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Cost-effectiveness of different diagnostic strategies in patients with nonresectable upper gastrointestinal tract malignancies |
Mortensen M B, Ainsworth A P, Langkilde L K, Scheel-Hincke J D, Pless T, Hovendal C |
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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 Eight different diagnostic imaging strategies for pretherapeutic detection of patients with disseminated or locally nonresectable upper gastrointestinal tract malignancies (UGIM). The eight strategies involved the use of the following imaging methods: computed tomography (CT) plus ultrasonography (US), endoscopic ultrasonography (EUS), CT plus US plus EUS, laparoscopy (LAP), CT plus US plus LAP, LAP plus EUS, LAP/LUS, and LAP/LUS plus EUS.
Economic study type Cost-effectiveness analysis.
Study population UGIM patients referred for treatment.
Setting Hospital. The economic study was carried out in Denmark.
Dates to which data relate Effectiveness and resource use data corresponded to patients admitted to the study institution between January 1995 and December 1996. The price year was not explicitly specified.
Source of effectiveness data The evidence for the final clinical outcomes was derived from a single study.
Link between effectiveness and cost data Costing was retrospectively undertaken on the same patient sample as that used in the effectiveness analysis.
Study sample Power calculations were not used to determine the sample size. Of 162 consecutive UGIM patients referred for treatment, 73 (45%) had disseminated or locally nonresectable disease, and these patients were eligible for evaluation. 50 patients with a median age of 63 (range: 39 - 82) years were assessed as having nonresectable or disseminated cancer disease and these patients, along with the 23 patients found to have disseminated disease during CT with US or EUS, were the objects of the present study. A total of 120 patients (74%) underwent surgery, and in all these patients CT with US, EUS, LAP, and LAP-LUS was performed before laparotomy (with or without resection). 19 patients were in too poor a condition to undergo surgery.
Study design This was a retrospective cohort study, carried out in a single centre. The duration of the follow-up appears to have been until discharge from hospital. Loss to follow-up was not reported. The final assessment of resectability was performed during surgery. If biopsy-verified evidence of disseminated disease was obtained during LAP, then this would be the final evaluation point. Otherwise, open surgery was performed.
Analysis of effectiveness The principle (treatment completers only or intention to treat) used in the analysis of effectiveness was not explicitly reported. The health outcomes were death and postoperative problems, the proportion of deaths or postoperative problems attributable to the diagnostic procedures, and sensitivity "effect" (defined as the number of patients with nonresectable disease found through the diagnostic strategy in question).
Effectiveness results Three of the patients (6%) with nonresectable cancer died postoperatively, and two (4%) had extended postoperative stay because of pneumonia and acute myocardial infarction. None of the deaths or postoperative problems could be related to the diagnostic procedures.
The effects of the different strategies were as follows:
CT plus US, 30%;
EUS, 76%;
CT plus US plus EUS, 82%;
LAP, 44%;
CT plus US plus LAP, 58%;
LAP plus EUS, 92%;
LAP/LUS, 86%;
and LAP/LUS plus EUS, 96%.
Clinical conclusions As a single diagnostic imaging method, LAP-LUS had the highest sensitivity followed by EUS, but the combination of EUS and LAP-LUS detected the highest number of patients with nonresectable disease. Although LAP had a tendency to provide more information in patients with gastric cancer, the results demonstrated no significant difference between the imaging methods when they were stratified according to the type of tumour.
Modelling A simple model was used to evaluate the cost-effectiveness of different diagnostic strategies.
Measure of benefits used in the economic analysis "Effect" (the number of patients with nonresectable disease found through the diagnostic strategy in question) was regarded as the measure of benefit.
Direct costs Costs were not discounted due to the short time frame of the cost analysis. Some quantities were reported separately from the costs and some cost items were reported separately. Cost analysis covered the costs of diagnostic procedures including hospitalisation and explorative laparotomy. The perspective adopted in the cost analysis was not explicitly specified. It is not clear whether charge data or true costs were used. The price year was not given.
Statistical analysis of costs A statistical analysis of costs was not conducted.
Indirect Costs Indirect costs were not included.
Currency US dollars ($). The conversion rate from Danish currency to US dollars was not reported.
Sensitivity analysis Sensitivity analysis was not conducted.
Estimated benefits used in the economic analysis The effect of the different strategies were as follows:
CT plus US, 30%;
EUS, 76%;
CT plus US plus EUS, 82%;
LAP, 44%;
CT plus US plus LAP, 58%;
LAP plus EUS, 92%;
LAP/LUS, 86%;
and LAP/LUS plus EUS, 96%.
Cost results The costs of procedures for the various strategies were as follows:
CT plus US, $1,125;
EUS, $800;
CT plus US plus EUS, $1,925;
LAP, $2,370;
CT plus US plus LAP, $3,495;
LAP plus EUS, $3,170;
LAP/LUS, $2,370;
and LAP/LUS plus EUS,$3170.
Synthesis of costs and benefits Incremental and average cost-effectiveness analyses were conducted by calculating the cost of detecting one additional patient with nonresectable disease when moving from one strategy to another, and the cost of each strategy in finding one patient with nonresectable disease.
The average (expected) cost-effectiveness values were:
CT plus US, $7,346;
EUS, $5,659;
CT plus US plus EUS, $6,606;
LAP, $8,177;
CT plus US plus LAP, $8,887;
LAP plus EUS, $7,555;
LAP/LUS, $6,932;
LAP/LUS plus EUS, $7,436.
The incremental cost-effectiveness values were:
for a change from EUS to LAP-LUS, $30,570;
from EUS to LAP-LUS + EUS, $21,330;
from LAP-LUS to LAP-LUS + EUS, $12,090;
and from CT + US to CT + US + EUS, +/-$2,970.
Authors' conclusions The combination of endoscopic and laparoscopic ultrasonography was cost-effective and had no complications in this study.
CRD COMMENTARY - Selection of comparators A justification was given for the choice of the comparator (the strategy of using CT plus US). It was the scanning method used extensively in the context in question. You, as a database user, should consider whether this is a widely used health technology in your own setting.
Validity of estimate of measure of effectiveness The internal validity of the effectiveness results cannot be guaranteed due to the retrospective nature of the study design. The patient sample appears to have been representative of the study population.
Validity of estimate of measure of benefit The estimate of benefits was obtained directly from the effectiveness analysis. The choice of estimate was justified.
Validity of estimate of costs Some quantities were reported separately from the costs. Insufficient details of the methods of cost estimation were given (such as price year, conversion rate, and whether cost calculations were based on charge data or true costs). The effects of alternative procedures on indirect costs were not addressed. Statistical analysis was not performed on resource use data or cost data. Cost results may not be generalisable to other countries or settings due to a lack of sensitivity analysis.
Other issues With respect to the retrospective nature of the study design, lack of sensitivity analysis and statistical analysis, the study results may need to be interpreted with some degree of caution. The issue of generalisability to other settings or countries was not addressed, although some comparisons were made with other studies. The representativeness of the study sample of the study population was not explicitly addressed. It was noted that both EUS and LUS are operator-dependent techniques with a long learning curve, indicating that a considerable resource consumption must be accepted before an economic benefit from this implementation can be expected. In addition, during the learning period, one must decide how to validate the new techniques and how to deal with false-positive and false-negative findings.
Implications of the study Considering the high effect of LAP-LUS with EUS along with its presumably very low complication rate (0% in this study), and the fact that the strategy is cost-effective, the authors have implemented this strategy as their standard for the pretherapeutic evaluation of UGIM patients in their department.
Bibliographic details Mortensen M B, Ainsworth A P, Langkilde L K, Scheel-Hincke J D, Pless T, Hovendal C. Cost-effectiveness of different diagnostic strategies in patients with nonresectable upper gastrointestinal tract malignancies. Surgical Endoscopy - Ultrasound and Interventional Techniques 2000; 14(3): 278-281 Indexing Status Subject indexing assigned by NLM MeSH Adult; Aged; Aged, 80 and over; Comparative Study; Cost-Benefit Analysis; Endosonography /economics; Female; Gastrointestinal Neoplasms /diagnosis /surgery /economics; Humans; Laparoscopy /economics; Laparotomy; Male; Middle Aged; Palliative Care; Reproducibility of Results; Retrospective Studies; Tomography, X-Ray Computed /economics AccessionNumber 22000000520 Date bibliographic record published 31/01/2001 Date abstract record published 31/01/2001 |
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