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Emergency nurse practitioners: a three part study in clinical and cost effectiveness |
Sakr M, Kendall R, Angus J, Sanders A, Nicholl J, Wardrope J |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The health intervention examined in the study was a nurse practitioner led minor injury unit (MIU) for the management of patients with minor injuries.
Type of intervention Emergency medical services.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised the general population with minor injuries requiring A&E services.
Setting The setting was A&E department. The economic study was carried out in Sheffield, UK.
Dates to which data relate Data on effectiveness and resource use were gathered from August to November 1996 for the A&E service and from September 1997 to January 1998 for the MIU service. Costs were calculated using the financial years 1996/1997 and 1997/1998.
Source of effectiveness data The effectiveness evidence came from a single study.
Link between effectiveness and cost data The costing was performed prospectively on a different sample of patients from that used in the effectiveness study.
Study sample All patients attending A&E or MIU during the separate study periods were enrolled into the relevant cohort. Before inclusion in the effectiveness study patients were subjected to two examinations: one by the A&E doctor or MIU nurse (dependent on which cohort the patient was in), and the second by the study investigators. There were 1,447 patients (mean age: 37 years; age range: 16 - 90 years; 58.2% men) in the A&E group and 1,315 patients (mean age: 30 years; age range: 16 - 89 years; 54.8% men) in the MIU group. Initially, the A&E sample included 1,500 patients, but 53 were excluded due to loss of clinical note
Study design This was a prospective cohort study, in which data on the two study groups were collected in different time frames, namely before and after the introduction of the new MIU service. Patients were not randomly allocated to study groups, neither was there any intervention by the researchers in the clinical decision process. There was no patient follow-up after visit or treatment. As reported above, a double examination was performed prior to inclusion in the study. The A&E doctor was unaware of the findings of the research and the researchers did not interfere in any clinical decision.
Analysis of effectiveness All patients included in the initial study sample were taken into account when estimating the effectiveness. The health outcomes used in the analysis were errors in clinical assessment, treatment, and disposal. The erroneous interpretation of the patient's conditions was compared with the radiologic report, which was considered as the gold standard. Errors were categorised as "not clinically significant", "clinically significant" (error occurred if the treatment would have been different had the error not been made), and "very significant" (an error where there was a high risk of adverse outcome for the patient). The waiting times and total time spent in the department were also recorded. The two groups were comparable at baseline with respect to age, sex, method of presentation, and triage category 4, although there were some differences in the type of diagnosis and the areas of the body examined. As there were some differences in the case-mix of patients in the two study groups, the authors performed regression analysis taking into consideration several possible confounders, such as age, sex, and type and location of injuries.
Effectiveness results The effectiveness results were as follows:
The rates of significant errors were 13.2% in the A&E department and 9.6% in the MIU service, (p=0.003). This difference was particularly relevant in the case of errors in past medical history and examination.
There was a very significant error in the A&E group (a missed tendon injury) and none in the MIU group.
The mean waiting times were 56.9 minutes in the A&E group and 19 minutes in the MIU group, (p<0.0001; 95% CI: 34.48 - 39.32).
The total time spent in the department was 95.4 minutes in the A&E group and 51.5 minutes in the MIU group, (p<0.0001; 95% CI: 36.27 - 42.75).
Clinical conclusions The effectiveness study showed that the MIU service was a safe and effective alternative to A&E services. Waiting times were lower and errors were significantly lower, above all in past medical history and examination.
Measure of benefits used in the economic analysis Health outcomes were left disaggregated and no summary benefit measure was used in the economic evaluation, thus a cost-consequences analysis was conducted.
Direct costs Discounting was not applied as costs per patient were incurred over a short period of time. Unit costs were not reported separately from quantities of resources used. The health services included in the economic evaluation were personnel and investigations such as radiography, drugs, and disposable items. The cost/resource boundary adopted in the study was that of the UK NHS. The data regarding resource use were derived from the charts of all patients attending the A&E department in the financial year 1996/1997 and in the MIU in the financial year 1997/1998. These data were adjusted for case-mix differences in order to calculate the revenue 'cost per workload unit' by using Health care Resource Groups (HRG). Unit costs were based on financial data. The costs for the A&E service were adjusted for inflation (pay 2.5% and non-pay 0.4%). The total costs of follow-up care for minor injury patients were calculated using actual costs of follow-up visits.
Statistical analysis of costs Costs were treated deterministically.
Indirect Costs Indirect costs were not included in the economic evaluation.
Sensitivity analysis Sensitivity analyses were not performed.
Estimated benefits used in the economic analysis Please refer to the effectiveness results reported above.
Cost results The actual number of patients attending the A&E service over one year was 37,427 and the corresponding number in the MIU service was 13,616.
After adjusting for case-mix differences, the workload units were 34,745 and 11,329, respectively.
The total revenue costs were 1,393,348 for A&E care and 464,604 for MIU care.
The revenue cost per workload unit was 40.01 for A&E service and 41.10 for MIU service.
The total referrals in the A&E service during follow-up were 3,644, giving estimated total costs of 173,094, and an average cost per referral of 9.66.
The total referrals in the MIU service during follow-up were 2,422, giving estimated total costs of 144,730, and an average cost per referral of 12.17.
Synthesis of costs and benefits Costs and benefits were not combined as a cost-consequences analysis was conducted.
Authors' conclusions The authors concluded that the MIU service was as safe and effective as the A&E care. The overall process of care was also similar with respect to costs. However, the nurse service was more effective in reducing waiting times and rates of errors.
CRD COMMENTARY - Selection of comparators The rationale for the choice of the comparator was clear. The A&E service was selected as the basic comparator because it represented the standard care service before the introduction of the MIU. You, as a user of this database, should decide whether it represents a valid comparator in your own setting.
Validity of estimate of measure of effectiveness The analysis of effectiveness was based on a prospective cohort study, which was appropriate for the study question. However, effectiveness data were collected in two different time frames and it was not clear whether factors other than the change in the care provision affected the estimated outcomes. The cohorts were shown to be comparable at baseline and appear to have been representative of the study population. Although the study sample was quite large, the authors did not provide any evidence that it was sufficiently large for the study question. The observational nature of the study can lead to issues of bias and confounding. The authors conducted some statistical analyses to take this into account, which may help the internal validity of the study.
Validity of estimate of measure of benefit No summary benefit measure was used in the economic analysis. The analysis was therefore categorised as a cost-consequences study (see validity of effectiveness comments above).
Validity of estimate of costs The perspective adopted in the study was stated and it appears that all relevant categories of costs were included in the analysis. Unit costs were not reported separately from quantities of resources used, but the years to which costs referred were stated. Costs were treated deterministically and no sensitivity analyses were conducted. Additionally, the cost estimates were specific to the study setting. These facts limit the generalisability of the cost results to other settings. The authors commented that the direct comparison between MIU and A&E care was difficult due to the different categories of costs involved in the care delivery process. A weakness of the cost study was the fact that a bottom-up costing approach was not used due to the lack of appropriate resources.
Other issues The findings were compared with those from a previous study carried out by the same authors. The issue of the generalisability of the study results to other settings was not addressed and sensitivity analyses were not conducted, thus the external validity of the analysis is low. The study referred to patients with minor injuries and this was reflected in the conclusions of the analysis. The authors discussed some limitations of their analysis.
Implications of the study The study results suggest that nurse practitioners working in a MIU may safely provide an effective service. However, waiting times, which could be considered as quality indicators, were better under the MIU service.
Source of funding M Sakr and J Angus were funded by Sheffield Health Authority.
Bibliographic details Sakr M, Kendall R, Angus J, Sanders A, Nicholl J, Wardrope J. Emergency nurse practitioners: a three part study in clinical and cost effectiveness. Emergency Medicine Journal 2003; 20(2): 158-163 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Aged, 80 and over; Clinical Competence; Cost-Benefit Analysis; Emergency Nursing /economics /standards; Emergency Service, Hospital /economics /organization & England; Female; Hospital Costs; Humans; Male; Middle Aged; Nurse Practitioners /economics /standards; Prospective Studies; Referral and Consultation /statistics & Workload; Wounds and Injuries /economics /nursing; administration /standards; numerical data AccessionNumber 22003000623 Date bibliographic record published 31/10/2003 Date abstract record published 31/10/2003 |
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