A cost-benefit analysis of respiratory syncytial virus hyperimmune globulin (RSV-IVIG) in high-risk infants Oelberg D, Reininger M, Van Eeckhout J

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1 A cost-benefit analysis of respiratory syncytial virus hyperimmune globulin (RSV-IVIG) in high-risk infants Oelberg D, Reininger M, Van Eeckhout J 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 Respiratory syncytial virus (RSV) hyperimmune globulin (RSV-IVIG) immunoprophylaxis of selected and all high-risk infants. Type of intervention Primary prevention. Economic study type Cost-effectiveness analysis. Study population The selected high-risk infants group included all infants with active BPD, younger than 2 years old, and receiving supplemental oxygen within the prior six months. The all high-risk group included infants at chronological age less than 2 years with associated history of either BPD or gestational age less than or equal to 32 weeks. Setting The setting was secondary care. The economic analysis was carried out at the Children's Hospital of the King's Daughters in Norfolk, Virginia, USA Dates to which data relate The baseline effectiveness data for the comparator dated from the period 1 November 1994 to 31 March The effectiveness for the RSV-IVIG was taken from a study published in The charges for hospitalisations of the same patient sample were used. No date for the charges for treatment of otitis media and the RSV-IVIG prophylaxis were reported, although this seems to refer to the same time period. The price year was not reported. Source of effectiveness data The evidence for final outcomes was based on a review of published studies as well as on data available from the hospital in which the economic evaluation was carried out. Modelling A decision tree model was used to analyse the three alternatives: no RSV-IVIG prophylaxis, RSV-IVIG prophylaxis for selected high-risk infants and for all high-risk infants in Norfolk, Virginia. The model analysed only the costconsequences of the different alternatives. Outcomes assessed in the review Page: 1 / 5

2 The primary health outcomes assessed in the review were the probability of requiring hospitalisation for RSV with and without the RSV-IVIG prophylaxis, the occurrence of acute otitis media during the first two years of life and the probability of having BPD. Study designs and other criteria for inclusion in the review Only one published study was included in the review (the PREVENT trial). The inclusion criteria for the review were not specified, although one study (NIAID trial) was excluded because the study population was different from that used in the model. The study design of the PREVENT trial was not described. Data, such as the hospitalisation rates for RSV without treatment and the probability of developing BPD, were obtained from the hospital at which the study was carried out. Sources searched to identify primary studies The sources searched were not specified. Criteria used to ensure the validity of primary studies The criteria used to ensure the validity of primary studies were not specified. Methods used to judge relevance and validity, and for extracting data Not specified. Number of primary studies included One published study was included in the review. Methods of combining primary studies The narrative method was used to combine information. Investigation of differences between primary studies Not specified. Results of the review The probability of requiring hospitalisation for RSV without RSV-IVIG was 0.14 and was 0.08 with RSV-ISIG. The probability of otitis media without RSV-IVIG was 0.44 and with RSV-ISIG was The probability of having BPD within the identified high-risk category was 50%. Measure of benefits used in the economic analysis No measure of benefits was employed. The cost-consequences of the different alternatives were analysed. Direct costs The costs were analysed from the perspective of the third party payer. Direct costs included cost of hospitalisation for RSV infection, acquisition and administration of RSV-ISIG and treatment with follow-up of otitis media. The cost of hospitalisation was based on the charges for the hospitalised infants. The treatment of otitis media and the cost of RSV- IVIG prophylaxis were based on local charges. Resource use and charges were analysed concurrently through the decision tree model. No discounting was employed and this was justified given that the duration of the study was less Page: 2 / 5

3 than 2 years. The price year was not reported. Statistical analysis of costs No statistical analysis of costs was reported. Indirect Costs No indirect costs were analysed. Currency US dollars ($). Sensitivity analysis One-way sensitivity analyses were carried out for a 50% increase and decrease of the probabilities of RSV hospitalisation and the probability of otitis media with and without RSV-IVIG, probability of BPD, average cost of RSV hospitalisation without RSV-IVIG, average cost of RSV-IVIG and otitis media and the estimated reduction of RSV hospitalisation costs with RSV-IVIG. Estimated benefits used in the economic analysis Not applicable. Cost results The cost of no RSV-IVIG prophylaxis was estimated at $3,832 per infant. The cost of RSV-IVIG prophylaxis of all high-risk infants was estimated at $6,169 per infant and the cost of RSV-IVIG prophylaxis of selected high-risk infants was estimated at $4,919 per infant. The ratios of costs of the comparator to the cost of analysed alternatives were 0.6 for all high-risk infants and 0.75 for selected high risk infants. These ratios varied from 0.30 to 0.89 for all high-risk infants and from 0.47 to 0.95 for selected high-risk infants. Synthesis of costs and benefits The combination of costs and benefits was not relevant for the design of the study. A scenario analysis based on a nonconfirmed assumption that the RSV-IVIG would reduce RSV mortality in infants with active BPD by 3.5% resulted in cost per life-year saved of $7,764. Authors' conclusions The authors did not find RSV-IVIG to be cost saving. However, under the assumptions made, RSV-IVIG is costeffective when limited to the prophylaxis of high-risk infants with active BPD. CRD COMMENTARY - Selection of comparators A justification was given for the comparator and alternative interventions analysed. You, as a user of this database, should determine whether these interventions apply to your setting. Validity of estimate of measure of effectiveness Some more information on the methods used to conduct the review of the literature and on the study used would have strengthened the validity of the measures of effectiveness. The effectiveness data on RSV-IVIG prophylaxis were based on a single published study. Insufficient information was available to evaluate the internal validity and generalisability of this data. The effectiveness data were applied to database data for the area of the study but the generalisability of Page: 3 / 5

4 these baseline estimates for other areas was not discussed. The scenario analysis for the cost-effectiveness of RSV-IVIG prophylaxis for infants with active BPD was based on non-confirmed effect on the infants' mortality. Validity of estimate of measure of benefit The authors did not derive a measure of benefits. The analysis was therefore categorised as a cost-consequences study. Validity of estimate of costs All categories of costs relevant to the perspective adopted were included in the analysis. The costs were estimated based on the local charges and this could have limited the generalisability of the results. A sensitivity analysis on charges was performed. The price year was not reported. Other issues The authors did make appropriate comparisons of their findings with other studies. The issue of generalisability to other settings was not analysed although the range of one-way sensitivity analyses could be informative. The study was a modelling study for the area of interest and no stochastic data were available to test different hypothesis. Implications of the study The RSV-IVIG prophylaxis for high-risk infants was not proved to be cost saving but the intervention is cost-effective when limited to high-risk infants with active BPD. In contrast to those infants who "may benefit" from RSV-IVIG, these are the infants who "should be considered" for RSV-IVIG. Source of funding D Oelberg has received funding from MedImmune, Inc as the principal investigator of clinical trials conducted at Children's Hospital of The King's Daughters. Bibliographic details Oelberg D, Reininger M, Van Eeckhout J. A cost-benefit analysis of respiratory syncytial virus hyperimmune globulin (RSV-IVIG) in high-risk infants. Neonatal Intensive Care 1998; 11(1): Other publications of related interest The PREVENT Study Group. Reduction of respiratory syncytial virus hospitalisation among premature infants with bronchopulmonary dysplasia using respiratory syncytial virus immune globulin prophylaxis. Pediatrics 1997;99: Indexing Status Subject indexing assigned by CRD MeSH Cost-Benefit Analysis; Costs and Cost Analysis; Female; Gestational Age; Hospitalization; Humans; Immunoglobulins, Intravenous /administration & dosage /economics /therapeutic use; Infant; Infant, Newborn; Infant, Newborn, Diseases /prevention & control; Male; Respiratory Syncytial Virus Infections /economics /virology /prevention & control; Respiratory Syncytial Viruses /immunology AccessionNumber Date bibliographic record published 31/07/2002 Page: 4 / 5

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