Asthma rescue and allergy medication use among asthmatic children with prior allergy prescriptions who initiated asthma controller therapy Luskin A, Bukstein D, Kocevar V S, Yin D D 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 use of montelukast (MON) and inhaled corticosteroids (ICS) among asthmatic children who initiated asthma controller therapy. The dosage levels and manufacturers' names were not reported. Type of intervention Secondary prevention and treatment of asthma and allergic rhinitis. Economic study type Cost-effectiveness analysis. Study population The study population comprised paediatric patients with asthma and allergic rhinitis who initiated MON or ICS therapy. Patients were included if they were continuously benefit eligible, new to asthma controller therapy, had initiated controller therapy with either MON or ICS from 1 February 1999 to 31 January 2002, and had 1 or more antihistamine or nasal steroid prescriptions during the 12 months before the first asthma controller prescription. Patients had to be younger than 16 to enter the study. Patients were excluded if they initiated long-acting beta-agonist therapy. Setting The setting was the community. The economic study was carried out in New Jersey, USA. Dates to which data relate The effectiveness and resource use evidence were collated during the course of the clinical trial, between 1 February 1999 and 31 January 2002. A price year was not reported. Source of effectiveness data The effectiveness data were derived from a single study. Link between effectiveness and cost data The costing was carried out retrospectively on the same patient sample as that used in the effectiveness study. Study sample The authors considered for inclusion all patients in the Medco Health Solutions Inc. Information Warehouse. A total of 3,217 met the inclusion criteria. Patients were then matched 1:1 in each treatment group to adjust for baseline differences. The study sample then comprised 1,236 patients, 618 in each study group. After matching, the average age was 9.9 years, approximately 60% were male, more than 75% had asthma classified as mild, and 5% or less had severe Page: 1 / 5
asthma. There was no report that power calculations were carried out to estimate the influence of chance on the results. Study design The authors designed a retrospective, longitudinal cohort study with patients defined according to their exposure to the two study drugs. The patients were followed for a 24-month period. As the charts were reviewed retrospectively, there was no loss to follow-up. The outcomes were assessed pre and post the 24-month study period. Prior to 1:1 matching the patients were compared in terms of their age, gender, the predicted probability of receiving MON based on patient characteristics (propensity score), asthma severity, asthma rescue medications and allergy medications. The matching aimed to account for these differences. Analysis of effectiveness The analysis was based on the treatment received by the patient. The primary health outcomes were: the change in resource use, as measured by a change in costs (see costing analysis for these results); and the change in the number of days of therapy in the pre- and post-study periods. Statistically significant differences were found in the mean age, the mean propensity score, and the mean duration of use of antihistamines before matching. There were no significant differences between the groups in any baseline characteristics after matching. Effectiveness results The results are presented for the likelihood of experiencing more days with asthma or allergy therapy in the post-study period compared with the pre-study period for ICS versus MON: all asthma rescue agents, odds ratio (OR) 1.66 (95% confidence interval, CI: 1.32-2.10); short-acting beta-agonists, OR 2.31 (95% CI: 1.83-2.92); all allergy medication, OR 1.27 (95% CI: 1.02-1.59); nasal steroids, OR 1.78 (95% CI: 1.40-2.27). The odds of using corticosteroids and antibiotics were similar for the two treatment groups. The odds of having more days of rescue agent therapy in the post-study period increased with age for both groups. Clinical conclusions The authors concluded that MON may be associated with better asthma control than ICS in their study population, owing to the reduced need for asthma rescue medications and acute asthma and allergy therapies. Measure of benefits used in the economic analysis The authors did not estimate a summary measure of benefit. Therefore, the study was categorised as a costconsequences analysis. Direct costs The authors estimated the average cost of asthma therapy using the Medco Health Solutions Inc. Information Warehouse administrative claims database. Asthma medications, allergy medications (including nasal corticosteroids and prescription antihistamines) and other respiratory medications were assessed. Although a perspective for the economic analysis was not explicitly stated, the use of a claims database suggests that the perspective was that of the third-party payer. The database was used for prescription information from the enrolled patients, and average wholesale Page: 2 / 5
prices (AWPs) were used for medication costs. There was no report that discounting was carried out despite the study continuing over a period of 2 years. Resource use was measured over the course of the clinical trial. A price year was not reported. Statistical analysis of costs Standard tests of statistical significance were carried out. Indirect Costs The indirect costs were not reported, which was appropriate as children are not economically productive. However, when asthma and allergic rhinitis in the child are severe they may affect the parent's ability to carry out economically productive work. Currency US dollars ($). Sensitivity analysis Sensitivity analyses were not reported. Estimated benefits used in the economic analysis See the 'Effectiveness Results' section. Cost results The cost results were presented as the mean difference in cost between the pre- and post-study periods per member per month. The combined cost of asthma drug therapy and allergy medications was $5.55 in the MON group and $12.08 in the ICS group, (p<0.001). The cost of rescue or acute asthma medications was $0.94 in the MON group and $3.82 in the ICS group, (p=0.003). The cost of allergy medications was $5.29 in the MON group and $10.06 in the ICS group, (p<0.001). The cost of other respiratory medications (xanthines, mast cell stabilisers, leukotrienes other than MON) was -$0.68 in the MON group and -$1.79 in the ICS group, (p=0.046). Synthesis of costs and benefits The costs and benefits were not combined as the study was, in effect, a cost-consequences analysis. Authors' conclusions The introduction of montelukast (MON) in children with asthma and allergic rhinitis was associated with better asthma control, as demonstrated by a significantly lower increase in the overall costs of rescue or acute asthma medications and allergy medications, compared with the introduction of inhaled corticosteroids (ICS). CRD COMMENTARY - Selection of comparators The authors compared ICS and MON as strategies for controlling asthma and allergic rhinitis. These technologies were believed to impact upon both health problems simultaneously, so both were relevant to the study. MON was reported to Page: 3 / 5
be approved for the treatment of both conditions in the same oral tablet preparation. You should decide if these comparators represent widely used health technologies in your own setting. Validity of estimate of measure of effectiveness The analysis was based on a retrospective, longitudinal cohort study. This design enabled the investigators to assess patient behaviour over a period of time without incurring any loss to follow-up. The use of a pharmacy claims database ensured that there were no missing data and ruled out reporting bias. The authors took steps to account for the lack of randomisation and improve the credibility of the study. For instance, they matched patients using a propensity score to improve the comparability of patients between the two groups. This also helped them to control for selection bias associated with the investigators selecting the patients. The authors also took steps to ensure that patient prescription continuity was maintained to ensure an accurate longitudinal view of prescribing behaviour. However, the authors acknowledged that "caution should be exercised when drawing conclusions, because causal relationships can not be determined from retrospective studies". Validity of estimate of measure of benefit The authors did not estimate a summary measure of health benefit. The study was therefore categorised as a costconsequences analysis. Validity of estimate of costs A perspective for the economic analysis was not reported. Nevertheless, the costs included seem to have represented the perspective of the third-party payer. The authors acknowledged that pharmacy costs represented only a small proportion of total asthma-related costs (including asthma-related physician visits and hospitalisations), and that the costs of MON and ICS were not included because of wide variability in amounts both charged and paid for any particular medications. AWPs were used as a proxy for costs. The authors acknowledged that AWPs do not reflect actual prices paid for prescriptions but argued that AWPs do provide a constant comparison across all agents, independent of benefit design, manufacturer discounts, and co-payments. The authors provided a useful breakdown of the cost components, which enables the reader to gain a good understanding of the main cost drivers. The costs should have been discounted given to the 24-month time horizon. The price year was not reported, which will hinder any future reflation exercises. Other issues The authors highlighted that, to their knowledge, this was the first such cost analysis. Nevertheless, they were able to make some comparisons with other clinical studies. The issue of generalisability was not explicitly addressed, though it was clear that the authors' results related to patients aged less than 16. To generalise to an adult population would not be appropriate. The costing analysis would need to be re-estimated, and a specific perspective adopted to apply these results to other patients and settings. Several limitations were presented. These included the inability to randomise the patients, and the inclusion of only patients receiving prescription treatments for their conditions. These limitations and their implications were well discussed. Implications of the study The authors did not make any recommendations for policy or practice further to their study, although it seemed that they favoured a policy shift towards using MON. There was no discussion of areas for further work. Source of funding Supported by a grant from Merck and Co Inc. Bibliographic details Luskin A, Bukstein D, Kocevar V S, Yin D D. Asthma rescue and allergy medication use among asthmatic children with prior allergy prescriptions who initiated asthma controller therapy. Annals of Allergy, Asthma and Immunology Page: 4 / 5
Powered by TCPDF (www.tcpdf.org) 2005; 95(2): 129-136 Other publications of related interest Grupp-Phelan J, Lozano P, Fishman P. Health care utilization and cost in children with asthma and selected comorbidities. J Asthma 2001;38:363-73. Thomas M, Zhang Q, Sazonov Kocevar V, Yin D, Price DB. Health care resource use by children with asthma and comorbid allergic rhinitis in general practice in the United Kingdom. Pediatrics 2005;115:129-34. Indexing Status Subject indexing assigned by NLM MeSH Acetates /administration & dosage /economics; Administration, Inhalation; Adolescent; Adrenal Cortex Hormones /administration & dosage /economics; Anti-Asthmatic Agents /administration & dosage /economics; Asthma /drug therapy /economics; Child; Cohort Studies; Drug Costs; Drug Prescriptions /economics; Female; Humans; Longitudinal Studies; Male; Multivariate Analysis; Quinolines /administration & dosage /economics; Regression Analysis; Research Support, Non-U.S. Gov't; Retrospective Studies; Rhinitis, Allergic, Perennial /drug therapy /economics AccessionNumber 22005006423 Date bibliographic record published 30/04/2006 Date abstract record published 30/04/2006 Page: 5 / 5