according to the individual
patients' needs. None of the many other studies that have compared
parenteral ketorolac with parenteral opiates in a variety of
settings
7-10 13 15-20 30-41
has compared one drug with the other as in this protocol. Secondly, the two drugs were studied within the context of an emergency department. Both morphine and ketorolac have been studied separately in emergency departments in
both controlled and uncontrolled studies,
10 30 42
but no study has compared one with the other in this setting. Thirdly, a cost
effectiveness analysis drew together the strands of efficacy, adverse
effects, resource demands, and participants' satisfaction. Other
studies have shown that ketorolac may be as efficacious as morphine and
tolerated better, but none has examined the issue in a broader economic context.
Study protocol versus routine practice
This study differs from normal emergency department practice in
several respects. In normal practice no delay occurs as a result of
patient information and consent procedures. The delay in this study was
kept to an absolute minimum, and no complaints were received from
patients or relatives. Secondly, in normal practice, analgesia is not
given in a blinded regimen and patients are not observed and questioned
closely by a research nurse. Some degree of artificiality has to be
accepted if vital data are to be recorded. As the study was randomised
and double blind, however, any deviations from normal should at least
be the same for both groups, leaving the effect of the two analgesics
as the only difference in outcome.
Strengths and shortcomings
The strengths of the study lie in its randomised controlled
design, delivery of analgesia according to individual needs, and its
attempt to reflect the real world as far as reasonably possible. The
economic evaluation follows recent guidelines published in the
BMJ. 43-45 Although every effort was made to
blind both the research nurses and the participants to treatment,
certain clinical clues
such as pinpoint pupils
might reveal the
identity to discerning medical and paramedical staff. This is a
shortcoming that is probably unavoidable and applies to all double
blind studies comparing opiates with other drugs. In an ideal double
blind regimen, treatment should not be prepared anywhere near the scene
of research, so that contamination is completely impossible. In this
study, nurses prepared the drugs within the department and used normal stock. This was important if we were to monitor the "real" time taken to prepare drugs for delivery and the different grades of nurses
taking part in the process. The delay in starting to administer morphine compared with ketorolac was due to the extra checking procedures necessary for administering opiates.
Implementing results
The management of pain remains one of the great challenges for
emergency departments worldwide, and so policies on rapid, cost
effective, and safe analgesia are essential for good patient care and
patient satisfaction. High demand and prolonged waiting times also
provide a drain on emergency departments' resources, and so any
intervention that reduces the time that patients spend in the
department is also important. This study showed that intravenous ketorolac is more cost effective than intravenous morphine in the
management of acute pain after blunt limb injury in an emergency department. Doctors may be more confident about using an effective analgesic with no risk of dependence, fewer adverse effects, reduced arrival to discharge times in their departments, and reduced costs. These results are relevant to emergency departments in Hong Kong and
are likely to be applicable to other systems that are organised along
similar lines. Differences in staff salaries and other costs, however,
may limit the application of our findings to some
environments.
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What is already known on this topic
Intravenous morphine sulphate is generally as effective as intravenous ketorolac tromethamine for surgical and cancer related pain Morphine may cause more adverse events than ketorolac No cost effectiveness analyses have compared the use of intravenous ketorolac and morphine titrated according to patient needs and none has evaluated such use in emergency departments What this study addsFor limb injury in an emergency department ketorolac is as effective as morphine for pain at rest; for pain with movement, however, ketorolac may be marginally better than morphine Ketorolac produced fewer, less severe, and shorter adverse events than morphine Participants receiving ketorolac left the emergency department sooner than those receiving morphine Ketorolac is a more cost effective analgesic than morphine in this setting and is associated with greater patient satisfaction |
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Acknowledgments |
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Contributors: THR had the idea for the study, obtained approval, and has overseen the entire planning, execution, and analysis of the study, and the preparation of the manuscript. He is guarantor of the paper. PJ and YCN participated in planning a detailed economic analysis. NKC, MT, and RAC participated in the planning, execution, and analysis. PKWL and THR prepared the statistical analysis. RW was involved in planning and costing analysis. THR wrote the first draft of the paper, and all authors have contributed to the final version.
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Footnotes |
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Funding: This study was supported by the direct grants scheme of the Chinese University of Hong Kong (project code 2040668) and the Health Services Research Committee of Hong Kong (project code 921020).
Competing interests: None declared.
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(Accepted 8 August 2000)
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