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Cost-effectiveness of alternative screening strategies for developmental dysplasia of the hip |
Rosendahl K, Markestad T, Lie R T, Sudmann E, Geitung J T |
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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 Using general screening (clinical screening combined with ultrasound screening of all infants) or selective screening (clinical screening plus an ultrasound screening of infants at high risk of developing developmental dysplasia of the hip (DDH)) in the diagnosis and treatment of DDH.
Type of intervention Screening, diagnosis and treatment.
Economic study type Cost-effectiveness analysis.
Setting Hospital. The economic study was carried out in Norway.
Dates to which data relate Effectiveness data were derived from a study published in 1994. The date to which the resource use data referred was not specified. All costs were converted to 1993 US dollars.
Source of effectiveness data Effectiveness data were derived from a single study.
Link between effectiveness and cost data Costing was undertaken (retrospectively) on the same patient sample as that used in the effectiveness analysis.
Study sample There was no report of the use of power calculations to determine the sample size. 11,925 newborn babies were studied in general (n=3,613), and selective (n=4,388) ultrasound screening programmes compared with clinical screening (n=3,924) alone, to compare differences in the rates of early, borderline, and late cases of DDH. Note: members of the selective group could only undergo ultrasound examination if they had high-risk factors (e.g. breech position, close DDH family history, and dislocated/dislocatable/unstable hips upon examination).
Study design Single-centre randomised controlled trial. Duration of follow-up was a minimum of 27 months (mean 42.4 months). Loss to follow up was not reported.
Analysis of effectiveness The principle (intention to treat or treatment completers only) used in the analysis of effectiveness was not explicitly specified. Timing of and rates of treatment for DDH were the primary health outcomes assessed in the analysis. The rate of late subluxation and dislocation was also reported.
Effectiveness results In comparison with infants undergoing clinical screening alone, the addition of an ultrasound examination for all infants resulted in a treatment rate of 3.4% compared to 1.8% of early DDH cases. Using ultrasound treatment on high-risk newborns only produced a treatment rate of 2%. The rate of late subluxation and dislocation for general and selective screening were 0.3 and 0.7 respectively. The corresponding rate for clinical screening alone was 1.3 per 1000 infants.
Clinical conclusions In contrast to other investigators, this study found a higher treatment rate for those subjected to general ultrasound screening than for those subjected to selective or no screening.
Measure of benefits used in the economic analysis The benefit measure was late treatments for DDH.
Direct costs Costs generally were not discounted (a discount rate was applied for the depreciation of ultrasound equipment). Quantities were partially reported separately from the costs. Direct health service costs were used, which included screening costs (personnel, training, equipment), with ultrasound and clinical examination time(s) obtained from a 1 month average of time sheet entries. Overhead costs (hospital administration costs, housekeeping, laundry, heat, inter-departmental resource use) were obtained from hospital accounts. Overhead costs were assumed to be the same for all three treatments. Early treatment and follow-up personnel costs were obtained from pediatric outpatient clinic time sheets. Hip ultrasound and x-ray examination costs were obtained from the department of pediatric radiology. Late diagnosis treatment costs were obtained from 24 similar cases at Hagavik Orthopaedic Hospital, as was the average patient cost of hospitalisation (from the 1991 accounts, converted into 1993 Norwegian kroner and US dollars). Retrospective personnel time was obtained from the same source. Outpatient contact costs (personnel time, departmental administration, hospital facilities) were also considered. The perspective adopted in the cost analysis was that of a health care system. All costs were expressed in 1993 dollars.
Currency Norwegian kroner (NKr). A conversion to US dollars was performed based on an exchange rate of $1 = Nkr7.57.
Sensitivity analysis One-way sensitivity analysis was carried out on the discount rate for ultrasound equipment lifetime, overhead costs, hospitalisation costs, screening numbers, and the incidence of late cases of DDH. Threshold analysis was performed to identify the cut-off points.
Estimated benefits used in the economic analysis The number of late treatments for DDH was reduced from 2.6 cases per 1000 with clinical screening to 2.1 per 1000 for selective and 1.4 per 1000 for general screening.
Cost results The (expected) total costs of screening, follow-up, and treatment for general screening were $27.90, for no screening were $29.20, and for selective screening were $29.60 per child. The average cost of a hypothetical programme involving general screening of all girls and selective screening of 12% of boys with a special risk factor for DDH was $20.70 per infant. The discounting rate for the ultrasound equipment was 5%.
Synthesis of costs and benefits Threshold analysis found that the general screening programme had a net economic benefit if average per diem costs for late treatment exceeded $343.50, or the annual number of deliveries exceeded 3500, or the incidence of late cases exceeded 3.6 per 1000 infants.
Authors' conclusions Application of costs from other centres to this study's data regarding frequency of clinical outcomes may yield different comparative programme costs. If the findings of this clinical study can be generalised to other centres, a strategy of screening all girls and boys with risk factors for DDH may be the most cost-effective approach.
CRD COMMENTARY - Selection of comparators The reason for the choice of the comparator is clear.
Validity of estimate of measure of benefit The estimate of benefit is likely to be internally valid given the use of a randomised controlled trial.
Validity of estimate of costs Resource use data were partially reported separately from the costs and adequate details of methods of cost estimation were given.
Source of funding Supported by the University of Bergen (Norway).
Bibliographic details Rosendahl K, Markestad T, Lie R T, Sudmann E, Geitung J T. Cost-effectiveness of alternative screening strategies for developmental dysplasia of the hip. Archives of Pediatrics and Adolescent Medicine 1995; 149(6): 643-648 Indexing Status Subject indexing assigned by NLM MeSH Cost-Benefit Analysis; Female; Follow-Up Studies; Health Care Costs; Hip Dislocation, Congenital /diagnosis /surgery; Humans; Infant, Newborn; Male; Ultrasonography /economics AccessionNumber 21995000740 Date bibliographic record published 29/02/2000 Date abstract record published 29/02/2000 |
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