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.

Morbidly obese patients were given laparoscopic gastric banding as an outpatient procedure and only stayed overnight if unexpected events occurred. One hour before the operation they received thromboprophylaxis with 0.6 mL nadroparin, general anaesthesia being induced with propofol (2.5 mg/kg), fentanyl (0.0025 to 0.005 mg/kg) and remifentanil (0.4 to 0.5 microg/kg per minute). If the patients suffered from nausea they were given 10 mg metoclopramide intravenously. Pain was treated when needed by paracetamol (1 g, 4 times daily) and diclofenac (50 mg, 3 times daily). The patients were not allowed to return home unless they were mobile and able to void. The surgeon and anaesthetist had to approve the patient's discharge after a clinical assessment. The day after surgery the patient had to return to the outpatient department and be seen by the nurse practitioner; the patient was given a contrast swallow to document the position of the band. A comparator group of patients were given the same treatment but they stayed in hospital for one night after surgery.

Treatment.

Cost-effectiveness analysis.

To be eligible for the study, morbidly obese patients had to have a body mass index (BMI) of greater than 40. The BMI could be between 35 and 40 if the patient also had a serious co-morbidity. The patients had to be at least 18 years old and be considered (by the anaesthetist) to be suitable candidates for day surgery. They also had to have a responsible adult available to watch over them during their first night home. Patients were excluded if they had particular morbidities or if they lived more than 30 minutes away from the hospital.

The setting was secondary care. The economic study was carried out in the Netherlands.

The effectiveness and resource evidence related to 2001 to 2003. The price year was not reported.

The effectiveness data were derived from a single study.

The costing was carried out prospectively on the same patient sample as that used in the effectiveness analysis.

No power calculations were reported. The study sample consisted of patients attending one hospital and who met the inclusion criteria. Initially 72 patients were recruited to the study. Of these, 14 were excluded because of co-morbidity, 4 because they lived too far away, 1 refused to participate, and 3 did not take part for other reasons. There were 25 patients in the outpatients group (OP) and 25 in the overnight stay (OS) group.

This was a single-centre randomised controlled trial (RCT) in which randomisation was carried out by sealed envelopes opened directly after inclusion into the study. There was no loss to follow-up. The duration of follow-up was 6 weeks.

The analysis was conducted on an intention to treat basis. The primary health outcomes were:

the length of hospital stay, complications within 6 weeks, and postoperative pain and nausea;

overall well-being; and

the resumption of normal activity, as assessed by visual analogue scales.

Patient satisfaction was assessed at 6 weeks.

The patient groups were shown to be comparable at baseline.

Seventy-six per cent of patients in the OP group were discharged the same day, while 72% of the OS group returned home the day after surgery.

The mean hospital stay was 1.48 days (range: 1 to 7) in the OP group and 2.32 days (range: 2 to 4) in the OS group, (p=0.004).

No patient was readmitted.

As far as conversions and complications were concerned, 1 patient in the OP group and 3 in the OS group had to have conversions to open surgery.

During the 6 weeks after surgery, 1 patient in the OP group suffered a major complication but recovered after 7 days, and another patient in the OP group had a corneal lesion which delayed discharge for 2 days.

The authors used bar charts to show the results of the assessments of pain, nausea, overall well-being and level of activity.

Patients in the OP group had a significantly worse level of postoperative pain, (p=0.009).

There were no significant differences in the measures of postoperative nausea, overall well-being or activity resumption.

At 6 weeks, mean patient satisfaction (maximum possible score 10) was 8.1 (range: 4 to 10) in the OP group and 8.8 (range: 7.5 to 10) in the OS group, (p=0.06).

Forty-eight per cent of the OP patients would have chosen day surgery again versus 8% of the OS patients.

The authors concluded that there was no clear difference between the patient groups, apart from the higher level of postoperative pain in the OP group and the longer hospital stay in the OS group.

No summary measure of benefit was used as the authors carried out a cost-consequences analysis.

No discounting was carried out as the patients were in hospital for less than one year. The quantities and the costs were not analysed separately, although the unit cost of a day on the day surgery unit was given. The costs were divided into admission costs (day case or clinical admission day), operation costs (including materials used and facilities such as time and personnel), and additional costs (including consultations from other specialists and unforeseen laboratory investigations and X-ray). The costs were based on actual data from the hospital. No price year was given.

No statistical analysis of the costs was carried out.

No indirect costs were reported.

Euros (EUR).

The cost results were given under the assumption that no unforeseen events occurred. They were compared with actual cost results.

See the 'Effectiveness Results' section.

The cost per patient was EUR 3,609 in the OP group and EUR 4,203 in the OS group

If it was assumed that no unforeseen events had taken place, the cost per patient would have been EUR 2,998 in the OP group and EUR 3,925 in the OS group.

The costs were calculated for 6 weeks. Knock-on costs were dealt with in the actual cost figures.

The costs and benefits were not combined as the study was a cost-consequences analysis.

Day surgery was as effective as surgery with an overnight stay for obese patients undergoing laparoscopic gastric banding, and it was less expensive.

The comparator, surgery with an overnight stay, was chosen because it represented current practice in many settings. You should decide if the comparator represents current practice in your own setting.

The source of the effectiveness data was a single study. The study design, an RCT, was appropriate for the hypothesis, but the lack of power calculations and the lack of significant differences between the two groups may indicate that there were insufficient patients in the study to fulfil the study's aims. The study sample appears to have been representative of the study population and the patient groups were shown to be comparable at baseline. The authors suggested that the evidence showed there to be no differences between the patient groups in terms of their overall well-being and activity resumption, yet their bar charts showed that the patients in the OS group did better than the patients in the OP group. Insufficient patient numbers might have been the reason for a lack of statistical significance. There were no other sources of effectiveness data.

The authors did not derive a summary measure of health benefit. The health benefits are therefore those associated with the effectiveness outcomes.

From the cost perspective adopted (i.e. the hospital), all the relevant categories of costs were included. A detailed breakdown of each cost category was not given, so it was not certain whether all the costs were included. The unit costs were not reported separately from the resource quantities, which will limit the generalisability of the authors' results. The resource use quantities were taken from a single study; no other sources were used. No statistical or any other analysis of the quantities was performed. Hospital charges appear to have been used as a proxy for costs. This has the limitation of not reflecting true opportunity costs, thus restricting the external validity of the results. The authors carried out one calculation which could be seen as a sensitivity analysis. Specifically, they calculated the costs under the assumption that no unforeseen events occurred. The unit costs were taken from the authors' setting; no other sources were used. No statistical, sensitivity or any other kind of analysis of the prices was conducted. Discounting was unnecessary, as all costs were incurred during less than 1 year, and was appropriately not carried out. No price date was reported, which will hamper any future inflation exercises.

The authors made appropriate comparisons of their results with the findings from other studies. The issue of generalisability to other settings was not addressed. The authors did not present their results selectively but their conclusions did not entirely reflect the scope of the analysis. Specifically, the authors did not address the fact that there was a trend towards better patient outcomes in the OS group, even though the results were not always statistically significant. Also they welcomed the lower costs in the OP group but did not acknowledge that this might have resulted from shifting the cost from the hospital to the relatives, as indirect or family incurred costs were not taken into account. The authors appear have placed too much emphasis on the cost-difference that would exist if no unforeseen complications occurred, and did not acknowledge that it is usual for such complications to occur. The authors did not report any limitations to their study.

The authors concluded that laparoscopic gastric banding can be safely carried out on an outpatient basis. They referred to the fact that patients seem to prefer to stay overnight after the surgery. Therefore, there is a need to improve the way day surgery is carried out to increase patient well-being.

None stated.

Because readers are likely to encounter and assess individual publications, NHS EED abstracts reflect the original publication as it is written, as a stand-alone paper. Where NHS EED abstractors are able to identify positively that a publication is significantly linked to or informed by other publications, these will be referenced in the text of the abstract and their bibliographic details recorded here for information.