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Costs and effectiveness of spacer versus nebuliser in young children with moderate and severe acute asthma |
Leversha A M, Campanella S G, Aickin R P, Asher M I |
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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 The study compared the administration of albuterol (salbutamol) by metered dose inhaler (MDI) and spacer versus nebuliser, in the treatment of young children with moderate and severe acute asthma.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised children aged from 1 to 4 years of age who presented to an emergency department with an acute exacerbation of asthma. Baseline observations of heart rate, respiratory rate, chest findings on auscultation, and a summary clinical asthma severity score were made. Only children with a known history of asthma and a clinical score over 3 (moderate and severe exacerbation) were eligible for inclusion. Children were excluded if they had received an inhaled bronchodilator in the hour before presentation, required immediate admission to the intensive care unit, or if examination confirmed a co-existing medical condition such as pneumonia.
Setting The setting was secondary care. The economic study was carried out in the Starship Children's Hospital in Auckland, New Zealand.
Dates to which data relate The dates during which the effectiveness and resource data were collected were not reported. The price year was 1996.
Source of effectiveness data The effectiveness data were derived from a single study.
Link between effectiveness and cost data The cost data were collected prospectively alongside the effectiveness data in the same patient sample.
Study sample No power calculations were used to determine the sample size. A total of 60 patients were randomly assigned to one of the two treatment arms. All of the 60 patients were included in the final analysis, with 30 assigned to the spacer treatment group, and 30 assigned to the nebuliser treatment group.
Study design The study was a randomised (allocation concealed), double-blind, placebo controlled trial carried out in the emergency department of Starship Children's Hospital in Auckland, New Zealand. The patients, clinicians and outcome assessors were all blinded. The duration of follow-up was 48 hours. The loss to follow-up was not reported.
Analysis of effectiveness The analysis was based on intention to treat. The primary health outcomes were clinical severity, heart rate, respiratory rate, oxygen saturation rate and wheezing at 60 minutes, admission to hospital and visits to the emergency department at 48 hours. The groups were shown to be comparable in terms of age, and in measures of asthma severity in history, usual asthma therapy, and medication received in the 24 hours prior to presentation at the emergency department. The two groups were not comparable in terms of gender, with 80% males in the nebuliser group compared to only 47% in the spacer group, (p=0.02). The authors' reported that these values were adjusted, but details about how the values were adjusted were not clearly stated.
Effectiveness results The results showed that wheezing was reduced more in the spacer group after the first treatment, than in the nebuliser group. Wheezing was reduced by -0.93 in the spacer group and -0.48 in the nebuliser group (mean difference 0.45, 95% CI: 0.07 - 0.9, p=0.03).
The increase in heart rate after the first treatment was significantly smaller in the spacer group than in the nebuliser group. The heart rate increased by 2.4 beats/min in the spacer group, compared to 10.5 beats/min in the nebuliser group after the first treatment (mean difference 10.8, 95% CI: 5.3 - 16.4, p<0.01). Furthermore, the authors reported that children in the nebuliser group continued to have a significantly higher heart rate than those in the spacer group throughout the remainder of the study period (p=0.03).
The two groups did not differ for clinical severity score, respiratory rate, oxygen saturation, tremor, or hyperactivity in response to the first treatment. Over the whole study period, the absolute change in clinical score was similar, with a -2.9 reduction in the spacer group and a -2.7 reduction in the nebuliser group, (p=0.55). Of the children in the spacer group 33% required admission to hospital compared with 60% in the nebuliser group (p=0.04 adjusted for sex). The median number of treatments required was 4 in the spacer group, compared to 4.5 in the nebuliser group.
Clinical conclusions The study indicated that the MDI and spacer combination was more effective, quicker to deliver, and had fewer side effects than a nebuliser in the delivery of albuterol to young children with moderate and severe acute asthma.
Modelling Kaplan-Meier survival curves were used to present the proportion of children admitted to hospital from each emergency department admission after each treatment.
Measure of benefits used in the economic analysis No summary measure of benefit was explicitly reported in the economic analysis and, as such a cost-consequences analysis was conducted.
Direct costs Costs and quantities were not reported separately. Only direct costs were included in the analysis. Total costs were calculated from the cost of the medication, equipment (spacer, masks and nebuliser bowl), the emergency department presentation (NZ$190), and for those requiring admission, the cost of the resulting admission (NZ$1,814). The Children's Hospital management unit provided cost estimates that included the fixed costs, human resources, and investigation and treatment. Discounting was not carried out because of the short time frame of the study. The price year was 1996.
Statistical analysis of costs No statistical analysis of costs was included in the study.
Indirect Costs No indirect costs were included in the analysis.
Currency New Zealand dollars (NZ$). The authors did not report any currency conversions.
Sensitivity analysis The authors did not report a sensitivity analysis.
Estimated benefits used in the economic analysis The reader is referred to the effectiveness analysis reported previously.
Cost results The mean total cost of each emergency department presentation was NZ$285 for the spacer group, and NZ$1282 for the nebuliser group, (p=0.03).
Synthesis of costs and benefits The authors did not report the synthesis of costs and benefits, and no incremental analysis was reported.
Authors' conclusions The authors concluded that the MDI and spacer combination was a more cost-effective alternative than nebuliser in the delivery of albuterol to young children with moderate and severe acute asthma.
CRD COMMENTARY - Selection of comparators The study, based in New Zealand, evaluated two methods for the administration of a drug called albuterol, (called salbutamol in the UK). A justification was given for the choice of comparator used, namely that the nebuliser represented the gold standard by which other aerosolised therapies for moderate and severe acute asthma are compared. You, as a user of the database, should decide if this is a widely used health technology in your own setting.
Validity of estimate of measure of effectiveness The analysis was based on a randomised, double-blind, controlled trial, which was appropriate for the study question. The study sample was representative of the study population, and the patient groups were shown to be comparable at analysis. Appropriate statistical analyses were undertaken to take account of confounding factors. However, no power calculations were reported and it is not possible to determine whether the sample size was adequate to detect a statistical difference between the two treatment groups included in the study.
Validity of estimate of measure of benefit The authors did not report a summary measure of benefit: see the commentary on effectiveness above.
Validity of estimate of costs All categories of cost relevant to the perspective adopted (hospital) were included in the analysis. The authors did not, however, report costs and quantities separately. A statistical analysis of quantities and prices was not performed, and the authors did not report currency conversions. Since all costs were incurred over a 48-hour follow-up period, discounting was unnecessary.
Other issues The authors made appropriate comparisons of their findings with those from other studies. The study did not include a sensitivity analysis and the issue of generalisability to other settings was only partially addressed. The authors reported that the cost savings of spacer therapy may be lower in populations of children with less severe asthma. The study enrolled young children with moderate and severe acute disease and this was reflected in the authors' conclusions.
Implications of the study The authors concluded that the MDI and spacer combination is a more cost-effective alternative than the nebuliser in the delivery of albuterol to young children with moderate and severe acute asthma.
Source of funding Supported by a grant from the Asthma and Respiratory Foundation of New Zealand.
Bibliographic details Leversha A M, Campanella S G, Aickin R P, Asher M I. Costs and effectiveness of spacer versus nebuliser in young children with moderate and severe acute asthma. Journal of Pediatrics 2000; 136(4): 497-502 Other publications of related interest Comment in: Journal of Pediatrics 2000;136(4):428-31.
Indexing Status Subject indexing assigned by NLM MeSH Acute Disease; Albuterol /administration & Anti-Asthmatic Agents /administration & Asthma /drug therapy /economics; Child, Preschool; Cost-Benefit Analysis; Double-Blind Method; Female; Humans; Infant; Male; Nebulizers and Vaporizers /economics; Time Factors; dosage /economics; dosage /economics AccessionNumber 22000000784 Date bibliographic record published 31/05/2002 Date abstract record published 31/05/2002 |
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