Cost-effectiveness analysis of dry powder inhaler and metered dose Inhaler with spacer in acute exacerbations of childhood asthma : a case study of King Chulalongkorn Memorial Hospital

The objective of this study was to analyse and compare the cost-effectiveness of the dry power inhaler (DPI) with the metered dose inhaler (MDI) and spacer for delivering salbutamol in the management of mild to moderate acute exacerbations of asthma in children aged 5 to 18 years. A retrospective analysis was performed based on clinical data form a multicenter, randomized clinical trial. King Chulalongkorn Memorial Hospital was chosen as the model for this economic evaluation A total of 80 patients with mild to moderate acute exacerbations of asthma were enrolled into the study, and followed up for 3 days. Equal number of patients (n = 40) were randomized to receive salbutamol administered via either the DPI or the MDI with spacer. The provider's and patient's perspectives were used to estimate costs of asthma treatment among patients. The total provider costs of delivering each treatment to the asthmatic patients was the sum of total routine service costs and total medical care costs. The total patient costs or total costs was calculated from the sum of total direct medical costs and total indirect costs. All costs in this study are presented in 2005 Baht. Outcome measures were the number and percentage of successfully treated patients at 60 minutes (defined as those with clinical scores reduce >= 50% from baseline, or clinical scores <= 3 as measured using the Modified Wood's Clinical Scores) There were not significant differences between the 2 treatment groups in the number and percentage of successfully treated patients, although there was a trend in favour of the DPI group compared with the MDI and spacer group (92.5% vs 90.0%). The means of total provider costs and total patient costs were also lower in the DPI group (Baht 180.98 vs Baht 239.63, and Baht 355.99 vs Baht 496.27, respectively), however, these differences were not statistically significant at 95% CI. The results from the cost-effectiveness analysis showed in favour of the DPI. This indicated that by switching to the DPI from the MDI with spacer, the costs for each additional percentage of successfully treated patients would be reduced by Baht 25.42 and Baht 60.79 according to the provider's and patient's perspectives, respectively. Sensitivity analysis demonstrated that these results were relatively robust over a wide range of assumptions.