Discussion
Our study suggests that intravenous MS are unequivocally cost-effective and dominant over standard treatment in children with moderate-severe acute asthma in emergency setting; achieving better outcomes at a lower cost. Although the variable that exhibited a significant effect on these results was the probability of hospitalization, MS was the dominant strategy overall ranges of this variable analyzed.
The findings of this study constitute a new argument to include the MS in clinical practice guidelines of pediatric asthma for treating acute asthma exacerbations. Due to the important burden of disease generated by asthma, especially in Colombia and other middle-income countries, this strategy will be useful not only for decreasing the probability of hospitalization due to acute asthma but also for decreasing associated costs. The potential magnitude of cost savings for the health system (US $ 448 per patient ) is no negligible if we consider that this disease affects between 10 to 13% of children in Colombia and only 2.4% of them meets criteria for total asthma control (26, 27)
The last version of Global Initiative for Asthma does no recommend the use of MS for routine use in children with acute exacerbation, despite acknowledging that there is evidence of its use and positive effects on hospitalization rates (28).Also the Colombian Clinical Guideline for Asthma do not recognize the MS as first line in this patients(29) . Our study provides evidence of beneficial clinical effects of MS when added to the standard treatment with bronchodilators, and corticosteroids in patient with moderate-severe asthma exacerbations.
Previous economic evaluation in the UK based on evidence from a randomized placebo-controlled multi-center trial of nebulized MgSO4 in severe acute asthma in children found that MS had a 67.6% of probability of being cost-effective at EUR 22.957 per QALY gained(30). However, they only had full costing in less than 50% of cases, limiting their conclusions. Our study is the second publication on this topic, using a societal perspective, and made in a setting with it more limited economic resources. The results from different countries are not easily comparable, mainly due to many differences in prices of labor, drugs, medical test, frequency of use of resources, adherence to clinical guidelines, and differences in access to and provision of specialized care instead of primary care, and payment schemes.
A very important aspect of our model is that it was robust to changing the values ​​of the model’s utilities and costs. MS was always the cost-effectiveness strategy un all ranges of thresholds evaluated with a low population EVPI. This was consistent with the finding that although that our utilities were collected from the other population, our results did not change when exploring the change in the ICER in the range of values ​​of each utility explored. The same happens with costs. Although the resources, frequencies of use, and costs were collected from tertiary centers, in Rionegro, and not from a national study with all hospitals in Colombia, modifications to their values ​​in the sensitivity analysis also did not significantly change the ICER. These aspects give us confidence regarding the ability to make decisions with our results; as is always necessary for science, more studies to replicate our results (31, 32). Our study has some limitations. The cost data were collected retrospectively. Asthma treatment and the costs in question, including hospital prices, did not markedly change to our days. Furthermore, our country has been characterized by having a very small price variation in the last 10 years, especially in health services (20). Additionally, we use utilities extracted from the literature and not estimated directly from our population. As was mentioned previously, the reliability and robustness of the results were evaluated by sensitivity analyses.
In conclusion, the MS in emergency settings was cost-effective for the hospital treatment of an infant with asthma moderate or severe. Our study provides evidence that should be used by decision-makers to improve clinical practice guidelines and should be replicated to validate their results in other middle-income countries.