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.

Laparoscopy and laparotomy in women requiring adnexal surgery for benign indications.

Treatment.

Cost-effectiveness analysis.

Women requiring adnexal surgery for benign indications. Patients with suspected or diagnosed malignancy, and those undergoing concomitant hysterectomy or major pelvic surgery, were excluded.

Hospital. The economic study was carried out in Finland.

Effectiveness and resource use data corresponded to patients treated between October 1993 and September 1994, whose hospital records (until October 1998) were reviewed. The price year was not explicitly specified.

The evidence for the final clinical outcomes was derived from a single study.

Costing was prospectively undertaken on the same patient sample as that used in the effectiveness analysis.

Power calculations were not used to determine the sample size. The study sample consisted of 228 women, 114 in the laparotomy group with a mean (SD) age of 37.5 (11.6) years and 114 in the laparoscopy group with a mean (SD) age of 32.1 (8.8) years. A total of 18 surgeons (senior consultant or residents under their supervision) performed the operations. Laparoscopic adnexal surgery was performed by 4 gynecologic surgeons qualified to perform operative laparoscopy.

This was a non-randomised prospective observational study, carried out in a single centre. Patients were prospectively followed for up to 1 year, and their hospital records were reviewed 4 years after operation to document later surgical procedures. Loss to follow-up was not reported. The response rate for the first questionnaire (4 to 6 weeks after operation) was 65% in the laparotomy group versus 38% in the laparoscopy group, (p=0.001). One year after the operation the response rate increased to 75%. There was no statistical significance between groups, (p=0.88). Preoperative evaluations consisted of ultrasound examination and measurement of CA 125 level.

The principle used in the analysis of effectiveness appears to have been intention to treat. The health outcomes were operative time, estimated blood loss (ml), hospital stay, rate of major complications (cases of injury to adjacent organs or blood vessels and postoperative thromboembolic disorder), rates of minor complications (cases of bleeding requiring transfusion, bowel or urinary tract dysfunction, and postoperative infection), readmission, need for additional adnexal procedures up to 4 years after operation, frequencies of subjective complaints and satisfaction with surgical procedure after 1 year. Two questionnaire-based evaluations were undertaken to determine subjective outcomes. The study groups were not comparable in terms of age, parity, prior laparoscopic adnexal procedure, prior pelvic surgery by laparotomy, prior hysterectomy, and indication for operation. Multivariate analysis of associations of complications, baseline and operative variables (except hospital stay), operative approach, and antibiotic prophylaxis was performed applying stepwise logistic regression analysis.

The mean (SD) operative time was 86 (34) minutes in the laparotomy group versus 60 (22) minutes in the laparoscopy group, (p<0.001). The mean (SD) estimated blood loss (ml) was 238 (350) and 103 (320), respectively, (p=0.003). The mean (SD) hospital stay was 5.5 (2) days versus 2.6 (1.2), respectively, (p<0.001). The rate of major complications in the laparotomy group was 0% versus 1.8% (two patients) in the laparoscopy group (intestinal injury and aortal injury, both in women who had previously undergone laparotomy). Rates of minor complications were 11.4% for laparotomy and 7% for laparoscopy. Two patients in both groups were readmitted. No difference was found between the groups in need for additional adnexal procedures up to 4 years after operation. After 1 year, frequencies of subjective complaints and satisfaction with surgical procedure did not differ significantly.

The study found no significant differences between the groups in the frequency of major or minor complications, or in overall numbers of patients with complications. However, this comparison is difficult because of selection bias.

No summary benefit measure was identified in the economic analysis, and only separate effectiveness outcomes were reported. It appears that the economic analysis proceeded as a cost-minimisation analysis because of equal outcomes between the groups in terms of frequency of complications and subjective outcomes.

Costs were not discounted due to the period of follow-up (1 year) although a 4-year review of patient records was conducted. Some quantities were reported separately from the costs and some cost items were reported separately. Cost analysis covered the hospital costs of major complications, cases of reoperation, and readmission. The perspective adopted in the cost analysis was not explicitly specified (it was only reported that in Finland, hospital charges are paid mostly by society). Charge data were used instead of true costs. The price year was not given.

Only descriptive data was provided (totals, means).

Indirect costs were not included.

Finish marks (FIM). Conversion rate was US$1= FIM5.73.

A sensitivity analysis was not conducted.

Not applicable. The reader is referred to the effectiveness results recorded above.

The mean hospital cost per patient was FIM 8,810 in the laparotomy group versus FIM 7,864 in the laparoscopy group.

Costs and benefits was not combined.

No statistically significant differences were seen after adnexal surgery by laparoscopy and laparotomy with regard to frequency of complications and subjective outcomes. Laparoscopy in women who have previously undergone laparotomy may be associated with a slightly greater risk of major complications than another laparotomy.

Performing laparotomy in the context in question was regarded as the comparator since it was the traditional approach. You, as a database user, should consider whether this is a widely used health technology in your own setting.

As acknowledged by the authors, the internal validity of the effectiveness results cannot be guaranteed due to selection bias (non-comparability of patients) and the relatively small sample size. It is possible that randomisation was not used because of the authors' view that women today are generally well informed about the advantages of laparoscopic surgery and they might not have accepted randomisation to laparotomy. Multivariate analysis was performed to assess the associations of complications, baseline and operative variables (except hospital stay), operative approach, and antibiotic prophylaxis. The patient sample appears to have been representative of the study population.

The analysis of benefits was based on therapeutic equivalence of treatment alternatives. The economic analysis therefore included only costs.

Some quantities were reported separately from the costs and adequate details of the methods of cost estimation were given. The inclusion of charge data instead of true costs may have adversely affected the internal and external validity of the cost results. The price year was not specified. The effects of alternative procedures on indirect costs and patients' out-of-pocket expenses were not addressed. Statistical analysis was performed on some of resource use data, but not on cost data. Cost results may not be generalisable to other countries or settings due to the lack of sensitivity analysis.

With respect to the non-randomised nature of the study design, the lack of comparability of the study groups, the relatively small sample size, and the lack of sensitivity analysis, the study results may need to be interpreted with some degree of caution. The issue of generalisability to other settings or countries was implicitly addressed and some comparisons were made with other studies. The representativeness of the study sample of the study population was not explicitly addressed.

A high frequency of major complications with advanced laparoscopic procedures is cause for concern. The frequency of 1.8% in this study is similar to that reported in large multicentre series. Another concern with laparoscopic adnexal surgery is possible inadequate treatment of a malignancy and worsening prognosis because of intraabdominal spillage of tumour cells. However, with careful preoperative evaluation, the frequency of undiagnosed malignancies is low. In this study no unexpected malignancies were found in either group. In planning adnexal procedures, individual consideration of surgical approach is recommended.

The source of funding was not stated.